The Turpan-Hami (Tuha) Basin in Xinjiang Uygur Autonomous Region of China, holds significant strategic importance as a key economic artery of the ancient Silk Road and the Belt and Road Initiative, necessitating a holistic understanding of the spatiotemporal evolution of land use/land cover (LULC) to foster sustainable planning that is tailored to the region's unique resource endowments. However, existing LULC classification methods demonstrate inadequate accuracy, hindering effective regional planning. In this study, we established a two-level LULC classification system (8 primary types and 22 secondary types) for the Tuha Basin. By employing Landsat 5/7/8 imagery at 5-a intervals, we developed the LULC dataset of the Tuha Basin from 1990 to 2020, conducted the accuracy assessment and spatiotemporal evolution analysis, and simulated the future LULC under various scenarios via the Markov-Future Land Use Simulation (Markov-FLUS) model. The results revealed that the average overall accuracy values of our LULC dataset were 0.917 and 0.864 for the primary types and secondary types, respectively. Compared with the seven mainstream LULC products (GlobeLand30, Global 30-meter Land Cover with Fine Classification System (GLC_FCS30), Finer Resolution Observation and Monitoring of Global Land Cover PLUS (FROM_GLC PLUS), ESA Global Land Cover (ESA_LC), Esri Land Cover (ESRI_LC), China Multi-Period Land Use Land Cover Change Remote Sensing Monitoring Dataset (CNLUCC), and China Annual Land Cover Dataset (CLCD)) in 2020, our LULC data exhibited dramatically elevated overall accuracy and provided more precise delineations for land features, thereby yielding high-quality data backups for land resource analyses within the basin. In 2020, unused land (78.0% of the study area) and grassland (18.6%) were the dominant LULC types of the basin; although cropland and construction land constituted less than 1.0% of the total area, they played a vital role in arid land development and primarily situated within oases that form the urban cores of the cities of Turpan and Hami. Between 1990 and 2020, cropland and construction land exhibited a rapid expansion, and the total area of water body decreased yet resurging after 2015 due to an increase in areas of reservoir and pond. In future scenario simulations, significant increases in areas of construction land and cropland are anticipated under the business-as-usual scenario, whereas the wetland area will decrease, suggesting the need for ecological attention under this development pathway. In contrast, the economic development scenario underscores the fast-paced expansion of construction land, primarily from the conversion of unused land, highlighting the significant developmental potential of unused land with a slowing increase in cropland. Special attention should thus be directed toward ecological and cropland protection during development. This study provides data supports and policy recommendations for the sustainable development goals of Tuha Basin and other similar arid areas.

Since 2015, the newly discovered slit-type Danxia landform on the Chinese Loess Plateau has become a hot topic in the field of geomorphology worldwide. However, the relationships among its formation, evolutionary mechanism, and mechanical characteristics of its strata and rocks are not clear. In this paper, the Ganquan canyon group is used as the research object. Basic physical and mechanical indices of sandstone in the Ganquan canyon group were measured through field investigation and indoor experiments, and the deterioration trends for the mechanical parameters of sandstone in this area under the action of infiltration, acid dry-wet cycles, and freeze-thaw cycles were revealed. Lastly, the formation and evolutionary mechanism of the slit-type Danxia landform were discussed. The results showed that: (1) The sandstone in the canyon group had a low cementation degree and weak cohesive force, which was easily weakened under the action of water, resulting in a decrease in compressive strength and elastic modulus. (2) Acidic dry-wet cycles caused the mineral composition of the sandstone to be dissolved, and the micropores continued to grow and develop until new cracks were produced. Macroscopically, the compressive strength and elastic modulus of sandstone were greatly reduced, and this damage was cumulative and staged. The greater the acidity, the greater the damage. (3) As the number of freeze-thaw cycles increased, the uniaxial compressive strength and elastic modulus of the sandstone decreased continuously. During the freeze-thaw cycle process, the growth and development of cracks were primarily in fracture mode and usually developed along parallel bedding positions. (4) The interaction of tectonic activity and lithology with different weathering processes was a key factor in the formation and evolution of the slit-type Danxia landform. In conclusion, the intricate process of weathering influenced by historical climatic fluctuations has been pivotal in shaping the topography of Danxia landform.

