Trade-off Analyses of NDVI and Soil Moisture Relations on the Loess Plateau

Abstract

Water resources are key factors that restrict ecosystem productivity and sustainable junctions in arid and semiarid regions. However, the interaction between vegetation development and soil moisture balance on the Loess Plateau has not been extensively studied. This study aims to assess the relationship between vegetation development and soil moisture balance across different years and precipitation areas on the Loess Plateau using a quantitative trade-off method.. The results showed that precipitation had the greatest influence on root-zone soil moisture, while the surface soil moisture was affected by meteorological and topographic factors. In most precipitation areas, the benefit of soil moisture was higher than that of the normalized difference vegetation index (NDVI) and mean annual evaporation (MAE), but in forest areas, the benefits of the NDVI and MAE were higher than that of soil moisture. The relative benefits of land conversion vary over time. During the initial stage of converting farmland to forest, the soil moisture benefit is lower compared to the NDVI and MAE benefits. However, in the later stages, the soil moisture benefit gradually becomes more prominent. The deviation in relative benefits over time is relatively small, indicating a stable overall ecological benefit on the Loess Plateau. Understanding the relationship between the NDVI and soil moisture in different times and spaces will help improve our ability to sustainably manage vegetation construction and water resources.