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Part 4 Plant science.


A Horizon--The leached upper member of a soil profile; the eluvial layer.

A.U.M.--(Abbr.) Animal unit month.

A-Harrow--A spike-tooth harrow, shaped like the capital letter A, which is dragged from a hitch at the apex to smooth plowed ground.

Abacterial--Free from bacteria.

Abaxial--Away from or facing away from the axis; dorsal; said of the surface or a part of a lateral organ. For example, the lower surface of a leaf is abaxial.

Aberration--In genetics, an irregularity in chromosome distribution during cell division that results in deviation from normal.

Abiotic Disease--A disease caused by an inanimate agent; a nonparasitic disease. Also called physiogenic disease; e.g., a mineral deficiency in plants or animals.

Abnormal--Deviating from that which is typical.

Aborescent--Approaching the size and habit of a tree.

Aborist--A specialist in the field of tree culture.

Aborvitae--Any plant of the genus Thuja, family Pinaceae; the species are valuable evergreen trees used for ornament and in the timber industry. White cedar or Thuja oil is used as a vermifuge. See Northern White Cedar.

Abrasion--(1) Wear in farm implements caused by friction, such as abrasion of a plowshare by the soil. (2) A section of skin or mucous membrane from which the surface layers have been rubbed or worn off.

Abscess--Localized collection of pus in a cavity formed by the disintegration of tissue.

Abscission--The dropping off of a leaf, fruit or flower; shedding. Abscission Layer--A narrow, transverse band of cells at the base of leaf, flower, stalk, fruit stalk, or a portion of stem, in which the cell walls dissolve, leaving the vascular bundles for support. These eventually break, and the leaf, flower, fruit, or even a portion of the stem falls. Also called absciss layer, separation layer.

Absorb--(1) To assimilate or incorporate one substance into another, as a blotter absorbs ink. (2) In botany, to assimilate water and nutrients.

Absorption--(1) The processes by which water enters the earth. (2) The passage of digested food from the alimentary tract into the circulatory system. (3) The intake of water, gases, nutrients or other substances by plants.

Absorption Rate--The rate at which a chemical enters the body.

Abundance--The number of plants or animals per unit area.

Acacia--Any shrub or tree of the genus Acacia, family Leguminosae; although basically tropical and short-lived, many species are grown in southern regions of the United States as ornamentals for their showy, dense clusters of small, usually yellow flowers.

Acariasis--The condition of plants or animals infested with mites or ticks.

Acaricide--A substance, solution, or paste which kills mites or ticks.

Acarid--Any mite or tick of the family Acaridae or order Acarina.

Acarine--Any mite or tick.

Acarology--The branch of science that deals with mites and ticks.


Acceptable Daily Intake (ADI)--The daily dosage of a drug or a chemical residue that appears to present no appreciable risk to health during the entire lifetime of a human being or animal.

Accessory Fruit--A fruit or assemblage of fruits in which the conspicuous, fleshy parts are not derived from the pistil; as in the strawberry (Fragaria), where the soft, red, edible flesh is the enlarged receptacle and the true fruits (seeds) are embedded in its surface.

Acclimate--To become conditioned to a new climate or different growing environment, usually applied to plants. (See Hardening-off.) May also be applied to animals adjusting to a new environment.

Accrescent--Refers to plants that continue to grow after flowering.

Accretion--(1) The gradual addition of new land to old by the deposition of sediment carried by the water of a stream. (2) The process by which inorganic bodies grow larger, by the addition of fresh particles to the outside. (3) The process of illuviation of soils is usually one of the addition of minerals by accretion. (4) Increase of height, diameter, quality, and value of a tree or woods; increment; growth. (5) Increase of soil water. (6) Process of recovering land from the sea by diking and draining. See Relict.

Accumulator Plant--A plant that absorbs certain elements and accumulates them in its tissues to a much higher degree than most plants; e.g., selenium accumulators.

Acetic Acid--An organic acid, CH3COOH, which is the chief active component of vinegar; also important as a product in lactic acid fermentation and therefore, an important constituent of flavor in many milk products.

Acetic Bacteria--The bacteria that produce acetic acid (vinegar acid) from alcohol.

Acetic Fermentation--The process by means of which acetic acid is formed from ethyl alcohol in weak solution through the action of bacterial ferments; e.g., the formation of vinegar from hard cider or from wine.

Acetobacter--A bacterium, family Nitobacteriaceae, which grows in beer and wine.

Acetone--C[H.sub.3]COC[H.sub.3], a ketone; a clear, rapidly evaporating liquid which: (1) in nature is obtained from fermentation of sugar and starch and is present in diabetic urine, breath, blood. Its presence in the breath of a lactating animal (cattle, sheep, milk goats) indicates her failure to oxidize the fatty material of her feed, making her deficient in carbohydrates; (2) is commercially obtained from distillation of wood and has wide application as a solvent.

Acetylene Reduction--A technique of measuring the change from acetylene (C D2H D2) to ethylene (C D2H D4) as a measure of the amount of atmospheric nitrogen (N D2) fixation.

Achene--Any small, dry fruit having but one seed whose pericarp does not burst when the fruit is ripe.

Aciculifruticeta--Needle-leaved plant.

Aciculilignosa--Narrow-leaf sclerophyll forest and bush.

Aciculisilvae--Needle-leaved forests.

Acid--(1) A substance containing hydrogen that dissociates to form hydrogen ions when dissolved in water (or which reacts with water to form hydronium ions). (2) A substance capable of donating protons to other substances. (3) A term applied to igneous rocks having a higher percentage of silica (66%) than orthoclase. (4) Term applied to any substance with a pH less than 7.0. See Acetic Acid.

Acid Food--Food with a pH of 4.6 or below. An acid food can be safely processed for canning in a boiling-water bath for specified times. Includes most fruits, some tomatoes, and pickled vegetables. See Low-Acid Food.

Acid Hydrolysis--Decomposition or alteration of a chemical substance by acid.

Acid Organic Material--An organic material that leaves an acid residue in the growing medium, e.g., sphagnum peat.

Acid Rain (Precipitation)--Rain or other precipitation that contains a higher than normal amount of acid. The condition is caused by raindrops absorbing substances from air pollution. Acid precipitation (acid rain) is generally considered to be harmful to the environment.

Acid Soil--A soil giving an acid reaction (precisely, below pH 7.0; practically, below pH 6.6) throughout most or all of the portion occupied by roots. A soil having a preponderance of hydrogen ions over hydroxyl ions in the soil solution. In common parlance, a "sour" soil, as opposed to a "sweet" soil.

Acid-fast--Property of not being readily decolorized by acids.

Acid-forming Fertilizer--Fertilizer that increases the residual acidity of the soil, e.g., ammonium sulfate.

Acid-tolerant Crops--Crops, such as oats and corn, which will grown in moderately high acid soils.

Acidification of Soils--The process by which soils become acid. In humid regions, soils become acid because of accelerated erosion, the use of fertilizers, lime removed in harvested crops, and acid precipitation. In arid regions, soils too alkaline can be acidified by applying sulfur, lime-sulfur solution, iron sulfate, or aluminum sulfate.

Acidified Silage--Silage preserved by the addition of acid, such as commercial phosphoric acid, sulfuric acid, or hydrochloric acid, or a combination of the latter two.

Acidity--The measure of how many hydrogen ions a solution contains. Acidophilus--Refers to organisms that grow well or exclusively in an acidic soil or medium.

Acidulation--The process of treating a material with an acid to make it more soluble. The most common acidulation process is the treatment of phosphate rock with an acid such as sulfuric acid ([H.sub.2]S[O.sub.4]), nitric acid (HN[O.sub.3]), or phosphoric acid ([H.sub.3]P[O.sub.4]).

Aciniform--(1) Having the shape of a bunch of grapes. (2) Containing small grapelike kernels.

Acorn--The fruit or seed of oaks, any species or the genus Quercus; eaten by domesticated grazing animals, cattle, hogs, and goats, and by several kinds of wildlife, both birds and mammals, and to a limited extent by humans.

Acorn Fruit--A symptom of a virus disease, Citrivir pertinaciae, citrus trees, characterized by acorn-shaped fruit; as much as one-half the production of a tree may be so deformed. the fruit has very thin skin toward the stylar (away from the stem) end. Also called pink nose, blue nose.

Acorn Squash--Hubbard group. A squash that is characterized by a small, deeply fluted diamond or acorn-shaped shell.

Acquired Character--A change in character of a plant or animal, morphological or physiological, due to the environment, which is not passed on to the next generation; not a genetic change.

Acre--A unit of land measure in England and the United States which is equal to 43,560 square feet, or 1/640 of a square mile, or 160 square rods, or 4,840 square yards, or 4,047 square meters. The Scottish acre is 1.26 and the Irish acre is 1.62 times as large. One acre, as used in England and the United States, equals 0.4 hectare, 0.96 feddan (Egypt), 0.31 carreau (Haiti), 1.03 cuerdas (Puerto Rico), 0.03 caballerias (Cuba), 5.00 shih mou (China), 4.08 tan (Japan), 0.84 arpent de Paris (some sections of Canada), 0.37 dessiatine (U.S.S.R).

Acre Inch--The quantity of water necessary to cover one United States or English acre to the depth of one inch: 3,630 cubic feet or 27,154.2 United States gallons of water.

Acreage--An indefinite quantity of land; a collective number of acres.

Acreage Allotment--As established from time to time by Congress, the individual farm's share, based on its previous production, of the national acreage needed to produce sufficient supplies of a particular crop.

Acrophytia--Plant communities in alpine regions.

Acrospire--The young spiral shoot of germinating seeds.

Acrostalagmus Fungi--A fungus belonging to the family Dematiaceae. (1) Acrostalagmus albus Pr., a fungus which attacks brown scale on citrus. (2) Acrostalagmus aphidum, a fungus which attacks the citrus-inhabiting aphid, cotton aphid, green peach aphid, and the black citrus aphid.

ACS--Agricultural Cooperative Extension Service.

Actinomorphic--Regular, radially symmetrical; capable of being divided vertically and in more than one plane into two essentially equal halves, as the flower of Tulipa or Rosa.

Actinomycetes--A large group of moldlike microorganisms which give off an odor characteristic of rich earth and are the significant organisms involved in the stabilization of solid wastes by composting. They are common in the soil. Selected strains are used for the production of certain antibiotics.

Actinomycosis of Potato--See Corky Scab of Potato.

Action Threshold--The level of competition or plant cover that triggers control action. For example, the point at which one plant or type of plant outgrows another and the larger plant crowds out the smaller.

Actium--A plant-animal community on a rocky seashore.

Activator--A chemical added to a pesticide to increase its activity.

Active Agent (Active Ingredient)--That part of an insecticide, herbicide, or fungicide formula that has toxic properties to target species.

Actophilous--Refers to organisms that grow well on rocky seashores.

Actual Analysis--The composition of a material based on a laboratory chemical analysis rather than a generalized guaranteed analysis.

Acuminate--Gradually tapering to a pointed apex.

Acute--(1) Usually refers to a disease that runs a short, severe course. (2) Having the shape of an acute angle.

Acute Toxicity--The potential of a substance to cause injury or illness when given in a single dose or in multiple doses over a period of 24 hours or less. In aquatic studies, exposure to a given concentration for 96 hours or less.

Adaptability--The capability of an organism to make changes that make it more fit to its environmental conditions.

Adaptation--(1) A measure of physiological fitness of the organism to one or several conditions of its environment. (2) The structures or activities of an organism, or of one or more of its parts, which tend to fit it better for life in its environment or for particular functions. See Adjustments.

Adapted Variety--Varieties of plants that have been developed or adapted to grow in a particular area or climate.

Additivies--Materials added to food to help manufacture and preserve it and to improve nutritive value, palatability, and eye appeal. May be classified as emulsifiers, flavors, thickeners, curing agents, humectants, colors, nutrients, or as mold, yeast, or bacterial inhibitors. Amounts used in food are regulated by law.

Adherence--The act of sticking to a surface.

Adhesion--Molecular attraction which holds the surfaces of two unlike substances in contact, such as water and soil particles. See Cohesion.

Adhesions--The adherence of separate tissues or organs of the body to each other as the result of an inflammation.

Adhesive Agent--A material that acts as a cementing agent between two solids. In spraying, it causes the dispersed material to cling to leaves and fruit.

Adjustments--(1) Range management: changes in animal numbers, seasons of use, kinds or classes of animals, or management practices as warranted by specific conditions. (2) Ecological: the processes by which an organism becomes better fitted to its environment; functional, never structural. See Adaptation.

Adjuvant--(1) Any solid or liquid added to a substance, such as a pesticide or a fertilizer, to increase its effectiveness, e.g., solvents, diluents, carriers, emulsifiers, stickers, spreaders, or sometimes a pesticide to another pesticide or a fertilizer to another fertilizer. (2) A carrier for a biological that releases the biological into the bloodstream over an extended period, thus serving the function of a series of booster shots; consequently, the adjuvant helps lengthen the period of immunity provided by the biological.

Adnation--The vertical fusion of flower parts in different whorls.

Adobe Soil--Any clayey soil of the arid and semiarid regions of the western United States Soils included under the term may vary widely in different localities. Also called dobe, dobie, dobby, doby, adaubi, adabe, dogie.

Adsorption--The increased concentration of molecules or ions at a surface, including exchangeable cations and anions on soil particles. Adsorption is an advanced way of treating wastes in which activated carbon removes organic matter from waste water. It is also used in flavor control in the milk industry.

Adulterant--An impurity not allowed by law in a food, plant, animal, fertilizer, or pesticide formulation.

Adulterate--To lower the quality of a product by mixing in another substance; as to adulterate milk by adding water to it. The federal government and most states legislate against the adulteration of food, drugs, fertilizers, and pesticides.

Advective Frost--Frost produced by cold air that has moved downslope; as in a frost pocket.

Adventitious--Out of place; not in the normal, expected place. Arising from the secondary meristem. See Aerial Root.

Adventitious Buds--Buds that develop in an abnormal position and are usually caused by a wound to the plant.

Adventitious Root--A root growing from stem or branch, not from primary root tissue.

Adventive Species--Organisms which have invaded from a distance and become more-or-less naturalized.

Adverse Weather--Weather not suitable for farm/ranch operations, such as making hay.

Aeolian--Refers to soil materials which are subject to wind movement or have been moved by the wind action. See Loess.

Aerate--(1) To force a thin layer of cooled air over milk to remove odors. (2) To cause air to pass throughout or around a substance.

Aeration, Soil--The process by which air in the soil is replenished by air from the atmosphere. In a well-aerated soil, the air in the soil is similar in composition to the atmosphere above the soil. Poorly aerated soils usually contain a much higher percentage of carbon dioxide and a correspondingly lower percentage of oxygen. The rate of aeration depends largely on the size, volume, and continuity of pores in the soil.

Aerial Bulblet--A bulb capable of producing a plant, found in the leaf axis or in the place of flowers on certain plants, as in the tiger lily and onion. Also called bulblet, bood bud, bulbil, bulbel.

Aerial Dusting--Spreading insecticides, fungicides, or herbicides in the form of powder from an airplane. Commonly called crop dusting.

Aerial Fertilization--The broadcast distribution of fertilizers from aircraft.

Aerial Propagation--The production of roots on a cutting, under moss or the like, without a covering of sand or soil. See Air Layering.

Aerial Root--(1) The root of an epiphyte or air plant, which anchors the plant and, in some cases, functions in photosynthesis. (2) A root growing from the stem that is exposed to the air. Also called adventitious root.

Aerial Seeding--Broadcast seeding from aircraft, especially used in seeding rice.

Aerify--To cultivate (turfgrass) by loosening soil, removing cores, and leaving holes or cavities in the turf.

Aerobe--Bacteria or other organisms which live only in free oxygen.

Aerobic--Pertaining to organisms that grow only in the presence of oxygen, as bacteria in a properly prepared compost.

Aerobiology--The study of microorganisms carried in the air.

Aerogens--Gas-producing bacteria.

Aerology--The science of atmosphere at all elevations but sometimes limited to the upper atmosphere.

Aeroplankton--Small plants, spores, pollen grains, insects, bacteria, and small animals that are suspended in the atmosphere. See Plankton.

Aerosol--Finely atomized spray or smoke with particles ranging in size between 0.1 and 50 microns. The particles are produced by blasts of heated air, or exhaust gases, or rapid volatilization of a liquefied gas containing a nonvolatile chemical solution. Aerosols include insecticides, antibiotics, germicides, and deodorants.

Aestilignosa--Broad-leafed, summer-green forests and shrubs; deciduous.

Aestisilvae--Summer-green forests.

Aestival--Pertaining to summer.

Aestivation--(1) The manner in which parts of a plant are folded up before expansion. (2) The passing of summer in an inactive or dormant state.

Affluent--(1) A stream that flows into another stream or lake; a tributary stream. (2) A plant that flowers abundantly.

Afforestation--The establishment of trees where they never existed before, such as on a prairie.

Aflatoxin--The substance produced by some strains of the fungus Aspergillus Flavus, the most potent natural carcinogen yet discovered; a persistent contaminant of corn, other grains, and peanuts.

African Millet--See Pearl Millet.

African Oil Palm--Elaeis guineensis; a palm of the family Palmaceae, important for the African oil trade, but an ornament in the southern United States.

African Violet--Saintpaulia ionantha; an herbaceous plant of the family Gesneriaceae, native to Africa. Grown outside the tropics as a house plant or in greenhouses. The flowers are usually deep violet-blue; in some varieties they are streaked with white or are entirely white. Not related to the true violet.

After-ripening--The biochemical and physical changes occurring in tubers, seeds, fruits, and bulbs after harvest; necessary for germination.

Aftermath--The regrowth of range or artificial pasture forage after grazing or mowing. More commonly used to refer to grazing of forage or cropped areas after harvest where there may not always be regrowth but just crop residues.

Agave--See Lechuguilla Agave, Sacahuista.

Age Stand--The average age of the trees that compose a stand. In practice, applied to even-aged stands by obtaining the average age of representative dominant trees.

Age Tree--The number of years elapsed since the germination of the seed, or the budding of the sprout or root sucker of a tree.

Agent--One who represents another from whom he has derived authority.

Agent Orange--An herbicidal mixture of 2, 4-D and 2, 4, 5-T made by Dow Chemical Company and used by the United States military in Vietnam in the 1960s to defoliate vegetation serving as hiding places for the enemy. More than 11 million gallons (41.6 million liters) were used. An estimated 220 pounds (100 kg) of dioxin, a very potent toxin, was a contaminant in the herbicide. Although now more restricted, this combination of 2, 4-D and 2, 4, 5-T is used extensively by farmers and ranchers to kill broad-leaved plants, including poison ivy. See Dioxin. Ager--(Latin) Field.

Agglomeration--A processing step in the granulation of fertilizers. The assembling of small particles into larger, stable granules.

Agglutination--(1) A joining, as by adhesion. (2) The gathering together of the fat globules in milk or of bacteria suspended in immune sera. (3) The sticking together of bacteria, other organisms, or cells suspended in a fluid by antibodies called agglutinins.

Aggregate Fruit--A "fruit" composed of several separate ripened ovaries of a single flower, as in blackberry ((Rubus).

Aggregate Soil--Many fine particles held in a single mass or cluster. Natural soil aggregates, such as granules, blocks, or prisms, are called peds. Clods are aggregates produced by tillage or logging.

Agitation--The process of stirring or mixing in a sprayer.

Agitator--Revolving paddles which keep a liquid, powder, or gas in motion to maintain a proper mixture within a tank. Used in dairying, spraying, fertilizer drill, etc.

Agostadero--A pasture used only in the summer (southwestern United States).

Agrarian--(1) Pertaining to agriculture. (2) Pertaining to political action or movements for the benefit of farmers. See Rural Population, Urban.

Agrarian Zone--Of or pertaining to the cultivated portion of an area. Agrestal; (Agrestial)--Uncultivated; growing wild.

Agribusiness--A term referring to the full scale of operations related to the business of agriculture. It connotes the interrelationships of farming, farm services, soil science, agronomy, land grant universities, county extension services, state and federal experiment stations, soil and water conservation services, plant and animal nutrition, plant and animal protection, transportation, finance, and marketing.

Agrichemicals--A term used to designate chemical materials used in agriculture, such as herbicides, insecticides, fungicides, and fertilizers.

Agricola--(Latin) Farmer.

Agricultural Chemistry--The branch of the science of chemistry which is concerned with the composition and transformation of the plants and animals on which the economy of the farmer rests.

Agricultural College--An educational institution devoted to study, research, and the dissemination of knowledge in agronomy, horticulture, animal husbandry, agricultural economics, etc. The U.S.D.A. works in conjunction with most agricultural colleges (sometimes called a school or college of agriculture within a university).

Agricultural Gypsum--See Gypsum.

Agricultural Land--All the land devoted to raising crops and livestock, including farmstead, roadways, drainage and irrigation ditches, ponds, water supply, cropland, and grazing land of every kind. (The term is not strictly synonymous with land in farms, cropland, pasture land, land suitable for crops or land suitable for farming).

