Soil
moisture is a key factor for hydrological processes, plant growth and vegetation rehabitation in semi arid environments. A better understanding of the characteristics of
Soil moisture differentiation in space and time is important for improving hydrological processes and land management in both runoff and erosion control. However, the knowledge about spatial and temporal variability of soil moisture for different land use types and structures is rare in the hilly area of
Loess Plateau of China. In order to analyze the relationships between land uses and soil moisture in space and time, five representative land use structures and seven land use types were selected to monitor soil moisture in Da Nangou catchment (3 5 km\+2) in Loess Plateau from May to October, 1998. The five
land use structure combinations from top to foot of the hillslope were:
cropland - cropland - cropland, cropland - woodland - orchard, fallow land - grassland - cropland, fallow land -
shrubland - intercropping land - woodland and fallow land - shrubland - cropland - orchard. Soil moisture measurements have been performed biweekly at about 26 locations. The measurements were carried out on regular plot by using portable Time Domain Reflectometry (TDR) at five depths: 5 cm, 15 cm, 25 cm, 40 cm and 70cm. Based on above data, the spacial and temporal distribution of soil moisture are analyzed in seven land use types. The results showed that the changes of soil water content presented 3 peaks and 3 valleys during growing season and that the lag influence on soil moisture was found in woodland and intercropping land. Soil moisture changes of profile can be clustered into three groups, they are increasing, decreasing and fluctuant. The effect of five land use structures on soil moisture along hillslope were analyzed, two better land use structures for runoff and erosion control, were put forward, they were fallow land - shrubland - intercropping land (terrace)-woodland and fallow land - shrubland - cropland (terrace) - orchard. At the same time, benching terrace for crop-fruit tree intercropping system and breeding for deep-root plants were proven to be effective approaches in soil and water conservation in hilly area of loess.
More abstracts about the The impact of land use on spatial and temporal distribution of soil moisture on the Loess Plateau