To reveal the mechanisms of water conservation and soil salinity control in the biochar interlayer, the effects of biochar addition as an interlayer on soil water infiltration, evaporation, and salt transport were studied. Through the indoor soil-column simulation test, soil columns were set up by packing homogeneous soil (CK) and biochar spacers into columns at different burial depths of 10, 20, and 30 cm. The biochar interlayer decreased the infiltration capacity of the soil, with the average infiltration rate decreasing from 0.72 cm·h⁻¹ to the ranges of 0.39–0.48 cm·h⁻¹ in the CK soil column, and salt leaching efficiency was improved. The salt content in the bottom layer of soil in the CK column was reduced to within the range of 19.96–47.46% compared with that in the barrier soil column. The presence of the biochar interlayer improved the distribution of soil water and salt. The soil water content in the upper layer above the interlayer was around 7.79–13.68% higher than that in CK, whereas the average salt content was 6.44–60.40% lower than that in CK. The biochar interlayer inhibited soil water evaporation, and cumulative evaporation in this layer decreased by 32.34–42.10% compared with that in CK. The salt accumulation in the interlayer in the soil column decreased within the range of 16.36–51.36% compared with that in the CK soil column. The biochar interlayer could not only retain water for a long time, but also adsorb the salt leached from the upper layer, and thus, inhibit the reverse salt flux from the lower layer. The creation of the biochar interlayer of 30 cm could play a role in soil salinity control and water conservation, and can also provide a basis and reference for the improvement of saline-alkali farmland in arid and semi-arid areas.

In the context of global warming, the acceleration of the water cycle increases the risk of meteorological drought (MD) and hydrological drought (HD) in the arid region of Northwest China. The Manas River Basin is a typical agricultural oasis and the largest oasis farming area in Xinjiang, Northwest China. Droughts in this basin have significant implications for both agricultural production and the livelihoods of inhabitants. To evaluate the MD and HD and provide information for drought relief in the MRB, the standardized precipitation evapotranspiration index (SPEI) and standardized runoff index (SRI) were calculated using long-term rainfall and runoff data. Subsequently, combined with ArcGIS 10.3 software and the trend analysis method, the SPEI and SRI characteristics were evaluated at different time scales (1-, 3-, 6-, and 12-month). There were three main findings. First, both MD and HD were alleviated, with significantly more HD alleviation. MDs in spring and autumn exhibited a trend of aggravation. The SRIs in summer, autumn, and winter increased significantly at a confidence level of p < 0.01, with an insignificant decline in spring. In the 2010s, the frequency of light drought of MD was stable at 10% to 20%, while severe and extreme droughts increased. The frequency of HDs has decreased since the 1990s. Second, on annual and seasonal scales, MDs occurred mainly as light and moderate droughts. The highest frequency of MD was 24% of moderate droughts in winter. Spatially, the northern region of the MRB was characterized by more frequent light and extreme droughts. Third, runoff in the Manas River Basin increased significantly during the 1990s, which may have been related to the acceleration of glacial retreat in the Tianshan Mountains. This study can effectively reveal the changes in meteorological and hydrological drought in NWC and provide the basis for risk decision-making and management for watershed managers.

This study examined land-use/land-cover (LULC) change in the Manas River Basin from 2000 to 2020 due to rapid socioeconomic development. It aims to provide a scientific basis for protecting the ecological security of the river basin and achieving sustainable development of the land. The LULC data of 2000, 2010, and 2020 were utilized to establish the LULC transition matrix and calculate the LULC dynamics to analyze the dynamic evolution of LULC in the basin from 2000 to 2020. The PLUS model was constructed to explore the driving mechanism of the conversion between various land types in the basin. The key findings include the following. (1) From 2000 to 2010, grassland experienced the most significant reduction (3222.08 km²), whereas farmland expanded the most (3126.77 km²). (2) The most rapid expansion occurred in farmland (6.24%) and built-up areas (2.25%) in the 2000–2010 and 2010–2020 periods, respectively. Conversely, forest land showed the most rapid decrease, with −6.07% from 2000 to 2010, and −0.86% from 2010 to 2020. (3) The degree of influence of each driving factor on different LULC types (contribution degree) obtained by constructing the PLUS model shows that, during the twenty years, population was the predominant factor affecting farmland changes and built-up areas, with contribution degrees of 0.17 and 0.26, respectively. Temperature was the primary influencer of forest-land changes, with a contribution degree of 0.17, and elevation significantly impacted grassland changes, with a contribution degree of 0.21. This study provides crucial insights into the interaction between LULC dynamics and environmental and demographic factors in the Manas River Basin.

Against the global push for “carbon peak and carbon neutrality” and Xinjiang’s role as a major arid-region agricultural base in China, balancing agricultural development with low-carbon transitions remains challenging due to its fragile ecology and resource-intensive farming. However, county-scale dynamics of cultivated land carbon emission intensity (CEI) and its drivers in Xinjiang are understudied, limiting targeted mitigation. This study analyzed Xinjiang’s cultivated land CEI (2000–2020) using the Geographically and Temporally Weighted Regression and Stochastic Impacts by Regression on Population, Affluence and Technology (GTWR-STIRPAT) model, geodetector, and spatiotemporal analysis, with counties as units. Data included 30 m-resolution land use data and socioeconomic statistics. Results showed CEI rose from 0.270 to 0.377 t/hm², with marked spatial differences: northern Xinjiang saw fluctuating growth and a 58.65 km northeastward shift of emission gravity, while southern Xinjiang had lower western CEI (ecological constraints) and higher eastern CEI (agricultural expansion). Key drivers were total sown area (TSAC), agricultural film usage (UAPF), and rural agricultural population (RAP). Factor interactions (machinery power × sown area, q = 0.844) non-linearly amplified CEI. The GTWR-STIRPAT model (R² = 0.97) outperformed OLS and captured heterogeneity—mechanization/area expansion dominated northern CEI, while film use/population mattered more in the south. Region-specific strategies are needed: northern Xinjiang should optimize machinery energy and control area expansion; southern Xinjiang, strengthen ecology and promote low-carbon inputs; eastern Xinjiang, leverage efficient oasis agriculture. This study supports precise carbon management in Xinjiang and similar arid regions globally.

The rapid socioeconomic development of the Manas River Basin from 2000 to 2020 has substantially altered land use patterns, thereby exerting considerable influence on regional sustainable development. This study employed GIS techniques, the Optimal Parameters-based Geographical Detector (OPGD) model, and the PLUS model to analyze the evolutionary patterns of land use, investigate the underlying driving mechanisms, and simulate the spatial patterns of land use under multiple scenarios for 2030. The results indicate that: (1) from 2000 to 2020, the spatial pattern of land use in the basin underwent notable changes, with cropland and built-up land expanding by 3300.80 km² and 219.87 km², respectively, reflecting a continuous increase in land use intensity; (2) Distance to highway emerged as the strongest driving factor, with its q-value consistently exceeding 0.80 throughout the study period. Interaction detection further revealed that the interactive q-values of all driving factors were greater than their corresponding single-factor q-values, indicating that the spatial differentiation of land use in the basin is governed by the synergistic control of multiple factors; (3) among the simulated scenarios, the ecological protection scenario effectively maintained the stability of ecological land while preserving land use type changes, demonstrating greater potential for regional sustainable development. The findings of this study can provide a reasonable scientific basis for the sustainable allocation of land resources in the Manas River Basin.