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Conserving the Great Plains for all.

The Great Plains is a unique and wondrous ecosystem...harsh, yet productive...slow, but inexorable in its rate of change...unpredictable, except in its changeability.

So believes Jan van Schilfgaarde, the Agricultural Research Service's national program leader for natural resources and systems research based at the agency's Beltsville, Maryland, facility.

Van Schilfgaarde says, "Because of the harsh climate and generally low precipitation, damage done to the plains soils or vegetation tends to be slow to heal. The balance between regeneration and deterioration, between economic production and heartbreaking failure, is precarious and subtle."

"What affects agriculture affects almost everyone in this area," says James R. Welsh, Director of ARS' Natural Resources Research Center (NRRC), Fort Collins, Colorado. "For example, when farm income drops, local merchants feel the pinch, too. Tractor and truck dealers, fertilizer and seed sales people, even general merchants suffer lost or reduced sales. Farther down the line, suppliers of tractor parts and consumer goods are hurt by the reduced demand. So you might say that what's good for the Great Plains is good for America."

Farmers and ranchers in the 10 Great Plains states produce agricultural commodities that are vital to the nation's domestic and foreign markets. Agriculture is the number one industry for almost all communities in this vast area extending from northern Mexico into Canada.

The Great Plains has about a third of the total U.S. land committed to farms and ranches, but it produces more than 40 percent of America's beef cattle and more than 50 percent of its wheat. Just across the border, Canada's portion of the Great Plains makes up about 80 percent of that country's farm land.

From the dawn of agriculture about 10,000 years ago, agriculture was pretty much self-supporting, not using much fossil fuel energy or synthetic pesticides and fertilizers.

Then, along with the industrial revolution, farming changed and became more mechanized, requiring the purchase of additional inputs such as fertilizers and pesticides.

As farming systems have become more efficient in the last 100 years, the rate of agricultural impact on the land has accelerated. And soil erosion and water pollution have become serious problems for the Nation.

Soil is being lost faster than it's being created on 48 million acres from wind erosion and on an additional 28 million acres from water erosion. That represents about 70 percent of the arable acreage of the Great Plains.

In 1991, the NRRC was formed in the Colorado-Wyoming area to address excess erosion and other agricultural problems of the central Great Plains in an integrated fashion. Research units contributing to the NRRC include Water Management, Soil-Plant-Nutrient, Great Plains System, and Sugarbeet Production at Fort Collins; Central Plains Resources Management at Akron, Colorado; and Rangeland Resources at Cheyenne, Wyoming.

Problems to be addressed include irrigation management, range and livestock issues, dryland cropping practices, and associated environmental concerns. Solutions should lead to both increased agricultural profitability and improved natural resource preservation.

Says Welsh, "We at the NRRC hope to protect the environment and sustain productivity by using a systems approach - one in which all parts of the agricultural system are integrated into a complete computer-based information package that takes into account production, marketing, and social concerns."

A Century's Worth of Data

A wealth of scientific information has been generated since research first began more than 100 years ago in the Great Plains. But the very nature of the data collected from diverse locations and the regional bias that influenced its gathering make its use and interpretation for other locations difficult - if not impossible.

A system approach will permit scientists to extrapolate from these existing data sets and generate new computer models to test hypotheses critical to the survival of agriculture in semiarid and arid environments. for example, conservation tillage research done at Mandan, North Dakota, might yield information useful to farmers in Nebraska or Colorado if properly adapted through the use of these computer models.

A committee of farmers, ranchers, industry leaders, scientists, and administrators recommended creation of a Great Plains Agrisystems Project to formulate a systems approach to agricultural management. The NRRC will provide administrative and structural leadership and support for the project.

"Over the years, relatively little attentions was given to collecting information in common design or compatible formats. Our first challenge will be to identify and evaluate current agricultural research data from both Canadian and U.S. groups.

"Next, we will begin building farm-level decision support systems that integrate and use various data sets that represents scientific and technological advances. Finally, the system will be tested by the intended users to evaluate its possible applications and to identify knowledge gaps requiring further research and information," says Welsh.

