Changes in soil physical and chemical properties after short drought stress in semi-humid forests

Abstract

The Loess Plateau region of China is under increasing water shortage due to declining soil water content after reforestation. Thus, assessing the changes in soils properties in reforested lands is critical for sustainable restoration of vegetation. We conducted a continuous rainfall manipulation experiment from June 2015 to November 2016 using mature black locust (Robinia pseudoacacia) on southern Loess Plateau of China. The soil hydrological properties, aggregate distribution and aggregate organic carbon (OC) and total nitrogen (N) concentrations were measured. Two years of drought stress caused a significant decline in saturated hydraulic conductivity and total porosity, but an increase bulk density in the 0–10 cm soil layer. The short drought stress significantly decreased soil aggregate stability due to a decline in macro-aggregate mass. Drought stress significantly decreased total soil OC concentration and macro- and micro-OC or N concentrations, but had no significant effect on total N concentration after two years of drought. Furthermore, the influence of short drought on soil hydrological properties, aggregate distribution and aggregate OC and total N concentrations was mainly evident at the depth of 10 cm. Our results indicated that short drought has the potential to damage soil properties. The results of this study could provide more insight into the sustainability of afforestation in semi-humid areas of China's Loess Plateau.