Land use/cover change has become an indispensable part of global eco-environmental change research. The Tarim River Basin is the largest inland river basin in China. It is also one of the most ecologically fragile areas in the country, with greening and desertification processes coexisting. This paper analyzes the evolution of land-use/cover change in the Tarim River Basin over the past 30 years based on remote sensing data. The research also explores the contribution of conversion between different land types to the ecological environment by selecting methods, such as transfer matrix and ecological contribution rate. Results indicate that grassland and barren land are the main land types in the region, accounting for 72.46% and 18.87% of the basin area, respectively. From 1990 to 2019, cropland area increased from 33,585.89 km² to 52,436.40 km², an increase of 56.13%, while barren land areas decreased from 781,380.57 km² to 760,783.29 km². Most of the land-use conversion was grassland to other land types and other land types to barren land. Since 1990, the conversion of barren land to grassland and cropland in the basin has led to ecological improvement, whereas the conversion of grassland to cropland has caused deterioration, but with a generally improving trend. It is anticipated that, over the next decade, changes in land types will involve increases in grassland and woodland area, decreases in barren land and cropland, and an overall improvement in the ecological environment in the watershed. Since agriculture and animal husbandry are the main industries in the Tarim River Basin and the land-use structure is dominated by cropland and grassland, several key measures should be implemented. These include improving land use, rationalizing the use of water and soil resources, slowing down the expansion of cropland, and alleviating the contradiction between humans and land, with the ultimate aim of achieving sustainable development of the social economy and ecological environment.

Groundwater is essential to residents, ecology, agriculture, and industry. The depletion of groundwater impacted by climatic variability and intense human activities could threaten water, food, and socioeconomic security in arid regions. A thorough understanding of groundwater level dynamics and its response to land-cover change is necessary for groundwater management and ecosystem improvement, which are poorly understood in arid desert regions due to a scarcity of field monitoring data. In our study, spatiotemporal characteristics of groundwater level impacted by land-cover change and its relationship with vegetation were examined using 3-years in-situ monitoring data of 30 wells in the desert regions of Tarim Basin during 2019–2021. The results showed that the depth to groundwater level (DGL) exhibited obvious spatial and seasonal variations, and the fluctuation of DGL differed significantly among the wells. The cultivated land area increased by 1174.6, 638.0, and 732.2 km² during 2000–2020 in the plains of Yarkand, Weigan-Kuqa, and Dina Rivers, respectively, mainly transferring from bare land and grassland. Annual average Normalized Difference Vegetation Index (NDVI) values increased with time during the period in the plains. DGL generally exhibited a weakly increasing trend from 2019 to 2021, mainly due to human activities. Land-cover change significantly affected the groundwater level dynamic. Generally, the groundwater system was in negative equilibrium near the oasis due to agricultural irrigation, was basically in dynamic equilibrium in the desert region, and was in positive equilibrium near the Tarim River Mainstream due to irrigation return water and streamflow. NDVI of natural desert vegetation was negatively correlated with DGL in the desert regions (R² = 0.78, p < 0.05). Large-scale land reclamation and groundwater overexploitation associated with water-saving irrigation agriculture development have caused groundwater level decline in arid oasis-desert regions. Hence, controlling groundwater extraction intensity, strengthening groundwater monitoring, and promoting water-saving technology would be viable methods to sustainably manage groundwater and maintain the ecological environment in arid areas.

Land use change greatly affects groundwater hydrochemical cycling and thereby food and ecosystem security in arid regions. Spatiotemporal distribution of groundwater hydrochemistry is vital to understand groundwater water-salt migration processes in the context of land use change, while it is not well known in the oasis-desert region of arid inland basins. Here, to investigate the influences of land use change on groundwater hydrochemistry and suggest sustainable management, 67 water samples were obtained in the Luntai Oasis, a typical oasis desert of Central Asia. Stable isotopes and chemical components of samples were analyzed. Piper and Gibbs plots were used to elaborate the chemical type and major mechanisms controlling water chemistry, respectively. The results showed that cultivated land area has markedly expanded in the Luntai Oasis over the last 20 years (increasing by 121.8%). Groundwater seasonal dynamics and groundwater–surface water interaction were altered dramatically by farmland expansion and groundwater exploitation. Specifically, the spatial heterogeneity and seasonal variability of groundwater hydrochemistry were significant. Compared with the desert area, the δ¹⁸O and TDS of river water and shallow groundwater in the oasis cropland exhibited lower values but greater seasonal variation. Higher TDS was observed in autumn for river water, and in spring for shallow groundwater. The chemical evolution of phreatic water was mainly controlled by the evaporation-crystallization process and rock dominance, with a chemical type of Cl-SO₄-Na-Mg. Significant spatiotemporal heterogeneity of groundwater hydrochemistry demonstrated the influence of climatic, hydrogeological, land use, and anthropogenic conditions. Groundwater overexploitation would cause phreatic water leakage into confined water, promoting groundwater quality deterioration due to fresh saltwater mixing. Improving agricultural drainage ditches in conjunction with restricting farmland expansion and groundwater extraction is an effective way to alleviate groundwater environment deterioration and maintain oasis-desert ecosystems in arid regions.