Systems analysts will play a major role in integrating historical databases with recently collected information. But these scientists will also coordinate their work with specialists in other fields and with end users - farmers and ranchers. The Great Plains Systems Research Unit will serve as the lead group working cooperatively with other U.S. and Canadian computer modelers in order to best use available scientific expertise.

Says John D. Hanson, ARS range scientist in the Great Plains Systems Research unit, "Ranching has always been a risky industry. Profits or losses are largely determined by factors such as market demand for red meat and weather conditions - factors that ranchers have no control over."

Today, new variables must also be considered, including exotic breeds of cattle, new federal grazing regulations, and a host of environmental concerns such as water quality, wildlife habitats, and soil erosion.

Ranchers need a way to optimize their income for both short-term and mid-term periods that will also preserve natural resources for the long term. The systems approach will allow problems to be evaluated through computer programs, suggest alternative management choices, and spell out the potential economic impact each choice will have.

Creating a Model System

"We are developing an Agricultural Resource Management System to help sort though million of bits of information and to guide ranchers in making the best decisions," continues Hanson.

The central model, called SPUR II, is being developed in cooperation with Colorado State University and will be combined with two expert system and a linear model. The combined system will be unique because it could provide ranchers with estimates of how different sets of management practices affect both long- and short-term profits and long-term productivity.

Conserving Water

Water is a major limiting factor in Great Plains productivity. Researchers have developed computer programs that calculate the exact amount of irrigation water crops need and advise the irrigator on which pumps to use to keep energy costs low.

"In studies with multiple center pivot systems, we saved cooperating farmers $10 to $40 per acre per year because of improved water management and from about 46 to $15 in reduced energy charges," says Gerald W. Buchleiter, agricultural engineer at the NRRC's Water Management Research Unit, Fort Collins. Similar computer programs are designed to reduce water use in furrow irrigation.

Precipitation in the Great Plains frequently occurs in intense busts. Often, part of a 12- to 14-inch annual rainfall - such as is normal near Nunn, Colorado - runs off rather than soaking into the soil.

"We need to find farming and ranching methods that increase water infiltration, preserving this limited resource for plant production," says Gary Frasier, hydraulic engineer at the NRRC's Rangeland Resources Research Unit, Fort Collins. So far, researchers have developed terraces, grass waterways, and plastic mulches to conserve precipitation.

Frasier is modelling the problem, using a rainfall simulator to recreate sudden, intense rain showers typical of the plains. He's looking for techniques that will increase water infiltration into soils of the area.

A method for gathering large-area precipitation data involves a state-of-the-art Doppler radar system located near Greeley, Colorado, and operated by the National Science Foundation.

In recent cooperative studies with Colorado State University, scientists used the radar to measure the intensity of rainstorms as they occurred over ARS' Central Plains Experimental Range near Nunn. Twelve rain gauges recorded rainfall while other device measured runoff on the 16,000-acre research site.

Scientists hope to tie the radar data to the amount of water in the rain gauges. So, in the future, radar alone could measure rainfall intensity and, when used in conjunction with stimulation models, predict runoff and erosion. This would eliminate the need for labor-intensive and expensive gauges.

Replenishing Depleted Nutrients

Cultivation of prairie soil generally leads to reduced organic carbon, nitrogen, and phosphorus - the three most important elements plants need.

ARS soil scientist Rudolph A. Bowman, at the Central Plains Resources Management Research unit, Akron, Colorado, discovered that after 60 years of cultivation, more than half of these elements have been either used up by plants or washed or blown away. And more than 30 percent of the loss occurred during the first 3 years.

"Phosphorus appears to reach an equilibrium after 20 years of tillage in which no more is lost than gained, but carbon and nitrogen continue to disappear. This loss is from sandy soils typical of the Great Plains and is a far more rapid loss than has been reported on loamy or clay soils," Bowman says.

Bowman's work is part of the larger cropping systems research program under the direction of ARS soil scientist Ardell Halvorson at Akron. Halvorson and his team are studying alternative crops and cropping sequences to increase farming profitability beyond that yielded by conventional wheat-fallow rotation. The researchers learned that corn and millet can be grown profitably in the area and can be included in the older crop rotation.

