NC174: Management of Eroded Soils for Enhancement of Productivity and Environmental Quality
Statement of Issues and Justification
Soil erosion results in a tremendous economic loss to society. Crosson (1984) estimated a monetary loss in the USA from soil erosion effects on cropland productivity to be 40 million dollars in any one year. For many soils, continued erosion results in degraded topsoil and declines in yield which are cumulative over time as root restrictive layers, such as fragipans, high clay content, or coarse sand, move closer to the soil surface (Langdale et al., 1985). Offsite damages to the environment from soil erosion are also considerable. Environmental costs due to soil erosion in the USA are estimated at 3.1 billion dollars each year (Pimentel, 1992).JUSTIFICATION:
This research project was initially designed to strengthen the scientific foundation for describing the potential crop production of selected soils, for predicting changes in the potential crop production of these soils as erosion occurs, and for evaluating the potential to extrapolate this information to other soils not studied. A coordinated regional effort provided the diverse range in soil and climatic characteristics necessary to develop the basic principles relating erosion to soil and crop productivity.
In the first 5-year phase of the NC-174 project (1983-1988) we identified and documented the effects of erosion on soil properties and corn or small grain yield. Five years of data were collected to better document the effects of weather on the interaction between soil properties and corn yield in the north central United States.
Once the database was enlarged emphasis was placed on selection of management and restoration alternatives at either the initial or a new site. The NTRM (Nitrogen, Tillage, Residue and Management) and EPIC (Erosion-Productivity Impact Calculator) models were used in conjunction with the existing data base collected during the initial phase of the NC-174 project to identify factors limiting crop productivity of each soil series. The models were used to evaluate long-term effect of management and restoration alternatives prior to field testing. The second phase of the project (1988-1993) was to field test the practices selected to maintain or enhance current productivity and to determine the extent to which productivity of eroded soils can be restored. The third phase of the project (1993-1998) determined threshold soil property values for the restoration of productivity and quality of eroded soils.
Understanding soil erosion in relationship to crop productivity, environmental, and economic impacts is of particular importance since the passage of The Food Security Act of 1985 (P.L. 99- 198) (U.S. Congress, 1985) and the 1990 and 1996 Farm Bills. These acts significantly change the adoption of soil and water conservation practices because they required strict conservation measures be used on land classified as highly credible if the farm operator chose to continue eligibility for farm price and income support programs. Getting needed information on land management requires substantial regional effort.
The North Central Regional Association of Agricultural Experiment Stations developed a May 1995 list of research priorities for seven Cross-cutting Research Areas and Objectives. The proposed Regional Project address the top three objectives for the Natural Resources and the Environment. These include: (1) Identify and apply ecosystem management principles and practices or the utilization and protection of resources, restoration of natural systems and management of rural landscapes. (2) Define sustainable principles for resource management, utilization and land use. (3) assess the relationships of agricultural/forestry practices (primary production) upon soil and water systems and bio-diversity.
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