Converting hydric cropland to wetland in Missouri: a geoeconomic analysis.
Agriculture is a major contributor to wetland losses and a major beneficiary of wetlands protection and development. Drainage of wetlands for agricultural production accounts for 87% of national wetland losses and two-thirds of the remaining wetlands are in agricultural areas (Tiner). Adverse effects of agricultural nonpoint source pollution can be reduced through headwater wetlands that are upstream of rivers, lakes, estuaries, or fringe wetlands adjacent to such water bodies. In addition, vegetative filter strips along stream corridors and riparian areas can stabilize banks, trap sediments and nutrients and reduce peak flows (U.S. Army Corps of Engineers). Other economic benefits of wetlands include flood protection, shoreline erosion control, fish and wildlife habitat, natural products, and recreation and aesthetics (U.S. Environmental Protection Agency).
There are two deficiencies with respect to analyzing the potential for enhancing wetland development in agricultural areas. First, systematic methods have not been developed for identifying cropland that has high potential for conversion to wetland. Second, the benefits and costs of converting cropland to wetlands has not been adequately evaluated. The major purpose of this paper is to evaluate the physical and economic feasibility of converting Missouri cropland to wetland. Specific objectives are to (1) demonstrate how a geographic information system (GIS) can be used to identify hydric cropland that is suitable for conversion to wetland, and (2) evaluate the net private and social benefits of converting hydric cropland to wetland.
Studies by Heimlich et al. and Carey et al. indicate that the average easement and restoration costs for a least-cost wetland reserve from hydric cropland would be $845 million for a 1 million ha (2.5 million ac) reserve ($835 [ha.sup.-1], $338 [ac.sup.-1]) and $2.4 billion for a 4 million ha (10 million ac) reserve ($1185 [ha.sup.-1] $480 [ac.sup.-1]) in 1988 dollars. Their analysis indicates that between 81,000 and 202,500 ha (200,000 and 500,000 ac) would be located in Missouri. Only Minnesota and Iowa have higher acreages. Several studies have estimated the present value of net returns from converting wetlands to agricultural uses, including land clearing and preparation costs. These values can be viewed as the opportunity cost (loss in net agricultural income) of converting agricultural land to wetland. Per hectare present values were estimated to be $376 ($151 [ac.sup.-1]) in the Mississippi Delta region (Kramer and Shabman), $1,573 ($637 [ac.sup.-1]) in North Carolina (Danielson, Gantt, and Noffsinger; Danielson and Hamilton), and $635 ($257 [ac.sup.-1]) in Central Minnesota (Danielson and Leitch).
The Des Plaines River Wetland Demonstration Project in Wadsworth, Illinois, studied the economic efficiency and political acceptability of building and managing wetlands for nonpoint pollution control in a 182-ha (450-ac) site (Hey). Hey's results can be applied to areas along the Mississippi River, where 25 million ha (61 million ac) of wetlands have been lost over the past 150 years. Restoring 10% of the lost wetlands along the Mississippi River (2.5 million ha, 6.1 million ac) in a 15-year period would require that 164,844 ha (407,000 ac) be converted to wetlands each year. Construction and land costs would equal $24 billion or $988 [ha.sup.-1] ($400 [ac.sup.-1]). Annual operating cost would be $160 million or $64 [ha.sup.-1] ($26 [ac.sup.-1]). Such a restoration effort would entail an annual investment of $247 million.
Wengrzynek and Terrell studied five prototype nutrient/sediment control systems for controlling nonpoint source pollution from cropland. These systems included watershed land treatment practices, sediment basins, grass filter strips, wetlands, deep ponds, and polishing areas for reduction of soluble phosphorus, nitrogen, organic matter, bacteria, and fine sediments reaching lakes and streams. Construction costs ranged from $14,000 to $22,500 for systems between 8.5 and 66 hectares (21 and 163 acres) in size, or $1,647 to $341 [ha.sup.-1] ($667 to $138 [ac.sup.-1]), respectively. Average annual costs of construction and maintenance was $49 [ha.sup.-1] ($20 [ac.sup.-1]). In addition to controlling non-point source pollution from cropland, wetlands can also protect forest, wildlife, and recreational resources (Leventhal).
