Restoration of sand-stabilizing vegetation reduces deep percolation of precipitation in semi-arid sandy lands, northern China

Abstract

Changes in precipitation patterns and vegetation variability generally affect deep percolation and increasingly limited groundwater resources in arid and semi-arid regions. However, the dynamics of deep percolation and its response to precipitation patterns after vegetation restoration in semi-arid sandy lands are not well understood. Thus, in this work, four typical geomorphologic landscapes with different vegetation types (M: mobile sandy land without vegetation; SH: semi-mobile sandy land with Caragana microphylla shrub but not herbaceous plants; SH&H: semi-fixed sandy land with C. microphylla shrub and herbaceous plants; H: fixed sandy land with herbaceous plants but not C. microphylla shrub) were simulated by an underground observation chamber to monitor daily variability in deep percolation, and characteristics of precipitation and vegetation growth were recorded during the growing seasons from 2010 to 2018. Our results showed that precipitation amount and duration were the most critical factors affecting deep percolation in M, H, SH and SH&H. The response of deep percolation to precipitation events in M was more sensitive than that in SH, H, and SH&H. The amount of deep percolation in M varied consistently with precipitation, and was significantly higher than that in SH, H and SH&H. Deep percolation had a weak negative correlation with species richness and mean height, and a strong negative correlation with mean plant cover and total aboveground biomass. Restoration of sand-stabilizing vegetation reduced deep percolation, and the reduction was greater in H than in SH. Average annual coefficients of deep percolation were 53.3 %, 9.9 %, 7.3 %, and 4.7 % in M, SH, H, and SH&H, respectively. Our results highlight that restoration of sand-stabilizing vegetation and subsequent increases in plant cover and aboveground biomass significantly reduce deep percolation and even groundwater recharge in semi-arid sandy lands.