Nitrogenase is the key enzyme driving the natural nitrogen cycle， as it catalyzes the conversion of inert dinitrogen （N₂） into bioavailable ammonia （NH₃）. The most extensively studied nitrogenases， molybdenum nitrogenase （Mo-nitrogenase） and vanadium nitrogenase （V-nitrogenase）， differ significantly in their structure， catalytic properties， and environmental responses. Structurally， V-nitrogenase contains a unique δ subunit and has distinct encoding genes compared to Mo-nitrogenase. For catalytic mechanisms， Mo-nitrogenase exhibits higher specificity for N₂ reduction， whereas V-nitrogenase demonstrates broader substrate range and reduces alternative substrates such as acetylene. Furthermore， the two enzymes exhibit different sensitivity to carbon monoxide （CO）： Mo-nitrogenase is easily inhibited by CO， while V-nitrogenase can reduce CO even under high concentrations. These differences shape their functional performance in diverse environments. By systematically illustrating the structural， catalytic， and environmental differences between these nitrogenases， this study deepens the understanding of dynamic biological nitrogen fixation. The findings provide a critical theoretical basis for optimizing nitrogen management in grassland agriculture and offer guidance for the restoration of degraded ecosystems， such as grasslands， forests， and deserts.

With the continued development of the livestock industry and the growing imbalance between feed supply and demand, the utilization of crop straw as feed has become an important strategy for ensuring feed security and promoting sustainable agriculture. However, the inherent characteristics of crop straw, including high fiber content, low protein level, and structural recalcitrance, severely restrict its efficient utilization as animal feed. Microbial fermentation technologies, mainly silage fermentation and microbial pretreatment, can effectively degrade fiber, improve nutritional composition, and enhance palatability and digestibility through microbial metabolic activities, and have therefore become key biological approaches for promoting the feed utilization of crop straw. This review systematically summarized recent research progress and practical applications of microbial fermentation in the feed conversion of major crop straws, including maize, rice, wheat, soybean, peanut, sweet potato, and sunflower. Particular attention was given to differences in physicochemical properties among straw types and to corresponding fermentation strategies, including single material silage, mixed silage, and combined microbial and enzyme treatments. In addition, the review discussed the regulation of key fermentation parameters, the mechanisms underlying improvements in nutritional quality, and the effects of fermented straw feed on ruminant production performance and economic benefits. Current challenges in practical application were also highlighted, including limited adaptability of microbial inoculants, low process standardization, instability in large scale production, and insufficient monitoring methods. Future research should focus on developing highly efficient microbial agents tailored to specific straw types, clarifying the synergistic mechanisms between microorganisms and enzymes, advancing intelligent and standardized fermentation technologies, and establishing integrated industrial chain models. These efforts will provide systematic support for technological innovation and large scale application in straw feed utilization, and will contribute to the development of grain saving livestock production systems and a circular agricultural economy.

Ecosystem services （ES） and ecological risk （ER） respectively represent the capacity of ecosystems to support human well-being and the potential for degradation under external disturbances. In recent years， the cumulative impacts of glacier retreat， permafrost degradation， and grassland deterioration have led to a decline in ES and an increase in ER on the Qinghai-Xizang Plateau. Therefore， exploring the coupling relationship between ES and ER on the Plateau is of great importance for accurately identifying ecological degradation processes， improving regional ecological resilience， and supporting effective environmental management. Based on remote sensing and statistical data from 2000 to 2020， this study evaluated important ES indicators and constructed an ER assessment framework using the InVEST model and landscape ecological risk assessment methods. The results showed that： （1） From 2000 to 2020， mean annual grassland productivity increased from 91.63 g/m² to 107.52 g/m²， while carbon storage declined from 6 571.73 Mg to 5 897.60 Mg. Water yield decreased from 122.10 mm to 86.55 mm in 2015 and rebounded to 110.71 mm in 2020. Habitat quality declined from 0.51 to 0.45， and soil conservation showed periodic fluctuations， ranging between 33 391.59 g/m² and 25 772.08 g/m². （2） The overall ER level showed a slight decline， but high-risk areas still accounted for over 19%， primarily concentrated in ecologically fragile zones such as Kekexili， the Qiangtang Plateau， and the Qaidam Basin. （3） Correlation analysis revealed significant negative correlations between ER and both grassland productivity （R² = -0.66， P < 0.05） and habitat quality （R² = -0.73， P < 0.05）. Carbon storage， water yield， and soil conservation also exhibited moderate negative correlations， suggesting that ER exerts an overall inhibitory effect on ES.