Heimlich conducted a survey to evaluate the value of waterfowl production in the Prairie Pothole region. Waterfowl habitat values were estimated to be between $432 and $721 [ha.sup.-1] ($175 and $292 [ac.sup.-1]) per year in 1988 dollars. Gupta and Foster estimated the economic value of preserving freshwater wetlands in Massachusetts. Annual benefits per hectare of wetlands for wildlife production, visual-cultural (open space, recreation, and aesthetics), water supply, and flood control were $86, $333, $3457, and $99 ($35, $135, $1400, and $40 [ac.sup.-1]), respectively.
Raphael and Jaworski estimated the gross annual return from Michigan's 42,870 ha (105,855 ac) of coastal wetlands. Benefits of sport fishing, non-consumptive recreation, waterfowl hunting, trapping of fur bearers, and commercial fishing were $706.13, $341.41, $77.11, $75.16, and $9.33 per wetland ha per year ($286, $138.24, $31.23, $30.44, and $3.78 per wetland acre per year), respectively. Smith estimated losses from converting wetland to cropland in terms of the percentage of the annual value of the crops produced after conversion. Losses ranged from 0.36% in coastal areas to 1.54% in nontidal areas.
The analytical procedures consist of using ARC/INFO GIS to identify hydric cropland suitable for conversion to wetlands (site assessment) and economic procedures to estimate the net social and private benefits of converting hydric cropland to wetlands (economic assessment). Details of each step are discussed below.
Site assessment. The study area is Linn and Livingston counties located in north central Missouri. Economic activity in both counties is dominated by crop and livestock production. Considerable agricultural acreage in the area has been converted from pasture to cropland, which has increased the areas vulnerability to soil erosion and agrochemical contamination of surface and groundwater. Since soil, land cover, and land ownership data for the study area are not available in digital format and soil type is the major determinant of wetland suitability, the GIS is based primarily on the soils database. The latest soil survey for Livingston county was issued in December, 1956, and the most recent soil survey for Linn county in July, 1990. Soils in the study area vary widely in texture, natural drainage, and other characteristics. Broader ridge tops in the uplands are formed in loess. Upland side slops and narrow ridges are formed in loess over glacial till or entirely in glacial till. Nearly all of the upland soils are well suited for cultivation. Soils on moderately and steeply sloped land have high erosion rates. Soils on the terraces and floodplains are well suited for cultivation, although drainage is a problem.
Development of the soil digital and associated tabular databases for the two counties required digitization of 44,743 arcs which were then used to describe 15,062 separate soil polygons. Tabular databases were created for each of the two soil surveys. Linn county has 25 soil types and Livingston county has 31 soil types. For each soil type, extracts from their respective soil survey were tabulated and encoded to allow the creation of eight associated databases which were linked to the spatial file using a soil type code. Database names and associated attributes are given in Table 1.
Overall suitability of sites was based on three criteria: soil, size, and shape. The soil criterion evaluates a site in terms of soil attributes that favor the construction, maintenance, and productivity of a wetland. The following six indices were used to evaluate and rank soil suitability of a site: permeability, moist bulk density, overall engineering properties, flooding properties, water table characteristics, and wildlife habitat potential. The physical-chemical index accounted for moist bulk density and permeability and the engineering index was based on the percent passing sieve 200 which was then ranked. Flooding was evaluated by an index - the product of flooding frequency and flood duration. A water table index was calculated by multiplying the depth to water table and the kind of water table. A wildlife habitat index was assessed through the evaluation and summation of the wetland associated potential for each type of soil.
Each index had a possible range of -99 to 99. An overall soils index was created by subtracting the sum of those indices in which a low value was desirable for wet-land development from the sum of the indices in which a high value favored wetland development. Simple summation and subtraction of indices implies that the indices have equal weight. The overall soils index has a range of -294 to 294. Those cropland parcels that had a soils index of 100 or greater were deemed favorable for wetland development.
