Variation of soil water stability and dominant influencing factors after sparse forestation in the loess alpine hills of northwest China

Abstract

Study region: Datong County, located in the loess alpine hills of north-western China. Study focus: This study investigated soil moisture and environmental factors in three catchments (10, 20 and 40 years after afforestation with sparse forests) to examine the influence and dominant factors of afforestation with sparse forests on the stability of soil moisture patterns in the catchment. New hydrological insights for the study region: The results show that long-term afforestation with sparse forests improved the soil moisture in the catchment. The spatial patterns of soil moisture (SMSP) were highly stable in all three catchments, except for surface (0–20 cm) soil moisture. Afforestation with sparse forests improved the stability of the spatial patterns and the fitting of representative locations (R2:0.818–0.878). In the early and middle afforestation periods, soil moisture was mainly influenced by plant indices such as fine root biomass, shrub grass biomass and leaf area index, whereas in the middle and late periods, the temporal stability of soil moisture gradually became more dependent on soil indices such as the clay content and soil organic carbon. This study provides a scientific basis for improving the understanding of soil hydrological processes in areas afforested with sparse forests and for optimising the selection of sample sites in the loess alpine hilly region.

Keywords

• Returning farmland to forests
• Catchment
• Soil moisture
• Temporal stability
• Redundancy analysis