With the continuous development of China's livestock industry，the supply-demand gap of protein feed is expanding. As the primary protein source in contemporary animal feeds，soybean meal is subject to significant price volatility due to food security concerns and international trade dynamics，which poses substantial challenges to supply chain stability. As an important feed source，forage has significant strategic development value. This article provides systematic review of forage as a substitute for soybean meal. It analyzes the nutritional profiles of forage and their effects on animals，offering a comprehensive assessment of the practical application across diverse livestock and poultry production systems. However，the substitution is limited by multiple factors，including animal species，growth stage，forage quality attributes，processing methods，and substitution ratio. Currently，the primary bottleneck hindering the widespread adoption of forage-based substitution is the immature technology for reducing soybean meal in forage production. Future efforts should focus on strengthening the forage industry to improve production efficiency and product quality. Additionally，increased scientific research investment is essential to break through key technological challenges in soybean meal substitution. These efforts will deepen the application of forage resources in soybean meal reduction initiative.

To identify suitable forage oat cultivars and determine the optimal cutting stage for saline alkali soils in the Hetao Irrigation District, 14 domestic and foreign forage oat cultivars were evaluated. Differences in yield, forage quality, and digestibility characteristics were analyzed across different growth stages, and comprehensive screening was conducted using grey relational analysis. The results showed that plant height differed significantly among cultivars and growth stages, and all cultivars exhibited an "S" shaped growth curve. In terms of cultivar main effects, fresh forage yield and hay yield ranged from 21 451.67 to 38 916.53 kg/hm² and from 5 620.76 to 8 359.18 kg/hm², respectively. The crude protein (CP) contents of the ‘Leader’ (Souris), ‘Baler’ and ‘Baler No.2’ exceeded 10.00% of dry matter (DM) and were significantly higher than those of other varieties except ‘Yellow oat’. The neutral detergent fiber (NDF) contents of ‘Baler’, ‘Baler No.2’, and ‘Yellow oat’ was significantly lower than those of most other varieties, except ‘Leader’ (Souris). The acid detergent fiber (ADF) contents of ‘Leader’ (Souris), ‘Baler’, and ‘Baler No. 2’ were significantly lower than those of other cultivars, except ‘Yellow oat’, while acid detergent lignin (ADL) content was lowest in ‘Haymaker’, ‘Baler’, and ‘Helios’. ‘Haymaker’ had the highest ether extract (EE) content. Regarding cutting stage, hay yield and dry to fresh ratio followed the order milk stage > flowering stage > heading stage. At the flowering stage, fresh forage yield and water-soluble carbohydrate (WSC) content were highest, while CP, dNDF₃₀, dNDF₄₈, NDFD₃₀, NDFD₄₈, IVTDMD₃₀, and IVTDMD₄₈ were second only to those at the heading stage. ADL content was also significantly lower at flowering than at the milk stage. The relative feed quality (RFQ) values of ‘Haymaker’ and ‘Baler’ were significantly higher than those of all other cultivars except ‘Leader’ (Souris). Gray relational analysis showed that NDF, IVTDMD₄₈, ash, dNDF₃₀, and IVTDMD₃₀ ranked as the top five weighted indicators. Both equal weight and weighted correlation degrees ranked ‘Baler’, ‘Haymaker’, and ‘Leader’ (Souris) among the top three cultivars. In conclusion, NDF was the primary indicator for evaluating the production performance of forage oats in saline alkali soils of the Hetao Irrigation District. ‘Baler’, ‘Haymaker’, and ‘Leader’ (Souris) showed the best overall performance and were suitable for cultivation in this region. The flowering stage provided the best comprehensive production performance and was recommended at the optimal cutting stage.

