Accurate weather forecasting in the Kunlun Mountains relies on accurate determination of the physical-quantity characteristics and atmospheric circulation of different types of rainstorms on the northern slope of the mountains. This paper newly classifies the rainstorms on the northern slope of the Kunlun Mountains into short-term rainstorms, non-short-term rainstorms, and mixed rainstorms. The climatic characteristics, physical quantity parameters, and synoptic system configurations of these three rainstorm types are comparatively analyzed using data from ground automatic weather stations, conventional sounding data, and ERA-5 reanalysis data collected from 2016 to 2024. The results show that (1) rainstorms on the northern slope of the Kunlun Mountains are dominated by non-short-term rainstorms in summer, most frequently by nonshort-term rainstorms and mixed rainstorms in August and by short-term rainstorms in July. As the elevation increases, the frequency of mixed rainstorms increases while the frequencies of short-term rainstorms and non-short-term rainstorms increase and then decline. The range of rainstorms is wider in the western section than in the central section of the northern slope of the Kunlun Mountains. The western section experiences many short-term rainstorms whereas the central section experiences a high incidence of non-short-term and mixed rainstorms. (2) The South Asia High presents a Qinghai-Xizang high pattern during short-term rainstorms, an Iran high pattern during non-short-term rainstorms, and a two-center pattern during mixed rainstorms. All three rainstorm types occur to the right of the entrance zone of the upper level jet streams, where strong divergence and rising motion occur. (3) The rainstorms are dominantly influenced by the Central Asian trough system. During the short-term rainstorms, the Tarim easterly low level jet is not formed and the systematic dynamic uplift effect is relatively weak. Therefore, such rainstorms will more likely occur in areas with good thermal conditions. Non-short-term and mixed rainstorms are accompanied by abundant water vapor transported by the southern path and the formation of a strong Tarim easterly low level jet. The substantial forced-uplift effect facilitates rainstorm formation on the windward slope. (4) The water vapor conditions negligibly differ among the three types of rainstorms but the instability parameters are significantly higher during short-term rainstorms than during the other rainstorm types. The intensity of the deep vertical wind shear is typically moderate (weak) during short-term rainstorms (non-short-term rainstorms) and the short-term (non-short-term) precipitation is mainly generated by convective (stratiform) clouds. The deep vertical wind-shear intensity of mixed rainstorms is between those of the short-term and non-short-term rainstorms and is characterized by convective-cloud and stratiform-cloud precipitation.
In the arid regions of Xinjiang, warm-season precipitation exhibits strong spatial locality and pronounced intermittency. Understanding its diurnal cycle is crucial for improving high-resolution regional precipitation forecasts. Using hourly precipitation records from 17 automatic weather stations in northern Bazhou Prefecture (Bazhou), Xinjiang, for the period 2013-2022, together with ERA5 reanalysis data, this study systematically examines the diurnal variation characteristics of warm-season (May-September) precipitation. The results reveal that: (1) Both precipitation amount and frequency show a distinct bimodal diurnal pattern, with primary peaks from 02:00 to 06:00 and 16:00-22:00, and a pronounced minimum around noon (12:00). The timing of precipitation events demonstrates a west-to-east propagation pattern. (2) In the Yanqi Basin, long-duration precipitation events (>6 h) dominate, contributing the largest fraction to total precipitation (38.7%). In contrast, short-duration events (1-3 h) prevail in the Kuiwulun area, accounting for more than 50% of the total. Medium-duration precipitation (4-6 h) contributes 20%-40% in both regions. (3) Precipitation across different intensity categories exhibits a characteristic “nighttime primary peak and afternoon-to-evening secondary peak” pattern. For drizzle, the maximum precipitation amount occurs between 00:00 and 05:00, while its frequency peaks from 17:00 to 05:00. Light rain displays concurrent peaks in amount and frequency at 03:00-04:00, contributing most to the total precipitation (38.8%). Moderate and heavy precipitation events have their primary and secondary peaks at 05:00 and 18:00, respectively, with a contribution of 30.1%. (4) The diurnal distributions of precipitation amount and frequency are markedly nonuniform, with concentrations mainly during 02:00-07:00 and 14:00-19:00. The differences between the secondary peak phases of precipitation amount and frequency reflect the joint influence of orographic forcing and thermally driven circulations over the region.