Agricultural Lime--See Calcium Carbonate, Lime.

Agricultural Pollution--The liquid and solid wastes from all types of farming, including runoff from pesticides, fertilizers, and feedlots; erosion and dust from plowing; animal manure and carcasses; and crop residues and debris. Old cars and trucks are a part of aesthetic agricultural pollution.

Agricultural Slag--(1) A term applied to a fused silicate whose calcium and magnesium contents are capable of neutralizing soil acidity and which is sufficiently fine to react readily in the soil. (2) A low-grade agricultural lime. See Lime.

Agricultural Sulfur--A coarsely ground mineral which increases the acidity of soil or corrects sulfur deficiency. Also called brimstone, flowers of sulfur. See Sulfur.

Agriculture--The broad industry engaged in the production of plants and animals for food and fiber, the provision of agricultural supplies and services, and the processing, marketing, and distribution of agricultural products.

Agriculturist--A person engaged in the production of food and/or fiber; also ancillaries such as teachers of agriculture, farm editors, researchers, etc.

Agrobiology--The science of plant nutrition and growth, crop production, and soil management.

Agrology--That branch of agricultural science dealing with the origin, analysis, and classification of soils in relation to crop production. (A word used widely in Canada but not in the United States.) See Agronomy.

Agronomist--A specialist in soil and crop sciences.

Agronomy--The specialization of agriculture concerned with the theory and practice of field-crop production and soil management. The scientific management of land. See Agrology.

Agropyron Mosaic--A viral disease of wheatgrass (Agropyron spp.) characterized by leaf mottling and striping, necrosis, and stunting.

Agrostology--The branch of systematic botany dealing with grasses and grasslike plants.

Agstone--A term widely used to denote agricultural limestone, in contrast to limestone for making cement or used as building stones. See Lime.

Air Drainage--The flow of cold air down a slope and warm air up a slope that is caused by gravity rather than the wind.

Air Drill--A planter for small grains that uses an air stream created by a high-speed fan to carry seed from fluted seed-metering feed cups under the seed hopper through hoses to drop into the furrow behind double-disk or hoe-type openers.

Air Layering--A method of propagation by rooting branches of woody plants. An incision is made in the stem to be rooted, and sphagnum moss is wrapped around the wounded stem. The wounded area is moistened and covered tightly with an oil paper, cheesecloth, wire screen, or plastic film, and left until sufficient roots have established themselves in the sphagnum moss. Then the branch is cut away from the main stem and transplanted. Also called Chinese layer-age.

Air Plowing--Aeration by the pumping of air into the lower, oxygen-depleted layer of a water body to encourage the mixing of deep and surface waters and/or the oxidation of bottom sediments.

Air Porosity--The proportion of the bulk volume of soil that is filled with air at any given time or under a given condition, such as a specified moisture condition.

Air-Dry--To dry or dehumidify forage, hay, wood, etc., by means of natural air movement.

Air-slaked Lime--Burned limestone that has been allowed to weather. See Lime.

Airpotato Yam--Dioscorea bulbifera; an East Indian, tender, climbing, herbaceous vine, of the family Dioscoreaceae, grown for ornament and for its 8- to 12-inch long edible tubers, which are formed in the axils of the leaves.

Airshed--A term, now little used, denoting a geographical area the whole of which, because of topography, meteorology, and climate, shares the same air.

Ajowan--Fruit of the Eurasian plant Carum copticum, family Ammiaceae; i.e., valued as a seasoning and for medicinal properties. Antiseptic ajowan oil is made from it; also called Javanese seed, ajava.

Akala--Rubus macraci, family Rosaceae; a shrub grown in the Hawaiian Islands for its large, red, edible fruits.

Alang Grass--Imperata cylindrica; a grass used in paper making and thatching roofs. Grown in southern Europe.

Alaska Spruce Beetle--Dendroctonus borealis, family Scolytidae; a beetle which attacks the white and Englemann spruce in Alaska and northwestern Canada. It bores into the inner bark, and its larvae bore into the wood of the tree.

Alate--Winged; having wings.

Alba, Albidus, Albus--Terms meaning white.

Albedo--(Latin; albedo, whiteness.) The percentage of the sunlight reflected from a surface in relation to the total amount of light falling on that surface. Typical values are: snow, 55 to 80 percent; grass, 25 percent; forest, 10 to 20 percent.

Albino--(1) A human or animal with pink eyes and white skin and hair, caused by a congenital deficiency of pigment in the skin. (2) In botany, plants with a chlorophyll deficiency.

Albino Cherry--A viral disease of sweet cherry found in the Rogue River Valley, Oregon. The disease spreads rapidly and kills trees. The foliage turns bronze-green; the fruit turns white and fails to mature.

Albizzia--(1) A genus of trees belonging to the family Mimosaceae. These mimosa trees have twice-pinnated leaves, and bear clusters of pink and white flowers. Native to southern Europe.

Alburnum--The part of a tree trunk between the bark and the wood, consisting of the cambium and the phloem cells. The alburnum of some species of trees; e.g., the Ponderosa Pine (Pinus ponderosa) of the Northwest was eaten by American Indians during times of famine. See Sapwood.

Alcohol--The family name of a group of organic chemical compounds composed of carbon, hydrogen, and oxygen; a series of molecules that vary in chain length and are composed of a hydrocarbon plus a hydroxyl group, C[H.sub.2]-(C[H.sub.2])N-OH; includes methanol, ethanol, isopropyl alcohol, and others.

Alcohol Slime Flux--A white, frothy seepage from the bark or sapwood near the base of a tree trunk. Rich in starches, sugars, and proteins. Over long periods, it is fatal to the tree. See Brown Slime Flux, Slime Flux.

Alcoholic Fermentation--The transformation of simple hexose sugars, especially glucose, into alcohol and carbon dioxide. Useful as a method of preservation.

Aldehydes--Any of a class of highly reactive organic chemical compounds obtained by oxidation of primary alcohols, characterized by the common group CHO, and used in the manufacture of resins, dyes, and organic acids.

Alder--Any tree or shrub of the genus Alnus, of the family Betulaceae, some species are called tag alders. The lumber from alders is used in cabinet making.

Alder Buckthorn--Rhamnus frangula; a shrub cultivated for its lustrous green leaves, which turn bright yellow in autumn.

Alder Flea Beetle--Altica ambiens, family Chrysomelidae; it feeds on the leaves of alder, willow, and poplar trees.

Alder Witches' Broom--A European fungal disease of alders. Taphrina epiphylla, family Taphrinaceae; it causes profuse branching.

Aldrin--A white crystalline, chlorinated hydrocarbon insecticide.

Aleppo Grass--See Johnsongrass.

Aletophyte--A weed growing in a mesic habitat.

Aleukia--(1) Absence of leukocytes in the blood. (2) Alimentary toxic aleukia. Mycotoxicosis in people and some animals caused by ingesting one or more of the following genera of fungi that develop on damp grain crops: Actinomyces, Alternaria, Cladosporium, Fusarium, Penicillium, Piptocephalis, Rhizopus, Thammidium, Tricoderma, Trichothecium, and Verticillium.

Aleurone--Protein grains found in the endosperm of ripe seeds.

Aleurone Layer--In wheat and corn (maize), the outer differentiated layer of cells of the endosperm.

Alfalfa--Medicago sativa; a perennial, leguminous herb of the family Leguminosae; a native of central Asia. Used as forage, green manure, and hay. Also called lucerne, purple medic, purple alfalfa.

Alfalfa Caterpillar--Colias philodice eurytheme, family Pieridae; an insect pest in the southwestern United States, which feeds principally on leaves.

Alfalfa Dwarf--A viral disease of alfalfa characterized by dwarfing of the plant.

Alfalfa Gall Midge--Asphordylia websteri, family Itonididae; an insect pest of alfalfa in Arizona and New Mexico which attacks the floral head, causing the seed pods to become swollen.

Alfalfa Group--The group of Rhizobium bacteria used to inoculate seed of alfalfa and the clovers.

Alfalfa Leaf Meal--A stock feed consisting chiefly of ground, leafy materials separated from alfalfa hay or meal. It is reasonably free from other crop plants and weeds, and does not contain more than 18 percent of crude fiber.

Alfalfa Meal--A stock feed of ground alfalfa hay. It is reasonably free from other crop plants and weeds, and does not contain more than 33 percent of crude fiber.

Alfalfa Root Rot--Rhizoctonia crocorum; the imperfect stage of the more rarely found Helicobasidium purpureum, family Auriculariacease; a fungal, killing disease. The affected plants become yellow, wilt, and the tops and roots die.

Alfalfa Tea--Made from alfalfa leaves; credited with medicinal value and possible a slight tonic effect. Used in China.

Alfalfa Weevil--Hypera postica, family Curculionidae; a common insect pest in western and many eastern states of the United States. It destroys first cuttings and delays the subsequent cuttings.

Alfalfa Wilt--Corynebacterium insidiosum, family Bacteriaceae; a disease of alfalfa in which diseased plants are stunted and have excessively weak stems; the leaves curl up, turn yellow, and die; the taproot has a wet, yellow zone under the bark. Causes serious damage in the United States. Other organisms, such as Fusarium spp, and Cylindrocarpon spp; also cause wilt.

Alfalfa Yellow Leaf Blotch--Pseudopeziza jonesi (=Pyrenopeziza medicaginis), family Mollisiaceae; a worldwide, fungal disease which causes defoliation.

Alfalfa Yellows--A boron deficiency disease characterized by pale leaflets or bronzed leaves with green midribs, or, in some cases, a stopping of terminal growth. The margins of the leaves may dry up and shrivel. Also called alfalfa mosaic.

Alfileria--Erodium cicutarium; an annual herb, of the family Geraniaceae; native to southern Europe; an important forage plant in California and the southwest United States. Also called storksbill, pin grass, filaree, alfilaria, alfillerilla, red-stem filaree.

Alfisols--A soil order with gray to brown surface horizons, medium to high supply of bases, and B horizons of alluvial clay accumulation. These soils form mostly under forest or savanna vegetation in climates with slight to pronounced seasonal moisture deficit.

Algae--(singular, alga) Comparatively simple plants containing photosynthetic pigments. A majority are aquatic, and many are microscopic. They grow in sunlit waters. They are food for fish and small aquatic animals and, like all green plants, put oxygen in the water when carrying on photosynthesis. Although some forms of algae are necessary and desirable, excessive concentrations tend to discolor water and cause objectionable tastes and odors, severely limiting all uses of the water.

Algodon--(Spanish) Cotton.

Algology--The study of algae.

Alkali--(1) A chemical compound of oxygen and hydrogen with one element, such as sodium, potassium, calcium, magnesium, or the ammonium radical, capable of neutralizing acids. (2) A general term denoting salts of sodium, calcium, potassium, and magnesium which injure plant growth. (3) A general term for caustic soda, sodium hydroxide, caustic potash, sodium carbonate, etc., all cleansing agents in food processing plants.

Alkali Chlorosis--A yellowing or blanching of plant leaves caused by excessive alkali.

Alkali Disease--Selenium poisoning of animals caused by grazing on plants containing excessive amounts of selenium. Characterized by emaciation, loss of hair (mane and tail among horses), deformed hoofs, and blind staggers.

Alkali Muhly--Muhlenbergia asperifolia, family Gramineaae; a native grass of the northern and western United States; sometimes an undesirable weed pest in grazing lands. Frequently referred to as Sporobolus asperifolius. Also called fine-top salt grass, scratch-grass.

Alkali Sacaton--Sporobolus airoides, a grass native to the United States, of the family Gramineae; used in reseeding grazing lands. Also called alkali dropseed, tussock grass.

Alkali Sida--Sida hederacea, of the family Malvaceae; a weed pest.

Alkali Soil--A soil containing alkali salts, usually sodium carbonate (with a pH value of 8.5 and higher). The term frequently includes both alkali and saline soil as here defined. White alkali is applied to saline soil in some localities, and black alkali to alkali soils. See Alkaline Soil.

Alkaline--A chemical term referring to basic reaction where the pH reading is above 7, as distinguished from acidic reaction where the pH reading is below 7.

Alkaline Soil--A soil that gives an alkaline reaction, precisely, a reading above pH 7.0, but in practice, readings as high as pH 7.3 may be considered neutral. In humid regions alkalinity most commonly comes from calcium and magnesium carbonates; in drier regions nitrates and salts of sodium and potassium as well as calcium and magnesium may be the source. See Acid Soil, Alkali Soil, pH.

Alkaloids--Substances found in plants, many having powerful pharmacologic action, and characterized by content of nitrogen and the property of combining with acids to form salts. Alkaloids may be beneficial (atrophine) or toxic (from Seneciospp).

All-aged--Applied to a stand of trees in which trees of all ages up to and including those of the felling age are found.

Allegheny Blackberry--Rubus allegheniensis; an erect blackberry, of the family Rosaceae; common in the northern United States; the source of many cultivated varieties of blackberries.

Allele--(1) The alternative forms of genes having the same place in homologous chromosomes which influence the development of alternative traits or characters. (2) A pair of Mendelian genes at the same locus as a pair of homologous chromosomes. Also called allelomorph.

Allelopathy--The harmful influence of one living plant on another living plant by the secretion of a toxic substance. Examples are juglone secreted by black walnut roots and leaves and an unidentified toxin secreted by certain species of sedges that depresses rice plants.

Allergy--An exaggerated susceptibility to a substance harmless to most members of the same species.

Allethrin--A synthetic insecticide similar to pyrenthrins.

Alliaceous--Having the smell or taste of onion or garlic.

Allicin--An antibiotic derived from garlic.

Allite--Soils characterized by a silica-alumina ratio less than 2:1 in the hydrochloric acid extract. A soil from which silica has been removed during formation, and in whose clay fractions aluminum is in the form of A[L.sub.2][O.sub.3], as in bauxite and laterite.


Allogenic--Succession in which a plant community is replaced by another as a result of a change in the environment due to nonbiotic factors, e.g., improved drainage or irrigation.

Allohexaploid--Having six genomes or basic sets of chromosomes, with one or more sets derived from a species different from that of the other sets. In common wheat (Triticum aestivum), for instance, two each of three different chromosome sets are present, derived from three different parent species.

Allopolyploid--A polyploid containing genetically different chromosome sets, e.g., from two or more species.

Allosomes--Chromosomes distinguished by peculiarities of behavior or sometimes by a difference in size or shape.

Allotment--(1) The number of acres, etc., a producer is allowed to grow of a particular crop under a government program. (2) An area designated for the use of a prescribed number of cattle or sheep, or for common use of both.

Allspice--Pimenta officinalis; a tropical American tree, of the family Myrtaceae; so named because its spice resembles the favor of a mixture of cinnamon, nutmeg, and cloves. Grown in the United States only in Florida, and there as an ornament. Also called pimento allspice.

Alluvial--Pertaining to material that is transported and deposited by running water.

Alluvial Community--A boundary zone between water and land which is subject to inundation.

Alluvial Cone--A delta-form feature composed of soil and rock detritus, deposited as storm wash at the mouths of streams. Similar to alluvial fan, except that the angle of slope is greater.

Alluvial Fan--Soil and rock fragments moved by swiftly flowing water and deposited at the mouth of a stream in the form of fans or deltas. Alluvial fans are most common in arid regions at the bases of mountain slopes. Several fans may coalesce to form terraces and piedmont plains. The agricultural value of the soils in alluvial fans varies.

Alluvial Soil--Soil developed from transported and relatively recent water-deposited material (alluvium), characterized by little or no modification of the original material by soil-forming processes.

Alluvio Maris--Soil formed by the washing-up of the sea; sand or any other material adjoining land near the sea.

Alluvion--Land added by accretion, as that built up by deposition from sea, lake, or river, or that left by recession of water or by the natural shifting of the channel of a river. It always belongs to the owner of the land to which it is an accretion. The word is often erroneously used as the equivalent of alluvium.

Alluvium--Matter transported and deposited by streams; usually composed of mixed inorganic (mineral) and organic particles. The word most commonly refers to the recent deposits on the flood plains; more inclusively it embraces deposits on second bottoms or river valley terraces, with the detritus spread out as fans. See Alluvial Fan.

Almond--Prunus amygdalus (= Amygdalus communis); an Asiatic, deciduous, small-nut tree, of the family Rosaceae; cultivated for its popular edible kernel nut, the almond of commerce.

Almond Cherry--Prunus gladulosa; an Asiatic, deciduous shrub, of the family Rosaceae; grown for its clusters of white or pinkish-white flowers. Also called flowering almond.

Aloe Vera--Family Liliaceae; a succulent herb grown in a pot or tub as a specimen plant. The dehydrated sap of the leaves of Aloe vera and several other species of the genus Aloe is called bitter aloe. It has a medicinal value as a tonic, a purgative, and an agent promoting menstrual discharge. Native to the Mediterranean region. Also called Barbados aloe.

Alpestrine--Denoting plants growing on mountains below the timberline. Alpine Fescue--Festuca ovina var. brachyphylla, family Gramineae; a variety of sheep fescue, found from the Arctic to California, in the Rocky Mountains to New Mexico, and in the higher mountains of New England and New York.

Alpine Fir--Abies lasiocarpa; an ornamental, pyramid-shaped evergreen tree, of the family Pinaceae, of western America; also called Arizona fir, mountain balsam, Rocky Mountain fir.

Alpine Hemlock--Tsuga mertensiana, family Pinaceae; a tall evergreen tree valued for its timber. Found from Alaska to Montana, Idaho, and California.

Alpine Meadow Grassland--Summer pasturage (meadows or parks) near or above timberline.

Alpine Timothy--Phleum alpinum, family Gramineae; a smaller grass than cultivated timothy, common in alpine meadows from Alaska to northern New England and northern Michigan.

Alsike Clover--A short-lived perennial clover, Trifolium hybridum, used in much the same manner as red clover. Suitable for soils that are too wet, cold, or acid for red clover. See Red Clover.

Alter--(1) To neuter by castrating or spaying. Also called cut, geld, emasculate. (2) To prune. (3) To remove the comb from a beehive.

Alternate--Arranged singly at different heights and on different sides of the axis or stem, as alternate leaves or branches.

Alternate Host--A plant or animal upon which a disease organism exists for only a part of its life cycle; e.g., cedar and apple for rust.

Alternation of Generations--Reproduction in which common characteristics are found only in every second generation, e.g., one generation reproduces sexually and the next asexually.


Altherbosa--Tall herbage.

Alum--See Aluminum Sulfate.

Aluminum--A widely distributed element, commonly found as a silicate in various clays and rocks. While aluminum may be essential to the growth of some plants, the amount required, if any, is very small. The supply in all soils is abundant. Some acid soils contain sufficient aluminum in soluble or exchangeable form to kill certain plants. See Aluminum Sulfate.

Aluminum Dross--A by-product of refining aluminum metal. It consists of aluminum oxide, aluminum nitride, salt, and various other impurities. The N is slowly available in the soil. Dross is also relatively high in magnesium, copper, manganese, and zinc contents.

Aluminum Phosphate--(AIP[O.sub.4]) Occurs in quantity in the colloidal or soft phosphates found in Florida. It also occurs in small quantities in all grades of phosphate rock. It is insoluble in water and its phosphorus content is but slightly available in the soil unless treated with an acid. Much aluminum phosphate in phosphate rock is objectionable because of the tendency of the superphosphate made from such rock to become moist and sticky.

Aluminum Sulfate--A mineral soluble in water and usually made by treating bauxite with sulfuric acid. It is sometimes applied to soils, especially in the West, to make them less alkaline. In the East, it is used to produce an acid condition for such plants as rhododendrons, azaleas, camellias, and blueberries. Also used in tanning leather, sizing paper, and purifying water.

Alunite--A hydrated sulfate of aluminum and potassium mineral. There are large deposits in Utah and other western states. The potassium is insoluble in water, but is rendered soluble by roasting. Roasted material marketed in the West averages about 6.5 percent K2O.

Alyce Clover--Alysicarpus vaginalis; Asiatic, tropical, annual herb, of the family Leguminosae; grown for forage, hay, and green manure.

Ambient Air--The air which surrounds an object. See Atmosphere.


Amendment--Any material other than fertilizers such as lime, manure, or sewage sludge that is worked into the soil to make it more productive.

Ament--A catkin or dry, scaly spike, usually unisexual, such as the inflorescence of willows, birches, etc., and the staminate inflorescence in hickories.

American Beech--Fagus grandifolia, a hardy, deciduous tree, of the family Fagaceae; cultivated ornamentally and used commercially for hardwood distillation, crossties, pulp, slack-cooperage, veneer, etc.

American Bittersweet--Celastrus scandens; a woody vine of the family Celastraceae produces orange berries that remain on the vine throughout the winter; poisonous to livestock. Used as a winter decoration indoors. Found from eastern Canada to South Dakota and from North Carolina to New Mexico. Also called false bittersweet, waxs-work, stafftree, climbing bittersweet.