Using 370 Agropyron germplasms as experimental materials, this study systematically investigated their genetic diversity using 31 phenotypic traits and multiple statistical methods, including coefficient of variation, genetic diversity index, cluster analysis, correlation analysis, and grey relational analysis. Additionally, QGA software was employed to simulate and analyze genetic distance, sampling ratio, and clustering algorithms to determine optimal parameters for core germplasm construction. The effectiveness of the core subset was verified through principal component analysis and genetic diversity parameters. Results indicated significant phenotypic differentiation and rich genetic diversity in Agropyron germplasms. Quantitative traits (23 in total, with an average diversity index of 1.867) served as the primary carriers of genetic diversity, with their genetic diversity index was significantly higher than that of qualitative traits (1.328). Phenotypic correlations revealed a "source-sink-flow" coordinated development mechanism: leaves and stems exhibited coordinated growth; spike length was positively correlated with spikelet and floret numbers but negatively correlated with spikelet density, providing a basis for ecological adaptive breeding. Cluster analysis categorized the materials into three characteristic germplasm types: Type Ⅰ (24 resources, characterized by tall plants, long roots, and long spikes), Type Ⅱ (123 resources, emphasizing spike and leaf development), and Type Ⅲ (223 resources, with high spikelet density and numerous glume veins). Grey relational analysis identified seven core evaluation indicators: spikelet number, florets per spike, spike width, first rachis internode length, leaf color, leaf sheath length, and second internode stem diameter. Fifteen comprehensively excellent materials (GB3, BB34, MB15, BB55, XB6, MB25, MB32, GB11, MB7, SB55, SB52, BB68, XB3, BB110, XB2) were selected. A core germplasm consisting of 92 accessions was constructed using "Mahalanobis distance+deviation sampling+sum of squared deviations+25% sampling ratio." This core subset included all 15 excellent materials, achieving an organic unity of genetic diversity conservation (MD=0, CR=100%) and superior trait screening (VD=41.935%, VR=115.413%). Principal component analysis confirmed high consistency between the core germplasm and the original population in genetic structure (core germplasm cumulative contribution rate: 73.014%; original population: 64.407%). This study integrates phenotypic diversity analysis, grey relational evaluation, and core germplasm construction techniques, providing theoretical basis and material support for the efficient utilization and genetic improvement of Agropyron germplasm resources.

Overgrazing will destroy grassland， aggravate vegetation degradation， and induce soil wind erosion. In this study， wind erosion monitoring was conducted on Stipabreviflora desert steppe under different grazing intensity （CK: control， LG: light grazing， MG: moderate grazing， HG: heavy grazing）. Plant community coverage was also measured to explore the patterns of aeolian sediment flux at sand collection height of 0-120 cm aboveground and its relationship with vegetation under different grazing intensities. The results showed that during the growing season of Stipa breviflora desert steppe： (1) Under different grazing intensities， the plant community coverage from May to October demonstrated the pattern of CK>LG>MG>HG. Under the same grazing intensity， it initially increased then decreased. (2) With the increase of grazing intensity， the total aeolian sediment flux rose gradually， with the value under LG， MG and HG reaching 1.40， 1.82， and 1.95 times of that under CK， respectively. (3) There was a significant negative correlation between plant community coverage and total aeolian sediment flux across all grazing intensities （P<0.05）. (4) The functional relationship among grazing intensity （G）， plant community coverage （C）， and total aeolian sediment flux （Q） was constructed： Q=（0.003 5G²－0.020 2G－0.032 7） C+（-0.251 2G²+1.478G+2.463 6）. The goodness of fit （R²） of plant community coverage and total aeolian sediment flux in CK， LG and MG was greater than 0.9， indicating high goodness-of-fit， while R² of HG was only 0.54， which offers a more integrated solution by striking a viable balance between aeolian sediment flux reduction and herder livelihood needs.Despite ideal windbreak and sand fixation performance of the CK and LG treatments， the MG treatment integrated the requirement of grassland ecosystem multifunctional role on aeolian sediment flux bloking and livelihood needs of herdsmen. This finding provides a scientific basis for exploring ecological protection and resource utilization in desert steppe， and has important practical value for establishing a sustainable and coordinated human-land grassland management framework.