Finding enough forage for livestock stock is a serious problem for ranchers in the western Great Plains. Many producers rely on hay from irrigated mountain meadows to fill this need. Fertilizer can sometimes increase yields.

Scientists at the High Plains Grasslands Research Station, Cheyenne, Wyoming, want to help ranchers make decisions about their pastures. Says ARS range scientist Richard H. Hart, "We have developed a computer program that considers variables such as temperature, cost and rate of fertilization, and price of hay. We calculated the most profitable nitrogen application rate for smooth bromegrass, creeping foxtail, meadow foxtail, and reed canarygrass at various nitrogen costs and hay prices."

However, chemicals - including fertilizers and pesticides - move downward in soil if water soaks in faster than plant roots can absorb it. Warns Carlos Alonzo, a hydraulic engineer in the Great Plains Systems Research Unit, Fort Collins, "Just how these chemicals move under differing conditions is still not completely known. So we have developed a two-dimensional model that we hope will explain subsurface transport of these potential pollutants."

From Earth to Sky

Other chemicals move upward and have the potential to affect gases that make up our protective atmosphere. Arvin R. Moiser, an ARS chemist in the Soil-Plant-Nutrient Research Unit, Fort Collins, is studying how land use and management changes in cultivate crops and native ranges influence the soil/atmosphere exchange of gases. The three of greatest concern are carbon dioxide, methane, and nitrous oxide.

These so-called greenhouse gases influence how much energy is absorbed by or radiated away from our planet and its atmosphere. The concentration of these gases is increasing rapidly in the atmosphere. Nitrous oxide also plays a role in destroying the stratospheric ozone layer.

"Our studies indicate that changes in land use have probably contributed to the increasing atmospheric concentrations of greenhouse gases during the past century," says Mosier. "Agricultural management practices also influence the soil/atmosphere exchange of all three gases. Practices that conserve soil and fertilizer generally decrease nitrous oxide emissions from soil and influence carbon dioxide and methane exchange as well.

"We need to be on top of the situation, prepared to cope with potential changes in the environment," concludes Mosier. "We are developing computer models that can analyze the effect of various shifts in temperature and atmospheric gases. This will give farmers and ranchers some understanding of what management practices will work] best under these new conditions."

These and many other research projects in the NRRC have been sources of valuable information for the systems approach to Great Plains issues. Moreover, public research programs - both ARS and land-grant university - across the Great Plains have historically produced findings important to solving complex agricultural questions.

"It is vital that we take the next step in integrating this information to ensure viability for future agricultural enterprises," adds NRRC's director, James Welsh. - By Dennis Senft, ARS.

Settling the Plains

Major Stephen B. Long crossed the Great Plains in 1819 and 1820, noting in his diary that the area was the Great American Desert. Others followed him but did not settle in the area because it lacked the trees and water so familiar in the eastern United States.

Agricultural development of the plains in Colorado began in the 1860's near the mountains. Those first farmers supplied food to thriving mining communities. Large livestock herds from Texas were summer grazed in the area starting in the late 1870's. The open-range cattle industry peaked in the mid-1880's but soon declined after a severe winter in 1886.

About the same time, homesteaders attempted dryland farming, only to abandon the land during a severe drought in the mid-1890's.

Plains settlements grew slowly until World War I, when a sudden surge in demand for wheat turned native rangeland into instant farms. Mechanized farming enabled cultivation of large acreages of dryland wheat.

During the 1930's, drought and the Great Depression caused the abandonment of hundreds of thousands of acres of dryland farms, setting in motion the creation of a vast Dust Bowl that sometimes darkened the skies of downwind cities as far away as New York City.

But World War II saw the demand for wheat increase once again, and Great Plains lands were plowed to meet the demand. The most recent increase in grassland conversion occurred in the late 1970's and early 1980's.
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Title Annotation:includes related article on Great Plains history
Author:Senft, Dennis; McGinnies, William J.
Publication:Agricultural Research
Date:Aug 1, 1992
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