American Chestnut--Castanca dentata; a tree of the family Fagaceae, now nearly exterminated by chestnut blight; once found from Maine to Alabama, west to Michigan. It bears a sweet, edible nut, and its wood is used in making tannin, a semichemical pulp, poles, fence posts, crossties, slack-cooperage, and furniture. Also called chestnut.

American Elder--Sambucus canadensis; a shrub of the family Caprifoliaceae grown for its flowers and fruit, which are used in wine and jelly. The leaves, opening buds, and young shoots are lethal to cattle or sheep. Also called elderberry, sweet elder.

American Elm--Ulmus americana; a beautiful, long-lived deciduous tree of the family Ulmaceae; a popular street tree and used in shelter belts. The trees are subject to Dutch Elm disease. Used in slack-cooperage, crates, veneer, furniture, and wooden ware. Also called white elm, water elm.

American Holly--Ilex opaca; an evergreen tree of the family Aquifoliaceae. A popular Christmas decoration; used in inlay wood, engravings, scrollwork, carvings, scales, rules, piano keys, and other wooden ware. Also called white holly.

American Hophornbeam--Ostrya virginiana; a North American deciduous tree of the family Betulaceae; grown for its fruiting clusters. Also called ironwood.

American Hornbeam--Carpinus caroliniana; a native, small, deciduous tree of the family Betulaceae; cultivated for ornament. Slow-growing but hardy in shady and protected places. Used in handles, vehicle parts, and fuel wood. Also called bluebeech, ironwood, water beech.

American Mistletoe--Any epiphytic plant of the genus Phoradendron, especially the American Christmas mistletoe.

Amino Acids--Organic substances from which organisms build proteins, or the end product of protein decomposition.

Amitosis--Cell division without formation and splitting of chromosomes. See Mitosis.

Ammonia--N[H.sub.3]; a chemical compound composed of 82.25 percent nitrogen and 17.75 percent hydrogen. At ordinary temperatures, it is a colorless, pungent gas about one-half as heavy as air. Liquid ammonia is used as a fertilizer. Sometimes added to livestock feed to increase nutritional value.

Ammonia Liquor--N[H.sub.4]OH, aqua ammonia; ammonia and water combine readily to form ammonium hydroxide (N[H.sub.4]OH). Aqua ammonia made from anhydrous, ammonia usually contains from 27 to 30 percent N[H.sub.3] (22.2 to 24.7% N). The solution is strongly alkaline and unites with strong acids to form ammonium fertilizer salts; for example, with phosphoric acid ([H.sub.3]P[O.sub.4]) to form ammonium phosphates; with sulfuric acid ([H.sub.2]S[O.sub.4]) to form ammonium sulfate; and with nitric acid (HN[O.sub.3]) to form ammonium nitrate.

Ammonia Oxidation--When ammonia (N[H.sub.3]) and air are mixed and passed through a platinum alloy gauze, the ammonia burns, combines with the oxygen of the air, and forms nitric oxide (NO). This oxide is converted to nitrogen dioxide (N[O.sub.2]), which is absorbed in water to form nitric acid (HN[O.sub.3]). This process is used commercially not only to manufacture ammonium nitrate fertilizer, but also in the chamber process for the manufacture of sulfuric acid.

Ammonia Volatilization--The loss of gaseous ammonia to the atmosphere. This occurs during the application of urea fertilizer, anhydrous fertilizer, or any ammonia salt under these conditions: (1) when applied on the soil surface, (2) when applied on alkaline soil, or (3) when applied under high humidity and high temperatures.

Ammoniated Superphosphate--When superphosphate of any grade is brought into contact with free ammonia (N[H.sub.3]), the ammonia imme diately reacts with any free acid and acidic phosphates present. Gypsum, when present, also enters the reactions, and thus the fertilizers, dicalcium phosphate, monoammonium phosphate, and ammonium sulfate are formed.

Ammonification--The formation of ammonia in soil by microorganisms.

Ammonium Chloride--(N[H.sub.4]Cl) The ammonium salt of hydrochloric acid. Similar in fertilizer properties to ammonium sulfate, but more expensive and may acidify the soil more. Also called sal-ammoniac, muriate of ammonia.

Ammonium Nitrate--An ammonium salt with a nitrate radical, excellent as a source of nitrogen fertilizer. Made in large quantities from the atmospheric nitrogen and contains 30 to 35 percent nitrogen. Dangerous to work with in the pure state because of its explosive nature.

Ammonium Nitrate Limestone--A fertilizer mixture of ammonium nitrate and finely pulverized calcic or dolomitic limestone in a ratio of 3:2 prepared in pellet or prilled form suitable for mixing or direct application. It is not explosive and contains 20.57% N.

Ammonium Phosphate Nitrate--A fertilizer mixture of ammonium phosphate and ammonium nitrate. It is produced by ammoniating the solution separated from phosphate rock that has been acidulated with an excess of nitric acid. The average composition of the fertilizer is 27% N and 15% [P.sub.2][O.sub.5.]

Ammonium Phosphate Sulfate--A double salt of ammonium phosphate and ammonium sulfate or a mixture of these two salts. When first marketed in 1923 this material was called Ammophos-B. It is guaranteed to contain 16 percent N and 20percent available [P.sub.2][O.sub.5]. It contains 45 percent ammonium sulfate. The 13-39-0 grade contains about 20 percent ammonium sulfate.

Ammonium Phosphates--Both monoammonium phosphate (MAP) and diammonium phosphate (DAP) are valuable fertilizers. See also Ammonium Polyphosphate (APP), Monoammonium Phosphate (N[H.sub.4][H.sub.2]P[O.sub.4]) (MAP). Pure monoammonium phosphate contains 12.17 percent nitrogen and 61.71 percent phosphoric oxide. Some fertilizer materials containing 12 percent N and 61 percent available [P.sub.2][O.sub.5] are on the market for the manufacture of liquid fertilizers and starter solutions. The crude salt, originally sold under the trade name Ammophos-A (11-48-0), is made by neutralizing crude phosphoric acid with ammonia and evaporating the solution.

Ammonium Polyphosphate (APP)--Any ammonium salt of a polyphosphoric acid such as triammonium pyrophosphate [[(N[H.sub.4]).sub.3]H[P.sub.2][O.sub.7]] and pentamonium tripolyphosphate [[(N[H.sub.4]).sub.5][P.sub.3][O.sub.10]]. Fertilizer grades of ammonium polyphosphate generally are phosphate mixtures containing a substantial proportion of one or more ammonium polyphosphates and can be made by ammoniation of superphosphoric acid or by thermal dehydration of ammonium orthophosphate. Aqueous solutions of ammonium polyphosphates are used widely in the production of liquid fertilizers. The usual grades of these solutions are 10-34-0 and 11-37-0. A 12-44-0 is also available. Granular 15-620, made by ammoniating superphosphoric acid, is suitable for direct application, bulk blending, or as an intermediate in producing liquid fertilizers.

Ammonium Polysulfide (APS)--A combination fertilizer and soil acidifier containing 20% N and 36% S.

Ammonium Sulfate Nitrate--Formerly imported under the trade name saltpeter, this double salt, less hygroscopic than ammonium nitrate alone, is produced in many modern granulated fertilizers when hot solutions or slurries are mixed, or formed in processing, and dried. It contains 26% N.

Ammonium Sulfate (Sulfate of Ammonia)--[[(N[H.sub.4]).sub.2]S[O.sub.4]]; a white or grayish crystalline salt made by neutralizing 30 to 50 percent sulfuric acid with ammonia in a saturator. Ammonium sulfate is ammonia in a saturator. Ammonium sulfate is an ingredient of most mixed fertilizers. It is also widely used as a separate fertilizer in the western part of the country and on rice. It is seldom used on acid soils, because of its high physiological acidity (See Acidity). Where sulfur content in the soil is low it is valuable for its sulfur content also. Ammophilous--Denoting plants or insects in sand.

Amoeba--A genus of unicellular protozoan organisms of microscopic size, existing in nature in large numbers; many live as parasites; some species are pathogenic to humans.

Amorphophyte--Any plant which bears irregular flowers.

Ampherotoky--Production of both male and female from a parthenogenic ovum, seed, or spore.

Amphicarpogenous--Fruit, such as the peanut, which grows below ground before maturity.

Amphicarpus--Bearing two varieties of fruit which may mature at the same time.

Amphigean--Native of both the Old and New Worlds.

Amphiphyte--A plant growing in the border zone of wet land and water, with amphibious characteristics.

Amphispermous--A plant, such as grass, in which the pericarp tightly encloses the seed.


Amphoteric--Capable of reacting as either an acid or a base, as casein.

Anabatic Wind--Local breezes caused by heating of the land surface by the sun creating warmer air currents, which rise, moving up valleys and up hills. Upon cooling, the winds move down valleys and hills. Anabatic winds are very important in creating or reducing "frost pockets," which often kill fruit buds in the spring.

Anabolism--Constructive process by which simple substances are converted by living cells into more-complex compounds. See Catabolism.

Anacardiaceae--The cashew or sumac family, which includes approximately sixty tree and shrub genera of which many are of economic value; e.g., the mango.

Anaerobe--Organisms (usually bacteria) which live and multiply without free oxygen.

Anaerobic--(1) Living or active in the absence of free oxygen. (2) Pertaining to or induced by organisms that can live in the absence of free oxygen.

Anaerobic Bacteria--Bacteria not requiring the presence of free or dissolved oxygen for metabolism. Strict anaerobes are hindered or completely blocked by the presence of dissolved oxygen and sometimes by the presence of highly oxidized substances, such as sodium nitrates, nitrites, and, perhaps, sulfates. End-product gases include methane and hydrogen sulfide.

Anaerobic Decomposition--Reduction of the net energy level and change in chemical composition of organic matter caused by microorganisms in an anaerobic environment.

Anagreeta--A term used in the United States in Revolutionary or pre-Revolutionary times for corn gathered before maturity and dried in an oven or hot sun.

Analog Food--A food product that resembles, and is a substitute for, a traditional farm food product (e.g., a steak made out of soybean meal, with a plastic bone).

Analogous--Refers to an organ of one organism that corresponds in function to an organ of another animal or plant but which is not homologous. See Homologous.

Analysis--The percentage composition of fertilizers, feeds, etc., as determined by chemical analysis, expressed in terms specified by law.

Anastomosing--(1) Of a stream; branching, interlacing, intercommunicating, thereby producing a netlike or braided appearance. (2) Netted; interveined; said of leaves marked by cross veins forming a network; sometimes the vein branches meet only at the margin.

Anatomy--The branch of biology that deals with the structure of organisms.

Ancestor--An individual from whom an animal or person is descended.

Anchored Dune--Sand dune stabilized by growth of vegetation.

Andisols--The eleventh soil order in the United States system of soil taxonomy approved in 1989. It consists of a black mineral soil developed from volcanic ejecta including 5% glass.

Androecium--The mail element, the stamens, whether one or many, as a unit of the flower.

Androgametophore--A plant having male sexual organs.

Androgenesis--Development of offspring with the paternal chromosomes only.

Androgynous--In botany, a plant having stamens and pistils.

Androperianth--The fusion of perianth and stamen.

Anemochore--(anemochorous) An ecological term which denotes a plant, such as milkweed, with seeds distributed by wind.

Anemophilous--Pertaining to plants pollinated by wind.

Anemoscope--Any device used to indicate and/or record wind direction.

Aneroid Barometer--A device that measures air pressure by its effect on the thin sides of a partially evacuated hollow cylinder.

Aneuploid--An organism or cell which has a chromosome number other than an exact multiple of the monoploid or basic number; i.e., Hyperploids=higher; hypoploid=lower.

Angelica--Any plant of the genus Angelica, family Umbelliferae; usually aromatic herbs; livestock forage throughout the western United States; the garden angelica, A.archangelica, was formerly blanched and eaten like celery; the tender stalks were cut for candying.

Angiosperm--The subdivision of Spermatophytes (seed plants) in which seeds are produced within the ovary; includes monocotyledons and dicotyledons. See Gymnosperms.

Angleworm--See Earthworm.

Angleworm Cast--The aboveground accumulation of soil caused by the underground activity of the earthworm.

Angola Grass--See Paragrass.

Angular Leaf Spot--An infectious disease of cucumbers caused by the bacterium Pseudomonas lachrymans, in which the leaves look watersoaked and later turn brown.

Angular Winged Katydid--Microcentrum retinerve, family Tettigoniidae; a long-horned grasshopper that feeds on many plants.


Anhydride--An oxide that will react with water to form the corresponding acid or base; e.g., P2O5 is the anhydride of H3PO4; CaO is the anhydride of Ca [(OH).sub.2.]

Anhydrite--(CaS[O.sub.4]) Anhydrous calcium sulfate; used for the same purposes as land plaster or gypsum, i.e., as a soil amendment; also used in India and the United Kingdom for making sulfuric acid.

Anhydrous--A compound that does not contain water either absorbed on its surface or as water of crystallization; e.g., anhydrous ammonia.

Anhydrous Ammonia--A gas used as a chemical fertilizer containing approximately 82 percent nitrogen; normally sold as liquid under high pressure. Main advantages are low cost and high concentration, thus less handling. Changes to a gas when not under pressure, so it must be injected into soil and sealed.

Anion--The ion solution carrying one or more negative electrical charges depending on its valence or combining power with positively charge cations; e.g., NO3, H2PO4, SO42. Anions and cations are always present in the liquid phase of fertilizers; an ion carrying a negative charge of electricity. See Ion.

Anise--Pimpinella anisum; an annual herb, family Umbelliferae; grown for its aromatic seed, which causes the expulsion of stomach and intestinal gas. Native to eastern Mediterranean lands.

Ankee--Barnyard grass.

Annual Bearing--Producing fruit each year.

Annual Bluegrass--Poa annua, family Gramineae; native to Eurasia; an annual grass which may become a weed pest in turf; also called annual meadow grass, early meadow grass, low spear grass, annual poa, winter grass, goose grass.

Annual Layer--Sedimentary layer deposited or presumed to have been deposited during the course of a year; e.g., glacial varve.

Annual Precipitation--The water, usually expressed in inches of depth, deposited on the earth in one year by rain, snow, dew, hail, fog, mist, sleet, or other precipitation.

Annual ring--(1) The growth layer of a perennial plant which represents the growth of one year, as viewed on the cross-section of a stem, branch, or root. (2) The layer of xylem (wood) formed by one year's growth of cambium.

Annual Ryegrass--A fast-growing, competitive, winter annual grass used extensively as a cover crop, for erosion control, and for short-term forage production; quite tolerant of wet soils; very useful as an interim crop between permanent pasture seedings. Tetraploid annual ryegrasses have good early spring production, are quite palatable to livestock, and tolerate a wide variety of soil conditions.

Annual Snowfall--The snow falling in one year, usually expressed in inches in the United States. For conversion to its approximate water equivalent, the depth in inches is divided by 10. (In some other countries, for example, Australia, the ratio used is 12:1. However, the ratio can vary from 5:1 to 50:1 depending on many factors).

Annual Vernalgrass--Anthoranthum aristatum; an a aromatic grass, family Gramineae; sometimes a weed pest.

Annual White Sweetclover--See Hubam Sweetclover.

Annual Wildrice--Zizania aquatica; an annual marsh grass, family Gramineae; cultivated for its edible grain and for an ornament; widely planted by sportsmen as feed for waterfowl.

Annual Yellow Sweetclover--Meliotus indica; an herb, family Leguminosae; useful for pasture, hay, silage, soiling, soil improvement, and as a bee plant. Uncontrolled, it can become a weed pest. Also called sourclover.

Annuals--Plants living one year or less. During this time the plant grows, flowers, produces seeds, and dies; e.g., beans, peas, sweet corn, squash.

Annulation--The ring growths visible in the cross-section of a log or around the body of a worm, etc.

Anoxia--A deficiency of oxygen.

Ant--Any insect of the family Formicidae; ants modify natural soils; certain species damage crops, and some are lawn pests.

Antagonism--The loss of activity of a chemical when exposed to another chemical.

Antennae--Slender jointed feelers, which bear certain sense organs, on head of insects.

Anther--The saclike part of the stamen on seed-producing plants which develops and contains the pollen.

Antheridium--The male organ in cryptogams, producing male gametes (sperm), and corresponding to the anther in flowering plants.

Anthesis--Full blossom; the opening of a flower bud; by extension, the duration of life of a flower, from the opening of the bud to the setting of fruit.

Anthocyanin--Pigments in sap responsible for scarlet to purple or blue coloration in plants. Also called anthocyan. See Anthoxanthin.

Anthoecology--The study of flowers in relation to their environment.

Anthography--Flower description.

Anthophorous--A plant that bears flowers.

Anthopilous--Flower-eating or living amongst flowers.

Anthos--(Greek) Flower.

Anthotaxy--Arrangement of flower blooms.

Anthoxanthin--Yellow crystalline pigments in sap responsible for pale yellow to ivory white coloration in plants. See Anthocyanin.

Anthracnose--A fungal disease of plants characterized by spots that appear on the leaves and/or fruit.

Anthropic Soils--Soils that have been under cultivation for a long period of time.

Anthropogenic--Changes in soils caused by action of people, such as plowing.

Anthurium--Anthurium scherzerianum; a tropical perennial herb, family Araceae; grown intensively in greenhouses for its bright scarlet spathe and its coiled yellow spadix. Many varieties of different sizes and colors are cultivated. Native to Central America; also called flamingo flower.

Anti-caking Agent--See Conditioners.

Antibacterial--Any substance that has the ability, even in dilute solutions, to destroy or inhibit the growth or reproduction of bacteria and other microorganisms; used especially in the treatment of infectious diseases of people, animals, and plants.

Antibiosis--An association between two organisms in which one harms the other.

Antibiotic--Germ-killing substance produced by a bacterium or mold.

Anticarcinogen--A substance that inhibits or eliminates the activity of a carcinogen (cancer-producing substance).

Anticyclone--A large, relatively high-pressure, relatively cool air mass with winds which move downward and outward in a clockwise direction in the Northern Hemisphere and counterclockwise in the Southern Hemisphere. Fair weather is usually associated with anticyclones. See Cyclone.

Antidote Statement--A required statement on the containers of chemicals explaining methods that may be used to counteract the effects of the chemical.

Antifoaming Agents--Substances that reduce foaming caused by the presence of dissolved proteins or other substances.

Antisepsis--Prevention of infection by the exclusion, inhibition, or destruction of the causative organisms.

Antiseptic--An agent that destroys or severely inhibits microorganisms that cause disease, decomposition, or fermentation.

APA--Available phosphoric anhydride ([P.sub.2][O.sub.5], frequently called available phosphoric acid.

Apache Plume--Fallugia paradoxa; an evergreen shrub, family Rosaceae; good as browse for goats. Found in the southwestern United States and Mexico.

Apatite--(CaF)[Ca.sub.4][(P[O.sub.4]).sub.3]; phosphate of lime with fluorine; present as a mineral in very small amounts, but it is the primary source of phosphate deposits that are mined for use as fertilizers. Apetalous--Without petals. See Naked Flower.

Apex--The tip of leaf, twig, or other plant part.

Aphid--A small insect, family Aphidae, which sucks plant juices, often doing great damage. Many aphids secrete honeydew, of which ants are fond; common agents for conveying viral diseases of plants; also called plant louse.

APHIS--Animal and Plant Health Inspection Service.

Aphosphorosis--Phosphorus deficiency.


Apiarist--A beekeeper.

Apiary--Bee colonies, hives, and other honeybee equipment assembled in one location; also called bee yard.

Apical--Relating to the apex or tip.

Apiculture--The science and art of studying and using honeybees for human benefit.

Apidae--The bee family, including the subfamilies of the common bee (Apinae) and the stingless bee (Meliponinae).

Apiology--The scientific study of bees, especially honeybees.

Apis--The genus to which the honeybee belongs.

Apis cerana--Scientific name of the Eastern honeybee, the honey producer of South Asia; also called Apis indica.

Apis dorsata--Scientific name for the large honeybee of Asia, which builds open-air nests of single comb suspended from tree branches, rocky ledges, etc.

Apis florea--Scientific name for the small honeybee of Asia.

Apis mellifera--Scientific name of the Western honeybee.

Apogamous--Developed without fertilization; parthenogenetic.

Apomixis--Reproduction of many types in which a nonsexual process has replaced the sexual, and no fusion of male and female gemetes is involved. In many plants, seeds regularly develop from unfertilized egg cells or from cells other than egg cells; the resultant plants, termed apomicts, are genetically identical with the mother plant.

Apoplast--The total, nonliving continuum in a plant, including cell walls, intercellular spaces, and the xylem and phloem vessels that form a system and phloem through which water and solutes flow.

Apple--(1) The tree or fruit of the genus Malus (or Pyrus), family Rosaceae, especially M. pumila, variously designated as P. malus, M. malus, M. sylvestris, and M. domestica; specifically the fruit of the tree which is cultivated throughout the temperate zones. (2) A name applied to other plants, the fruit of which resembles the common apple, such as custard apple, mayapple, pondapple, roseapple.