Plant abscission is an active and highly regulated physiological process that occurs either as part of normal development or in response to environmental stimuli. It serves as an adaptive mechanism that enables plants to cope with environmental changes. Leaf abscission is closely related to the formation and degradation of the abscission zone and is tightly regulated by phytohormone signaling. These processes are controlled by complex genetic regulatory networks. This review synthesizes recent advances in understanding the mechanisms of leaf abscission from cytological，histological，physiological，biochemical，and molecular perspectives. By integrating key research findings，it provides a comprehensive overview of the regulatory framework underlying plant leaf abscission. Furthermore，it offers theoretical insights and methodological references to guide future studies on leaf abscission in forage grasses.

To explore the optimal legume-grass sowing ratio for synergistically improving yield and quality, a two-year field experiment with multiple mowings was conducted on the Loess Plateau. Five sowing patterns of white clover (Trifolium repens) and tall fescue (Festuca arundinacea) were evaluated, including monocultures of each species and mixtures at legume-to-grass ratios of 1:1, 1:2, and 1:3. The study aimed to assess the seasonal dynamics of forage yield and nutritional quality under different patterns and to identify the optimal strategy using a coupling coordination degree model. The results indicated that mixed sowing exhibited significant overyielding effects. Specifically, the mixtures with 1:2 and 1:3 ratios achieved the highest total yields, which were significantly increased by 23.92%-62.71% compared to monocultures (P<0.05). Regarding quality, compared with the monoculture of tall fescue, mixed sowing effectively increased crude protein content and reduced fiber content. The coupling coordination degree analysis of yield and quality demonstrated that the 1:2 legume-grass ratio is the optimal pattern for achieving synergistic development. This pattern not only achieved synchronous optimization in yield and quality but also maintained a high-level coordination state throughout the growing season. Consequently, it extends the window period for optimal utilization, making it the ideal strategy for establishing high-yielding, high-quality, and stable grasslands.

To examine the effects of photovoltaic panel shading on the quantitative characteristics of different plant communities and soil physicochemical properties in the grassland region of the Songnen Plain, a meadow steppe located at the National Photovoltaic Energy Storage Experimental Station in Daqing City, Heilongjiang Province, was selected as the study site. Three plant communities dominated by Leymus chinensis, Puccinellia tenuiflora and Phragmites australis were investigated in the areas beneath photovoltaic panels and in adjacent inter panel space. Community characteristics, soil physicochemical properties, and their relationships were compared between these two habitats. The results showed that, among the three communities, the L. chinensis community beneath the panels had fewer species than that in the inter panel areas, and all α-diversity indices were significantly lower (P<0.05). However, its coverage, plant height, and aboveground biomass were significantly greater beneath the panels, increasing by 12.60%, 14.70% and 58.30%, respectively (P<0.05). In the P. australis community, coverage beneath the panels was significantly lower, whereas plant height was significantly greater than in the inter panel areas (P<0.05). In the P. tenuiflora community, coverage beneath the panels was significantly lower, aboveground biomass was significantly lower, with a decrease of 89.47% (P<0.05). For all three communities, soil moisture content beneath the panels was significantly higher than in the inter panel areas, while electrical conductivity was significantly lower (P<0.05). In the P. australis community, soil total nitrogen, available nitrogen, available potassium, and organic matter contents beneath the panels were significantly lower than those in the inter panel areas (P<0.05). In the P. tenuiflora community, soil total nitrogen and organic matter contents beneath the panels were significantly lower, whereas available phosphorus content was significantly higher (P<0.05). In the L. chinensis community, no significant differences were detected in soil properties other than moisture content and electrical conductivity. Correlation analysis revealed that soil moisture content was mostly significantly positively correlated with community coverage and aboveground biomass in both habitats, indicating that soil moisture content was a key soil factor regulating grassland productivity. In conclusion, photovoltaic panel shading increased soil moisture content and thereby promoted aboveground biomass accumulation in L. chinensis and P. tenuiflora communities.

