The mean event soil loss in those large storms was 530 g/m2 on woodland, 922.9 g/m2 SB431542 purchase on alfalfa land, 477.2 g/m2
on grassland, 228.5 g/m2 on terraceland, and 1690 g/m2 on earth bank, representing 15.7%, 27.4%, 14.1%, 6% and 50.1% of the soil loss detected from the cropland, 3373 g/m2. Of those large storms, there were three extreme storms with recurrence intervals greater than 10 years, in which the mean event soil loss was 205.5 g/m2 on woodland, 2322.1 g/m2 on alfalfa land, 1271.8 g/m2 on grassland, 434.9 g/m2 on terraceland, and 4203.3 g/m2 on earth banks, representing 2.3%, 26%, 14.4%, 4.9% and 47.7% of the soil loss detected from cropland, 8809.3 g/m2. With respective of runoff reduction, it is important to know how effective of those practices in reducing runoff in extreme large storms which may selleck compound cause flooding. The mean event runoff for storms with recurrence intervals of greater than 10 years was 17.6 mm on woodland, 22.7 mm on alfalfa land, 5.2 mm on grassland, 5.9 mm on terraces, and 17.7 mm on earth banks, representing 75.9%, 97.8%,
22.4%, 25.4% and 76.3% of runoff generating from cropland, 23.2 mm on cropland. The following are the supplementary data to this article. Finally, soil loss by the maximum annual erosion event was compared to annual total soil loss on the cropland plot (Fig. 10). It can be seen that erosion rate by the maximum annual erosion event was widely varied among years, ranging from 409 to 19,127 g/m2, which contributed to a mean value
of 64% of the annual total Oxymatrine soil loss, ranging from 22.2 to 90.6%. The rainfall amount of the maximum annual erosion event accounted for a mean value of 9.1% of annual precipitation, ranging from 3.4 to 15.7%. In other words, a fraction of annual precipitation was often responsible for majority of annual total erosion in this semi-arid region. However, it is noted that the maximum annual erosion event was not necessarily the maximum annual rainfall event. For example, in 1958, the largest storm event with rainfall amount of 78.8 mm merely generated soil loss of 529 g/m2, in comparison of the largest erosion event of 5651 g/m2 caused by a storm of 50.9 mm in rainfall amount. This indicated the significance of other rainfall characteristics (e.g. intensity, pattern, duration, and antecedent rainfall) besides event rainfall amount in determining rainfall erosivity. The hilly loess region in China is dissected by dense gullies and the individual households farm the narrow and often steep lands in inter-gully areas. This justifies the purpose of the present study on soil and water loss on the slope plots with relatively short lengths and a wide range of slope angles up to 30°.