Cover crop impacts on watershed hydrology

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. Rs scale increases, so does the influence of hydraulically-controlling subsurface soil horizons. Unfortunately, mast 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.