Loss and conservation of soil organic carbon and nutrients in arid and semiarid China during aeolian dust emissions

Abstract

In this study, based on the application of the integrated wind erosion modeling system (IWEMS), we comprehensively simulated the loss and conservation of soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), and total potassium (TK) during aeolian dust emissions over 2001–2020 in the arid and semiarid areas of China (ASAC). It was found that the past two decades witnessed decreasing trends in nutrient losses over the central-eastern region of Inner Mongolia, most parts of Qinghai Province, the southern part of the Xinjiang Autonomous Region, and the northwestern part of the Tibet Autonomous Region. The results, being model-based estimates, showed that the ecosystems of the ASAC were crucial in preventing annual losses of SOC, TN, TP and TK: approximately 27318.25 Gg, 2311.18 Gg, 1077.28 Gg and 35780.10 Gg, respectively. Both the losses and conservation of SOC, TN, TP and TK were consistently greater in spring and winter than in summer and autumn. The losses of SOC and nutrients during aeolian dust emissions were more serious in the west of the ASAC than in the east, both in the actual situation and the potential degenerative status. The prevention rates of SOC, TN, TP and TK for different land cover types were all greater than 92%. Comparatively speaking, the prevention rates of SOC, TN, TP and TK were the lowest for barren or sparsely vegetated land (∼92.85%−93.12%), open shrublands (∼95.65%−96.10%) and grasslands (∼98.44%−98.50%). For other land cover types, the prevention rates of SOC, TN, TP and TK were all over 99.62%.