Many of the hydric cropland sites were considered too small to make an effective wetland and/or too difficult to secure because of multiple ownership. Sites smaller than 5 ha (12.3 ac) were eliminated because they are considered too small for wetland development (Young). Constructed wetlands on private land range in size from 4 to 122 ha (10 to 300 ac) with an average size of 10 ha (25 ac). The likelihood that the landowners for all portions of a potential wetland site would agree to convert their portions is expected to decrease as the number of owners increases. Therefore, a shape factor was used to eliminate long narrow sites along creeks and rivers, which are likely to have many owners.
Application of the soils, size, and shape criteria showed that 152 sites covering 1,837 ha (4,537 ac) were suitable for wetland development in Linn County and 202 sites covering 23,894 ha (59,012 ac) were suitable in Livingston County. The average size of these sites is 12 ha (30 ac) in Linn County and 85 ha (209 ac) in Livingston County. T and cover/ownership overages were assembled and digitized into the GIS. Coverages were compiled from plat maps and aerial slides. Land cover for Linn County indicates that 74.3% of the land area for the sites is in cropland, 10.4% is in grass/pasture, 8.2% is in forest, and 7.2% is in other land uses. Land cover data were not developed for Livingston County. Land ownership shows that 20% of the sites in Linn County have one owner, 38% have two owners, 20% had three owners, 14% had four owners, and 8% have five or more owners. In Livingston County, 13% of the sites have one owner, 19% have two owners, 14% have three owners, 11% have four owners, and 43% have five or more owners.
Economic assessment. Net benefits (benefits minus costs) of converting hydric cropland to wetland were estimated on a per hectare basis for suitable sites in Linn and Livingston counties. Net private (landowner) benefits of converting cropland to wetland equal the net income generated by the wetland, plus annual rental payments received on the wetland, plus cost sharing payments on wetland construction costs, minus the loss in net agricultural income from conversion, minus construction and maintenance costs on the wetland. Net value of activities/functions of wetlands that cannot be captured by the landowner (e.g., downstream flood control benefits) are excluded from private wetland benefits. The landowner would receive rental and cost sharing payments if the wetland is enrolled in the WRP or a similar program.
Net social benefits of converting cropland to wetland equal the gross value of all activities/functions supported by the wetland minus the loss in net agricultural income, minus construction and maintenance costs on the wetland. Rental and cost sharing payments are not included in net social benefits because they constitute transfer payments. Wetland activities and functions whose values should be included in social benefits include reduction in erosion, nonpoint source pollution, and flooding, and enhancement in fish and wildlife habitat, natural products, recreation, and aesthetics (U.S. Environmental Protection Agency).
Losses in net agricultural income or net returns from conversion of cropland to wetland equal gross returns from crop production minus costs of producing the crop. Since about 70% of hydric cropland in the U.S. meets the USDA definition for prime farmland, hydric cropland usually generates relatively high net returns to landowners (Heimlich). Gross returns per hectare for a crop equal crop yield times market price for the crop. Crop yields for the soils on potential wetland sites identified with the GIS are similar for Linn and Livingston counties. Average 1990 crop yields in bushels per acre were 99.8 for corn, 42.4 for wheat, and 29.2 for soybeans in Livingston County and 96.2 for corn, 42.1 for wheat, and 29.9 for soybeans in Linn County. Five-year average crop prices for the 1986-1990 period were used to calculate gross crop returns, namely: $.083 [kg.sup.-1], $.108 [kg.sup.-1], and $2.13 [kg.sup.-1] ($2.13, $2.95, and $5.81 [bu.sup.-1]) for corn, wheat, and soybeans, respectively (Missouri Department of Agriculture). Since corn and wheat prices are influenced by government programs, the prices for these crops are not a true indicator of the social losses from converting corn and wheat land to wetlands. Yet they are the only prices available for the benefit-cost analysis. Per hectare costs of production are based on 1990 Management Information Records (MIR) for Linn and Livingston counties (Ehlmann). Crop net returns to land and management in the study area were $58.39, $34.05, and $138.24 [ha.sup.-1] ($23.65, $13.79, and $55.99 [ac.sup.-1]) in Livingston county and $39.48, $31.87, and $148.29 [ha.sup.-1] ($15.99, $12.91, and $60.06 [ac.sup.-1]) in Linn county for corn, wheat and soybeans, respectively, in 1990. Average net returns per hectare were $76.90 ($31.15 [ac.sup.-1]) in Linn county and $73.20 ($29.65 [ac.sup.-1]) in Livingston county for the typical corn-soybean-wheat rotation.
