Source: Dabney, S.M. 1998. Cover crop impacts on watershed hydrology. J. Soil Water Conserv. 53:207-213.

The use of cover crops is a sustainable agricultural management practice that can help reduce erosion, minimize leaching of nutrients and water, and increase soil fertility. Cover crops affect the distribution and circulation of water in agricultural fields by influencing the partitioning of precipitation between infiltration, storage, and runoff. In this article, the author attempts to illustrate three interactions between cover crops and hydrology: (1) cover crops increase water filtration by preventing surface sealing, increasing available water storage capacity, and increasing soil macroporosity, (2) cover crops increase hydrologic resistance of the soil surface, resulting in a slowing down of runoff, and (3) roots of cover crops help bind soil together, increasing resistance to detachment and transport, thereby reducing soil erodibility. The author also cites several studies that show that cover crops are beneficial in both conventional tillage and no-till systems; however, most crop cover research has been done on plot scales rather than in a watershed context. By comparing two studies, one of a natural rainfall erosion plot and one of a small watershed, the author shows that the amount of runoff from the watershed was twice as large as that predicted from small plots. This illustrates the significance of scale when interpreting results. In his article, Dabney clearly illustrates the benefits of cover crops and their effects on hydrology. At the same time, he warns the reader to be careful when extrapolating plot data to watershed hydrology. Dabney concludes by emphasizing that cover crop usage could save millions of dollars per year in damage to the land, bridges, and other structures affected by runoff.

Abstract author: Devon J. Bradley, 27 October 1998.

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