Soil moisture dynamics of different land-cover types in the black soil regions of China

Based on collected soil moisture data from the fixed-position monitoring system in the black soil regions of China, soil moisture dynamics in different land-cover types were analyzed. The results show that the variation in soil water under the three land-cover types decreases with increasing soil depth for which vertical change in soil water along the soil profile can be put into four groups, vertiginous layer, active layer, transitional layer and relative stable layer. The depth of soil water cycle for the different land-cover types is as follows: soybean-land > grassland > bare-land, and the order of soil water cycle intensity is: grassland > soybean-land > bare-land. Soil water content in the three land-cover types increases with increasing soil depth, and water content of the surface layer (0~20 cm)in bare-lands is higher than in grasslands and soybean-lands. However, under 30 cm soil depth, soil water content takes the following order: grassland > bare-land > soybean-land. Water storage in the 170 cm soil layer is controlled by rainfall. Under the three land-cover types, the order of total evapotranspiration is: grassland > soybean-land > bare-land.