Soil Moisture Variability Under Different Land Uses in the Zhifanggou Catchment of the Loess Plateau, China

Soil moisture is an important variable that determines crop growth and vegetation restoration. In the Loess Plateau, China, soil moisture dynamics are dramatically affected by land use patterns. This study investigated seven-year soil moisture dynamics and vertical distribution under seven land use patterns. The soil moisture levels in the 0 to 300cm depth in two croplands, and those in 0 to 600cm depth in two shrublands, a forestland, a grassland, and an abandoned cropland for natural recovery were measured in late April and late October of 2004 to 2010. The soil moisture storage in the 0 to 300cm depth in the Zea mayscropland dramatically exceeded that in the other six land use patterns. The Caragana korshinskii shrubland and Robinia pseudoacaciaforestland exhibited the lowest soil moisture storage in the entire 0 to 600cm depth. The soil moisture storage in the Hippophae rhamnoides, Caragana korshinskii, Robinia pseudoacacia, and Medicago sativalands showed a decreasing tendency, whereas that in the abandoned cropland was almost stable. Rainfall recharged the entire 300cm soil profile in the two croplands. The maximum soil infiltration levels in the Hippophae rhamnoides, Caragana korshinskii, and Robinia pseudoacacialands were 200, 200, and 240cm. The results indicate that planted shrubs and forests deplete soil moisture in the deep soil profile. The construction of terraces and dams can improve precipitation utilization rate, and restoring native grasslands after abandonment may be the best option for vegetation rehabilitation in the Loess Plateau.