On Monday, October 25, USDA’s Natural Resources Conservation Service (NRCS) announced that it is seeking comments on a draft of its second Conservation Effects Assessment Project (CEAP) report, entitled “Assessment of the Effects of Conservation Practices on Cultivated Cropland in the Chesapeake Bay Region.”  The full report is available for download here.

Comments should be sent to Dr. Robert Kellogg, with NRCS’ Resources Assessment Division, no later than November 22, 2010.  Comments can be submitted to him via email at: robert.kellogg@wdc.usda.gov.

CEAP is a multi-partner effort to measure and report the environmental effects of conservation programs and practices.  The latest report is part of a series of thirteen CEAP reports that focus on particular river basins around the country.  The first such report was released in June of this year and focused on the Upper Mississippi River Basin.

According to NRCS, “This latest draft report shows that[…] conservation practices in use on cultivated cropland within the watershed are responsible for reducing total loads delivered to the Bay by 14 percent for sediment, 15 percent for phosphorus and 15 percent for nitrogen.   These reductions are significant, but there’s more work to be done.  This draft report helps to identify where future Bay restoration efforts should be concentrated…”

The report’s primary findings include:

• Use of soil erosion control practices is widespread, with most acres receiving some form of erosion control treatment.  Nevertheless, about 26 percent of the cultivated cropland acres still have excessive sediment loss from fields and require additional erosion control practices.

• Significant improvement is still needed in nutrient management (proper rate, form, timing, and method of application) throughout the region.  About 81 percent of the cultivated cropland acres require additional nutrient management to reduce the loss of nitrogen or phosphorus from fields.

• The most critical conservation concern in the region is loss of nitrogen through subsurface loss pathways, most of which eventually contribute to surface water loads.  About 65 percent of cropped acres require additional nutrient management to address excessive levels of nitrogen loss in subsurface flow pathways, including surface and subsurface drainage systems.  About 28 percent of cropped acres need treatment only for nitrogen loss in subsurface flows.

• About half of the cropped acres are critically under-treated, usually requiring treatment for multiple natural resource problems.  These are the most vulnerable and/or under-treated acres with the highest losses in the region.

• Model simulations of additional conservation treatment show that nutrient loss from fields is within acceptable levels when soil erosion control practices are paired with management of rate, form, timing, and method of nutrient application that maximizes the availability of nutrients for crop growth while minimizing environmental losses.

• Treatment of erosion alone can exacerbate the nitrogen loss problem because reducing surface water increases infiltration and, therefore, movement of soluble nitrogen into subsurface flow pathways.  A suite of practices that includes both soil erosion control and consistent nutrient management is required to simultaneously address soil erosion and nutrient loss.

• Conservation practices in the region have also been effective in reducing pesticide residues lost from fields as well as the associated environmental risk.

• Of the total loads delivered to rivers and streams from all sources, cultivated cropland is the source for 25 percent of the sediment, 27.5 percent of the phosphorus, and 32 percent of the nitrogen.

The report goes on to state that 81 percent (3.5 million acres) of the cultivated acres in the Chesapeake Bay watershed would need to add additional conservation practices in order to reduce sediment and nutrient loss.  According to the report, “if all of the under-treated acres (81 percent of cropped acres) were fully treated with the appropriate soil erosion control and/or nutrient management practices, total loads delivered to the Bay (all sources) would be reduced from current levels by 7 percent for sediment (bringing loads from cultivated cropland down very close to “background levels”), 17 percent for phosphorus, and 16 percent for nitrogen.”