Search Results (4)

The risk of soil salinization is prevalent in arid and semi-arid regions, posing a critical challenge to sustainable agriculture. This study addresses the need for accurate assessment of regional root-zone soil salt content (SSC) and understanding of underlying driving mechanisms, which are essential for developing effective salinization mitigation and water management strategies. A remote sensing inversion technique, initially proposed to estimate root-zone SSC in cotton fields, was adapted and validated more widely to non-cotton farmlands. Validation results (with a coefficient of determination R² > 0.53) were obtained using data from a three-year (2020–2022) regional survey conducted in the arid Manas River Basin (MRB), Xinjiang, China. Based on this adapted technique, we analyzed the spatiotemporal distributions of root-zone SSC across all farmlands in MRB from 2001 to 2022. Findings showed that root-zone SSC decreased significantly from 5.47 to 3.77 g kg⁻¹ over the past 20 years but experienced a slight increase of 0.15 g kg⁻¹ in recent five years (2017–2022), attributed to cultivated area expansion and reduced irrigation quotas due to local water shortages. The driving mechanisms behind root-zone SSC distributions were analyzed using an approach combined with two machine learning algorithms, eXtreme Gradient Boosting (XGBoost) and SHapley Additive exPlanation (SHAP), to identify influential factors and quantify their impacts. The approach demonstrated high predictive accuracy (R² = 0.96 ± 0.01, root mean squared error RMSE = 0.19 ± 0.03 g kg⁻¹, maximum absolute error MAE = 0.14 ± 0.02 g kg⁻¹) in evaluating SSC drivers. Factors such as initial SSC, crop type distribution, duration of film mulched drip irrigation implementation, normalized difference vegetation index (NDVI), irrigation amount, and actual evapotranspiration (ET_a), with mean ($\left|\mathrm{SHAP} \mathrm{value}\right|$) ≥ 0.02 g kg⁻¹, were found to be more closely correlated with root-zone SSC variations than other factors. Decreased irrigation amount appeared as the primary driver for recent increased root-zone SSC, especially in the mid- and down-stream sections of MRB. Recommendations for secondary soil salinization risk reduction include regulation of the planting structure (crop choice and extent of planting area) and maintenance of a sufficient irrigation amount. Full article

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. Full article

The investigation of water resource carrying capacity (WRCC) in oasis cities in Northwest China is useful for guiding the sustainable development of arid regions. To quantify the WRCC of Shihezi, an oasis city in the Manas River Basin (MRB), Northwest China, a total of 21 indicators from three subsystems were selected to construct an evaluation index system based on the theory of the water resource–socio-economic–ecological complex system. Our study utilized a combination of the CRITIC method and the entropy weight method to determine the synthesis weight, the GRA-TOPSIS approach to comprehensively evaluate the WRCC, and the obstacle degree model to identify its main obstacle factors. Our results showed that the WRCC of Shihezi showed an increasing trend from 2011 to 2020, with the compositive index increasing from 0.3454 to 0.5210. The carrying capacities of the ecological environment and socio-economic subsystems were generally on the rise, but the rate of change was relatively gentle from 2017 to 2020. The carrying capacity index of the water resource subsystem dropped significantly from year to year from 2016 to 2020. The irrigation coverage rate, the proportion of agricultural water, water consumption per 10,000 CNY of GDP, the modulus of water production, water resource development and its utilization ratio, the water supply modulus, and the proportion of ecological water were the seven most significant obstacles. Our findings could serve as scientific references for enhancing WRCC and promoting the sustainable development of oasis cities in arid regions. Full article

Due to the differences in the contributions of land use types to ecosystem health and human wellbeing, there is a trade-off and a coordinating relationship between ecosystem health and human wellbeing, which affects the sustainable development of a river basin. To explore the impacts of the responses of ecosystem health and human wellbeing and the combined effects under land use change, this paper, taking the Manas River Basin (MRB) as an example, evaluated the health status of the MRB by the model: Vitality (V), organization (O), resilience (R), and services (S). From a sustainability perspective, an index system of human wellbeing was constructed, which included society and the economy, health and safety, materials and resources, and ecology and the environment. On this basis, the coupling coordination relationship and sustainable development status of the basin was assessed. The results showed that as land use changed, the ecosystem health showed a downward trend, and human wellbeing grew exponentially. The sustainable development index and the coupling coordination degree of the MRB were similar, indicating that the level of balance between ecosystem health and human wellbeing was the key to the sustainable development of the basin, and the overall situation was in a state of moderate imbalance and moderate unsustainability. Therefore, it is necessary to carry out sustainable management of the whole basin. Full article