The Hotan Prefecture of Xinjiang Uygur Autonomous Region, China belongs to arid desert climate, with significant soil salinization issues. The study selected six rivers in Hotan Prefecture (Pishan, Qaraqash, Yurungqash, Celle, Kriya, and Niya rivers) to explore the spatial distribution of soil salinization in this area and its underlying mechanisms. Sampling was conducted along each river's watershed, from the Gobi in the upper reaches, through the anthropogenic impact area in the middle reaches, to the desert area in the lower reaches. Soil physical-chemical indicators, including total soluble salts, pH, K⁺, Na⁺, Ca²⁺, Mg²⁺, SO₄^2-, Cl^-, CO₃^2-, HCO₃^-, organic matter, available nitrogen, available phosphorus, and available potassium, were tested, along with the total dissolved solids of surface water and groundwater. The results revealed that the soil water and nutrient contents in anthropogenic impact area were higher than those in Gobi and desert areas, while the pH and total soluble salts were lower than those in Gobi and desert areas. The ions in the soil of the study area were primarily Cl^-, SO₄^2-, K⁺, and Na⁺, and the ion concentration of soil salt were positively correlated with surface water and groundwater. Overall, the study area exhibited low soil water content, low clay content, infertile soil, and high soil salinization, dominated by weak to moderate chloride-sulfate types. Compared with Gobi and desert areas, the soil in anthropogenic impact area had higher soil water content, lower pH, lower soluble salts, and higher nutrients, indicating that human farming activities help mitigate salinization. These findings have practical implications for guiding the scientific prevention and control of soil salinization in the arid areas and for promoting sustainable agricultural development.

Characterization of the spatial and temporal variability of stable isotopes in surface water is essential for interpreting hydrological processes. In this study, we collected the water samples of river water, groundwater, and reservoir water in the Burqin River Basin of the Altay Mountains, China in 2021, and characterized the oxygen and hydrogen isotope variations in different water bodies via instrumental analytics and modeling. Results showed significant seasonal variations in stable isotope ratios of oxygen and hydrogen (δ¹⁸O and δ²H, respectively) and significant differences in δ¹⁸O and δ²H among different water bodies. Higher δ¹⁸O and δ²H values were mainly found in river water, while groundwater and reservoir water had lower isotope ratios. River water and groundwater showed different δ¹⁸O-δ²H relationships with the local meteoric water line, implying that river water and groundwater are controlled by evaporative enrichment and multi-source recharge processes. The evaporative enrichment experienced by reservoir water was less significant and largely influenced by topography, recharge sources, local moisture cycling, and anthropogenic factors. Higher deuterium excess (d-excess) value of 14.34‰ for river water probably represented the isotopic signature of combined contributions from direct precipitation, snow and glacial meltwater, and groundwater recharge. The average annual d-excess values of groundwater (10.60‰) and reservoir water (11.49‰) were similar to the value of global precipitation (10.00‰). The findings contribute to understanding the hydroclimatic information reflected in the month-by-month variations in stable isotopes in different water bodies and provide a reference for the study of hydrological processes and climate change in the Altay Mountains, China.

In the context of changes in global climate and land uses, biodiversity patterns and plant species distributions have been significantly affected. Soil salinization is a growing problem, particularly in the arid areas of Northwest China. Halophytes are ideal for restoring soil salinization because of their adaptability to salt stress. In this study, we collected the current and future bioclimatic data released by the WorldClim database, along with soil data from the Harmonized World Soil Database (v1.2) and A Big Earth Data Platform for Three Poles. Using the maximum entropy (MaxEnt) model, the potential suitable habitats of six halophytic plant species (Halostachys caspica (Bieb.) C. A. Mey., Halogeton glomeratus (Bieb.) C. A. Mey., Kalidium foliatum (Pall.) Moq., Halocnemum strobilaceum (Pall.) Bieb., Salicornia europaea L., and Suaeda salsa (L.) Pall.) were assessed under the current climate conditions (average for 1970-2000) and future (2050s, 2070s, and 2090s) climate scenarios (SSP245 and SSP585, where SSP is the Shared Socio-economic Pathway). The results revealed that all six halophytic plant species exhibited the area under the receiver operating characteristic curve values higher than 0.80 based on the MaxEnt model, indicating the excellent performance of the MaxEnt model. The suitability of the six halophytic plant species significantly varied across regions in the arid areas of Northwest China. Under different future climate change scenarios, the suitable habitat areas for the six halophytic plant species are expected to increase or decrease to varying degrees. As global warming progresses, the suitable habitat areas of K. foliatum, S. salsa, and H. strobilaceum exhibited an increasing trend. In contrast, the suitable habitat areas of H. glomeratus, S. europaea, and H. caspica showed an opposite trend. Furthermore, considering the ongoing global warming trend, the centroids of the suitable habitat areas for various halophytic plant species would migrate to different degrees, and four halophytic plant species, namely, S. salsa, H. strobilaceum, H. glomeratus, and H. capsica, would migrate to higher latitudes. Temperature, precipitation, and soil factors affected the possible distribution ranges of these six halophytic plant species. Among them, precipitation seasonality (coefficient of variation), precipitation of the warmest quarter, mean temperature of the warmest quarter, and exchangeable Na⁺ significantly affected the distribution of halophytic plant species. Our findings are critical to comprehending and predicting the impact of climate change on ecosystems. The findings of this study hold significant theoretical and practical implications for the management of soil salinization and for the utilization, protection, and management of halophytes in the arid areas of Northwest China.