Addressing the conflict between water supply and demand and the issue of groundwater over-exploitation in Daman Irrigation District of the middle reaches of the Heihe River, this study developed a three-layer hierarchical model structured as “crop growth period-management station-irrigation district.” Methodologically, the model integrated the Jensen crop water production function to quantify crop yield-water relationships, dynamic programming to optimize water allocation across individual crop growth stages, and the A-NSGA-III algorithm to coordinate water distribution for multiple crops among management stations and multi-source allocation at the irrigation district scale. With objectives including improving crop water demand thresholds, overcoming water source constraints (surface water and groundwater), and maximizing economic benefits, the model employed backward recursion and adaptive reference-point strategies to achieve global optimization, accounting for spatial heterogeneity across management stations and regional disparities in water endowment. The results demonstrated that, from 2026 to 2030, the total agricultural water use in the irrigation district decreased by 3.8%, with groundwater allocation reduced by 21.6% (from 0.5243×108 m3 to 0.4108×108 m3) and surface water use increased by 3.0% (from 1.4013×108 m3 to 1.4440×108 m3). Meanwhile, the overall economic benefit increased from 10.3447× 108 CNY to 10.3830×108 CNY, a growth of 0.37%, confirming the achievement of “water savings without yield reduction.” Spatially, northern stations such as Jiantan and Xiaduan, leveraging surface water advantages, were predicted to reach surface water usage proportions of 98% and 77% by 2030, significantly reducing dependence on groundwater. Meanwhile, southern stations like Nianlipu, constrained by topography, optimized water source ratios to meet crop demand while reasonably regulating groundwater usage. At the crop level, seed maize, field maize, seed pumpkin, and wheat reached yield saturation at irrigation levels of 525, 625, 450, and 475 mm, respectively, illustrating clear water demand thresholds and the law of diminishing marginal benefits. This study concludes that the three-layer hierarchical model significantly enhances the precision with which water is allocated by synergizing patterns of crop water demand and regional water resources, effectively alleviating the typical contradiction between low utilization of surface water and over-exploitation of groundwater in arid irrigated areas, and provides a scalable management paradigm of “top-down regulation and bottom-up feedback” for the sustainable management of water within agriculture.
Using soil temperature, humidity and eddy observation data from the Haibei Pastoral Experiment Station of the China Meteorological Administration (hereinafter referred to as Haibei station), we analysed the characteristics of land-atmospheric water and heat exchange during soil freezing-thawing process of typical alpine meadowed grassland soils on the Qinghai-Xizang Plateau. The results showed that: (1) the soil freezing and thawing process significantly affected the shallow soil temperature and humidity. The soil temperature was the lowest during the stable freezing period (-13.8 ℃) and the highest during the complete thawing period (23.3 ℃), while soil humidity decreased to 5.7% during the stable freezing period and increased to 24.7% during the complete thawing period. (2) Soil freezing and thawing processes significantly changed the surface energy distribution, especially during the freeze-thaw transition season. Net radiation was highest during the complete thaw period (107.1 W·m-2) and lowest during the stable freeze period (8.9 W·m-2), and was mainly consumed by sensible and latent heat, accounting for 45.1% and 49.7% of the year, respectively. During the complete thaw (stable freeze) period, latent heat (sensible) fluxes predominated, whereas during the thaw (freeze) period, both were dominated by sensible heat fluxes. During the complete melting (stable freezing) period, the latent heat (sensible heat) flux was dominant, while during the ablation (freezing) period, the sensible heat flux was dominant. (3) The daily changes of temperature, humidity and energy fluxes in the shallow soil showed a single-peak pattern. The daily variation of soil temperature was the largest (10.9 ℃) during the complete melting period on sunny day and the smallest (1.8 ℃) during the freezing period, the daily variation of soil humidity was small, with a maximum of 1.5% during the melting period. The daily variation of net radiation was the largest (635.7 W·m-2) during the complete melting period, and the variation of latent heat fluxes was the largest (197.5 W·m-2), the variation of sensible heat flux reached its maximum during the melting period (315.1 W·m-2), while the variation of surface heat flux peaked during the stable freeze period (180.0 W·m-2). The weather type and the freeze-thaw phase jointly regulate the soil temperature and humidity changes, and influence the energy distribution by regulating the radiation input and the soil phase change.