Apple Butter--A sauce made from stewing apples in cider, or by allowing apple juice to thicken by evaporation.

Apple Cider--The juice pressed from apples; unless pasteurized it ferments rapidly. Unfermented juice is called sweet cider, and fermented juice is called hard cider.

Apple Cider Vinegar--Vinegar produced from long-fermented apple cider; also called cider vinegar.

Apple Cider Yeast--Saccharomyces malei, family Saccharomycetaceae; a yeast which occurs naturally in fruits; used in making sparkling hard cider.

Apple Maggot--The larvae of a fly, Rhagoletic pomonella, family Tephritidae, which bore through the flesh of apples, making winding galleries. It also infests wild crab apples, blueberries, European plums, and cherries. Also called railroad worm.

Apple of Love--Another term for the tomato.

Apple Redbug--Lygidea mendax, family Miridae; an important sucking insect that feeds on the sap of the leaves and the juice of apples, leaving the fruit misshapen and pitted with russeted spots; found east of the Mississippi River, especially in New England, New York, and southeastern Canada.

Apple Rust--A very serious fungal disease caused by Gymnosporangium juniperi-virginianae, family Pucciniaceae; characterized by rust spots on the leaves, rust lesions on the twigs, lesions on the fruit; results in defoliation, dwarfing, and reduction in the quality of the fruit. Found east of the Rocky Mountains. The fungus lives alternately on Juniperus spp. and on apples; also called cedar rust, cedar-rust disease of apples, cedar apple rust.

Apple Scab--A widespread parasitic fungal disease caused by Venturia inaequalis, family Pleosporaceae; it attacks species of Malus; characterized by lesions of the leaves, blossoms, and fruit; dwarfed or misshapen fruit, and premature dropping of fruit.

Apple Scald--A serious, physiological disorder caused by alcoholic esters emanating from the apples; characterized by browning of the skin after harvest, in storage, or after storage; usually associated with immaturity at harvest; more prevalent on green-skinned varieties.

Apricot--Prunus armeniaca; deciduous popular Asiatic tree, family Rosaceae; bears a drupe fruit, the apricot of commerce; resembles the peach.


Aqua Ammonia--A solution of ammonia dissolved in water with a usual nitrogen concentration of 20 to 21 percent; used as a fertilizer for direct injection into the soil.

Aqua Humus--A fertilizer concentration of water-dispersible (about 60 percent) humic and fulvic acid derivatives. Aqua Humus 60 percent Concentrate is used as a base in preparing various liquid and dry blends of nitrogen, phosphorus, and potassium. Aqua Humus has a grade of 12-9-6 and is a specialty fertilizer which contains 36 percent water-dispersible humic and fulvic acid derivatives.

Aqueous--(1) Pertaining to water. (2) Pertaining to sediment deposited by water. (3) Ammonia in water; also called ammonium hydroxide (NH4OH) solution. A low-pressure solution, about 20 to 21 percent N, used as a fertilizer.

Aquiclude--A geologic formation that will not transmit water fast enough to furnish an appreciable supply for a well or spring. See Aquifier.

Aquifer--A geologic formation or structure that transmits water in sufficient quantity to supply the needs for a water development, such as a well. The term water-bearing is sometimes used synonymously with aquifer when a stratum furnishes water for a specific use. Aquifers are usually saturated sands, gravel, fractured rock, or cavernous and vesicular rock.

Aquifuge--A rock which contains no interconnected openings or interstices and therefore neither absorbs nor transmits water.

Arabian Coffee--Coffee arabica; coffee made from the fruit of an evergreen shrub, family Rubiaceae, native to Yemen; grown in Florida as a curiosity. Also called mocha coffee.

Arable Land--Land so located that production of cultivated crops is economical and practical.

Arachnid--A group of arthropods having four pairs of legs and one or two body segments; mites, ticks, and spiders are examples.

Arachnoid--Cobwebby; of slender entangled hairs.

Aranose--Like a spider web.

Arbor--(Latin, tree) (1) A bower; small structure of latticework to support vines and provide a shady retreat. (2) A tree, as distinguished from a shrub. (3) A wooden platform used for sun-drying fibers. (4) The central or supporting beam or rod, as the arbor bolt on a disk gang harrow.

Arbor Day--In the United States, a ceremonial occasion for planting trees and shrubs; usually in early May, but varying by state.

Arboraceous (Arboreous)--From Latin arbor; treelike, or pertaining to trees.

Arborator--A tree tender.

Arboreal--Living in, on, or among trees.

Arboretum--A garden where trees and shrubs are grown for study and exhibition.

Arboriculture--Cultivation of woody plants, particularly those used for decoration and shade.

Archetype--In biology, the antecedent of a group of plants or animals from which certain typical characteristics have been inherited; a progenitor.

Arctic Alpine--Term used for plants of arctic and alpine distribution but found only south of the Arctic zone.

Arctic Timothy--Alopecurus alpinus, family Gramineae; a grass grown by Eskimos for stock feed.

Arctic Zone--The region within the Arctic Circle (66[degrees]30' N) and the North Pole (90[degrees] N). Little agriculture occurs in the Arctic zone. See Antarctic zone, Temperate Zone; Tropical zone.

Arena--(1) Sand. (2) Sphere of action, such as a livestock arena.

Arenarius--Of sandy places.

Argentine Ant--Iridomyrmes humilis, family Formicidae; a household and orchard insect. It also attacks shade trees, bees, their broods, and hives. Found in the southeastern United States and California.

Argillaceous--Applied to all rocks or substances composed of clay minerals, or having a notable proportion of clay in their composition, as shale, slate, etc. Argillaceous rocks are readily distinguished by the peculiar, "earthy" odor when dampened.

Argillic Horizon--The soil horizon where clay accumulates, usually the B horizon. See Soil Horizon.

Arid Climate--A dry desert, or semidesert climate with only sparse vegetation. Precipitation varies, with an upper limit for cool regions of 10 inches or less and for tropical regions of as much as 15 or 20 inches. (The Thornthwaite precipitation effectiveness [P-E] index ranges between 0 and 16.) See Precipitation-effectiveness.

Aridisols--A soil order with pedogenic horizons, low in organic matter, that are never moist as long as three consecutive months. They have an ochric epipedon that is normally soft when dry or that has distinct structure. In addition, they have one or more of the following diagnostic horizons: argillic, natric, cambric, calcic, petrocalcic, gypsic or salic, or duripan. See Soil Orders, Soil Taxonomy.

Aridity--The state of a region in respect to its dryness or lack of moisture. The amount of rainfall is not a sure index, for the aridity of a region depends in part on temperature, winds, and relative humidity.

Arizona Cypress--Cupressus arizonica; an evergreen tree, family Cupressaceae; grown as a windbreak and an ornamental in the southern and southwestern United States.

Arizona Fescue--Festuca arizonica, family Gramineae; an excellent forage grass growing at elevations of 6,000 to 10,000 feet. in southwestern United States.

Arizona Mistletoe--Phoradendron macrophyllum, family Loranthaceae; a parasite on alder, ash, poplar, hackberry, sycamore, walnut, and willow; also called bigleaf mistletoe.

Army Ants--Ants which group together to find and capture prey. Army Cutworm--The larva of the moth Chorizagrotis auxiliaris, family Noctuidae, which infests the roots of many kinds of green vegetation. Found in the western United States.

Aroostock--A county in Maine characterized by rolling topography and by a mellow, silty loam soil; world-famous for growing Irish potatoes.

Arrow Crotalaria--Crotalaria sagittalis; a poisonous annual herb, family Leguminosae; eating it green or in hay may kill a horse. Found in the southern and eastern United States. Also called rattlebox; rattleweed; wild pea.

Arrowroot--Starchy substance obtained from the root of the arrowroot plant; almost pure starch.

Arsenic Poisoning--A condition which results from ingestion or absorption through the skin of an arsenical; acute cases are characterized by trembling, weakness, prostration, and diarrhea.

Arsenicals--Pesticides containing arsenic.

Artemisia--See Sagebrush.

Arthropod--A phylum or division of the animal kingdom; includes insects, spiders, and Crustacea; characterized by a coating which serves as an external skeleton and by legs with distinct movable segments or joints.

Artichoke--Cynara scolymus; a perennial herb, family Compositae; the edible portions are the bracts of the unripe flower head; native to southern Europe; also called bur artichoke, globe artichoke. See Jerusalem Artichoke.

Articular--Pertaining to the joints of plants and animals.

Articulation--(1) The point of attachment of a leaf stem to the main stalk. (2) Any thickened portion of the plant stem which resembles such a point.

Artificial Manure--See Compost.

Artificial Pasture--Grazing lands under relatively intensive management, usually supporting introduced forage species and receiving periodic culture treatment, such as tillage, fertilization, mowing, and irrigation. See Pasture.

Artificial Revegetation--The establishment of vegetation by mechanical methods.

Artificial Soil--A mixture of materials designed for container growing of vegetable, flower, and woody plants. Artificial soils are lightweight, take water easily, drain rapidly, and do not shrink away from the sides of the container; less likely than garden soils to harbor diseases.

Artificial Substrate--A device placed in the water for a period extending to a few weeks that provides living spaces for a multiplicity of drifting and natural-born organisms that would not otherwise be at the particular spot because of limiting physical habitat. Examples include tiles, bricks, wooden shingles, concrete blocks, and brush piles.


Arviculture--The study of field crops.

Arzun--(1) The Italian millet Setaria italica, family Gramineae; cultivated as forage and cereal. (2) The American millet is Panicum miliaceum, family Gramineae.

Ascending--Growing obliquely or indirectly upward from point of attachment.

Ascomycetes--A group of fungi producing a sacklike ascus in which ascospores are borne. This group contains some of the most destructive fungi, but few cause wood decay; e.g., chestnut blight, nectria canker, larch canker, needle cast, and blights of conifers.

Ascorbic Acid (Vitamin C)--A chemical compound, [C.sub.6][H.sub.8][O.sub.6], which occurs in fruits and vegetables and prevents scurvy in mammals.

Aseptic--Being free from infectious microorganisms.

Aseptic Canning--A process that involves rapid heating of food to destroy food spoilage organisms, then transferring the cooked food into sterile cans by procedures that prevent the reentry of microorganisms into the cooked food during the filling and sealing operations.

Asexual Reproduction--Reproduction without fertilization, which includes various forms of vegetative reproduction, layering, stump sprouts, root sprouts; also includes grafting and reproduction by cuttings.

Ash--(1) Any tree of the genus Fraxinus, family Oleaceae; grown mainly for timber, sometimes for ornament. (2) Residue after combustion. (3) Specifically, minerals left after combustion has freed food from carbon. (4) In coal, the inorganic residue after burning.

Asparagus--Asparagus officinalis, family Liliaceae; a perennial herb whose tender new shoots are edible; native to Europe; also called garden asparagus.

Aspect--(1) Physical appearance of a plant type. (2) Seasonal appearance. (3) Direction in which a slope faces; also called exposure. Aspen, Quaking--Populus tremuloides; the most widely distributed tree species in North America; moisture-loving and growing to 75 feet (25 meters) high; valuable browse species; easily started from cuttings.


Asperous--Rough or harsh to the touch.

Asphyxiation--(1) Suffocation or death from the lack of oxygen. (2) A systemic condition of plants, etc., brought on by oxygen deficiency; characterized by seeds not germinating, blighting of plants, and breakdown of fruits, tubers, etc.

Assassin Bug--Any of the insects of the family Reduviidae which prey on other insects. Some species also attack mammals.

Association--(1) In botany, a grouping of plants having common growth requirements; the association is identified according to the dominant species, such as coniferous association, etc. (2) A grouping of soils to form a land type. (3) Persons united for a common end. Association of American Plant Food Control Officials

(AAPFCO)--The membership of the association consists of the officers charged by law with the active execution of the laws regulating the sale of commercial fertilizer and fertilizer materials; research workers employed by state, dominion, or federal agencies, who are engaged in the investigation of fertilizers. AAPFCO publishes an annual bulletin giving the official regulations and interpretations.

Assurgent--The curving upward of a plant stem.

Astringent--A drug, such as tannic acid, alum, and zinc oxide or zinc sulphate, that causes contraction of tissues.

Asymmetrical--Without proper proportion of parts; unsymmetrical.

Atavism--Reversion; reappearance of a characteristic or disease after a lapse of one or more generations.

Athel Tamarix--Tamarix aphylla; an Asiatic tree, family Tamaricaceae, whose blossoms provide nectar for bees; grown in beach and dessert gardens in the southwestern United States. Also called evergreen tamarix.

Atheroma--A fatty degeneration of the inner walls of arteries.

Atherosclerosis--A disease involving the fatty degeneration of the inner walls of the arteries; a form of arteriosclerosis.

Atlas--The first cervical vertebra; it connects to the occipital bone of the cranium.

Atmometer--An instrument for measuring evaporation; the Livingston porous cup style.

Atmospheric Drought--Transpiration from a plant in excess of the plant's ability to obtain moisture from the soil; e.g., a plant may wilt under hot dry winds, although there is moisture in the soil sufficient under normal conditions to supply the needs of the plant.

Atom--The smallest unit of an element to retain the chemical characteristics of that element. It consists of negatively charged particles called electrons orbiting around the nucleus and, within the small mass of the nucleus, other particles--protons (which are positively charged and balance the extranuclear electrons) and neutrons (which have no charge). It is the number and arrangement of the atom's electrons and protons that make one element differ from another; the number of neutrons distinguishes one isotope from another of the same element.

Atomic Energy--Energy released in nuclear reactions. Of particular interest is the energy released when a neutron splits an atom's nucleus into smaller pieces (fission) or when two nuclei are joined together at hundreds of millions of degrees of heat (fusion). Atomic energy is really a popular misnomer; it is more correctly called nuclear energy.

Atomic Weight--The average relative weight of an atom of an element as compared with another element (usually oxygen) that is taken as a standard. Isotopes of the same element have different atomic weights because the number of neutrons differs from isotope to isotope; a quoted atomic weight is the average weight unless a specific isotope is named.

Atomization--The process of breaking a liquid into a fine spray.

Atomize--To reduce a liquid into very fine particles in a sprayer.

Atropine--A poisonous, crystalline alkaloid used in medicine; a specific antidote for poisoning by organic phosphate insecticides.

Atrovirens--Dark green.

Attapulgite Clay--A fuller's earth. The main constituent is a hydrous magnesium aluminum silicate having high adsorptive and swelling properties; used in fertilizer production, including conditioning of fertilizer products, and as a suspending agent in suspension fertilizers.

Attenuate--To dilute, thin down, enfeeble or reduce. Specifically, to reduce the virulence of an organism; to destroy the power of disease-producing bacteria by means of chemical action, or of viruses by passing them through unnatural hosts, etc. This principle is used to develop certain bacterins and vaccines.

Attractant--Specifically, any substance that attracts or draws insects or other animals. A substance identified as gyptol, obtained from the terminal segments of the female gypsy moths, is an attractant for male gypsy moths.

Atypical--Disagreeing with the form, state, or situation usually found under similar circumstances; not typical.

Aubergine--The edible, blackish-purple fruit of the eggplant.

Aujeszky's Disease--A lethal viral disease of cattle; less so of dogs, cats, and pigs; characterized by intense itching, paralysis and convulsions. Death occurs within 36 to 48 hours after symptoms become evident; also called pseudorabies, infectious bulbar paralysis, mad itch.

Auriculate--A leaf base that is deeply lobed. The lobes are rounded.

Australian Saltbush--Atriplex semibaccata; an alkaline- and saline-tolerant herb, family Chenopodiaceae; it is of some feed value to livestock. Native to Australia but has spread by escape along the coast of California; also called creeping saltbush.

Austrian Pine--Pinus nigra; an evergreen tree, family Pinaceae; one of the most widely cultivated of all ornamental pines; used in shelterbelt planting.

Austrian Winter Pea--An annual legume often sown with small grains when an interim crop is being used between permanent pasture seedings. Good drainage is needed. Austrian peas are somewhat more winter-hardy than other field pea varieties but may still suffer substantial winter kill in prolonged freezing weather.

Autocidal Control--A technique that is used primarily for insect control. It involves the rearing and release of insects that are sterile or altered genetically in order to suppress members of their own species that are causing pest problems. A type of autocidal control is the sterile male method whereby large numbers of male insects are artificially sterilized by irradiation or chemical sterilants. This method is most popularly exemplified in the eradication of the screwworm fly in the Southwest and parts of Mexico.

Autoclave--Vessel in which high temperatures can be reached by using high pressure; e.g., the domestic pressure cooker.

Autoecious Rust--A rust having all stages of its life cycle on a single species of a plant.


Autolysis--Self-digestion. The natural softening process of fruits or vegetables after picking, or meat after slaughtering.

Autoparasitism--A parasite growing on a parasite; also called secondary parasitism or superparasitism.

Autopollination--The automatic transfer of pollen from anthers to stigma within a flower as it opens.

Autosomes--All the chromosomes except the sex chromosomes.

Autotrophic Nutrition--Also known as lithotrophic nutrition; the ability of an organism to manufacture its own food from inorganic sources, using C[O.sub.2] as the sole carbon source. Autotrophs are of two general types: photoautotrophs (photolithotrophs) whose energy is derived from sunlight, and chemoautotrophs or chemolithotrophs, which obtain energy for growth and reproduction from oxidation of inorganic materials. Important among the photoautotrophs are all higher plants, algae, and a few genera of bacteria. Principal chemoautotrophs are all higher plants, algae, and a few genera of bacteria. Principal chemoautrotrophs of vital concern in food and agriculture (with their substrate) are: Nitrobacter (nitrite), Nitrosomonas (ammonium), and Theobacillus (sulfur).

Autumn Olive--Elaeagnus umbellata; a deciduous, open growing shrub reaching 10 to 15 feet (3 to 5 meters) in height. It grows on low-fertility soil because it fixes atmospheric nitrogen, and is also adapted to acidic soils. It bears a prolific crop of red berries, which are used by wildlife; not adapted to poorly drained, shallow, or fine-textured soils; "Cardinal" is an improved variety.

Auxins--Plant hormones; substances that promote the growth of plants.

Available--Available plant nutrients is intended to mean that which is in a form capable of being assimilated by growing plants or of being converted into such a form in the soil during the current growing season; all essential elements in the soil solution and all of those adsorbed on clay and humus particles are available to plants.

Available Soil Water--The amount of water retained in a soil between field capacity and the permanent wilting percentage.

Avicide--A substance used to kill birds.

Avidin--A protein material that can combine with the B vitamin biotin, causing the vitamin to be unavailable to the body. Cooking renders avidin inactive.

Avirulent--Without the ability to produce disease.

Avocado--Persea americana; a green to greenish black tropical fruit that has a yellow flesh; used in salads.

Avoidance--A response whereby organisms prolong their dormancy, thereby achieving lesser vulnerability to environmental stresses.

Awn--A hairlike appendage found on glumes and lemmas in barley, oats, and many other grasslike plants; also called beard.

Axil--Upper angle between a leaf or other plant part and the stem to which it is attached.

Axillary--Developing in the axil of a leaf, as a bud or flower.

Axis--(1) The main stem of a plant. (2) The second cervical vertebra.

Azolla--A tropical fern that fixes atmospheric nitrogen; of the genus Azolla.

Azotobacter--A genus of free-living nonsymbiotic, aerobic, motile, and oval bacteria occurring in soils. They are capable of fixing atmospheric [N.sub.2] and belong to the family Azotobacteraceae.

Aztec Tobacco--Nicotiana rustica, family Solanaceae; a wild tobacco of high nicotine content; sometimes cultivated in flower gardens and used in the manufacture of insecticides; tobacco first grown by the Indians in the eastern United States; also called emetic weed, Indian tobacco, wild tobacco, eyebright.


B Horizon--See Horizon, Soil.

B. T.--See Bacillus thuringiensis.

Baccate--Berrylike, pulpy or fleshy.

Baccharis--A species of plant that invades the semi-arid regions of the United States and competes with forage grasses.

Bacciferous--Producing berries.

Bacillus--A genus of single-celled, rod-shaped organisms, family Bacillaceae. Although most species are harmless, they do cause chemical changes in animal and vegetable matter.

Bacillus Larvae--A bacterial organism causing a disease called American Foulbrood in bees. See American Foulbrood.

Bacillus thuringiensis--A bacterial insecticide effective against the army worm, cabbage worm, and the gypsy moth; not injurious to people, animals, or plants.

Back Flow Valve--A valve in an irrigation system that prevents water form flowing backward in the system. This prevents chemicals that are added to the water from contaminating the water supply. See Chemigation.

Back Furrow--A ridge of soil made when a turning plow throws soil on top of a previously plowed ridge made while moving in the opposite direction. This is the usual method of starting to plow a field with a one-way turning plow.

Backburn--A fire set deliberately to burn against the wind as a means of controlling advancing grass or forest fire. See Backfire.

Backfire--Controlled fire set ahead of a forest fire to create a firebreak by reducing fuel in the path of the main fire. See Backburn.

