Comprehensive assessment of land degradation in the arid and semiarid area based on the optimal land degradation index model

Abstract

Paying attention to land degradation in drylands is of international significance because it plays a crucial role in global food production. This study developed the optimal land degradation index (OLDI) model for arid and semiarid areas. The model utilized a system that assessed soil condition, climate response, human disturbance, and vegetation growth. It was based on a constrained optimization algorithm. Based on the analysis of the distribution pattern of the OLDI in the Hexi Corridor, this study aims to explore the spatial and temporal characteristics of land degradation and the variations in land sensitivity to degradation across different seasons through trend analysis. Furthermore, the main variables that control the environment and are responsible for land degradation or improvement were revealed through the analysis of driving factors. It was found that the oasis areas in the southern part of the Hexi Corridor experienced land improvement due to the combined influence of human activities and climate change, while the northern region underwent continuous land degradation. However, overall, the majority of the study area's land remained stable. The reduction in precipitation and the increase in wind speed were identified as the primary driving forces behind land degradation. Different vegetation types exhibited distinct responses to environmental control factors, and these responses varied significantly with the changing seasons. Based on the regional variations in land degradation and the observed sensitivity characteristics during different seasons, this study proposes a land management strategy that combines natural recovery with artificial restoration to achieve effective prevention, control, and management of land degradation. This study provided an effective tool for monitoring land degradation in arid and semiarid areas, which is of significant importance for land resource management and the sustainable development of the green economy, not only in the northwest region of China but also in arid and semiarid areas worldwide.