This study was conducted at Ningdong photovoltaic station in Ningxia, China, to investigate the effects of different patterns of sowing mixtures of forage species on soil organic carbon (SOC) and its active fractions. Through natural restoration and mechanical no-tillage mixed sowing techniques, five mixed sowing configurations were established to examine the distribution characteristics and factors influencing SOC and its labile fractions—including easily oxidizable organic carbon (EOC), dissolved organic carbon (DOC), and microbial biomass carbon (MBC)—in both inter-panel and under-panel habitats. The results showed that sowing a mixture of gramineous and leguminous species significantly increased SOC and its active carbon components. Specifically, “a mixture of Astragalus laxmannii+Lespedeza davurica+Astragalus laxmannii+Lespedeza davurica” exhibited the highest SOC, EOC, and MBC contents in the 0-20 cm soil layer between photovoltaic panels, reaching 3.91 g·kg-1, 2.34 mg·kg-1, and 151.30 mg·kg-1, respectively—representing increases of 26.13%, 141.24%, and 167.92% compared with the control (CK). “A mixture of Astragalus laxmannii+Lespedeza davurica+Astragalus laxmannii+Lespedeza davurica + Medicago sativa” performed best beneath the solar panels, with SOC reaching 3.95 g·kg-1 in the 0-20 cm soil layer—63.90% higher than CK—while EOC and MBC reached 1.61 mg·kg-1 and 127.69 mg·kg-1, respectively, significantly surpassing CK and most other patterns. In contrast, the sowing of a single gramineous species exhibited the lowest SOC content in the 0-20 cm soil layer between panels, at only 2.71 g·kg-1 14.39% lower than for CK. It also showed a weaker capacity to accumulate EOC and MBC, although SOC accumulation improved in the soil layer of 20-40 cm in depth. Overall, SOC levels were generally higher between photovoltaic panels than beneath them, while the DOC/SOC ratio was higher beneath the panels, indicating a short-term advantage in carbon supply in these areas. Redundancy and variance partitioning analyses revealed that SOC and its active components were significantly regulated by soil physicochemical properties, including total nitrogen, total phosphorus, available nitrogen, and electrical conductivity, with chemical factors exerting a greater influence than physical ones. In conclusion, the mode of sowing a mixture of Astragalus laxmannii, Lespedeza davurica, Astragalus laxmannii, and Lespedeza davurica demonstrated the best effectiveness in enhancing soil carbon sequestration and carbon pool activity, making it the most suitable option for deployment between photovoltaic panels, whereas sowing a mixture of Astragalus laxmannii, Lespedeza davurica, Astragalus laxmannii, Lespedeza davurica, and Medicago sativa performed optimally beneath the panels. The sowing of a single gramineous species showed relatively weak overall performance, with only some advantages in terms of carbon accumulation in deep soil.
This study explores the effects of different vegetation restoration modes on shallow soil during sandy land management in the treatment area. It also investigates the different shallow-soil particle sizes under different vegetation restoration modes, providing a theoretical basis along with scientific and technological support for the restoration of mobile sandy land. The mechanical composition of soil samples was determined using a laser-particle size analyzer and the particle size parameters—average particle size, standard deviation, skewness, kurtosis, and fractal dimension—were determined. It was found that (1) the soil in the study area is dominated by medium sand and fine sand, and the sand content can be reduced in each vegetation restoration mode, most prominently in tree shrub mode (where the decrease reached 11.53%). (2) The sample plot exhibited a high soil fractal dimension (2.30-2.52), which was mainly influenced by the silt and clay content. (3) The soil fractal dimension was highest (2.52) in tree shrub mode, where the average particle size was 18.18% lower than that in flowing sand and the sortability and kurtosis parameters were most optimal. The multi-level vertical structure of tree shrub grass more effectively intercepts the wind and sand and better retains the fine particles than the other restoration modes. Therefore, considering ecological function and sustainability, shrub grass is the preferred choice for vegetation restoration in this area.
