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United States Department of Agriculture

Agricultural Research Service

Title: Cover Crop Impacts of Watershed Hydrology

Author
item Dabney, Seth

Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 1, 1998
Publication Date: N/A

Interpretive Summary: Cover crops are an agricultural best management practice that reduce erosion, prevent leaching of nutrients, and increase soil productivity. This paper reviews available information on the impact that cover crops can have on the flow of water through agricultural fields. Cover crops increase evaporation of water to the atmosphere while they grow. By protecting the soil, they can increase the amount of rainfall that soaks into the ground instead of running off and contributing to flash floods. Cover crops are beneficial in both conventional-till and no-till systems throughout the year. However, the difference between the results of plot and watershed studies demonstrate that caution should be taken in extrapolating plot data to watershed scales. As scale increases, so does the influence of subsurface soil horizons that prevent the deep percolation of soil water. Unfortunately, most of the available cover crop research comes from relatively small plots and very few watershed studies have been initiated in recent years. Perennial cover crops offer the potential for altering the porosity of subsurface soil horizons so as to increase future soil productivity and reduce future runoff amounts and rates. Millions of dollars are spent annually to preserve and repair bridges. With greater use of cover crops on agricultural fields, offsite damage of storm runoff may be reduced

Technical Abstract: Cover crops alter many aspects of the hydrologic cycle. They increase evapotranspiration while growing and can enhance water infiltration into soil, slow runoff rates, and reduce soil erosion in both conventional- till and no-till systems throughout the year. However, the difference between the results of plot and watershed studies demonstrate that caution should be taken in extrapolating plot data to watershed scales. As scale increases, so does the influence of hydraulically-controlling subsurface soil horizons. Unfortunately, most of the available cover crop research comes from relatively small plots and very few watershed studies have been initiated in recent years. Perennial cover crops offer the potential for altering the porosity of subsurface soil horizons so as to increase future soil productivity and reduce future runoff amounts and rates.

Last Modified: 7/28/2014
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