The loss in net agricultural income from conversion of cropland to wetland over a finite time horizon of T years ([L.sub.1]) and over an infinite time horizon ([L.sub.2]) are as follows:
[Mathematical Expression Omitted]
[Mathematical Expression Omitted]
Per hectare construction and maintenance costs for wetlands are as follows:
CM = CC + [summation of] M[C.sub.t]/[(1 + r).sup.t] where t=1 to T
L = present value of loss in net agricultural income;
[P.sub.i] = price of the ith crop in the rotation;
[Y.sub.i] = yield [ha.sup.-1] for the ith crop in the rotation;
[C.sub.i]= [ha.sup.-1] cost of production of the ith crop in the rotation;
N[R.sub.i] = net return from production of the ith crop;
n = number of crops in crop rotation;
CM = construction cost plus present value of maintenance cost;
CC = construction cost;
MC = maintenance cost;
r = discount rate [(10%).sup.1];
i = crop index (i = 1,...,n);
t = time index (t = 1,...,T); and
T = length of time horizon (years).
Under the WRP, the government makes rental payments to landowners whose bids are accepted. Rental payments cannot exceed the maximum bid levels established by the government. From the landowner's viewpoint, the rental payment offsets the loss in net crop returns from converting cropland to wetland.
Construction costs are the costs for establishing the wetland and include earth work for dikes and levees, water control structures, and grass seeding for erosion control. Average construction costs vary from $123.45 [ha.sup.-1] ($50 [ac.sup.-1]) to $493.80 [ha.sup.-1] ($200 [ac.sup.-1]) for wetland construction on private land in Missouri (Young). Most constructed wetlands are at the high end of this cost range. In the WRP, landowners receive cost-share payments from the Agricultural Stabilization and Conservation Service equal to 75% of construction costs. In addition, the Missouri Department of Conservation (MDC) pays the remaining 25% of construction costs. Wetland maintenance costs for mowing levees and keeping vegetation growing are assumed to be $12.35 [ha.sup.-1] [year.sup.-1] ($5 [ac.sup.-1] [year.sup.-1]) (Young). Lack of data and information precluded estimation of many of the social benefits of converting cropland to wetland. The only benefits included here are those associated with waterfowl hunting. This simplification should not unduly distort the social benefits because waterfowl hunting is likely to be a major benefit of wetlands in the study area due to its proximity to Swan Lake National Wildlife Refuge and Fountain Grove Wildlife Area.
Table 2. Annual benefits and coats of wetland construction in Missouri, 1990 dollars [ha.sup.-1]
Benefits 640.19 2.69 Costs Net loss in agricultural income Linn 76.91 76.91 Livingston 73.21 73.21 Construction 493.80 123.45 Maintenance 12.35 12.35 Table 3. Net social benefits of cropland conversion to wetlands, Linn and Livingston counties, Missouri, on an annual basis and for four different time horizons, 1990 dollars per [ha.sup.-1]
County Annual 25-year 50-year 75-year Permanent
High Benefits-High Costs
Linn 57 4507 4969 5011 5016 Livingston 57 4528 4992 5035 5039
High Benefits-Low Costs
Linn 428 4877 5339 5382 5386 Livingston 430 4899 5362 5405 5409
Low Benefits-High Costs
Linn -580 -1279 -1352 -1359 -1359 Livingston -577 -1246 -1315 -1322 -1322
Low Benefits-Low Costs
Linn -210 -909 -982 -988 -989 Livingston -208 -888 -658 -965 -966
A landowner can lease the hunting rights to a private wetland in exchange for an annual fee. Since income from hunting leases has not been surveyed in the study area, hunting lease returns estimated by Byford were used. He estimated that the annual fee for duck hunting leases ranges from $74.07 to $740.70 [ha.sup.-1] ($30 to $300 [ac.sup.-1]). Using a wide range in the income potential from hunting leases is appropriate because of variability in the income of hunters, availability of private and public hunting sites relative to demand, and other factors. Costs of managing wetlands for waterfowl hunting (installing nesting boxes, fences, and dikes and planting feed patches) range between $71.79 and $100.51 [ha.sup.-1] ($28.91 and $40.71 [ac.sup.-1]) in 1990 dollars. Therefore, net income to landowners from waterfowl leases is expected to be between $2.69 and $640.19 [ha.sup.-1] ($1.09 and $259.29 [ac.sup.-1]) in 1990 dollars.
