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Measuring and Understanding the Effects of Conservation Within Watersheds

JSWC CEAP Watersheds Special cover image

On May 12, 2020 the Journal of Soil and Water Conservation released a Special Issue on the CEAP-Watersheds Assessment Studies for its May/June issue (cover shown at left). “The scientific findings in this special issue of the Journal of Soil and Water Conservation show that conservation programs work,” said NRCS Chief Matthew Lohr. “The programs improve water and soil quality, and these scientific studies have also taught us how to improve our programs in the future.”

The issue, “Measuring and Understanding the Effects of Conservation Within Watersheds,” contains 15 peer-reviewed research papers (published in collaboration with USDA’s Agricultural Research Service), 2 introductory papers (one an overview of CEAP-Watersheds findings from more than 15 years of assessment, and the second a review of the impact of the STEWARDS database from CEAP), and an editorial paper from the FPAC Under Secretary about the importance of measuring outcomes.

Study findings show that conservation practices are working to reduce runoff, improve soil quality, and mitigate contaminants in small watersheds across the country. Impacts measured in the studies include reduction of sediment and nutrients lost in runoff, improvement in soil quality, and improved understanding of conservation practices mitigating contaminant losses. Practices were assessed at multiple scales and included drainage management, conservation tillage, cover crops, buffers, irrigation, nutrient management, water management and Conservation Reserve Program (CRP) practices. Some examples of results in the papers include:

  • In the Central Mississippi River Basin, combining no-till and cover crop practices reduced sediment losses by 87% and nitrate losses by 57% on a monitored field due to changes in soil moisture, timing of nitrogen applications, and use of cover crops (Baffaut et al. 2020).
  • In the Western Lake Erie Basin, edge-of-field monitoring revealed that subsurface placement of fertilizer in tile-drained fields reduced dissolved phosphorus losses by 66% (Williams et al. 2018). In addition, an innovative conservation practice was developed to treat contaminant losses from drainage water – replacing tile risers with blind inlets. This new practice reduced sediment losses by about 78% (Smith and Livingston 2013), total phosphorous losses by 66%, and dissolved phosphorus losses by 50% (Feyereisen et al. 2015).
  • In the Choptank Watershed in the Chesapeake Bay, novel satellite remote sensing techniques were developed and evaluated, along with program data, to assess the extent of cover crop implementation over an 8-year period (2008-2016). These techniques documented a 62% increase in winter cover crop use in corn fields and a 37% increase in soybean fields in a sub-watershed. In addition, modeling results indicate that this cover crop adoption led to a 25% reduction in nitrate leaching from cropland over a 10-year period (2008-2017) (Hively et al. 2020).

All papers in the Special Issue are open access and are available for free download.

A webinar presenting findings from the overview paper and other research papers will be presented on May 28, 2020 and a recording will be made available.

For more information, contact Lisa Duriancik, NRCS CEAP-Watersheds Assessment Studies Component Leader at lisa.duriancik@usda.gov.

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