Bacteria--Single-celled microorganisms; some cause human, animal, or plant diseases; others are beneficial.

Bacteria, Facultative--Bacteria capable of adapting to an aerobic or anaerobic environment.

Bacterial Gummosis--Exudation of gumlike liquid resulting from bacterial infection, particularly bacterial canker of stone fruits.

Bacterial Neutralization of Pesticides--The use of genetically altered bacteria to neutralize and render safe such chemicals as parathion, diazinon, and malathion. The bacteria break the pesticides into simpler, less toxic forms.

Bacterial Wilt of Alfalfa--One of the most destructive diseases of alfalfa, caused by Corynebacterium insidiosum; characterized by yellowing and dwarfing of the stems and leaves; sometimes by a rot of the crown, a yellow ring just under the epidermis, and a yellowing of the roots. The disease is most serious in wet areas.

Bacterial Wilt of Corn--A disease which is particularly troublesome on sweet corn. It is caused by Bacterium stewartii, which infects the whole plant; characterized by long, wavy streaks on the leaves, which emit a yellow exudate; also called Stewart's disease.

Bacterial Wilts--Plant diseases in which the causative bacteria produce slime that plugs the water-conducting tissue of the invaded plant.

Bactericide--Anything which destroys bacteria; a germicide.

Bacteriophage--A viruslike, bacteria destroying agent that can propagate itself only in the presence of young, active, susceptible bacteria.

Bacteriostat--A compound which inhibits growth and reproduction of or kills certain bacteria.

Baffle--The planting and growing of plants to make a wall or partition.

Bag Worm--Thyridopteryx ephemeraeformis, family Psychidae; the larvae of this moth spin a silken bag or sack about themselves for protection. They infest nearly all species of trees. Found in the eastern United States.

Bagasse--Residue from sugarcane stalks after the juice has been extracted by crushing. Used in the manufacturing of wall boards, insulating materials, and in mixtures with molasses for livestock feeds; also denotes sugar beet, sorghum, and sisal residue.

Bagging--Cotton, jute, or other material used in covering cotton bales; any cloth used for making bags.

Bahia Grass--Paspalum notatum, family Gramineae; a rapidly growing palatable range grass whose seed is low in germination. It is grown as a forage in the south and is also used to control erosion.

Bait Insecticide--An appetizing mixture of poison and food which, when eaten by an insect, results in its death.

Bait Shyness--The tendency for rodents, birds, or other pests to avoid a poisoned bait.

Balanced Fertilizer--A soil additive containing the proper proportions of each essential mineral element to develop a plant or crop.

Bald--(1) A small treeless area in a forested hilly or mountainous region, especially a crest, as bald knob. (2) Beardless, as bald wheat.

Baldcypress--Taxodium distichum; a deciduous swamp tree, family Pinaceae; very durable in water or moist conditions; grown as an ornamental and used in outdoor construction.

Baldwin--A good quality, large, red, winter apple grown in New York and New England.

Bale--A large, tightly pressed and bound bundle of produce, as a bale of cotton, straw, hay, wool, etc.

Balk--(1) A ridge of untilled land missed in plowing. (2) The act of an animal stopping and refusing to move.

Ball--(1) The compact earth adhering to the roots of a plant in transplanting. (2) A large pill. (3) A mass of bees formed tightly around a queen bee.

Ball Planting--A method of transplanting in which plants are taken from the ground with enough compact soil on the roots to provide nourishment and help their growth in a new location.

Balled and Burlapped--The covering with sacking of the compact mass of earth left on the roots of a plant in transplanting.

Balling--(1) The clustering of bees tightly around a queen bee, usually in an attempt to kill her. (2) A measurement of sugar percentage in simple syrup at fixed temperature (20[degrees] C); also called brix.

Balsam Fir--Abies balsamea; an evergreen tree used as Christmas trees, and in the making of cooperage, boxes, etc. Native to the northern United States.

Bamboo--A woody stemmed perennial of the genus Bambusa, family Gramineae; apparently the most primitive grass tribe known. More than 20 genera and 200 species are recognized, some growing 60 feet or more in height. The hollow stems may die down to the ground or remain living for many years. They are often thick enough to be used in building construction, etc.; in the tropics and subtropics, the succulent young shoots of some species are used for food.

Banana--A herbaceous treelike perennial, Musa paradisiaca var. sapientum, bearing clusters of pulpy fruit ranging from 4 to 9 inches in length and usually 1 inch in diameter; native to southeastern Asia, but there are also many varieties in other tropical zones cultivated for their high food value and agreeable flavor.

Band Application--(1) A herbicide application made in a narrow band, usually over or alongside a row. (2) A method of applying fertilizer in bands near plant rows, where the fertilizer will be more efficiently used rather than applying it in an application to the entire soil surface.

Band Seeding--(1) Planting seed in close proximity to a row of fertilizer that has been drilled in at a shallow depth and covered over. (2) The surface sowing of legumes and grasses on drilled ground by using a special attachment to the grain drill.

Banded Cucumber Beetle--Diabrotica balteata, family Chrysomelidae; a pest of beans, legumes, and cucurbits.

Banding--(1) The marking of animals or birds by fastening bands to their legs or ears or by painting their fathers for identification. (2) The placing of a collar or band around the stem of a plant or the trunk of a tree to poison, repel, or trap insects. (3) A method of castration in which a tight rubber band is placed around the scrotum; circulation is stopped and the testicles atrophy. (4) The placement of fertilizer or herbicide in a band along a row.

Banking--The mounding of earth or soil to preserve moisture or coolness or to cover the crowns of cultivated plants.

Banner Crop--A crop which is high in yield, quality, or both.

Baobab Tree--Adansonia digitata, family Bombacacae; a huge tropical tree which bears a large edible fruit called monkey's bread; fibers are used in making cloth, rope, and paper; native to Africa and long cultivated in India; also called cream-of-tartar tree.

Barb--(1) A breed of horses related to the Arab and native to Barbary; probably introduced into Spain by the Moors and probably smaller and coarser than the Arab; its strain is evident in all known present breeds. (2) A hairlike side branch of a feather. (3) Mucous membrane projections for the openings of submaxillary glands under the tongue of horses and cattle. (4) A pointed projection on a fence wire. (5) In botany, a hooked hair or bristle. (6) The teeth or spines on the awns of grasses, especially barley.

Barberry--Any shrub of the genus Berberis, family Berberidaceae; often grown for its ornamental foliage and for its berries, which are of great value to birds.

Bare Fallow--Land unsown for a season but kept in cultivation or sprayed with herbicides to keep down weeds; also called bare summer fallow, naked fallow.

Bare Root--A method of transplanting in which plants are taken from the ground with little soil left on the roots.

Bare Root Grafting--A method of joining a scion to a plant by grating a plant onto bare root stock before growth has started.

Barium Carbonate--A solid material used as a rat poison and as a water purifier; a mineral known as witherite in its natural state.

Barium Fluosilicate--BaSiF6; a compound used as an insecticide and a rodent poison.

Bark--(1) The exterior of a woody stem containing phloem tubes and usually some bast fibers. Cork cells may develop in the outer layer. (2) To bark is to remove the external layer form a log or tree. (3) To cure or dye with bark extract; to tan. (4) To enclose or surround with bark.

Bark Grafting--A method of joining plants in which the scion is inserted between the bark and the xylem of the stock.

Barley--One of the cereals; Hordeum spp., family Graminae; cultivated since prehistoric times for human and animal consumption, for malting, or as nurse or smother crop; Hordeum vulgare is the commonly cultivated barley. See Six-Row Barley.

Barley Corn--A grain of barley.

Barley Malt--Fermented barley used in the manufacturing of beverages, foods, and medicines.

Barley Yellow Dwarf--A viral disease of cereals, marked by leaves rapidly turning light green and yellow, beginning at the tips; transmitted by certain species of aphids.

Barn Curing--The artificial drying of hay with natural or heated air, usually to reduce exposure time in the field and possible weather damage.

Barn Swallow--A migratory bird; Hirundo rustica, family Hirundidae; native to North America; beneficial to farms and ranches because it builds its nest in barns and eats many flying insects.

Barnyard Grass--Echinochloa crus-galli, family Gramineae; an annual grass which is often a weed in cultivated grassland; can be cut for hay if special care can be given to the curing, as it is a host for ergot; also called ankee, barn grass; cockspur grass, water grass, barnyard millet. See Ergot.

Barrel--(1) The trunk of a domesticated animal. (2) A measure of corn on the ear: one barrel equals one bushel of shelled corn. (3) In the earlier period of flour milling in the United States, the wooden barrel, net weight 196 pounds of flour, was a common container for shipment. (4) A cylindrical container. (5) A liquid measure of 42 United States gallons.

Barrens--An area relatively free of vegetation in comparison with adjacent areas, because of adverse soil or climatic conditions, wind, or other adverse environmental factors; e.g., sand barrens or rock barrens.

Bartlett--A widely grown variety of pear; genus Pyrus, family Rosaceae; introduced to the United States by Enoch Bartlett of Dorchester, Massachusetts, from England where it is known as bon chretien.

Basal--Leaves growing or arising at the base of a plant or stem.

Basal Application--The application of a herbicide to the lower portion of the stems of woody plants.

Basal Area--(1) The area in square feet of the cross-section at breast height of a single tree or of all trees in a stand, usually expressed as square feet per acre. (2) The area or proportion of soil surface occupied by the stems and root crowns of range plants; sometimes called basal cover.

Basal Meristem--Latent or actively growing plant cells at the base of plants.

Basalt--(1) An extrusive rock composed primarily of calcic plagioclase and pyroxene, with or without olivine. (2) Any fine-grained, dark-colored igneous rock. Soils developed from basalt are usually dark-colored and productive.

Base--(1) In chemistry, a substance which reacts with an acid to form a salt; a substance which gives off hydroxyl ions when dissolved in water, as contrasted with an acid, which gives off hydrogen ions. (2) In botany, the part of a leaf or branch attached to a stem or trunk. (3) The portion of a machine on which the operating parts are mounted.

Base Exchange--(1) In soil science, denoting a physical-chemical process in which cations adsorbing by soils can be replaced by other cations in chemically equivalent quantities. (2) A term used in medical science usually in relation to the acid-base exchanges of the blood necessary to keep the blood and tissues at a physiologic constant.

Base Exchange Capacity--(1) In soil science, the cations that a soil can absorb; expressed in milli-equivalent per 100 grams of soil. (2) In medical science, the maximum capacity of the blood to exchange base (alkali) for acid in maintaining a physiologic balance.

Base Flow--That portion of the water flowing in a stream that is due to ground water seeping into the ground.

Base Goods--Various grades of fertilizer mixtures that can be mixed with other materials to produce the grade of fertilizer requested by the customer.

Basic--On the basic side of neutral pH (above 7.0).

Basic Slag--A finely ground by-product of steel mills containing 12 to 25 percent [P.sub.2][O.sub.5], 40 to 50 percent CaO, and 5 to 15 percent Si[O.sub.2]. It has some value as fertilizer because of the total phosphorus content.

Basidiomycetes--A group of fungi containing the wood and root rots and the rusts that form a clublike structure on which spores are borne after nuclear fusion and meiosis. Some fungi in the group are responsible for the formation of beneficial root mycorrhizae. See Mycorrhizae.

Basin--(1) A hollow for holding water, as around a tree, made by forming a ridge or levee of earth on all sides. (2) The depression in a pome fruit such as apple and pear, in which calyx lobes are located; also called eye. (3) An extensive depressed area into which the adjacent land drains with no surface outlet; use of the term is almost wholly confined to the arid West. (4) The drainage or catchment area of a stream or lake.

Basipetal--Toward the base of a plant organ, generally downward in shoots and upward in roots.

Basswood--Tilia americana; a deciduous tree commonly grown as a shade or street tree or as a bee plant. The wood is used for making veneer core for plywood, slack-cooperage, excelsior, boxes, apiary supplies, piano keys, etc. Also known as American linden, lime, whitewood, linwood, American basswood.

Bastard--In botany, a hybrid; an offspring between species that do not ordinarily mate.

Bastard Clover--See Alsike Clover.

Bat--Any of the winged, flying mammals of the order Chiroptera. The animals are nocturnal and are very beneficial to agriculture because of the large number of insects they devour. Bat Guano (Bat Manure)--Bat excreta used for fertilizer.

Batting--Cotton, flax, or wool loosely matted and not spun.

Bauxite--The principal ore of aluminum.

Bay--(1) A horse with a body color ranging from tan to red to reddish brown. The mane and tail are black, and the lower legs are usually black. (2) The laurel or its berries. (3) A shallow swamp supporting dense tree and shrub vegetation, and containing peat or muck soil. See Pocosin. (4) A coastal inlet. (5) A compartment in a barn for storage or for a special use, as a horse barn.

Bay Leaves--The leaves of the bay-rum tree (Pimenta acris), which are used for flavoring and as a source for bay rum.

Beachgrass, European--Ammophila arenaria; a tall, stout, perennial grass adapted to coastal sand. It has long rhizomes. The panicle is thicker in the middle and tapers somewhat to the tip. The leaves have a long membranous ligule at the collar. Propagation is by transplanting of culms. Seed propagation is not feasible because very fewer viable seeds are produced and because seed on coastal dunes is often removed by wind before establishment.

Beachpea, Purple--Lathyrus japonicus; slow-developing, long-lived native legume that spreads by rhizomes. Used to seed into beach-grass after initial coastal dune stabilization. Commercial seed is unavailable and must be collected from native stands. The seeds are often severely affected by pea moth larvae.

Beak--(1) The upper and lower mandibles or nibs of a fowl. (2) The awn on the outer chaff of wheat. (3) Any part of a plant resembling a bird's beak.

Bean--(1) A vegetable grown for its highly nutritive value to people and animals, and eaten when green, dried, or ground into meal. The kidney-shaped (or in the broad bean the flattened) seeds of leguminous annual or perennial herbs, which are more often climbing or trailing. (2) Any plant bearing such seeds. When a bean sprouts, the bean seeds emerge through the soil; whereas, when a pea sprouts, the pea seed stays underground. (3) Protuberance on the upper part of the beak of certain water fowl.

Bean Group--The group of beans including navy, garden, and kidney beans that are capable of being inoculated by the same rhizobial bacteria.

Bean Pole--A stick usually 6 to 10 feet tall used to support climbing beans.

Bean Rust--A fungal disease caused by Uromyces phaseoli var. typica, family Pucciniaceae; characterized by reddish-brown pustules on the leaves; most prevalent in humid areas.

Bean Weevil--Acanthoseelides obtectus; a stout beetle that feeds on beans until the pods are formed and then lays its eggs in the seed; the larvae burrow into and devour the dried beans. It attacks the growing kidney bean, lima bean, and cowpea, and beans, peas, and lentils in storage.

Bearberry--Arctostaphylos uva-ursi; an evergreen, trailing shrub, family Ericaceae; grown to control erosion on steep exposed slopes because its branches quickly take root; also grown for its red berries in winter; found in the United States and Eurasia.

Beard--(1) Hairy appendages on the face of a man or animal, such as the whiskers of a goat. (2) A group of feathers hanging from the throat of certain breeds of chickens. (3) A tuft of bristly hair projecting from the upper part of a turkey's breast. (4) A long awn or bristlelike hair, as in the inflorescence of some grasses. (5) A tuft, line, or zone of pubescence, as on the falls of the bearded irises. (6) The part of a horse's lower jaw which carries the curb of the bridle.

Beardless Bluebunch Wheatgrass--Argopyron inerme; a good perennial forage plant; also grown to control soil erosion; found in the western United States. Sometimes called beardless wheatgrass.

Bearing Tree--See Witness Tree.

Beaufort Wind Scale--A system of estimating wind velocities, originally based (1806) by its inventor, Admiral Sir Francis Beaufort of the British Navy, on the effects of various wind speeds on the amount of canvas that a full-rigged frigate of the early nineteenth century could carry; since modified and widely used in international meteorology.

Bed--(1) A small plot of soil used for growing seedlings, vegetables, flowers or shrubs, and often raised above the level of the surrounding soil. (2) A place for animals to sleep. (3) The hauling platform of a wagon or truck.

Bed Shaper--An implement that makes wide beds on which up to four rows of crops are planted. Furrows between beds are used for irrigation and to guide cultivators.

Bedder--See Lister.

Bedding--(1) Plowing or otherwise elevating surface soil into a series of crowned parallel beds or lands with shallow surface drains separating them. (2) A method of surface drainage consisting of narrow plowed lands in which dead furrows run parallel to the prevailing slope; the land between adjacent dead furrows is called a bed. (3) Straw, leaves, sawdust, sand, peat moss, etc., to make a bed for an animal. It is used where an animal may lie to absorb its urine. (4) Flowers that are appropriate for growing in flower beds for a massed decoration effect.

Bedding Planes--Fine stratifications, less than 0.2 inches (5 mm) thick, in unconsolidated alluvial, eolian, lacustrine, or marine sediments.

Bedding Plants--Flower and vegetable plants planted in beds.

Bedrock--Unweathered hard rock that lies directly beneath the soil layers or beneath superficial geological deposits, such as glacial drift.

Bee--(1) Any insect of the families Prospidae, Colletidae, Megachillidae, Xylocopidae, Ceratinidae, Nomadidae, Andrenidae, Anthophoridae, Bomidae, or Apidae. They are generally beneficial, being insect parasites, predators, pollenizers, or producers of honey and beeswax. (2) See Honeybee, Drone, Worker, Queen Bee, Bumblebee. (3) A social gathering of neighbors, especially in rural areas, to husk corn, to raise a barn, or to quilt in the home, etc.

Bee Gum--Usually a hollow log used as a hive. The term is also used to refer to any beehive.

Bee Martin--Any birds of the genus Tyrannus which catch and kill bees in large numbers; also called kingbird.

Bee Pasture--Vegetation, attractive to bees, which is within flying distance of a hive; also called bee pasturage.

Bee Tree--(1) A hollow tree which is occupied by a colony of bees. (2) A tree whose flowers are a source of nectar or pollen.

Beech--Any tree of the genus Fagus, family Fagaceae; lumber from the tree is valued for its density and hardness.

Beehive--A domicile prepared for a colony of honeybees.

Beet--(1) Any plant of the genus Beta, family Chenopodiaceae. (2) Beta vulagaris; the garden beet, grown for its root and young edible leaves.

Beet Webworm--Loxostege sticticalis, family Pyraustidae; a caterpillar which feeds on cabbage, beets, sugar beets, beans, peas, potatoes, spinach, cucurbits, and other vegetables, as well as field crops. Found in the western United States.

Beetle--Any insect of the order Coleoptera. The upper pair of its four wings form hard cases to protect the true wings when folded.

Bell Glass--A glass covering which is sometimes used in greenhouses for covering special plants and cuttings.

Belladonna--Atropa belladonna; a perennial herb, family Solanaceae; its berries are poisonous, and its sap yields alkaloid atropine from which the drug is made. Also called death herb, deadly nightshade, doftberry. Native to Eurasia; grown in the United States, where it is sometimes found escaped, particularly in the eastern United States.

Belt--(1) A geographical term denoting an area of similar soil and climate particularly suited to specific crops or animals, such as the wheat belt. (2) A band of hair or skin of another color, often white, around an animal's body, as in Dutch belted cattle. (3) In machinery, a broad flexible band passed around two wheels to transmit motion from one to the other.

Belted--(1) Any fruit which has a retarded growth area extending completely around its middle; often due to frost injury when the fruit is very young; band is usually shrunken; also called banded fruit. (2) Any animal having a band of different color around its body.

Bench Terrace--A steplike embankment of earth with a flat top and a steep or vertical downhill face constructed along land contours to control runoff and erosion.

Benchlands--(1) Terraces or shelflike land features representing former water levels or shorelines of lakes, rivers, or seas; usually composed of alluvium or unconsolidated coarse sediments. (2) A foothill below a mountain.

Benders--Cotton staple of intermediate length.

Beneficial Insect--Insects that are of economic or other value; often refers to insects that prey on other insects; also refers to insects that pollinate or produce honey, such as the honeybee.

Benign--In reference to disease or disease processes, mild or nonmalignant, such as a benign tumor or growth, in contrast to malignant or cancerous tumor or growth.

Bentgrass, Colonial--Agrostis tenuis; long-lived, creeping turf-grass, adapted to a wide variety of soil conditions; has both stolons and rhizomes; not suited for improved pastures because of poor production, but it does provide good erosion control on road cuts and fills.

Bentgrass, Creeping--Agrostis palustris; very similar to colonial bentgrass, creeping bentgrass spreads aggressively by stolons, is especially moisture-tolerant, and provides excellent stabilization at the waterline of drainage channels and irrigation ditches, where it is compatible with big trefoil and white clover.

Bentgrass, Redtop--Agrostis alba; widely adapted to wet, acid-to-neutral, low-fertility soils; can withstand short summer droughts; provides a low-growing dense cover; develops more rapidly than other bentgrasses, but is shorter lived.

