Soil surface strength and infiltration rate as affected by winter cover crops

Abstract

Soil surface crusts greatly influence seedling emergence, water infiltration, and soil erosion. It has been hypothesized that cover crops may strongly influence crust strength and infiltration. Thus, studies were conducted at three sites within the Central Valley of California to investigate the effects of cumulative impact energy of simulated rainfall and of winter cover crops on surface soil strength and infiltration. Increasing levels of cumulative impact energy of rainfall resulted in an increase of up to five times in soil surface strength as measured by a micropenetrometer. Oat/vetch and vetch cover crops at the Davis site lowered the surface soil strength by 24–41% and improved cumulative water intake relative to the treatment without a cover crop. However, steady infiltration rate was not significantly affected. At another location (Ceres), the use of bromegrass, resident vegetation and strawberry clover as cover crops not only reduced surface soil strength by 38–41% but also increased steady infiltration rate and cumulative water intake by 37–41% and 20–101%, respectively.