In calculating the net private and social benefits of converting cropland to wetland, it is assumed that potential wetland sites are enrolled in the WRP, the rental payment received by the landowner equals the present value of the loss in net agricultural income from conversion(2), no cash crop is produced on the wetlands,(3) the entire area converted to wetland is leased for hunting, and wetland construction costs are fully subsidized by the WRP and the MDC. In the pilot WRP, the rental payment is in the form of a periodic or lump-sum payment. Per hectare net social and private net benefits of wetland development were determined for four time horizons: 25 years, 50 years, 75 years, and infinite. An infinite time horizon corresponds to a permanent easement. Table 2 summarizes the range of annual benefits and costs of restoring hydric cropland sites to wetlands in Linn and Livingston counties.
Table 4. Net landowner benefits of cropland conversion to wetlands in Linn and Livingston counties, Missouri, on an annual basis and for four different time horizons, 1990 dollars [ha.sup.-1]
Annual 25-year 50-year 75-year Permanent
627.64 569.95 6224.94 6273.48 6278.42
-9.65 -87.62 -95.70 -96.46 -96.54
Benefits and costs of cropland conversion to wetland varies from parcel to parcel. It was not feasible to estimate benefits and costs for each suitable site identified with the GIS because of data limitations. Therefore, net private and net social benefits of conversion were evaluated using the range of benefits and costs given in Table
2. The following cases were evaluated:
Case 1: High benefits and high costs
Case 2: High benefits and low costs
Case 3: Low benefits and high costs
Case 4: Low benefits and low costs
High benefits/costs refer to high water-fowl benefits and high conversion costs. Low benefits/costs correspond to low waterfowl benefits and low conversion costs. Net social benefits are given in Table 3.
Positive (negative) net social benefits imply that conversion of hydric cropland to wetlands is socially efficient (inefficient). Net social benefits per hectare are positive in both counties when benefits and costs are high, and when benefits are high and costs are low. As expected, net social benefits are highest when benefits are high and costs are low. Net social benefits are negative in both counties when benefits are low and costs are high and when benefits and costs are both low. Consideration of wetland benefits other than hunting could result in positive net social benefits even in these two cases. Linn county has smaller net social benefits [ha.sup.-1] than Livingston county because net returns to cropland are higher in Linn county than in Livingston county.
Choice of time horizon influences the efficiency of wetland conversion. Compared to annual net benefits, net social benefits for 25-year, 50-year, 75-year, and permanent wetland easements are 77.88%, 85.95%, 86.70%, and 86.77% higher in Linn County and 73.64%, 81.28%, 81.98%, and 82.05% higher in Livingston County, respectively. Hence, net benefits of conversion increase with the time horizon but at a decreasing rate.
Because it is assumed that rental payments equal the loss in net agricultural income and that wetland construction costs equal cost sharing payments, the only distinction between net landowner benefits is whether hunting benefits are high or low. Therefore, there is no difference between net landowner benefits per hectare in Linn and Livingston counties. Net landowner benefits for high and low hunting benefits are displayed in Table 4. Positive net landowner benefits indicate it is economically feasible for a landowner to convert hydric cropland to wetland. Negative net landowner benefits indicate infeasibility. Results show that if a landowner receives high waterfowl hunting benefits, enrolls the constructed wetland in the WRP, and receives full cost sharing on wetland construction, then conversion is economically feasible. However, if the landowner can only achieve low hunting benefits on the wetland, then conversion would not be economically feasible. In summary, under the assumptions of this analysis, it is economically feasible for a landowner to convert hydric cropland to a wetland provided the revenue from waterfowl hunting leases on the wetland exceeds maintenance costs for the wetland.