This study aims to explore the temporal trends of water use efficiency (WUE) and carbon use efficiency (CUE) in the arid and semi-arid regions of China, as well as the trade-off and synergy relationship between carbon and water processes in these regions. Based on Moderate-resolution Imaging Spectroradiometer (MODIS) data, we quantitatively estimated carbon-water use efficiency from 2001 to 2022. Trend analysis, partial correlation coefficients, geographic detectors, correlation analysis, and multiple regression analysis were employed to examine the variation characteristics of ecosystem WUE and CUE, conduct attribution analysis, and evaluate the coupling relationship between the two. The results show that, overall, WUE and CUE remained relatively stable (P>0.05) from 2001 to 2022 in arid and semi-arid regions, although significant trends were observed in certain areas. The dominant factor influencing WUE changes was soil moisture (SM). The influence of climatic factors on WUE was significantly greater than on CUE. Synergistic regions accounted for 21.24% of the study area, mainly located in the northern North China Plain, the northern and southern slopes of the Tianshan Mountains, and the eastern Greater Khingan Mountains. In synergy zones, the annual mean vapor pressure deficit (VPD) predominantly ranged from 0.8 kPa to 0.9 kPa, while in trade-off zones, it ranged from 0.2 kPa to 0.3 kPa. The variation in the WUE-CUE trade-off and synergy relationship in China’s arid regions was primarily driven by the response of WUE to changes in climatic factors, with VPD being the main factor responsible for these variations.
To understand the responses of nutrient levels and carbon, nitrogen, and phosphorus stoichiometry in different plant communities to soil factors in semiarid grassland ecosystems, this study focused on four representative plant communities in the Bairin Right Banner Grassland, located at the western edge of the Horqin Grassland: Leymus chinensis, Phragmites australis, Ephedra sinica, and Chloris virgata. Based on the methodology of ecological stoichiometry, we examined differences and interrelations in carbon, nitrogen, and phosphorus concentrations and their stoichiometric ratios among dominant species, associated species, plant communities, and their soils. Dominant species exerted strong control over nutrient levels within plant communities, supporting the “mass ratio hypothesis.” C. virgata displayed notably high N and P concentrations (17.3 g·kg-1 and 1.41 g·kg-1, respectively), with its community similarly exhibiting higher N (17.6 g·kg-1) and phosphorus concentrations (1.36 g·kg-1) than other species and communities. L. chinensis and its community had the highest C concentrations (395 g·kg-1 and 365 g·kg-1, respectively). Soil nutrient contents and carbon, nitrogen, and phosphorus stoichiometry varied significantly among communities. The E. sinica community had higher soil organic carbon (1.36%) and total nitrogen levels (0.118%) than the other communities, whereas the soil total phosphorus level was lowest under Phragmites australis (0.0137%). The C. virgata community displayed notably lower soil C: P (33.0) and N: P (3.04). Additionally, soil pH was significantly elevated in the Ephedra sinica community (9.67). Redundancy analysis demonstrated that the soil carbon:phosphorus ratio, a key indicator reflecting the degree of phosphorus availability constraint, is the primary factor regulating the stoichiometric balance of C, N, and P in plants and soils across different plant communities in the Horqin grassland, highlighting its critical role for ecosystem nutrient cycling and management.
Drought is a major obstacle to ecological restoration and aeolian erosion control in China’s Three-North Regions. Bacillus subtilis demonstrates plant growth-promoting properties and robust environmental adaptability, yet its regulatory mechanisms underlying stress resistance in psammophytes remain unclear. This study comparatively analyzes variations in aeolian soil properties, seedling root morphology, and antioxidant capacity under differential drought gradients (no, mild, or moderate stress) and bacterial inoculant concentrations (0, 1, 5, or 9 g·kg-1) by conducting controlled pot experiments on Astragalus laxmannii and Corethrodendron fruticosum. The key findings were as follows. (1) B. subtilis significantly enhanced soil organic carbon content, total nitrogen content, and root morphological traits (P<0.05) without elevating soil pH (P>0.05). (2) Under drought stress, B. subtilis augmented seedling antioxidant capacity through elevated antioxidant enzyme activities (P<0.05). Under mild drought stress, the optimal inoculant concentrations for enhancing antioxidant capacity were 5 g·kg-1 for A. laxmannii and 9 g·kg-1 for C. fruticosum. Under moderate drought stress, 9 g·kg-1 of inoculant was optimal for both species. (3) Drought indirectly suppressed antioxidant capacity through soil nutrient depletion (P<0.01), whereas B. subtilis alleviated oxidative damage through antioxidant enzyme activation (P<0.05). Through species-specific quantification of response thresholds across drought gradients, this study identified two pathways through which B. subtilis enhances drought resistance: soil amelioration and antioxidant regulation. These findings establish a theoretical foundation for drought-resistant psammophyte cultivation and optimized inoculant strategies in the Three-North Regions.
