Interaction of soil water storage and stoichiometrical characteristics in the long-term natural vegetation restoration on the Loess Plateau

Knowledge of the soil water and stoichiometrical characteristics (SC) during long-term natural vegetation restoration is essential for managing the restoration of vegetation. To evaluate the response of soil water storage (SWS), soil organic carbon (SOC), total nitrogen content (TN) and total phosphorous content (TP) to long-term natural vegetation restoration (∼160 a), we examined the soil moisture and SC in areas with different restoration ages located in the central part of the Loess Plateau, China. Our results showed that the SWS decreased significantly with vegetation restoration and that the C:P ratio, N:P ratio, TN and TP increased significantly. The SWS increased gradually, whereas the SOC, C:P ratio, N:P ratio, TN and TP in each restoration stage decreased significantly with increasing soil depth in the 0-60 cm soil layer. These parameters tended to be stable in the soil layer below 60 cm. Vegetation acts as a link between SWS and soil SC, and they interact with each other indirectly. SWS and SWC showed an significant positive relationship (P < 0.01), whereas SWS and SOC, TN, TP, C:P ratio, and N:P ratio showed significant negative relationships (P < 0.01), thus, SOC, TN and TP are the key chemical factors affecting SWS.. These results could help estimating the productivity and sustainability of semiarid ecosystems and improve future eco-environmental reconstructions.