Chinese researchers recently found that the interaction between precipitation pattern and vegetation cover type affect deep percolation and groundwater recharge in semi-arid sandy land.
Exploring the effects of vegetation restoration and precipitation pattern changes on deep percolation in semi-arid sandy land can provide theoretical support for the sustainable utilization of regional precipitation and groundwater resources, the selection of sand-fixing vegetation types and the rational allocation of density
The researchers led by LIU Xinping from the Northwest Institute of Eco-Environment and Resources (NIEER) of the Chinese Academy of Sciences conducted a study by a large underground observation chamber to simulate four typical geomorphic landscapes with different vegetation types in the Horqin Sandy Land.
They recorded the daily variability of precipitation, deep percolation and vegetation growth during the growing seasons from 2010 to 2018.
The researchers demonstrated that changes in precipitation patterns interacting with vegetation cover types positively affect deep percolation. Deep percolation in different vegetation cover types in semi-arid sandy land depends more on precipitation amount and duration than on precipitation intensity.
The response sensitivity of deep percolation to precipitation events in non-vegetated sand region is significantly higher than that in vegetated sand region. The average annual coefficients of deep percolation in mobile, semi-mobile, semi-fixed and fixed sandy land were 53.3%, 9.9%, 7.3% and 4.7%, respectively.
Besides, they also showed that deep percolation has a weak negative correlation with species richness and mean height, and a strong negative correlation with mean plant cover and total aboveground biomass.
The 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.
Consequently, the extent of bare areas, vegetation type, and vegetation cover and productivity need to be considered in vegetation restoration to protect the continuously decreasing groundwater resources in this semi-arid sandy land.
The research results have been published in Catena in an article entitled "Restoration of sand-stabilizing vegetation reduces deep percolation of precipitation in semi-arid sandy lands, northern China."