Runoff features of pasture and crop slopes at different rainfall intensities, antecedent moisture contents and gradients on the Chinese Loess Plateau: A solution of rainfall simulation experiments

Pastures are important components of artificial vegetations for controlling soil erosion on the hilly region of Loess Plateau of China. However, runoff features of pastures and the differences with crops are not fully understood in this region. This study focused on two widely-planted pastures including ryegrass (Lolium perenne L) and alfalfa (Medicago sativa L) and one common crop spring wheat (Triticum aestivum L), and investigated their runoff features at soil boxes under different rainfall intensities, antecedent moisture contents and slope gradients through rainfall simulation experiments. And bare ground was set as control. The results indicated that the presence of vegetation delayed time to runoff and reduced runoff coefficient. The average values of time to runoff were ranked as: ryegrass > spring wheat > alfalfa > bare slope. Contrarily, the rank for slope runoff coefficient was: ryegrass < spring wheat < alfalfa < bare ground. Time to runoff and runoff coefficient showed significant (P < 0.05) correlations with rainfall intensity, antecedent moisture content, and slope gradient. Time to runoff showed a negative and exponential relationship with rainfall intensity and antecedent moisture content and a negative and linear relationship with gradient. Runoff coefficient indicated a positive and linear relationship with rainfall intensity and antecedent moisture content and a positive and power-function relationship with gradient. The results presented here could provide insights into understanding the effects of rainfall intensity, slope gradient, and antecedent moisture content on surface runoff for the Loess Plateau region. (C) 2014 Elsevier B.V. All rights reserved.