Soil and water conservation effects of contour grass hedges on sloping croplands

Soil and water loss are one of the global environmental problems. The contour grass hedges have been proved to be very effective in preventing soil and water loss. This study was conducted under simulated rainfall experiments to evaluate the effectiveness of grass hedges in reducing soil and water loss under different slope gradients (5%, 10%, 15%, 20%). The results showed that the runoff and soil loss on the plots with grass hedges were decreased by 57% and 72%, respectively; while the loss of total nitrogen and phosphorus were decreased by 58% and 55%, respectively. Moreover, the results also showed that there was a negative relationship between slope gradient and the effectiveness of grass hedges. The effectiveness of grass hedges gradually decreased with the increase of slope gradient. The regression results showed that the loss of soil, total nitrogen and phosphorus in runoff were positively correlated to the runoff.