On Thursday, December 5, USDA released an updated Assessment of the Impacts of Conservation Adoption on Cultivated Acres of Cropland in the Chesapeake Bay Region.  The report is part of the USDA’s Conservation Effects Assessment Project (CEAP).

By combining edge-of-field and in-stream modeling along with farmer surveying, the report examines the impact that conservation practices such as cover cropping, crop rotation, and buffers are having on a variety of resource concerns in the Chesapeake Bay watershed.  The assessment is limited to cropland acres, which make up roughly 10 percent (4.35 million acres) of the Chesapeake Bay region.

To assess the impact of farm-based conservation in the Bay, the report compares soil erosion, nutrient loss, the scope of conservation practice adoption, and other measures between 2006 and 2011.  More specifically, the report analyzes landscape-level changes by comparing data collected between 2003 and 2006 to more recent data collected between 2009 and 2011.

Key Findings of the Report

Modeling scenarios indicate that since 2006:

• Sediment loss from fields decreased by 63 percent, from 5.1 to 1.9 tons per acre per year;
• Nitrogen loss through surface runoff decreased by 38 percent, from 15.7 to 9.7 pounds per acre per year;
• Subsurface nitrogen loss decreased by 12 percent, from 25.9 to 22.9 pounds per acre per year;
• Total phosphorus loss from fields decreased by 44 percent, from 3.4 to 1.9 pounds per acre per year;
• Soil carbon loss from fields decreased by 50 percent, from 189 to 95 pounds per acre per year.

A survey of farmers in the region indicates that since 2006:

• Use of practices designed to trap sediment and nutrients at the edge-of-field increased by 17 percentage points, from 14 percent to 31 percent of cropped acres;
• Use of conservation tillage (without any conventional tillage) increased by 23 percentage points, from 56 to 79 percent of cropped acres;
• Use of cover crops increased by 40 percentage points, from 12 to 52 percent of cropped acres; and the percent of acres that had cover crops planted annually nearly quadrupled from 5 percent to 18 percent;
• Despite very significant reductions in nutrient loss, as modeled for edge-of-field and in-stream impacts, the survey indicates that farmers applied more fertilizer, less efficiently than they did between 2003 and 2006;
  • Annual nitrogen applications increased by 10 percent, including a 9 percent increase in commercial fertilizer application and a 13 percent increase in manure application; and the number of acres on which farmers used the appropriate rate, timing, and method of nitrogen application on all crops in the rotation decreased by 6 percentage points, from 13 to 7 percent of acres;
  • The amount of phosphorous applied annually increased by 6 percent, though the number of acres on which farmers used the appropriate rate, timing, and method of phosphorous application on all crops in the rotation did not change;
  • Manure application increased by 10 percentage points, from 38 to 48 percent of cropped acres, and rate of application increased by 25 percent;
  • The number of “manured” acres applied with off-farm-sourced manure increased by 17 percentage points, from 17 to 34 percent.

Conclusions

The findings of the latest assessment are a testament to the importance of farm-based conservation management practices.  However, practices will not work effectively in isolation.  For example, the report states, “nutrient applications and tillage management are necessary for crop production and even when appropriately applied will have losses of sediment and nutrients.  Therefore losses that cannot be avoided with these management approaches should be controlled within the field with practices such as terraces, grassed waterways, or contouring.”

While adopting a suite of conservation practices is the most effective way for farmers to limit resource degradation, cover crops play a particularly important role in limiting nutrient and soil loss.  According to the report, “relative to the 2003-06 baseline condition, the increased annual use of cover crops in the 2011 conservation condition enhanced reduction in sediment loss by an average of 78 percent, surface loss of nitrogen by 35 percent, subsurface nitrogen loss by 40 percent, and total phosphorus loss by 30 percent.”

Since 2006, tens of thousands of farmers have used federal conservation programs such as the Chesapeake Bay Watershed Initiative, Conservation Stewardship Program, and Environmental Quality Incentives Program to implement a variety of conservation activities, including nutrient management, resource-conserving crop rotations, cover cropping, and conservation tillage.  These conservation activities are improving the ecological health of the Chesapeake Bay.  However, more can and should be done.  While the number of acres with a high need for additional conservation treatment decreased by 15 percentage points, for example, the number of acres with a moderate need for additional treatment increased slightly from 40 to 42 percent.

The farm bill currently being considered by Congress would cut between $3.5 billion and $5 billion from farm bill conservation programs.  This report should serve as a wake up call that these programs are vital to the long-term health of our natural resources and to the industries and consumers who depend upon them.  Of particular concern is a proposed 14-21 percent cut to the Conservation Stewardship Program, the nations largest working lands conservation program.  A number of other key conservation programs, including the Wetlands Reserve Program, also face the threat of going without any funding whatsoever, if we are faced with another farm bill extension rather than a full farm bill.  For more on that, read our blog post from earlier this week.

For More Information

The Chesapeake Bay update is the eighth of 15 regional reports (including the original Chesapeake Bay report) on conservation practices on cropland that will be issued as part of the Conservation Effects Assessment Project (CEAP).  CEAP is intended to assess the effects of conservation practices on the nation’s cropland, grazing lands, wetlands, wildlife, and watersheds.  It is a multi-agency, multi-resource effort led by the USDA’s Natural Resources Conservation Service.  Additional information is available on the NRCS CEAP webpage.