This study estimates the net social and private (landowner) benefits of converting hydric cropland to wetland in two Missouri counties. To account for uncertainty in the revenue that landowners receive from waterfowl hunting on wetlands, and the costs of wetland construction and maintenance, economic feasibility was evaluated for a range of benefits and costs. Of the four benefit-cost cases used to evaluate the social feasibility of conversion, two cases showed positive net social benefits and two cases indicate negative net social benefits. Of the two benefit-cost cases used to evaluate the private feasibility of conversion, net private benefits were positive in one case and negative in the other. Positive (negative) net benefits imply that conversion is economically feasible (infeasible). Therefore, the social and private economic feasibility of conversion are sensitive to the range of benefits and costs evaluated here.
If the rental payment received by the landowner is greater than or equal to the loss in net agricultural income from conversion and the cost of wetland construction is fully subsidized, then the landowner would gain by converting hydric cropland to wetland provided the income earned from the wetland equals or exceeds the maintenance cost on the wetland.
The economic assessment conducted here can be improved in several ways. First, an accounting should be made of the other economic and environmental benefits of wetlands, such as flood control, timber production, non-consumptive recreation, and water quality protection. Second, wetland construction and maintenance costs should be determined based on site specific factors including soil type, slope, size, shape, and function/purpose of the wetland. Third, potential returns from hunting leases should be based on wetland site characteristics that are important in attracting wildlife. Fourth, site-to-site variability in crop yields, crop rotations, and production costs should be taken into account when estimating the loss in net agricultural income from converting cropland to wetland. Fifth, the possibility of supporting both wetland functions and commercial crop production on wetland sites should be considered.
RELATED ARTICLE: Table 1. Database names and attributes for GIS
Land capability and crop yield
* Land capability class
* Corn yield (bu [ac.sup.-1])
* Soybean (bu [ac.sup.-1])
* Sorghum (bu [ac.sup.-1])
* Wheat (bu [ac.sup.-1])
* Orchard grass - Alfalfa (tons [ac.sup.-1])
Physical and chemical properties
* Percent clay
* Moist bulk density
* Available water capacity
* Erosion factor K
* Erosion factor T
Engineering index properties
* Fragment size
* Percent passing sieve 4
* Percent passing sieve 10
* Percent passing sieve 40
* Percent passing sieve 200
* Liquid limit
Woodland Management, Building Development, Sanitary Facilities and Prime Farmland
* Erosion hazard
* Equipment limitation
* Limitations to shallow excavations
* Limitations to sewage lagoon areas
* Prime farmland
* Orchard grass - Clover (tons [ac.sup.-1])
* Orchard grass (tons [ac.sup.-1])
* Alfalfa hay (tons [ac.sup.-1])
* Switch grass (animal unit months)
* Fescue (animal unit months)
Soil and Water Features
* Hydrologic group
* Flooding frequency
* Flooding duration
* Flooding months
* High water table depth
* High water table kind
* High water table months
* Grain and seed crops
* Grasses and legumes
* Wild herbaceous plants
* Hardwood trees
* Coniferous plants
* Wetland plants
* Shallow water areas
* Open land/wildlife
* Woodland wildlife
* Wetland wildlife
* Limitations for pond reservoir areas
* Limitations for embankments, dikes and levees
* Features affecting drainage
* Features affecting irrigation
* Features affecting terraces and diversion
* Features affecting grass waterways
1 Choice of discount rate is somewhat arbitrary. The 10 percent rate selected here is considered to be an appropriate private rate for evaluating losses in agricultural income.
2 In cases where land is rented, them would need to be an agreement regarding whether cropland would be converted to wetland and how the rental payment would be shared between the landowner and the tenant.
3 While the WRP does not allow production of agricultural crops, grazing of cattle and timber production are permitted. If economically feasible, such activities would generate cash income that would offset the losses from crop production.
Byford, J.L. 1990. Assessing/evaluating/improving your potential from wildlife. In: W.N. Grafton, A. Ferrise, D. Colyer, D.K. Smith, and J.E. Miller (eds).Conference Proceedings: Income Opportunities for the Private Landowner through Management of Natural Resources and Recreational Access. West Virginia University Extension Service, Morgantown.
