SOIL QUALITY INDICATORS IN RELATION TO LAND USE AND TOPOGRAPHY IN A SMALL CATCHMENT ON THE LOESS PLATEAU OF CHINA

Better understanding of how the loess soils respond to topography and land use under catchment-scale vegetation restoration is needed to enable science-based land management interventions for the policy-driven Grain-for-Green eco-restoration program in the Loess Plateau of China. The objective of this study was to characterize the relationships of four selected soil quality indicators to land use under vegetation restoration and topography for a small catchment (058km(2)) in the Loess Plateau. The major land uses established in the catchment are cropland, fallow (i.e., natural revegetation), grassland, and jujube orchard. The four soil quality indicators were soil organic carbon (SOC), soil total nitrogen (STN), soil total phosphorus (STP), and mean root zone soil water content during the wet season (MRZSWwet). SOC, STN, and MRZSWwet were significantly different (p<005) for different land uses. Grassland showed the highest values for these three properties, whereas cropland had relatively low values for SOC and STN. Land use had no effect on STP, although the lowest value was observed in grassland. Spatial analysis showed that various relations between soil quality indicators and topography (slope and elevation) were observed. These relations were generally weak for most of them, and they varied with land uses. Further analyses indicated that land uses, slope, and elevation had significant effects on the relations between different soil quality indicators. The results here should provide useful information for the further development of Grain-for-Green program. Copyright (c) 2012 John Wiley & Sons, Ltd.