Shrub encroachment is widespread in arid and semi-arid regions, and it produces a fertility island effect, whereby soil nutrients under shrub patches become enriched, thereby influencing ecosystem nutrient cycling and structural stability. We selected 17 shrub-encroached grassland sites in typical grassland and desert-steppe regions of Xilingol League, Inner Mongolia and analyzed the soil stoichiometry of carbon (C), nitrogen (N) and phosphorus (P). By combining climatic data with structural equation modeling, we examined the characteristics of the fertility island effect under the two grassland types and the influence of climatic factors. Following shrub encroachment, C, N, and P concentrations under shrub patches were significantly higher than those in the herbaceous matrix (all P<0.05), indicating a pronounced fertility island effect. The relative interaction intensity (RII) of the fertility island effect was greater in the typical grassland region than in the desert-steppe region, with significant between-region differences in the RIIs of ammonium nitrogen (NH4+-N), nitrate nitrogen (NO3--N), and available P (P<0.05). The RIIs of different soil elements exhibited non-linear responses to mean annual temperature (MAT) and mean annual precipitation (MAP). In the typical grassland region, the RIIs of NH4+-N, NO3--N and available P increased significantly with MAT (all P<0.05), whereas in the desert-steppe region, these RIIs significantly decreased with increasing MAT (all P<0.05). The relationships of the RIIs of these three elements with MAP exhibited opposite patterns to those with temperature. Excluding the RII of available P, which was negatively correlated with aboveground biomass, the RIIs of the other elements were positively correlated with aboveground biomass. This study elucidated the fertility island effects induced by shrub encroachment and their relationships with climate and grassland type, providing a scientific basis for the ecological restoration of shrub-encroached grasslands and management of C, N, and P biogeochemical cycles.
With increasing urbanization, the interaction among production, life, and ecological spaces in urban agglomerations has become increasingly intense, and the severity of ecological risk due to conflicts among spaces has increased. Scientific assessment and analysis of the ecological risk of land use in urban agglomerations is highly significant for optimizing the spatial pattern of urban agglomerations and maintaining ecosystem stability. Using the land use data from 2000 to 2023, this study analyzed the evolution characteristics of the production-living-ecological spaces of the northern slope of the Tianshan Mountains and developed a land use ecological risk assessment model for assessing the severity of regional ecological risk. Using GIS spatial analysis, the spatial and temporal evolution of the ecological risk of land use in the northern slope of the Tianshan Mountains was examined. The results showed that the study area was dominated by ecological space during the study period, accounting for 86.47% of the total area of the study area.Notably, the ecological space significantly decreased, whereas production and living spaces exhibited increasing trends. The most significant transfer type in the production-living-ecological space occurs between the agricultural production space and the grassland and other ecological spaces.From 2000 to 2023, the average ecological risk of land use decreased from 0.136 to 0.130, and the proportion of high-risk areas was relatively high, which indicates a general trend of change from high to low risk. The study observed a high correlation between production-living-ecological spaces and the ecological risk of land use in the study area, and the ecological risk exhibited distribution characteristics of “low in the middle and high around the edges.” Other ecological spaces (e.g., water and forest ecological spaces) dominated the high-risk area, whereas the low-risk area was mainly concentrated in contiguous agricultural production and grassland ecological spaces. Lastly, the ecological risk of land use was positively correlated with the spatial scale. High-high agglomeration was mainly distributed in the northern and southern regions, whereas low-low agglomeration was concentrated in the central region.