Carey, M., R. Heimlich, and R. Brazee. 1990. A permanent wetland reserve: Analysis of a new approach to wetland protection. U.S. Department of Agriculture, Economic Research Service, Agriculture Information Bulletin No. 610.
Conservation Foundation. 1988. Protecting America's Wetlands: An Action Agenda. Final report of the National Wetlands Policy Forum, Washington, D.C.
Danielson, L.E., and J.A. Leitch. 1986. Private vs public economics of prairie wetland allocation. Journal of Environmental Economics and Management. 13: 81-92.
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Ehlmann, G. 1992. Calculation of Production Costs from Management Information Records (MIR) for Linn and Livingston Counties. Department of Agricultural Economics, University of Missouri-Columbia.
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Heimlich, R.E., M.B. Carey, and R.J. Brazee. 1989. Beyond swampbuster: A permanent wetland reserve. Journal of Soil and Water Conservation, 44(5): 445-450.
Hey, D.L. 1988. Wetlands: A future nonpoint pollution control technology. Technical Publication Series No. 88-4, American Water Resources Association, Minneapolis, Minn.
Kramer, R.A, and L.A. Shabman. 1986. Incentives for agricultural development of U.S. wetlands: A case study of the bottomland hardwoods of the lower Mississippi River Valley. In: T.T. Phipps, P.R. Crosson, and K.A. Price (eds.), Agriculture and the Environment. Resources for the Future, Washington, D.C.
Leventhal, E. 1990. Alternative Usages of Wetlands Other Than Conventional Farming in Iowa, Kansas, Missouri, and Nebraska. U. S. Environmental Protection Agency, Region 7.
Missouri Department of Agriculture. 1991. Missouri Farm Facts.
Raphael, C.N., and E. Jaworski. 1979. Economic value of fish, wildlife, and recreation in Michigan's coastal wetlands. Coastal Zone Management Journal, 5(3).
Smith, V.K. 1992. Environmental costing for agriculture: Will it be standard fare in the farm bill of 2000? American Journal of Agricultural Economics, 74(5) 1076-1094.
Tiner, W., Jr. 1984. Wetlands in the United States: Current Status and Recent Trends. U.S. Fish and Wildlife Service, Massachusetts.
U.S. Army Corps of Engineers. 1986. Wetlands and Water Quality: A Regional Review of Recent Research in the United States on the Role of Freshwater and Saltwater Wetlands as Sources, Sinks and Transformers of Nitrogen, Phosphorus and Various Heavy Metals. Waterways Experiment Station, Vicksburg, Mississippi.
United States Department of Agriculture, Agricultural Stabilization and Conservation Service. 1992. Wetlands Reserve Program (WRP) Sign Up Starts June 15 in Missouri. Missouri Notice WRP-2, Washington, DC.
U.S. Environmental Protection Agency. 1988. America's Wetlands: Our Vital Link Between Land and Water. Office of Wetlands Protection, Washington, D.C.
U.S. Soil Conservation Service. 1985. Missouri Land - Its Use and Condition: Summary of 1982 National Resources Inventory, Washington, D.C.
Wengrzynek, R.J., and C.R. Terrell. 1990. Using constructed wetlands to control agricultural non-point source pollution. International Conference on The Use of Constructed Wetlands in Water Pollution Control, Churchill College, Cambridge, United Kingdom.
Young, S. 1992. Personal communication. Missouri Department of Conservation, Columbia, Mo.
Tony Prato is professor of agricultural economics and director of the Center for Agricultural, Resource and Environmental Systems (CARES), Yun Wang is a former research assistant in CARES, Tim Haithcoat is program director, Geographic Resources Center, and Chris Barnett and Chris Fulcher are research associates in CARES, University of Missouri-Columbia, 65211. The activities on which this report are based were financed in part by the Department of the Interior, U.S. Geological Survey, through the Missouri Water Resources Research Center, and by the Missouri Agricultural Experiment Station, University of Missouri-Columbia.
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|Author:||Prato, Tony; Wang, Yun; Haithcoat, Tim; Barnett, Chris; Fulcher, Chris|
|Publication:||Journal of Soil and Water Conservation|
|Date:||Jan 1, 1995|
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