Horizontal ridge rupture
As shown in Figures 6 and 7, mulching could not totally prevent contour ridge rupture, especially under heavy rainfall conditions; for example, the ridge of Hr was destroyed at both rainfall intensities, while that of Hr+Cm occurred only at 100 mm h-1. The ridge rupture occurred earlier at 100 mm h-1 than at 50 mm h-1. The averaged runoff rate of Hr was 3.83-fold greater after ridge rupture than before at 50 mm h-1, being 22.63- and 1.55-fold greater under Hr and Hr+Cm at 100 mm h-1, respectively. Meanwhile, the average soil loss rate of Hr was 13.84-fold greater after ridge rupture than before at 50 mm h-1, being 94.70- and 1.14-fold greater under Hr and Hr+Cm at 100 mm h-1, respectively.