Assessing the importance of ecological protection in candidate areas of Tianshan National Park is critical to ensuring regional ecological security, biodiversity conservation, and sustainable development. This study employed the analytic hierarchy process and weighted overlay method to analyze the importance of ecosystem service and ecological sensitivity in the candidate areas of Tianshan National Park in 2000, 2010, 2020, and 2023. Based on these analyses, the importance of ecological protection of three key sectors, namely the Western Tianshan, Bogda Peak, and Tomur Peak areas, was systematically evaluated. From 2000 to 2023, the areas of both extremely important ecosystem service zones and extremely ecologically sensitive zones in the study region displayed an overall decreasing trend. The proportion of extremely important ecosystem service zones decreased from 8.55% to 6.76%, whereas that of extremely sensitive ecological areas declined from 13.32% to 9.78%. Conversely, the area of extremely important ecological protection zones demonstrated an overall increasing trend, rising from 9.82% to 12.68%. In the Western Tianshan sector, the areas of extremely important ecological protection zones were 1413.88 km2, 1510.75 km2, 1366.69 km2, and 2025.13 km2 in 2000, 2010, 2020, and 2023, respectively, and all values were significantly larger than those in the Bogda Peak and Tomur Peak sectors. Since 2000, the importance of ecological protection of Tianshan National Park’s candidate areas has tended to increase, with the Western Tianshan sector playing a crucial role in ecological conservation. These findings provide scientific support for the future establishment and development of Tianshan National Park.
A sand-blocking and sand-fixing belt serves as a crucial barrier for safeguarding the ecological security of an oasis, and its stability directly impacts the sustainable development of the region. Focusing on the characteristics of the artificial-natural composite ecosystems in the sand-blocking and sand-fixing belts in the Hexi Corridor, in this study we constructed a multiscale-evaluation indexing system consisting of a criterion layer (encompassing the three dimensions: biology, ecology, and function) and an indicator layer (including 36 survey factors). We determined the weights of the indicators using an analytic hierarchy process and expert scoring. We quantified and graded each indicator based on literature reviews and subject-specific books. Finally, we employed this comprehensive indexing method to calculate a stability index for a sand-blocking and sand-fixing belt, and we conducted practical case studies to demonstrate the usefulness of this method. These case-study results classified the sand-blocking and sand-fixing belt at the junction of Gaotai County and Linze County in Zhangye City as being “weakly unstable.” In addition, they categorized the sand-blocking and sand-fixing belts at two sample sites—in Minqin County of Wuwei City and in Dunhuang City—as being “unstable.” The stability of these belts is mainly affected by factors such as the degradation of vegetation, sand-barrier damage, and insufficient management and protection. The evaluation framework proposed in this study thus provides a scientific basis for the construction of ecological barriers in wind-sand areas and provides references for the optimized management of sand-blocking and sand-fixing belts in similar regions.
This study elucidates the dynamics of wind-blown sand movement across degradation gradients in farmland shelterbelts during spring wind hazards. Thirty-five-year-old Mongolian Scots pine (Pinus sylvestris var. mongolica) shelterbelts (healthy, slightly, moderately, and severely degraded) along the southern margin of Horqin Sandy Land were selected for the study, along with open areas as controls (CK). The wind speed parameters were monitored at 1 m and 2 m heights within a protective distance of -4 to 4 H (where H is the mean tree height) on the windward and leeward sides from March to May. The parameter values were combined with soil-particle size analysis to determine the windbreak efficiency and soil anti-erosion mechanisms. It was found that (1) healthy shelterbelts significantly reduced the near-surface wind speeds (mean reduction: 49.63%±14.14%) between -4 H and 4 H, decreased the leeward fine sand (50-250 μm) content by 12.22%-32.37% from that of CK, and increased the coarse sand (250-1000 μm) content by 18.57%-42.83% from that of CK, forming a dual protective “fine-particle interception and surface coarsening” mechanism. (2) The windbreak efficiency decreased with increasing degradation severity and the moderately and severely degraded shelterbelts provided no effective protective zone from -4 to 4 H. The wind stability of severely degraded belts was higher at 2 m height than at 1 m height (ΔE2 m-1 m= 1.12%), with canopy fragmentation disproportionately impairing the near-surface (≤1 m) protection. (3) The coarsening indices (coarse/fine sand ratios) on the leeward side were 0.71-0.94 and 0.89-1.09 lower, respectively, in the moderately and severely degraded belts than in CK. The wind erosion intensity reached extreme levels (> 5000 t·km-2) across all areas. In summary, healthy farmland shelterbelts suppress the wind erosion dynamics through multi-layer energy dissipation, whereas moderately/severely degraded shelterbelts lack an effective protective distance, lose their anti-erosion functionality, and trigger accelerated erosion. To reconstruct the near-surface (≤1 m) stand structure, we recommend the priority reconstruction of moderately degraded shelterbelts (deadwood ratio: 11%-39%; gap ratio: 30%-49%; wind erosion modulus >5000 t·km-2) through structural optimization (e.g., by adding shrub layers). This approach will enhance the turbulence control capacity and inhibit the selective loss of fine sand particles (50-250 μm). This study provides theoretical and technical support for defining the restoration sequence of degraded farmland shelterbelts and controlling wind erosion in semiarid regions.
