Seasonal variations of soil water in red-soil hillslopes with ephemeral gullies

The soil water contents in the four red-soil hillslope plots at 15 degree with artificial ephemeral gullies were monitored from late-May 2007 to early-January 2008. Seasonal variations of soil moisture and influencing factors, such as rainfall, soil texture, contour hedgerow and gully micro morphology, were analyzed and discussed. The results showed that the seasonal variations of the soil water contents of 0-45 cm in all plots responded well to the precipitation, indicating that the precipitation played the most important role in controlling the soil water content of the studied gullies. Whereas, the soil water contents in the hedgerow plots showed slightly different from others. In both the dry and rainy seasons, the average soil water content of 0-45 cm in the hedgerow plots was significantly higher than those of plots with no hedgerow. Both the soil texture and the gully micro morphology presented an important influence on the variation of soil water content in the slope surface of the ephemeral gullies. However, their effects were not statistically significant compared with the precipitation and the hedgerow. Our collective results indicated that the contour hedgerow does help to maintain the soil water in the hillslopes.