Bentonite--A porous rock of clay minerals derived from weathered volcanic ash or tuff. It is used: (a) as a dust diluent and carrier for insecticides; (b) in clarifying or refining wines, fruit juices, etc.; (c) as a wetting agent; and (d) as a seepage retardant in the bottom of a water storage reservoir.

Benzene--[C.sub.6][H.sub.6]; a volatile and inflammable hydrocarbon which is a derivative of coal tar and is used: (a) in degreasing bones, etc., in fertilizer manufacture, and (b) for destroying larvae. It is particularly effective against the screwworm fly.

Bermuda Onion--Any species of mild onion introduced into the United States from Bermuda. Now commonly grown in the southwestern United States.

Bermudagrass--Cynodon dactylon, family Gramineae; a perennial grass providing excellent forage, but becoming a weed in cultivated fields; also excellent for making lawns; commonly found in the southern United States. Also called scutch grass, bahama grass, devil grass, doob, couchgrass. Hybrids are now available.

Berry--(1) Any small pulpy fruit, as the raspberry, strawberry, etc.; usually edible. (2) Any fruit which has either a fleshy or pulpy pericarp, such as the banana, cranberry, tomato, etc. (3) The dry seed of certain plants, as the coffee berry, which is really a seed contained in the fleshy true berry.

Berry Picker--A machine that straddles berry rows and harvests the berries through the use of long thin flails that shake the vines, causing the berries to fall onto a conveyer.

Berseem Clover--See Egyptian Clover.

Bessey Cherry--Prunus besseyi, family Rosaceae; a shrub bearing a small, sweet, juicy, edible, fruit, which is purplish-red. Also grown as an ornamental. Found in the central United States.

BGR--"Big Gam Repellent," a putrefied-egg product originally developed by Weyerhaeuser Company scientists; now sold under various trade names as a repellent to animal browse.

Bicolor--Having two colors.

Biennial--A plant that lives for two years and then dies.

Big Bluegrass--Poa ampla, family Gramineae; this grass is used in reseeding rangeland. Found in the Yukon Territory of Alaska and southward to New Mexico and California. See Bluegrass.

Big Bluestem--Andropogon furcatus, family Gramineae; a tall grass, producing good forage. It grows in the central and southwestern United States in dry places, on prairies, and in open woods.

Big Trefoil--A good legume for soils that are wet the year around or subject to prolonged flooding or ponding in the winter. It can be used for pasture or hay. It is more grazing-tolerant than birdsfoot trefoil because of its rhizomes; not winter-hardy in cold areas; requires a special inoculum (not the same as birdsfoot inoculum).

Bigleaf Maple--Acer macrophyllum; a deciduous tree, family Aceraceae; grown as a shade and park tree. Its large leaves turn bright orange in the fall. Native to North America; also known as Oregon maple.

Bilateral--Having two sides.

Bilateral Symmetry--Similarity of form, one side with the other.

Biltmore Stick--A rule graduated so that the height and diameter of a standing tree may be calculated; used to estimate board feet in a tree.

Binder Tobacco Leaf--Tobacco wrapped around the filler leaves and segments of a cigar to hold the cigar together.

Bindweed--Twining or creeping species of Convolvulus, family Convolvulaceae; also called glorybind, wild morning glory.

Binomial--By international agreement, all plants and animals have two Latin names: genus and species.

Bioaccumulation--The process by which plants and animals accumulate substances, especially pollutants, that may not be injurious to that organism but may injure other organisms that eat them. For example, nitrates may accumulate in corn and oats and be injurious to animals feeding on them but not to the plants themselves. In a like manner, fish may accumulate DDT or PCB in their fat, which may be toxic to an animal eating the fish but not to the fish themselves.

Bioassay--The quantitative or qualitative determination of herbicides by the use of sensitive indicator plants or other organisms.

Biodegradable--Substances capable of being degraded into their constituent elements. This term is used especially in reference to toxins, such as pesticides, being degraded to nontoxins.

Biogenesis--(1) Formation by the action of organisms. (2) The doctrine that all life has been derived from previously living organisms.

Biological--Products derived from a living process or living matter, such as sera, vaccines, bacterins, and antitoxins, etc. Also called biologics.

Biological Control--A method of pest control by the use of predatory insects, fungi, or viruses; as contrasted to control by chemical pesticides. See Biophage.

Biological Erosion--Erosion by water or wind as a result of soil being exposed by the burrowing of rodents, destruction of vegetation by insects, etc.

Biological Growth Potential--The average net growth attainable in a fully stocked natural forest stand.

Biological Lag--The time period necessary for a changed production decision to influence market supplies, owing to the biological nature of agricultural products.

Biological Magnification--The concentration of certain substances up a food chain. A very important mechanism in concentrating pesticides and heavy metals in organisms such as fish.

Biological Mineralization--The conversion of an element occurring in organic compounds to the inorganic form through biological decomposition.

Biologist--A person who studies living organisms as a career.

Biology--The field of study dealing with living organisms. It may be divided into the study of plants (botany) and of animals (zoology).

Biomass--The amount of matter of biological origin in a given area; e.g., the living and decaying matter in the soil as opposed to the inorganic mineral components such as sand, silt, and clay.

Biome--A term derived form the Greek, bios, meaning relation to life; used in ecology to include major life in the area, such as tundra biome, tropical rainforest biome, and grassland biome.

Biometry--The application of statistical methods to the study of biological problems.

Bionomics--The study of relations among organisms and the relationships between them and their environment. See Ecology.

Biophages--Organisms that obtain nourishment from other organisms, e.g., predators, parasites, and pathogens. See Biological Control.

Biopsy--The microscopic or chemical analysis of tissue removed from a living body, usually to discover the cause of illness.

Biostress--Difficulties that plants and animals have in obtaining the necessities of life: food, water, and living space.

Biotechnology--Technology concerning the application of biological and engineering techniques to microorganisms, plants, and animals, sometimes used in the narrower sense of genetic engineering.

Biotic--Pertaining to life; biological.

Biotic Influence--Biological influences on plant and animal life as contrasted to climatic influences.

Biotic Potential--(1) The maximum reproduction power or ability. The inherent ability of an organism to reproduce and survive in greater numbers. (2) The ability of an organism to reproduce in an optimum, unrestricted, and noncompetitive environment.

Biotype--Groups of plants or animals primarily distinguishable on the basis of interaction with relatively genetically stable varieties or clones of host plants; a strain of plant or animal species.

Bipinnate--Twice pinnate, the primary pinnae or leaflets being again divided into secondary leaflets; often written 2-pinnate.

Bipyridyliums--A group of synthetic organic pesticides that includes the herbicide paraquat.

Birch--Any tree of the genus Betula, family Betulaceae; species are valuable as timber having a hard, close-grain wood; also used for ornamentals.

Bird--(1) Any member of the class Avis of the phylum Vertebrata, the body of which is covered with feathers. (2) Domesticated birds: chickens, turkeys, ducks, geese, guineas, etc.

Bird Guano--See Guano.

Bird Peck--A small hole or distortion in the grain of wood resulting from sapsuckers attacking a tree; may be associated with discoloration, such as mineral stain.

Bird's-eye Maple--The lumber of the sugar maple having natural grain markings resembling eyes.

Birdsfoot Trefoil--A long-lived, deep-rooted legume suitable for hay or pasture in areas of wet soils or low soil pH. Very winter-hardy and tolerant of dry summer conditions. Useful on irrigated or dry land. Nonbloating legume suitable for sheep or cattle but not a good horse pasture, because of the presence of tannins. Not tolerant of early spring grazing or continuous grazing. It establishes slowly and with some difficulty, but is vigorous once established. Requires a special inoculum.

Bisexual--An animal or plant that produces both eggs and sperm, or a flower that bears both stamens and pistils.

Bitterbrush--Purshia tridentata; a valuable forage plant, family Rosaceae; found in the high mountain areas of the western United States.

Bittern--A concentrated solution of salts which remains after the common table salt has been refined out. Sometimes used as an herbicide.

Bitternut Hickory--Carya cordiformis; a deciduous tree, family Juglandaceae; grown for shade, and for its wood, which is used in making tool handles, ladders, furniture, sporting goods, implements, woodenware, and for fuel and smoking meat.

Bitterweed Actinea--Actineae odorata; an annual herb, family Compositae; poisonous to sheep, which may eat it during a shortage of forage. Poisoning is characterized by loss of appetite, cessation of chewing of the cud, abdominal pain, bloating, frothing at the mouth, and a green nasal discharge; found on overgrazed ranges in the western United States; also called bitter rubberweed, Colorado rubberweed, bitterweed.

Biuret--A compound, toxic to some crops, formed by thermal decomposition of urea; to be avoided in the manufacture of fertilizer urea. See Urea.

Black Alder--See European Alder.

Black Alkali--An obsolete term meaning a soil high in exchangeable sodium. The modern term is sodic soil.

Black Ash--Fraxinus nigra; a deciduous tree, family Oleaceae, which grows in a swampy, moist soil; used in cabinet making, and basket making; found in eastern North America; also called brown ash, hoop ash, basket ash, swamp ash.

Black Blizzards--Clouds of dust consisting of organic matter and the finer particles of soil from bare fields and grazing land denuded of vegetation; prevalent in the southwestern United States.

Black Carpenter Ant--Camponotus herculeanus pennsylvanicus, family Formicidae; the largest American common ant; attacks tree stumps, tree trunks, telephone poles, windowsills, and old timbers; found in the eastern United States.

Black Cherry--Prunus serotina, a deciduous tree, family Rosaceae; an important timber tree used in making furniture; the leaves are poisonous to livestock; also called wild black cherry, black choke.

Black Cloth--A means of providing artificial short days in a greenhouse so that short-day plants will bloom.

Black Cutworm--Agrotis ypsilon, family Phalaenidae; a surface cutworm which attacks truck crops; found throughout the United States.

Black Fallow--A field left bare (no crop) to accumulate enough soil moisture from precipitation to grow a crop.

Black Frost--A blackening of vegetation which occurs when the temperature drops low enough below the freezing point to destroy vegetation, including staple crops; there is no actual deposit of frost crystals.

Black Gramagrass--Bouteloua eriopoda, family Gramineae; an excellent forage grass; found in the southern desert ranges of the United States.

Black Mangrove--Avicennia marina; an evergreen tree, family Verbenaceae, whose flower is a good source of honey in Florida.

Black Maple--Acer nigrum; a hardy deciduous tree, family Aceraceae; one of the American sugar maples. Grown in highway plantings and in city yards. Also used in hardwood distillation and for railroad ties, veneer (especially good for birdseye), shoe lasts, bowling pins, fuel, furniture, flooring, and boxes. Also called black sugar maple.

Black Medic--Medicaago lupulina; an annual prostrate herb, family Leguminosae; regarded as a weed in lawns, but has value as a pasture plant; also called hop medic, nonesuch, blackseed, hop clover, yellow trefoil.

Black Mustard--Brassica nigra; an annual herb, family Crucifereae; largely grown for its seed used in the manufacture of mustard. Escaped, it is a weed pest. Native to Europe.

Black Nightshade--Solanum nigrum; an annual herb, family Solanaceae; a common weed pest. Poisonous to livestock and to bees. Poisoning of livestock is characterized by salivation, vomiting, diarrhea, and bloating. Also called poison berry, deadly nightshade, petty morel, and stubbleberry.

Black Oak--Quercus velutina; a hardy, columnar, deciduous tree, family Fagaceae; the lumber is used for railroad ties, cooperage, fence posts, mine timbers, pilings, veneers, firewood, flooring, mill products, and furniture. Native to North America. Also called tanbark oak, quercitron, yellowbark oak.

Black Pepper--Piper nigrum; a woody vine, family piperaceae; grown for its fruits, which yield white and black pepper. Native to the East Indies.

Black Rot--(1) A fungal disease of apples, pears, quinces, and other hosts caused by Physalospora malorum, family Pleosporaceae; characterized by cankers on the twigs and limbs, by a leafspot, and by rotting of the fruit as it approaches maturity or when in storage. Also called frog eye, ring rot, blossom end rot, brown rot. The symptoms on twigs and limbs are also known as dieback, twig blight, apple canker, black rot canker, New York apple tree canker. (2) A fungal disease of citrus fruit, particularly oranges, caused by Alternaria citri, family Dematiaceae; the infected fruits turn deep orange. They appear sound but are decayed near the stylar end. The inside is brown to black. (3) A general marketing term describing bad eggs.

Black Rot of Crucifers--A bacterial disease caused by Xanthomonas campestris. Characterized, especially in cabbage, by yellowing of the leaves and blackening of the veins at the leaf margins and developing toward the petiole and the main stem. Once established, the disease rapidly affects the entire plant, causing the leaves to wilt, turn yellow, dry up, and become thin and parchmentlike. Also called bacteriosis, bacterial rot, brown rot.

Black Sage (Brush)--Salvia mellifera; a perennial herb, family Labiateae; important as a bee plant and sometimes as forage. Found on the Pacific Coast of the United States.

Black Shank of Tobacco--A disease caused by the parasitic fungus Phytophthora parasitica var. nicotianae, family Pythiaceae; characterized by blackened and dead roots, by decay at the base of the stalk, brown blotches on the leaves, and by damping-off of the seedlings.

Black Spot--(1) Bull's-eye rot; a disease of apple caused by Neofabraea malicorticis, family Mollisiaceae. (2) A fungal disease of citrus caused by Phoma citricarpa, family Sphaeropsidaceae; characterized by reddish-brown spots on the fruit. Reddish-brown halos form, and the brown centers become depressed. The spots then turn dark, sometimes black. (3) A disease of potatoes. The tissue beneath the skin breaks down and turns black or blue-black. The blackening frequently does not show up until the potatoes have been removed from storage. Heavy fertilization with nitrogen and excessive soil moisture seem to increase blackening following storage. (4) A fungal disease of roses caused by Diplocarpon rosae, family Mollisiaceae; characterized by black spots having rays and fibrils, which sometimes cover the leaves. In some cases, entire leaves turn yellow and defoliation follows. Similar spots also appear on canes. Inconspicuous spots on the petioles, stipules, flower receptacles, sepals, and petals may cause distortion of the flower. (5) A minor bacterial disease of sugar beets caused by Pseudomonas aptata, which blights plants that are grown for seed. Also called black streak. (6) A low-grade infection resulting from mechanical injury to the teat of a cow. See Apple Scab, Peach Scab.

Black Spruce--Picea mariana; a hardy, slow-growing, often stunted, evergreen, coniferous tree, family Pinaceae; grown in moist soils, it is a most common species in strongly acid peat bogs. Used for pulpwood, boxes, planing-mill products, furniture, woodenware, etc. Native to North America. Also called double spruce, eastern spruce, bog spruce.

Black Sugar Maple--See Black Maple.

Black Tupelo--Nyssa sylvatica; a deciduous tree, family Nyssaceae; grown for its fine, red autumnal foliage. Used in making veneer, pulp, cabinet work, boxes, etc. Native to North America. Also called black gum (forestry name), sour gum, pepperidge, tupelo.

Black Turpentine Beetle--Dendroctonus terebrans; an insect pest of pine trees. The larvae feed on the inner bark of the trees, causing the trees to die.

Black Walnut--See Eastern Black Walnut.

Blackberry--Rubus spp.; vigorous growing, rambling, thorny, deciduous vines. The edible berry crop is well utilized by many species of animals, and the rambling growth forms a soil-protecting cover. Easily started from cuttings.

Blackberry Leaf and Can Spot--A fungal disease caused by Septoria rubi. Characterized by light-colored, small spots with red or purple borders on the leaves. The spots also appear on the canes and result in premature defoliation of the fruiting cane. Found mostly on dewberry in Oregon and Idaho and in the coastal regions of California.

Blackeyed Peas--A variety of the cowpea, Vigna sinensis; grown mainly for livestock forage and for green manure. The seeds are eaten as a vegetable.

Blackland--Generally, areas having dark-brown or black surface soils. Specifically, the prairies of central Texas, the soils of which are black, waxy, clayey. See Vertisols.

Blackstrap--The liquid by-product of crystallization of sugar from sugarcane or sugarbeet juice; used as a feed for livestock having about 75 percent of the feed value of corn. Also called blackstrap molasses.

Blade--(1) The expanded portion of a leaf. (2) A cutting tool, as the blade of an axe or the blade of a bulldozer. (3) A retail cut of meat from the forequarter or shoulder. (4) The hind part of a fowl's single comb.

Blanch--(1) To bleach or whiten a vegetable as it is growing by wrapping the stalk and leaves with paper or by mounding soil around the portion to be whitened, as celery is blanched. Also called etiolate. (2) To heat vegetables and fruit in water, live steam, or dry heat to inactivate enzymes preparatory to processing.

Bland--Mild-flavored, not stimulating to the taste; smooth, soft-textured.

Blast-furnace Slag--The dross from the smelting of iron ore, which contains calcium silicate, a low-grade source of lime for agricultural use in the southeastern United States. It is also a carrier of low-grade total phosphorus.

Blastula--A mass of cells with a cavity that occurs from the dividing of a fertilized egg. From this stage the cells begin to differentiate.

Bleaching Clay--Any clay in its natural state or after chemical activation that has the capacity for adsorbing coloring matter; generally montmorillonitic clays are used.

Blight--Disease symptoms, parasite, fungi, bacteria, viruses, or unfavorable atmospheric conditions which cause the withering and death of a plant.

Blind Area--In forestry, an area which cannot be seen from a lookout station.

Blind Furrow--A double furrow caused by plowing two adjacent furrows and throwing the soil in opposite directions; also called a dead furrow.

Blind Knot--An overgrown knot that forms a pronounced swelling on the trunk of a tree; also called blind cork. See Knot.

Blizzard--A severe storm of high wind, low temperatures, and heavy snow.

Block--(1) A piece of wood used as a divider between two bales of hay. (2) A pulley used to increase pulling or hoisting power. (3) In logging, an administrative division of a forest. (4) About 5 pounds of cotton hanks. (5) A portion of hay thrown into a baler. (6) To thin out plants, especially sugar beets, into smaller bunches, which will be again thinned into single plants. (7) To trim fleece to enhance the appearance of a sheep. (8) See Cutting Block.

Blocky Structure (Soil)--The arrangement of particles which indicates that soil units exceed 1 cc.

Bloodtwig Dogwood--Cornus sanguinea; a showy shrub, family Cornaceae; grown for its white flowers, black fruit, and blood-red twigs. Native to Eurasia. Also called dog tree, red dogwood.

Bloom--A word with several contrasting meanings: (1) Plants in the state of flowering. (2) Plants reproducing and growing. (3) Fruits with a white covering. (4) Minerals that absorb one wavelength of light and reflect another. (5) A very fine, often waxy, powdery coating on the surface of certain leaves, stems, fruits, or other organs; usually whitish, grayish, or bluish, and easily rubbed off, as the bloom on a plum. See Algal Bloom.

Blossom--(1) The flower or bloom of a seed plant; to flower. (2) A horse with a sorrel or bay coat mixed with white.

Blowings--Cotton waste from gins.

Blowout Grass--Redfieldia flexuosa, family Gramineae; used in reseeding ranges and establishing pastures and to control blow-outs. It grows naturally on deep, loose sands in the Great Plains of the southwestern United States.

Blue Gramagrass--Bouteloua gracilis; a native American grass, family Gramineae, used for reseeding in the western ranges of the United States.

Blue Loco--Astragalus diphysus; a common poisonous herb, family Leguminosae; causes death in cattle and horses. Symptoms are characterized by a shaggy coat and by loss of muscular control in walking, nervous sensibility, and loss of weight and appetite. It grows extensively in Arizona and New Mexico during January and February; also called blue locoweed.

Blue Mold of Tobacco--A disease in plant beds caused by Peronospora tabicina, family Peronosporaceae; characterized by cupped leaves with a whitish or violet-colored moldy growth over the lower surfaces. It kills young plants and the leaf tissues of older plants. Found in tobacco areas throughout the United States except in Wisconsin.

Blue Ribbon--A prize or award for the best livestock or other agricultural commodity in a class; made of inscribed blue cloth.

Blue Spruce--See Colorado Spruce.

Blue Wildrye--Elymus glaucus; a fairly good forage grass, family Gramineae; with strong seed habits. Found up to 9,000 feet in altitude from Ontario and Michigan to Alaska and south as far as South Dakota, New Mexico, and California.

Blue-stain--Blue coloration of light-colored wood caused by species of the fungi genera Ceratocystis, Aureobasidium, and Lasiodiplodia.

Bluebeech--See American Hornbeam.

Blueberry--About 50 species of Vaccinium, family Ericaceae, of which the most important are the highbush blueberry, V. corymbosum, the large-fruited blueberry of the northeastern and eastern north-central United States; the rabbiteye blueberry, V. virgatum, of the southeastern United States; and the low-bush blueberry, V. angustifolium, of Canada and the northeastern and northcentral United States (often incorrectly called huckleberry).

