[Spatial variability of soil moisture, nutrients, and productivity on slopeland in loessial semiarid region].
For the sustainable development and ecological construction in the loessial semiarid region, it is important to describe the variability of slopeland soil properties and the affecting factors of slopeland productivity. In this study, soil samples were taken from eroded steep slopeland, and leaf area index (LAI) and above-ground biomass (AGB) were measured at the sampling locations. The soil water content (WC) of 2 m depth at 20 cm intervals, and the soil organic matter (OM), total nitrogen (TN), total phosphorus (TP), available nitrogen (AN) and available phosphorus (AP) contents of 0-20 and 20-40 cm soil layers were determined in the laboratory. The results showed that the majority of the properties was normally distributed, and the nutrient contents were higher in 0-20 cm than in 20-40 cm layer, but the variations of soil nutrients were much smaller in 0-20 cm than in 20-40 cm layer. Soil nutrients had a significantly larger variation than soil moisture. Soil nutrient contents in 20-40 cm layer kept increasing from upslope to downslope, while those in 0-20 cm layer varied slightly. Slope topography had more obvious impact on soil organic matter, total nitrogen and available phosphorus than other affecting factors. Soil water and nutrient contents on the shallow gully trough were notably higher than those on the upslope, but above-ground biomass was less than that on the upslope. Though longitudinal slope (35 degrees-45 degrees) was obviously larger than the horizontal one (5 degrees-10 degrees), horizontal slope position had a greater influence on soil nutrients, but much weaker effect on soil moisture than longitudinal direction. There were significant correlations between 0-120 cm soil moisture and 20-40 cm soil nutrients, and among soil nutrients except 0-20 cm soil available phosphorus. Slopeland position had a great impact on soil moisture and nutrients, but soil moisture and/or nutrients had no significant impact on above-ground biomass.
Pan
Chengzhong
C
State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling 712100, China. czpan@ms.iswc.ac.cn
Shangguan
Zhouping
Z
D018533:Biomass; D002681:China; D003889:Desert Climate / Q000009:adverse effects; D017753:Ecosystem; D009584:Nitrogen / Q000032:analysis*; D010758:Phosphorus / Q000032:analysis; D012987:Soil / Q000032:analysis*; D014908:Triticum / Q000254:growth & development*; D014867:Water / Q000032:analysis*
D012987:Soil; D014867:Water; D010758:Phosphorus; D009584:Nitrogen