The effects of narrow grass hedges on soil and water loss on sloping lands with alfalfa (Medicago sativa L.) in Northern China

Grass hedges provide an efficient way to prevent soil and water loss on sloping croplands in numerous countries throughout tropical and subtropical regions. However, the effects of grass hedges on sloping land are still not well understood in temperate regions where there is severe soil and water loss. Therefore, the soil and water conservation benefits of two native grass hedges, Pennisetum alopecuroide (Pennisetum alopecuroides (Linn.) Spreng.) and Arundinella hirta (Arundinella hirta (Thunb.) C. Tanaka), were investigated using simulated rainfall with different slope gradients (5, 10, 15 and 20%), rainfall intensities (14, 22, 36 and 63 mm h− 1), and coverage of alfalfa (Medicago sativa L.) on sloping lands of northern China. The results showed that Pennisetum hedges were more efficient in controlling soil and water loss compared with Arundinella hedges, possibly due to the more numerous, finer, and deeper roots in Pennisetum hedges. Overland flow and soil loss in sloping cropland were decreased by 52% and 75%, respectively, using Pennisetum hedges and 29% and 52%, respectively, using Arundinella hedges. The contribution of independent variables to overland flow followed the order rainfall intensity > coverage of alfalfa > type of grass hedges > slope gradient. The contribution to soil loss followed the order slope gradient > types of grass hedges > coverage of alfalfa > overland flow > rainfall intensity. Tillering ability and root characteristics should be considered in the selection of grass species when designing grass hedges. These findings may be helpful in the remediation of serious soil and water losses on sloping croplands in northern China and similar regions.

► Pennisetum hedges on the average decreased overland flow by 52% and soil loss by 75%.
► Arundinella hedges decreased overland flow by 29% and soil loss by 52%.
► Effects of grass hedges negatively correlated to slope gradient and rain rate.
► Grass hedges were very efficient in reducing soil and water loss on sloping croplands.