Bluegrass--(1) Any grass of the genus Poa, family Gramineae. Valued for hay and lawns and as the most palatable range and pasture grasses. (2) Grasses of the genus Andropogon in Australia. (3) Agropyron scabrum in New Zealand. Alpine, Poa alpina; annual, Poa annua; big. Poa ampla; Canada, Poa compressa; Kentucky, Poa pratensis; mutton, Poa fendleriana; roughstalk, Poa trivialis; Texas, Poa arachnifera.

Bluegrass, Kentucky--Poa pratensis; a major lawn and sod grass, adapted to cool climates and moist growing conditions. Although characteristically low-yielding, it may persist and outyield other forage species at high altitudes. It is an excellent erosion control grass where adapted.

Bluejoint Reedgrass--Calamagrostis canadensis, family Gramineae; a perennial grass; fair forage. Found throughout the United States up to 12,000 feet and usually in marshy or wet soil. Also called bluejoint, bluetop.

Board--(1) Lumber less than 2 inches thick and more than 8 inches wide. (2) Lumber 11/2 inches thick, 6 or more inches wide, and 8 or more feet long (British). (3) Lumber of all widths 1 inch thick; widths of less than 6 inches are sometimes called strips. (4) Plank floor on which sheep are sheared (New Zealand).

Board Foot--A lumber measurement; a board 1 foot long, 1 foot wide, 1 inch thick, based on the original cut before planing and surfacing; also called super foot (Australia).

Board Mill--A sawmill that cuts 1- and 2-inch lumber, as compared with a timber mill, which cuts thicker lumber.

Bob--(1) Veal from calves slaughtered when less than four to six weeks old; also called slunk. (2) The docked tail of a horse. (3) In transporting lumber, a single pair of runners on which the forward ends of the logs are placed. (4) To transport logs on a bob.

Bobtail Barley--Hordeum jubatum var. caespitosum, family Gramineae; a subspecies of foxtail barley with short awns; of fair forage value. Found from North Dakota to Alaska, south to Kansas and Arizona.

Body--(1) The physique of an animal. (2) The consistency of a substance, such as honey, butter, cheese, etc. (3) The fullness of flavor, especially of a beverage.

Boer Lovegrass--Eragrostis chloromelas, family Gramineae; a grass used for reseeding for forage on the western ranges of the United States. Native to South Africa.

Bog Iron--A spongy variety of hydrated oxide of iron (limonite). Found in layers and lumps on level, sandy, acid soils which have been covered with a swamp or bog.

Bogie--Tobacco leaves twisted into small rolls.

Boil Down--To concentrate a liquid, such as a fruit juice or sap of a sugar maple tree into a thick syrup or sugar.

Boiling Point--The temperature at which the vapor pressure of a liquid equals the atmospheric pressure. At the boiling point, bubbles of vapor rise continually and break on the surface. The boiling temperature of pure water at sea level (barometric pressure of 30 inches of mercury) is 212[degrees]F (100[degrees]C). At high altitudes, the boiling point of water is lower because the atmospheric pressure is lower. At 5,000 feet above sea level, for example, the boiling point of water is 203[degrees]F (95[degrees]C); at 10,000 feet it is 194[degrees]F (90[degrees]C).

Boiling-water-bath Canner--A large kettle with lid, rack, and cover; must be deep enough to allow jars to be covered with 1 to 2 inches of water and still have additional height for water to boil actively. Suitable for processing acid foods.

Bois d'Arc (Osage Orange)--Malcura poomifera; a tree used extensively in the United States Great Plains for a shelterbelt and for fence posts.

Bolander Waterhemlock--Cicuta bolanderi; a perennial California herb, family Umbelliferae; it is poisonous to stock, causing vomiting, diarrhea, dilated pupils, difficult respiration, frothing at the mouth, weak but rapid pulse, convulsions.

Bole--The trunk of a tree. It may extend to the top of the tree as in some conifers, or it may be lost in the ramification of the crown, as in deciduous species.

Boll--(1) The leathery capsule that contains the seed and lint of the cotton plant. (2) The seed pod of flax.

Boll Period--That phase in the growth when cotton bolls have formed but not opened.

Boll Weevil--Anthonomus grandis, family Curculionidae; a beetle that causes cotton losses of more than $100 million annually. The larvae feed only on cotton, but the adults may feed on okra, hollyhock, and hibiscus. Native to Mexico and Central America.

Bollies--Unopened bolls of cotton that contain usable lint.

Bolling--A tree whose branches have been removed.

Bollworm--Heliothis zea, family Phalaenidae; an insect whose larvae feed on cotton bolls, corn, tobacco, tomatoes, beans, vetch, alfalfa, and other garden plants and flowers. Also called corn earworm; tomato fruitworm.

Bolly--A boll of cotton which remains unopened after frost.

Bolly Cotton--The lint extracted from the bollies.

Bolster--(1) The padded undersection of a saddle. (2) In growing plants, the excrescence at the leafstalk where it joins the axis. (3) A cross member of a vehicle on which the bed, rack, or load rests.

Bolt--(1) A section sawed or split from a short log from which blocks, shingles, staves, etc., are made. (2) A short log used in making pulpwood or veneer. (3) A strong, metal pin with a head at one end and threads at the other. (4) To sift coarse elements from fine, as bran from flour. (5) To flower or to produce seed stalks, often prematurely. (6) To eat rapidly. (7) To run away.

Bolter--(1) A sieve. (2) A circular ripsaw and a mechanically driven carriage used for sawing round bolts into boards. (3) A plant, such as the sugar beet, which produces a seed stalk from the crown of the plant.

Bolting--Production of flowers and seeds by such plants as spinach, lettuce, and radishes, generally occurring when days are long and temperatures warm.

Bolting Cloth--A sieve cloth, usually silk.

Bone Ash--The highly calcic and phosphatic residue of bones burned in air; of limited use as a fertilizer. Also used in making assay cups and in cleaning jewelry.

Bone Black--The residue from heating bones in a closed retort similar to that of making coke. Bone black is used in refining sugar, oil, etc. After use, it is sold as spent bone black for fertilizer manufacture. Also called bone charcoal, bone char, animal charcoal, animal black.

Bone Meal--(1) The product of drying and grinding animal bones not previously steamed under pressure. The composition is nitrogen 3.3 to 4.1 percent, bone phosphate 43 to 50 percent or phosphorus 10 to 12 percent, and calcium 21 to 24 percent. Used as a fertilizer and stock feed. (2) (Steamed) A product of grinding animal bones previously steamed under pressure. The composition is nitrogen 1.65 to 2.5 percent and calcium 24 to 33 percent. Used as a fertilizer and stock feed.

Bone Phosphate--The calcium phosphate obtained from bones; also in commerce, applied to calcium phosphate obtained from phosphatic rocks, e.g., those of Florida.

Bone Products--The skeleton of vertebrates (20 to 30 percent total [P.sub.2][O.sub.5]); earliest source of fertilizer phosphorous, now used largely in animal feeds and, to some extent, in specialty fertilizers such as for growing roses.

Boot--(1) The hollow metal casting on a planter or a drill through which the seed passes to be planted. (2) Profuse feathering on the shank and toes of fowls. (3) The sheathlike leaf structure on the upper end of grain or grass plants that encloses the inflorescence prior to its emergence. During inflorescence the plant is said to be in the boot stage or in boot. (4) In a grain elevator, the box which contains the lower pulley or sprocket.

Boot Leaf--The leaf arising from the protective sheath enclosing the young inflorescence of grain.

Bora--(Latin, boreas-north wind) A cold, dry, violent downslope wind, named after the north winds that move rapidly down the Alps in Yugoslavia to the Adriatic Sea. The name is now used for a similar wind any place in the world.

Borage--(French, bourrache) Borago officinalis; an herb with rough spiny leaves and blue flowers, excellent for flavoring lettuce salads.

Borax--Sodium tetraborate, [Na.sub.2][B.sub.4][O.sub.7] x 10 [H.sub.2]O. It is sometimes applied directly to soil, or added to commercial fertilizer in very small quantities (toxic to plants in high concentrations) to supply boron. It is also used as an herbicide and an insecticide, especially to kill the maggots of flies in manure and refuse piles. Borax is 11 percent boron. Also called borac, tincal.

Border Dyke--Ridges of earth constructed to hold irrigation water within certain limits in a field.

Border Irrigation--A system of irrigating land which has a slope of 2 to 4 feet per 1,000 feet. Parallel levees are built, and the area between levees is flooded.

Border Strip--A zone or strip surrounding a field research plot usually given the same treatment as the plot but not included in sampling or study.

Boreal Forest--The forest consisting chiefly of conifers extending across northern North America from Newfoundland to Alaska.

Borer--An insect that bores into and feeds on the woody sections or bark of trees.

Boron--An element essential for plant growth. The original source of boron is tourmaline, but available forms are from soil organic matter.

Boron Deficiency--A soil deficiency. In vegetables, the terminal buds and phloem tissue are killed, and the development of lateral buds is arrested. In citrus trees, the surface and main veins of the leaves cork or split, and the leaves curl downward; long, narrow splits occur on the trunk bark of small citrus trees. In deciduous trees, an internal bark necrosis occurs, which can often be detected on the surface.

Boron Injury--Slowed or arrested germination, killing or stunting of plants, fading of color, premature ripening, or small yields, caused by an excess of boron in the soil.

Boscage--A thicket of shrubs.

Bosque--A name given to a wooded thicket, usually of tamarisk, willow, and cottonwood, on the flood plains of the southwestern United States.

Botanical Garden--A garden of plants that have scientific interest.

Botanical Name--The scientific name of plants, which includes the genus and species.

Botanical Pesticide--A pesticide made from plants; also called a plant-derived pesticide.

Botany--The science of plants; anatomy, cytology, ecology, morphology, mycology, paleobotany, pathology, physiology, phytogeography, taxonomy, etc.

Botryose--Used to describe a plant whose flowers grow in clusters.

Botrytis--A genus of parasitic fungi, family Moniliaceae, whose various species cause spots on flowers, leaves, and stems of plants. In wet weather, the spots spread and are covered by a gray, moldy, sporal growth of the fungus.

Bottom--(1) (Often plural) Low-lying land adjacent to a river, usually rich in alluvial deposits, e.g., Mississippi River bottoms. (2) A section of a plow consisting of the moldboard, share, frame, and landside. (2) Stamina in a horse.

Bottom Heat--The use of heating cables or mats to achieve the hoptimum growing media temperature for producing plants.

Bottomland--Lowland along a river (sometimes flooded).

Botulism--A food poisoning caused by the bacterium Clostridium botulinum in preserved foods or feed for animals. The poison can be fatal to humans or animals. Called limberneck in poultry. Also called food poisoning, allantiasis.

Boulder Clay--Massive, compact deposits of gritty clay of glacial origin, containing imbedded gravel and boulders. It is the parent material for a number of highly productive soils.

Bound Water--Water adsorbed by colloids and therefore not easily freezable; also called unfree water, hygroscopic water.

Boundary Tree--An old, tall distinguishable tree standing on a property line, usually blazed or otherwise marked.

Bourbon Cotton--Gossypium purpurascens; a perennial shrub or small tree, family Malvaceae; grown in the tropics as a source of commercial cotton. Also called Puerto Rico cotton, Siam cotton.

Box--(1) Buxus sempervirens; a shrub or small tree; family Buxaceae; one of the most valuable broad-leaved evergreens. Since the days of the Romans it has been planted for hedges and topiary work. It is lethally poisonous to cattle, horses, sheep, and pigs, having emetic and purgative properties. Native to southern Europe. (2) The lowest grade of softwood lumber. (3) A cavity cut into the base of a pine tree to collect sap to make turpentine and rosin. (4) A system for bracing branches of trees. (5) To chip back on the underside of a cut in a tree to prevent the main stem of the tree from splitting when it falls. (6) An accidental mixing of two herds of sheep or cattle (Australia). (7) To corral animals. (8) A device for dividing water in an irrigation system into two or more ditches. (9) A canyon with one entrance and no exits.

Box Elder--Acer negundo; a deciduous, fast-growing shade tree, family Aceraceae; its branches are brittle; the wood is used for paper pulp and woodenware; also called ashleaved maple.

Box Scraper--An implement mounted on the rear of a tractor that is used in grading and leveling soil.

Box the Heart--To cut boards from the sides of a log so that the center or heartwood is left as one piece of timber.

Boysenberry--(Boysen) Rubus spp., family Rosaceae; a large, sweet, deep-red, high-quality berry, the hybrid of blackberry, loganberry, and raspberry. Commercially important on the West Coast of the United States.

Brace Roots--The supporting roots of corn, etc., which spring from the first two or three nodes above the ground; also called aerial roots, prop roots, adventitious roots.

Brachiate--Being branched in pairs that sprout from opposite sides of a stem, as on all species of ash and maple trees.

Brachyism--A dwarfing of plants by shortening of the internodes.

Bracken--Pteridium aquilinum; a widely distributed fern, family Polypodiaceae; sometimes grown in gardens, but, if escaped, is a weed pest. Also called female fern, fern brake.

Bract--A small leaf at the base of the flower.

Brake--(1) An irrigation check. (2) A place overgrown with bracken, brush, wood, cane, etc., e.g., a cane brake, a thicket.

Bramble--(1) Any plant of the genus Rubus, family Rosaceae, as the blackberry, raspberry, and dewberry, called bramble fruits. (2) Any prickly, clinging shrub.

Bran--The broken seed coat of the cereal grains, most commonly of wheat, separated by fine sieves or finer cloth after grinding of the grain into flour. The bran is a desirable "bulk" feed for livestock or fiber food for people.

Branch--(1) A lateral stem arising from the main stem of a plant, bough, or limb. (2) Part of a horseshoe from the first nailhole to the end of the heel. (3) A tributary stream. (4) An ancillary pipe attached to a main pipe.

Branch Wilt of Walnut--A fungal disease of Persian walnut (Juglans regia) caused by Hendersonula toruloidea, family Sphaeropsidaceae; characterized by sudden wilting of the leaves in summer. It appears on small twigs and branches, but eventually involves the larger limbs as well.

Brand Tillage--A system of farming in which new land is periodically cleared for plowing, while abandoned fields are allowed to regain their natural cover. Common in the tropics. See Shifting Cultivation.

Brashy Soil--Soil composed almost entirely of coarse, angular rock fragments, with fine soil matter filling the interstices.

Brassica--A genus of plants, family Crucifereae, which includes the common cabbage, turnip, black mustard, etc. Native to Asia, Africa, and Europe.

Brasswood--A common name for osage orange. See Bois d'Arc, Osage Orange.

Bread Grain--A cereal, such as wheat or rye, which yields flour for leavened bread. Other cereals are called coarse grains or feed grains.

Breadbasket of the Nation--Colloquial name for the Corn and Wheat Belt regions of the north-central United States.

Breadfruit Tree--Artocarpus communis; a tropical tree, family Moraceae that has heavy foliage of thick oval leaves, small flowers, and bears an edible fruit, called breadfruit. Native to Polynesia; grown rarely in the extreme southern tip of Florida.

Breadroot Scurfpea--Psoralea esculenta; a perennial herb, family Leguminosae, which has large, tuberous roots. Native to western North America, and once extensively eaten by the American Indians. Also called pomme de prairie, pomme blanche, prairie potato, meadow potato.

Breadstuffs--Various grains used for making bread. Break Ground--To plow land for the first time.

Breaker--(1) A wave meeting a shore, reef, sandbar, or rock and collapsing. (2) For watering: a widened fan-shaped device screwed on the end of a hose to decrease (break) the velocity of water; used in watering plants. (3) For plowing: an extended moldboard on a turning plow to more completely turn heavy sod upside down. (4) For electrical overloading: an automatic flip switch on an electrical circuit that breaks (shuts off) the current when overloaded. (5) Utility-grade slaughtered cattle in which some degree of marbling is in the meat. The loins and rounds are "broken out" and sold as steaks.

Breaking--Plowing a native or planted sodlike crop.

Breaks--(1) Bluff land or steeply sloping escarpments broken by stream dissection, as in the eastern edge of the High Plains, south of the Arkansas River to the Texas Panhandle. This area is known as Breaks of the Plain. (2) The broken land at the border of an upland that is dissected by ravines. (3) An area in rolling land eroded by small ravines and gullies; also used to indicate any sudden change in topography, as from a plain to hilly country.

Breast High Diameter--In forestry, the point at which the diameter of a tree is measured. Custom has fixed this point at 41/2 feet above ground level. Also called diameter at breast height.

Breathing Pore--See Lenticel, Stoma.

Breed--(1) Animals having a common origin and distinguishing characteristics. (2) To improve, through control, characteristics in plants and animals.

Breeder--(1) The owner of the dam when she was bred. The definition holds true in registering all classes of livestock. (2) A specialist in breeding. (3) An animal or plant used for breeding. (4) Also known as a converter; a nuclear reactor that converts nonfissionable atoms of one element into fissionable atoms of the same or a different element. An advanced breeder is a converter that produces more fissionable fuel than it consumes.

Breeder Seed--Seed directly controlled by the originating or sponsoring plant-breeding institution, person or designee thereof; the source for the production of the foundation, registered, and certified classes of seed.

Brewer Oak--Quercus oestediana, family Fagaceae; an oak used for forage on the western ranges of the United States.

Brewers' Dried grains--The dried residue left after wort has been extracted form barley malt; used in mixed feeds and equals corn gluten in content of digestible protein; it is unpalatable; also called dried brewers' grains, beer grains.

Brewers' Dried Yeast--A source of B complex vitamins from yeast filtered from fermented beer. It has roughly 50 percent protein and 1.5 percent phosphorus.

Bridge Graft(ing)--A method of preserving trees which have suffered from winter injury, rodents, or disease. A split with loose ends is made in the bark above and below the wound. Then a scion longer than the affected spot is cut and inserted in the slit. The ends are finally covered with wax.

Brier (Briar)--(1) Any plant or bush bearing thorns or prickles on a woody stem, as Rosa, Rubus, Similax, etc. (2) A thorn, twig, or branch of a brier. (3) Erica arborea; a shrub whose roots are used in making pipe bowls. Native to southern Europe.

Bright Tobacco--Cured light-yellow tobacco.

Brimstone--See Sulfur.

Brindle--(1) An animal which is tawny, gray, or brown, having irregular, dark streaks or spots. (2) Tobacco mosaic.

Brine--A salt solution of water used for food preservation, refrigeration, etc.

Brine Poisoning--Excessive consumption of salt by animals, resulting in severe vomiting, thirst, salivation, diarrhea, flatulence, dilation of the pupils, and hypersensitivity to touch. Convulsions and blindness occur in severe attacks. Also called salt poisoning.

Bristle--Stiff, sharp hair or hairlike parts which grow on animals and plants.

Broad-base Terrace--An erosion control system for steep slopes. It consists of a horizontal ridge of earth 10 to 30 inches high, 15 to 30 feet in base width with gently sloping slides, a rounded crown, and a broad, shallow water channel along the upper side. It may be level or have a slight fall toward one or both ends. Crops can be planted on the terrace. See Narrow-Based Terrace, Nichols Terrace.

Broad-leaved Evergreen--Evergreen plants which are not coniferous, e.g., the box, rhododendron, eucalyptus, wattles, etc.

Broad-leaved Plants--Botanically, those classified as dicotyledons. Morphologically, those that have broad, usually compound leaves.

Broad-spectrum Pesticide--A pesticide that kills a wide variety of insects. It may kill many beneficial insects, fish, birds, and mammals as well as target pests.

Broadbean--Vicia fabia, family Leguminosae; one of the most ancient cultivated food plants. It has a strong, upright stalk with small leaflets, and fruits in a pod, 1/2 to 1 foot long, which contains edible seeds. Native to North Africa and southwestern Asia; seldom grown in the United States. Also called horsebean, Windsor bean.

Broadcast--(1) To scatter seed or fertilizers uniformly over the soil surface rather than placing it in rows. (2) To sow seed in all directions by scattering. (3) To scatter manure, lime, etc. (3) To plow, throwing the soil in one direction, so that the field is left level.

Broadcast Burning--Allowing a prescribed fire to burn over a designated area within well-defined boundaries for the reduction of fuel hazard, as a silvicultural treatment, or both.

Broadcast Seeding--Scattering seed on the surface of the soil; contrast with drill seeding, which places the seed in rows in the soil.

Broadleaf--(1) Cigar tobaccos with broad leaves. (2) Tobacco leaf used for wrapping cigars. (3) A tree or a plant, usually a weed, with wide leaves.

Broads--In Canada, lumber 12 or more inches wide.

Broccoli--Brassica oleracea italica; an herb, family Crucifereae; the thickened flower branches are popular as a food; also called asparagus broccoli, sprouting broccoli, branching broccoli, Italian broccoli, calabrese.

Broken--(1) Describing land plowed for the first time. (2) Of plants or flowers, having irregular color distribution.

Broken Flat--Designating land which has been broadcast plowed. See Broadcast.

