Assessment of the Effects of Conservation Practices on Cultivated Cropland in the Chesapeake Bay Region
On March 15, 2011, NRCS chief Dave White announced the release of the CEAP-Cropland report on the effects of conservation practices on cropland in the Chesapeake Bay region. This report is the second in a series of regional reports that continues the tradition within USDA of assessing the status, condition, and trends of natural resources to determine how to improve conservation programs to best meet the Nation’s needs. These reports use a sampling and modeling approach to quantify the environmental benefits that farmers and conservation programs are currently providing to society, and explore prospects for attaining additional benefits with further conservation treatment.
Computer modeling simulations indicate that conservation practice use in the Chesapeake Bay region has reduced sediment, nutrient, and pesticide losses from farm fields. However, there remain significant opportunities for reducing nonpoint agricultural sources of pollution.
Major findings from the study are listed below. More specific details on effects of practices are in the full report and the summary documents.
The voluntary, incentives-based conservation approach is working. Most cropland acres have structural or management practices—or both—in place to control erosion. Nearly half the cropland acres are protected by one or more structural practices, such as buffers or terraces. Reduced tillage is used in some form on 88 percent of the cropland. Adoption of conservation practices has reduced edge-of-field sediment loss by 55 percent, losses of nitrogen with surface runoff by 42 percent, losses of nitrogen in subsurface flows by 31 percent, and losses of phosphorus (sediment attached and soluble) by 41 percent.
Opportunities exist to further reduce sediment and nutrient losses from cropland. The study found that 19 percent of cropped acres (810,000 acres) have a high level of need for additional conservation treatment. Acres with a high level of need consist of the most vulnerable acres with the least conservation treatment and the highest losses of sediment and nutrients.
Targeting enhances effectiveness and efficiency. Use of additional conservation practices on acres that have a high need for additional treatment— acres most prone to runoff or leaching and with low levels of conservation practice use— can reduce sediment and nutrient per-acre losses by over twice as much as treatment of acres with a low or moderate conservation treatment need.
Comprehensive conservation planning and implementation are essential. Suites of practices that include soil erosion control and comprehensive nutrient management—appropriate rate, form, timing, and method of application— are required to simultaneously address soil erosion, nutrient losses in runoff, and loss of nitrogen through leaching.
Technical information on the methodology for CEAP Cropland studies in general, including the one on the Chesapeake Bay region, and documentation reports on the modeling methodology, models and databases, are available as part of the Cropland National Assessment. Detailed information on the CEAP Cropland Farmer Surveys conducted by NASS is available.
Information on other CEAP projects addressing watersheds, wetlands, wildlife, and grazing lands in the Chesapeake Bay region are also available.
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