Leymus racemosus (Lam.) Tzvel is a perennial tetraploid herbaceous species in the Triticeae tribe of the Poaceae family, exhibiting both high disease resistance and stress tolerance. This species not only serves as an excellent ecological grass for sand fixation, but also hold broad application prospects in wheat disease resistance breeding and ecological management in the desert regions of Northwest China. This article provides a systematic review of Chinese and international research on L. racemosus, including aspects such as germplasm distribution, morphological characteristics, genetic traits, stress tolerance mechanisms, wheat breeding, and forage resource utlization. Given the current status of breeding, promotion, and application of new L. racemosus varieties, this review provides an in-depth analysis of the application value in soil improvement, windbreak and sand fixation, and soil and water conservation. Based on current status, research aspects are proposed for future:while also emphasizing the development of new L. racemosus varieties with greater stress resistance and biomass; and breeding stress-resistant wheat cultivars, using L. racemosus and wheat varieties lacking incompatible distant hybridization genes as parents; strengthening whole-genome research of L. racemosus to explore genes related to stress resistance and disease resistance, and screening potential genetic resources for wheat breeding; systematically conducting restoration research on L. racemosus in marginal lands such as sandy and saline-alkaline soils, improving its standardized cultivation techniques and adaptability evaluation system, thereby providing scientific support for the promotion and application of the L. racemosus; carrying out conservation studies on wild germplasm resources of L. racemosus to preserve the foundation for breeding.

The typical steppe has long experienced high intensity grazing pressure， resulting in biodiversity loss and the degradation of ecosystem services. Although appropriate grazing can promote nutrient cycling and improve soil nutrient levels in grassland ecosystems， the specific effects of rational grazing on soil nutrient dynamics in typical steppe regions remains insufficiently understood. In this study， five representative steppe zones in Hulunbuir City were selected as research sites. Comparative experiments were conducted between grazing balance zones （supporting 0.6 to 1.5 sheep units per hectare） and grazing exclusion areas to examine soil nutrient variations across different soil depths. The results showed that soil nutrient indicators， including organic carbon， total nitrogen， total phosphorus， total potassium， and available phosphorus， were consistently higher in grazing balance zones than in grazing exclusion areas. Grazing exclusion exerted positive effects on soil organic carbon and total nitrogen across all layers （0-30 cm） in regions with lower aridity indices. The grazing response ratios of major soil nutrients exhibited strong correlations with climatic factors： grazing response ratio of soil total nitrogen was significantly positively correlated with grazing response ratio of soil total phosphorus， available phosphorus and aridity index， grazing response ratio of soil total phosphorus showed a highly positive correlation with aridity index， while all nutrient response ratios were negatively correlated with precipitation. In conclusion， rational grazing effectively enhances soil nutrient levels in typical steppe ecosystems.

As a pillar industry in the pastoral and agro pastoral regions of China, animal husbandry plays an essential role in ensuring national food security, ecological security, and income growth for herding households. With the rapid expansion of large-scale livestock production in pastoral areas, tensions between scale enlargement and production efficiency, as well as conflicts between grassland carrying capacity and livestock development, have become increasingly pronounced. Balancing production improvement with ecological protection has therefore become an urgent demand for the sustainable development of the pastoral sector. Based on survey data from 1 374 herding households, this study used a stochastic frontier production function (SFA) to estimate production technical efficiency and combined Tobit regression with a mediation effect model to examine the effects of operation scale and forage and livestock coupling on production efficiency. Robustness and heterogeneity tests were further conducted to verify the reliability of the results. The results showed that the average technical efficiency of the sampled households was 0.58, indicating a moderate to low level with substantial room for improvement. Technical efficiency was higher in the Gannan agro pastoral ecotone than in the pastoral areas of Hexi and Qinghai. Operation scale had a significant inverted U-shaped effect on technical efficiency. Moderate expansion of production scale improved efficiency by optimizing factor allocation, whereas excessive expansion reduced efficiency because of rising management costs and resource misallocation. Forage and livestock coupling also played a significant mediating role, not only directly enhancing production technical efficiency but also alleviating tensions between forage resources and livestock production. These findings suggest that promoting appropriately scaled operations, strengthening forage and livestock coupling, enhancing technical service support, and implementing region specific policies are essential for achieving coordinated improvements in production efficiency and ecological sustainability in pastoral animal husbandry.