Broken Knees--A term used to describe horses whose knees have scars on them, indicating that the horse has fallen. Often scars are an indication that the horse is awkward and inclined to stumble.

Brome Mosaic--A viral disease of smooth bromegrass, caused by Marmor graminis; characterized by local lesions, yellow stripes on the foliage, and death of new growth. Occurs in Kansas and Nebraska.

Bromegrass, Field--Bromus arvensis; a winter annual bunchgrass which develops a fibrous mass of roots useful in cover cropping to control erosion and improve soil tilth. Seedlings are winter-hardy to -30[degrees]F (-34[degrees]C) and produce tall rank growth, tillering profusely in the spring. Should be fall planted.

Bromegrass, Smooth--Bromus inermis; highly variable, coolseason, cross-pollinated, palatable, long-lived, sod-forming grass. Long grown for hay and pasture, it is also very useful in erosion control seedings. Adapted to fertile, well-drained soils. Often planted in mixture with alfalfa.

Broom Pine--Long-leaf pine

Broom, Scotch--Cytisus scoparius; a nitrogen-fixing, small, leguminous, tap-rooted shrub adapted to well-drained, low-fertility soils in the mild climate west of the Cascades. It is used for secondary stabilization on coastal sand and for roadside or erosion control plantings. It has a prolific crown of yellow flowers in early summer.

Broomcorn--Sorghum vulgare var. technicum; a stiff grass, family Gramineae; used in making brooms and brushes. The mature seed is fed to poultry.

Broomrape--A root-parasitic herb of the genus Orobanche, family Orobanchaceae; subsists on herbaceous and woody plants. Orobanche ramosa, native to Eurasia, injures tobacco, tomato, muskmelon, etc.

Broomsedge--A grass, Andropogon virginicus, family Gramineae; a widespread weed on poor land in the southeastern United States. It is an inferior livestock forage, but a covering of it protects poor soils from erosion. Also called broom grass, yellowsedge, bluestem.

Brown Grain Sorghum--A market classification which includes all varieties of brown grain sorghum and very few other varieties.

Brown Hay--Hay discolored by fermentation because of insufficient drying, which decreases its nutrient value.

Brown Heart--A common disease of beets and turnips caused by a boron deficiency.

Brown Lacewing--An insect, family Chrysopidae, that preys on citrus mites.

Brown Leaf Rust--A fungal disease of rye caused by Puccinia dispersa, family Pucciniaceae; a widespread, injurious rust of rye. Long brown or reddish-brown, granular pustules burst through any part of a plant, but mostly on the stem and leaf sheath.

Brown Leaf Spot of Tobacco--A fungal disease occurring in periods of high temperature and humidity; caused by Alternaria tenuis, family Dematiaceae; large, circular brown spots appear on the mature leaves after harvesting.

Brown Lint--Brown fibers which occasionally appear on any variety of cotton.

Brown Patch--A fungal disease of grasses occurring during periods of high temperature and humidity, caused by Pellicularia filamentosa, family Thelephoraceae; spots appear over the entire turf area; in time the turf turns brown and dies. See Dollarspot.

Brown Rat--Rattus norvegicus, family Muridae; the common rat; also called Norway rat, house rat, wharf rat, sewer rat.

Brown Rice--Rice with the hull removed but not polished. It retains the bran layers normally removed by milling.

Brown Slime Flux--A foul-smellling seepage from cuts in shade trees, usually birch, elm, and maple of declining vigor. The clear sap, which contains nutrients, is fed upon by fungi, bacteria, and insects, and then turns brown and slimy.

Brown Spot of Rice--A fungal disease caused by Helminthosporium oryzae, family Dematiaceae, which kills the seedling plants, discolors leaves with reddish-brown spots, and rots the stalk at the base of the head. It specks the seeds, reducing the yield. Serious in the United States. Also called rotten neck of rice.

Brown Spot of Smooth Bromegrass--A common disease caused by Helminthosporium bromi, family Dematiaceae; characterized by small, dark brown, oblong spots on the leaves in spring. The spots coalesce into large, yellow areas, the leaves later turn brown from tip to base and die. The disease attacks plants in the United States in wet June weather.

Brown Spot of Soybeans--A fungal disease caused by Septoria glycines, family Sphaeropsidaceae; it causes defoliation, especially in wet seasons, with eventual spotting of stems and pods. Widespread in Europe, Asia, and North America.

Brown Spot of Sugarcane--A widespread, minor disease, caused by Cercospora longipes, family Dematiaceae; narrow spots appear on the leaves, enlarging into ovals with straw-colored centers. The leaf blades die.

Brown Stem Rot--A fungal disease of soybeans, caused by Cephalosporium gregatum, family Moniliceae; characterized by a sudden blighting of leaves which resembles frost damage in fall. Leaf tissues become brown, and the entire leaf soon withers. A badly infested field has a brownish appearance.

Browning Root Rot of Cereals--A fungal disease of cereals caused by Pythium arrhenomanes, family Pythiaceae; characterized by rotting of root; common in central North America in marshy areas. The same organism attacks sugarcane in Louisiana and Hawaii.

Browntail Moth--Nygmia phaeorrhoea, family Lymantriidae; this moth is destructive to foliage of many trees. Its hair carries a poison which irritates the skin of humans.

Browse--Leaves, small twigs, and shoots of shrubs, seedling, and sapling trees, and vines available for forage for livestock and wildlife.

Brush Control--Control of woody plants.

Brush Matting--(1) A matting of branches placed on badly eroded land to conserve moisture and reduce erosion while trees or other vegetative cover are being established. (2) A matting of mesh wire and brush used to retard streambank erosion.

Brush Monkey--A lumber term for someone who cuts down small trees so that logs may be removed.

Brushland--An area of little commercial value except perhaps for grazing goats and sheep.

Brussels Sprouts--Brassica oleracea var. gemmifera; an annual or biennial herb, family Cruciferae; grown for its axillary buds, which develop into small, edible heads. An important vegetable plant related to the cabbage.

Bryology--That branch of botany dealing with mosses. Bucare Coralbean--Erythrina poeppigiana, a common coral tree, family Leguminosae; grown for its striking cinnabar-red flowers. Also used in the tropics to shade young coffee and cacao plants. Probably native to Peru; grown in Florida and California.

Buck--(1) A male goat, sheep, rabbit, deer, or antelope. (2) Wool from rams. See Bucks. (3) To saw felled trees into logs. (4) The common beech or its nuts. (5) Of a horse, to quickly leap with back arched and head held low.

Buck Moth--Hemileuca maia, family Saturniidae; a moth whose caterpillars infest oaks and willows in the autumn and feed voraciously on the leaves.

Buckbrush Ceanothus--Ceanothus cuneatus, a shrub, family Rhamnaceae; a forage for livestock on the western ranges of the United States. Also called wedgeleaf ceanothus.

Buckhorn Plantain--Plantago lanceolata, family Plantaginaceae; a common, serious weed found in lawns and fields. Eaten with some relish by sheep. Native to Europe, but widespread in the United States. Also called buckhorn, English plantain, narrow-leaved plantain, ribwort, ripple-grass, rattail, ribgrass.

Bucking--Cutting a felled tree into specified log lengths.

Buckra--Denoting whiteness of certain vegetables.

Buckshot Soil--(1) Soils containing hard, round iron and manganese concretions of buckshot size. Occurs in the southern United States. (2) Wet clay soil, which upon drying disintegrates into aggregates about the size of buckshot. Descriptive of the soils of the Yazoo bottomland of the Mississippi River in the southern United States. Most common soil is Sharkey clay.

Buckskin--(1) A disease of citrus, usually grapefruit and oranges, caused by the mite Phyllocoptes oleivorous; characterized by a crusted, leathery condition of the rind. (2) A term for a grayish-brown horse. (3) The skin of a buck deer. (4) A disease of sweet cherry, the symptoms of which vary according to the strain of virus and the stock. In general, the fruit loses its luster and drops or fails to ripen. (5) A horse that is light brown and has a black mane and tail.

Buckthorn--(1) Rhamnus cathartica, family Rhamnaceae; a poisonous shrub once used for hedges but now escaped in fence rows and pastures in the eastern United States. Its bark, leaves, and berries contain a purgative, but being bitter, are seldom eaten by livestock. Native to Eurasia. Also called Hart's thorn, waythorn, Rhineberry. (2) Ceanothus sordiatus; a thorny shrub, also called jimbrush. It is the alternate host for the fungus causing the crown rust of oats.

Buckwheat--Fagopyrum sagittatum, family Polygonaceae; a fleshy, annual herb whose grain is sometimes erroneously considered a cereal. It is used in making griddle cakes and as a stock and poultry feed. It is harmful to unpigmented stock, which developed photosensitization after eating it. Native to Asia; a minor grain crop in the United States. Also called fat hen, brank.

Bud--(1) A protuberance containing miniature leaves or flowers, located terminally or laterally on a stem. (2) An undeveloped shoot or stem. (3) To graft by inserting a bud in a slot in the stem of a different plant. It is economical, as only a single bud, instead of a scion, is used. Also called budding.

Bud Blasting--The death of the developing flower bud, usually because of water stress.

Bud Cutting--A method of quick propagation of plants. Parts of a stem are cut and split lengthwise so that each cutting has one bud. These are then buried under a shallow covering of soil to germinate. Also called single eye cutting, leaf bud cutting.

Bud Graft--The union of two plants by inserting the bud of one into the stem of the other.

Bud Mutation--A genetic change in the tissues of a shoot of a grafted bud. See Bud Variation, Sport.

Bud Variation--Abnormal variations in stems, leaves, or fruit which can be transmitted by asexual reproduction. See Bud Mutation, Sport.

Budburst--In woody plants, the time in the spring when flower or leaf buds begin their annual growth.

Budcap--A piece of paper or other suitable material attached to a young seedling, covering the terminal bud to prevent animal browse.

Budding--A form of grafting whereby a bud from a parent plant is placed in a normal position on the cambium of the stock.

Budworm--Larvae of the spruce budworm (Choristoneura fumiferana) and the black-headed budworm (Acleris variana), both serious forest pests in Canada and the United States.

Buffalobur Nightshade--Solanum rostratum, family Solanaceae; an annual herb commonly found in waste places with light, sandy soil. Its berries or herbage may poison animals. Native to North America. Also called buffalobur, beaked nightshade, prickly nightshade, Texas thistle, Colorado bur, sand bur, yellowbloom sticker weed.

Buffalograss--Buchloe dactyloides, family Gramineae; a short, valuable, native forage grass of the Great Plains of the West, occasionally used as a lawn grass in that area. Also called early mesquite.

Buffer--(1) A substance in soil, such as organic matter, clay, carbonates, or phosphates, which resists changes of soil pH. (2) Animals which serve as food for predators, thus reducing danger to game. (3) A tool used to cut clinches from horseshoe nails before removing the shoe; also called clinch cutter.

Buffer Capacity of Soils--The ability of a soil to resist a change in its hydrogen-ion concentration; or to resist the tendency to become more acid upon the addition of an acid (or an acid-forming material), or more alkaline upon addition of a base (or a base-forming material). Buffer Solution--A solution to which large amounts of acid or base may be added with only a very small resultant change in the hydrogenion concentration.

Buffer Strip--Rows of vegetation planted along contours to reduce erosion.

Buffer Zone--Public land surrounding and supplementing private range lands.

Buffering Action--Resistance to change in acidity or alkalinity. Also called buffering.

Buffering Agent--Substance that adjusts the pH level of a spray mixture on a plant or soil surface. Often these materials can make a pesticide work better and last longer.

Bug--(1) Any insect, specifically of the order Hemiptera. (2) A flaw in the construction and operation of machinery.

Bug Kill--Trees or timber stands killed by insects.

Bulb--(1) The subterranean bud of some plants, which has a short stem bearing overlapping, membranelike leaf bases, as in onions and tulips. It stores food for reproduction and represents the inactive stage of the plant. (2) Any plant or flower shaped like a bulb. (3) The upper part of a horse's heel.

Bulb Cellar--A room used to give bulb crops a cold temperature treatment; also called a rooting room.

Bulb Planter--A device consisting of a tube connected to a handle that is used for making an opening in the ground to plant a bulb.

Bulb Waterhemlock--Cicuta bulbifera; a perennial herb, family Umbelliferae, which causes stock poisoning, the symptoms of which are nausea, difficult respiration, dilated pupils, frothing, weak and rapid pulse, and convulsions. Native to North America.

Bulbel--A small bulb produced above the ground, among the flowers or in the axil of a leaf. It is capable of reproducing the plant. Also called bulbil, brood bud.

Bulblet (Bulbil)--A small bulb or bulblike structure, usually borne in leaf axils, or among or in the place of flowers, or in other unusual places, as in pineapple.

Bulbous Bluegrass--Poa bulbosa, family Gramineae; a perennial grass with a bulblike growth; occasionally found in pastures. Native to Europe. Also called winter bluegrass.

Bulgur--Wheat which has been parboiled, dried, and partially debranned for later use in either cracked or whole-grain form.

Bulk Density--The relative weight of a soil aggregate (air space plus solid soil particles) compared with the weight of the same volume of water.

Bulk Fertilizer--Commercial fertilizer delivered to the purchaser, either in the solid or liquid state, in a nonpackaged form to which a label cannot be attached.

Bull Pine--See Ponderosa Pine.

Bull Thistle--Cirsium lanceolatum; a weed found in pastures and waste places. Its prickly leaves are an annoyance and, when numerous, interfere with grazing.

Bullace--(1) A European plum, Prunus domestica institia. (2) Any wild grape or muscadine (southeastern United States).

Bulrush, Alkali--Scirpus paludosus; a coarse, perennial marsh plant growing 2 to 4 feet (61 to 122 centimeters) tall with underground, tuber-bearing rhizomes. It has triangular stems and bears a cluster of small, conelike seedheads at the apex of the top leaves. It is adapted to saturated soils and areas of shallow water. It is choice food for some waterfowl.

Bumblebee--An insect of the genus Bombus; valued for flower pollination and honey, which it often stores in underground nests. Its colonies are small.

Bunch--(1) A cluster of plants or fruits, as a bunch of grapes. (2) In pigs, an improperly healed wound following castration. (3) To skid logs together for hauling. (4) To pile harvested crops in the field.

Bunch Beans--Green beans that grow on a bush rather than on a vine.

Bunch Peanut--A type of peanut whose plant is bushy and erect; largely grown for forage. See Runner Peanut.

Bunchgrass--A grass with bunch or tussock habit of growth due to the absence of rhizomes and stolons.

Bunt of Wheat--A fungal disease caused by infection at germination by parasites. Tilletia caries and T. foetida. The stricken plant and its head remain undersized. The glumes tend to be loose; the head becomes bluish-green and never regains the normal color of ripened wheat. individual grains in the head are filled with an oily black powder, mainly smut spores and, if broken, give an offensive odor, hence the name stinking smut. In bearded varieties, awns are often shed. Also called high smut, low smut, pepper brand, smut ball.

Bur--(1) The rough, sticky, or prickly envelope of any fruit. (2) A mature hull on the cotton boll. (3) The cone on the hop plant at flowering. (4) A weed with burrs. (5) To remove burrs, as in wool cleansing.

Bur Artichoke--The flower head of artichoke; used as a vegetable along with its oval bracts.

Bur Oak--Quercus macrocarpa, family Fagaceae; a very hardy massive oak, with its acorns nearly covered by big, fringed, scaly cups. Its wood is pest-free and very durable, and is commonly used for railroad ties, agricultural implements, furniture, etc. Also called mossycup oak.

Bur Sage--Any shrub of the genus Franseria, family Compositae; the characteristic vegetation of the southwestern deserts in the United States; often a cause of hay fever.

Burdekin Plum--Pleiogynium solandri, family Anacardiacae; an evergreen tree with clusters of greenish flowers. It bears an edible, plumlike, red fruit. Native to Australia; grown in Florida and California.

Burdock--Plants of the genus Arctium, family Compositae, all of which are weeds.

Burgeon--(1) To bring forth; to sprout buds. (2) To grow forth, as an appendage or a disease in an animal. (3) A young bud.

Buried Soil--The soil of an original land surface which is buried to considerable depths by subsequent geologic deposition. Such soils have been observed in sections of thick alluvial deposits; soils of interglacial periods, e.g., found in glacial deposits; and soils in regions of volcanic action.

Burl--(1) A knotlike growth on the trunks of trees or plants; often produced with adventitious buds. (2) A distorted grain in lumber surrounding the pits of undeveloped buds. Considered valuable, if of sufficient size.

Burley--A strain of tobacco, very light-colored when cured. Grown in Kentucky and Tennessee.

Burn--(1) An area in which the trees and/or grass have been destroyed by fire. (2) A branding iron. (3) In plants, to give a scorched appearance by excessive use of pesticides. (4) To blister the skin of an animal by friction with a rope or hobble, etc. (5) To become withered due to lack of moisture, as the foliage of a tree. (6) To become discolored because of insufficient drying, as in lumber.

Burn of Potato--A disease caused by heat, intense light, and a lack of moisture. The tips of potato leaflets become wilted, turn yellow, and later brown. The browning kills the tip tissues and spreads further in the vascular system of the leaf, destroying its various portions.

Burned Lime--Limestone that has been heated until it forms a powder. Burning, Prescribed--See Prescribed Burning.

Burrel--(1) A variety of pear with soft, tasty flesh. (2) Blue-colored wild sheep found in the Himalayas.

Burroweed--Suaeda fruticosa, family Chenopodiaceae; a common weed which has lowered the grazing capacity of large areas in the western United States.

Burrowing Nematode--Radopholus similis, family Tylenchidae; a worm which attacks citrus, banana, sweet potato, sugarcane, edible canna, etc.

Bush--(1) A grove of sugar maple trees. See Sugar Bush. (2) A forest wilderness or vast scrubland (Canada, Alaska, New Zealand, and Australia; formerly used in the northern United States also). (3) A shrub. (4) A method of training plants and fruit trees to assume a desired shape by means of stakes, ties, wires, and other supports. (5) The brush of an animal; the tail. (6) To force a seller to accept a lower price for a horse than was bid in the auction ring.

Bush Bean--Beans cultivated for food which grow in bush form and do not send out climbing runners.

Bush-fallow--An Appalachian region term for growing in rotation a crop on cleared land before allowing wild vegetation to cover it. In ten years or so the trees are cleared and a cultivated crop is again grown. See Shifting Cultivation.

Buster--(1) One who trains animals for saddle or work. (2) Middlebuster (a lister) that moves soil to the right and left simultaneously.

Butt--(1) The thick base or lower end of a tree or plant. (2) A stump, especially a walnut stump. (3) In butchering, the upper half of a ham or shoulder. (4) In Australia, a package of wool containing 196 pounds greasy or 112 poundsscoured, with a tare weight of more than 11 pounds. (5) To strike with the head or horns, as do cattle, goats, or rams.

Butt Cut--(1) In tree harvesting, the first log to be cut above the stump. (2) Bark removed from the butt of a tree before it is felled; specifically for tanbark; also called butt log.

Butter Bean--Any of the several types of lima bean found in the southern United States.

Butternut--(1) Juglans cinerea, family Juglandaceae; a tall, deciduous nut tree. The husk of the fruit was once used to dye cloth yellow. The nut meat is oily, rich, and spicy. The wood is used for furniture, cabinet work, interior trim, and novelties. Found from New Brunswick to Georgia and west to the Dakotas and south to Arkansas. Also called white walnut. (2) In the early settlement period of the eastern United States, a backwoodsman who wore clothing dyed yellow with butternut bark.

Button--(1) An irregularly shaped berry. (2) A bud. (3) A round seed vessel. (4) Any stunted or immature fruit. (5) A round, firm, cheesy curd of condensed milk; a defect of the body of the milk. (6) A nipple, especially of a hog. (7) A partially dismantled queen bee cell in a beehive, which resembles a small acorn cup. (8) Onion set. (9) A stunted or immature horn growth, as on a calf. (10) A metal clasp used to connect sections of a check row wire. (11) Cartilage on the chine bone of cattle (12) Any shell-like bone construction of the body; also called concha. (13) A leather ring for adjusting a horse's bridle.

Button Clover--Medicago orbicularis, family Leguminosae; a forage plant introduced into the United States from Europe. Also called button medic.

Button Weed--Malva rotundifolia; a common weed found in fields and around buildings.

Buttoning--The formation of tiny heads of cole crops on small plants, caused by the late transplanting of overly mature seedlings.

Buttress--Swelling (ridges) of a tree at its base near the soil, common among trees of the humid tropics and subtropics, especially on wet soils.

By-product--A product of significantly less value than the major product. In beef cattle, the major product is meat; by-products include the hide and other items.

By-product Lime--Any material containing calcium and/or magnesium resulting from the manufacture of another product, e.g., iron smelting, sugar factory lime.
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Title Annotation:Part 1: A-B
Publication:Delmar's Agriscience Dictionary
Article Type:Definition
Date:Jan 1, 2000
Previous Article:Part 3 Forestry and natural resources management.
Next Article:Part 4 Plant science.

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