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USDA Assessment of Conservation in Lower Mississippi Basin

August 29, 2013

On Tuesday, August 27, Agriculture Secretary Tom Vilsack announced the release of the report, Assessment of the Effects of Conservation Practices on Cultivated Cropland in the Lower Mississippi River Basin.  The report is a comprehensive look at the effects of NRCS conservation practices on the approximately 105,000 square miles that the basin covers.

The Lower Mississippi River Basin is one of five Mississippi River drainage basins, and stretches into Kentucky, Tennessee, Missouri, Arkansas, Mississippi, and Louisiana.

Roughly one third of the lower basin is cultivated cropland.  It features mostly corn, soybeans, cotton, and rice, and produces two-thirds of the U.S. rice crop and one-quarter of the U.S. cotton crop.  Key findings of the report include:

  • Better and more comprehensive conservation planning is needed (note: this finding has been consistent across CEAP reports);
  • Farmers meet criteria for good nitrogen management on only about 14 percent of the cropped acres and good phosphorous management on 17 percent; and
  • Roughly 33 percent of the cultivated cropland in the region has a high level of need for additional conservation treatment, while 53 percent has a moderate level of need.
  • Although the Lower Mississippi River Basin has a higher proportion of level-to-nearly-level soils than do the other Mississippi River basins, the much higher and more intense precipitation in this region results in very high levels of sediment and nutrient loss from farm fields.

The report argues that due to the duration and intensity of rainfall and storms, the region requires enhanced soil erosion and nutrient management measures, even on soils with low or moderate risk of erosion and nutrient loss. 

Relative to a hypothetical situation in which no conservation practices are used, the CEAP report shows that producers in the region have reduced sediment loss by 35 percent by applying erosion control practices.  Much work, however, is left to be done.  The Lower Mississippi River Basin is responsible for nearly one-third (54 million tons) of all soil lost to the Gulf of Mexico each year.

As with sediment loss, the producers have reduced total loads of nitrogen delivered from cropland to rivers and streams by 21 percent, relative to a hypothetical baseline in which no conservation practices are used.  According to the report, “application of additional conservation practices on the high- and moderate-treatment-need acres would further reduce nitrogen loads to rivers and streams by 43 percent.”

Producers have had the most success in reducing phosphorous loss in the region.  The use of conservation practices has reduced phosphorous loads by 52 percent from baseline.  The report notes, however, that much work remains to be done to further control phosphorous loss.

The Lower Mississippi River Basin report is the seventh of twelve regional reports on conservation practices on cropland that will be issued as part of the Conservation Effects Assessment Project (CEAP).  The Project 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.

Categories: Conservation, Energy & Environment

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