The vegetation growth status largely represents the ecosystem function and environmental quality. Hyperspectral remote sensing data can effectively eliminate the effects of surface spectral reflectance and atmospheric scattering and directly reflect the vegetation parameter information. In this study, the abandoned mining area in the Helan Mountains, China was taken as the study area. Based on hyperspectral remote sensing images of Zhuhai No. 1 hyperspectral satellite, we used the pixel dichotomy model, which was constructed using the normalized difference vegetation index (NDVI), to estimate the vegetation coverage of the study area, and evaluated the vegetation growth status by five vegetation indices (NDVI, ratio vegetation index (RVI), photochemical vegetation index (PVI), red-green ratio index (RGI), and anthocyanin reflectance index 1 (ARI1)). According to the results, the reclaimed vegetation growth status in the study area can be divided into four levels (unhealthy, low healthy, healthy, and very healthy). The overall vegetation growth status in the study area was generally at low healthy level, indicating that the vegetation growth status in the study area was not good due to short-time period restoration and harsh damaged environment such as high and steep rock slopes. Furthermore, the unhealthy areas were mainly located in Dawukougou where abandoned mines were concentrated, indicating that the original mining activities have had a large effect on vegetation ecology. After ecological restoration of abandoned mines, the vegetation coverage in the study area has increased to a certain extent, but the amplitude was not large. The situation of vegetation coverage in the northern part of the study area was worse than that in the southern part, due to abandoned mines mainly concentrating in the northern part of the Helan Mountains. The combination of hyperspectral remote sensing data and vegetation indices can comprehensively extract the characteristics of vegetation, accurately analyze the plant growth status, and provide technical support for vegetation health evaluation.

Characteristics of root pullout resistance determine the capacity to withstand uprooting and the slope protection ability of plants. However, mechanism underlying the uprooting of taproot-type shrub species in the loess area of northeastern Qinghai-Xizang Plateau, China remains unclear. In this study, a common taproot-type shrub, Caragana korshinskii Kom., in northeastern Qinghai-Xizang Plateau was selected as the research material. Mechanism of root-soil interaction of vertical root of C. korshinskii was investigated via a combination of a single-root pullout test and numerical simulation analysis. The results indicated that, when pulling vertically, axial force of the roots decreased with an increase in buried depth, whereas shear stress at root-soil interface initially increased and then decreased as burial depths increased. At the same buried depth, both axial force and shear stress of the roots increased with the increase in pullout force. Shear stress and plastic zone of the soil surrounding the root were symmetrically distributed along the root system. Plastic zone was located close to the surface and was caused primarily by tensile failure. In nonvertical pulling, symmetry of shear stress and plastic zone of the soil surrounding the root was disrupted. We observed larger shear stress and plastic zones on the side facing the direction of root deflection. Plastic zone included both shear and tensile failure. Axial force of the root system near the surface decreased as deflection angle of the pullout force increased. When different rainfall infiltration depths had the same vertical pulling force, root axial force decreased with the increase of rainfall infiltration depth and total root displacement increased. During rainfall infiltration, shear stress and plastic zone of the soil surrounding the root were prone to propagating deeper into the soil. These findings provide a foundation for further investigation of soil reinforcement and slope protection mechanisms of taproot-type shrub species in the loess area of northeastern Qinghai-Xizang Plateau and similar areas.

Serious riverbank erosion, caused by scouring and soil siltation on the bank slope in the lower reaches of the Tarim River, Northwest China urgently requires a solution. Plant roots play an important role in enhancing soil shear strength on the slopes to maintain slope soils, but the extent of enhancement of soil shear strength by different root distribution patterns is unclear. The study used a combination of indoor experiments and numerical simulation to investigate the effects of varying plant root morphologies on the shear strength of the sandy soil in the Tarim River. The results showed that: (1) by counting the root morphology of dominant vegetation on the bank slope, we summarized the root morphology of dominant vegetation along the coast as vertical, horizontal, and claw type; (2) the shear strength of root-soil composites (RSCs) was significantly higher than that of remolded soil, and the presence of root system made the strain-softening of soil body significantly weakened so that RSCs had better mechanical properties; and (3) compared with the lateral roots, the average particle contact degree of vertical root system was higher, and the transition zone of shear strength was more prominent. Hence, vegetation with vertical root system had the best effect on soil protection and slope fixation. The results of this study have important guiding significance for prevention and control of soil erosion in the Tarim River basin, the restoration of riparian ecosystems, and the planning of water conservancy projects.