The farming-pastoral zone of northern China serves as a critical ecological security barrier for central and eastern regions. However， the combined pressures of overgrazing and climate change have led to severe grassland degradation， resulting in substantial declines in vegetation productivity and soil quality. Reseeding is a widely adopted restoration strategy， yet its effectiveness varies among plant species， potentially due to differences in root system architectures on soil physicochemical properties. In this study， a degraded typical steppe was selected to examine the effects of reseeding plants with distinct root types， including taproot， tuberous root， and fibrous root systems， with non-reseeded plots as control. The impacts on grassland productivity and soil characteristics were comprehensively assessed. The results showed that alfalfa reseeding achieved the greatest productivity improvement， with aboveground biomass increasing by about 1.38 times compared to the control. Both oat and alfalfa reseeding treatments significantly enhanced soil quality. From the perspective of root architecture， fibrous rooted plants were the most effective in improving soil organic matter， porosity， moisture content， and aggregate stability. Tap rooted plants contributed to increases in surface soil organic matter， porosity and moisture content， whereas species with straight roots were effective in improving deep soil conditions. Overall， reseeding with fibrous rooted plants yields the most pronounced restoration benefits for degraded grasslands. These findings provide a theoretical basis and practical guidance for optimizing plant selection in grassland rehabilitation based on root system architecture.

This study was conducted on the typical grassland hayfield in Xilingol League， Inner Mongolia. Three experimental treatments： control （CK）， reseeding of forage oat （RA）， and reseeding of forage oat + fertilization （RA + DP）， were established to investigate the effects of reseeding forage oat on the forage production capacity， forage quality， community diversity， and soil nutrients of natural grassland. The results showed that under the RA + DP treatment， the dry hay yield was 3 286.47 kg/hm²， of which the oat yield was 2 020.52 kg/hm² and the natural forage yield was 1 264.95 kg/hm². The total forage yield under the RA + DP treatment was 208.94% higher than that of the control and 139.61% higher than that of the RA treatment. The dry oat hay yield under the RA + DP treatment improved 1 816.94 kg/hm² compared with that of the RA treatment. In the 0-10 cm soil layer， the available phosphorus content of the in-row soil under the RA + DP treatment was 3.92 mg/kg， which was 246.90% higher than that of the control， while the available phosphorus content of the inter-row soil under the RA + DP treatment was 1.43 mg/kg， showing no significant difference from the control. The study on community diversity indicated that the Shannon index under the RA + DP treatment （1.02） was not significantly different from that of the control （1.20）， while there was no significant difference in the number of species among the three groups. The reseeding of forage oat + fertilization measures can significantly increase the grassland production capacity and forage quality in natural grassland with sufficient precipitation， which is an effective measure to enhance grassland productivity. Moreover， short-term reseeding + fertilization （diammonium phosphate） did not reduce the species diversity of the grassland.