Potassium in Xinjiang cotton fields predominantly exists as insoluble minerals, where low utilization efficiency of chemical fertilizers and their excessive application may lead to salinization. Potassium-solubilizing bacteria (KSB) can enhance potassium availability and promote crop growth but their effectiveness in arid regions is influenced by their application frequency, concentration, and bacterial strains, with no optimized protocols. Therefore, this study, based on Xinjiang’s agricultural realities, used typical loess soil as a substrate. Through pot culture experiments, we compared the effects of Pseudomonas aeruginosa A, commercial Bacillus cereus J, and a composite microbial agent D on potassium cycling in cotton-soil systems, rhizosphere microecology, and growth physiology under different application frequencies (T5, T7, and T15) and concentrations (N1 and N2). Control experiments (CK1: inactivated bacteria + conventional potassium fertilizer; CK2: conventional potassium fertilizer only) were established. The results indicated that: (1) P. aeruginosa (A) demonstrated optimal performance, significantly increasing soil water-soluble potassium (+17.32%), available potassium (+6.88%), and potassium-to-sodium ratio (+40.65%). Moreover, it promoted root development (+23.41%) and potassium uptake in the bud area (+11.42%) while enhancing photosynthesis (net photosynthetic rate +57.87%) and dry matter accumulation (bud weight +18.62%). (2) B. cereus (J) showed significant seedling-stage growth promotion (plant height +69.08%) but limited later-stage potassium solubility (available potassium +12.43%). The composite microbial agent (D) exhibited stable and synergistic effects, with a coefficient of variation under 15% throughout the growth period, making it a suitable agent for balanced potassium supply. (3) Optimization experiments demonstrated that high bacterial concentrations (109 CFU·mL-1，N1) and a 7-day application frequency (T7) yielded the best results. The combined regimen A-N1-T7 achieved optimal performance with an average score of 0.9458, significantly enhancing soil potassium levels (available potassium +10.73% and potassium-to-sodium ratio +60.93%), plant growth (leaf area +55.85%), and photosynthetic efficiency (net photosynthetic rate +89.15%). Furthermore, it promoted boll and root development (buds dry weight +25.52% and root volume +47.11%). The study findings provide new strategies for elucidating the mechanisms of potassium-depleting probiotics in potassium cycling and their growth-promoting effects in the cotton-soil system in Xinjiang cotton fields, thereby enhancing the application potential of KSB in sustainable agriculture.
The health of farmland shelterbelts is crucial for ensuring the sustainable development of agriculture. This study focused on the 150th Regiment of the Mosuowan Reclamation Area as the study area and constructed a farmland shelterbelt health evaluation system comprising three first-level indicators (stand structure, soil characteristics, and climatic characteristics) and 22 second-level indicators. The entropy method was used to calculate the indicator weights and the shelterbelt health index, and the health status of the shelterbelts in the study area was analyzed. The results showed that the farmland shelterbelts in the study area exhibited significant gradient degradation, following a “core-vulnerable-edge” pattern. Overall, the farmland shelterbelts were unhealthy, with a health index of 0.4810. Among them, the core area (health index=0.7227) and the vulnerable area (health index=0.7667) were classified as healthy, while the edge area (health index=0.2167) was unhealthy. Targeted soil improvement is necessary for the degraded forest belts in the core area. Forest belt repair and phosphate fertilizer supplementation should be prioritized in the vulnerable area, and systematic management of salinized land is required in the edge area. This evaluation system provides a multidimensional assessment tool for the precise restoration of degraded shelterbelts in arid areas and effectively supports the scientific decision-making of systematic restoration projects for degraded forest stands.