Biochar has shown great potential for improving soil physicochemical properties and enhancing crop productivity. However， the mechanisms by which the combined application of biochar and nitrogen fertilizer influences forage yield， soil nutrient dynamics， and soil microbial communities in legume-grass mixed pastures remain unclear. In this study， a mixed pasture of alfalfa （Medicago sativa） and smooth bromegrass （Bromus inermis） was used to examine the effects of biochar and nitrogen fertilizer co-application on soil physicochemical properties， microbial biomass， diversity， and community structure， as well as their interrelationships. The results showed that the combined application of biochar and nitrogen fertilizer significantly enhanced soil nutrient availability. Compared with application of nitrogen fertilizer alone at 180 kg/hm²， the treatment of 8 t/hm² biochar plus 180 kg/hm² nitrogen fertilizer increased soil total nitrogen by 35.71%， ammonium nitrogen by 42.19%， and available potassium by 34.38% （P < 0.05）， while no significant difference was observed in total phosphorus content. Biochar addition markedly altered soil microbial community structure， increasing the number of unique bacterial ASVs （e.g.，10 372 in the 8 t/hm² biochar plus 180 kg/hm² nitrogen treatment） and elevating the relative abundance of Actinobacteria， Chloroflexi， Gemmatimonadota， and Sphingomonas. Alpha diversity analysis indicated that nitrogen fertilization alone reduced bacterial richness， whereas biochar addition had no significant effect on alpha diversity indices. Correlation analysis revealed that variations in the relative abundance of different soil bacterial groups were primarily associated with soil total nitrogen， nitrate nitrogen， available potassium， and forage yield. In conclusion， the combined application of 8 t/hm² biochar and 180 kg/hm² nitrogen fertilizer significantly improves soil fertility， promotes nutrient cycling， and enhances forage productivity. These findings provide a theoretical basis for the use of biochar-nitrogen integration to support degraded grassland restoration and sustainable pasture management.

Salt stress is a major abiotic stress limiting sustainable agricultural development. Screening and identifying salt-tolerant forage soybean varieties is crucial for enhancing high-protein forage yield and utilizing saline-alkali land in China. In this study, seven forage soybean cultivars (S001-S007) were evaluated, with wild soybean (GS) and cultivated soybean Williams 82 (W82) used as controls. Under 150 mmol/L and 200 mmol/L NaCl stress, emergence indicators (emergence rate, emergence potential, and emergence index) and seedling morphological traits (plant height, leaf area, root length, and shoot and root fresh/dry weights) were measured. The salt tolerance at the seedling stage was comprehensively evaluated using the membership function method and cluster analysis. The results showed that all evaluated indicators decreased significantly with increasing salt concentrations, and distinct differences in salt tolerance were observed among the varieties. The membership function analysis ranked the salt tolerance of the nine soybean varieties from high to low as follows: S007>S002>S003>S004>S005>W82>S001>S006>GS. Furthermore, cluster analysis categorized the nine varieties into three groups: highly salt-tolerant (S002, S003, and S007), moderately salt-tolerant (S004), and salt-sensitive (GS, W82, S001, S005, and S006).

To evaluate the differences in salt tolerance among new lines of bermudagrass (Cynodon dactylon), identify key indicators for salt tolerance assessment, and thereby facilitate the breeding of new salt-tolerant cultivars, this study used 'Xinnong No. 1' bermudagrass as the control. Three new lines (C_138, C₂₂, C₆₃) were subjected to NaCl stress at concentrations of 0.5%, 1.0%, 1.5%, 2.0%, and 2.5% during both seed germination and seedling stages. Germination, growth, and physiological parameters were measured. A comprehensive evaluation of salt tolerance was conducted by integrating the entropy-weighted TOPSIS method, membership function analysis, and the Comprehensive Salt Tolerance Index (CSI). The results indicated that salt stress significantly inhibited seed germination and seedling growth of bermudagrass, with clear differential tolerance observed among the lines. C₁₃₈ demonstrated the best performance across both stages, maintaining relatively high levels of germination rate, vigor index, aboveground biomass, and leaf relative water content under salt stress. C₆₃ performed well under low to moderate salinity (≤1.0%). The entropy-weighted TOPSIS analysis revealed that germination potential and vigor index were major contributing factors during the germination stage, whereas aboveground and belowground biomass were key during the seedling stage. Based on the combined analysis of the membership function and CSI, the salt tolerance of the four bermudagrass materials was consistently ranked (from strongest to weakest) as follows: C₁₃₈, C₆₃, 'Xinnong No. 1' bermudagrass, and C_22. In summary, C₁₃₈ exhibits strong comprehensive salt tolerance and shows promise as an excellent material for saline-alkali land improvement, while C₆₃ is suitable for mildly saline environments. These findings provide a basis for the breeding and promotion of salt-tolerant bermudagrass varieties.

This study examined subalpine meadows on Mount Wutai in Shanxi Province to elucidate the spatial patterns of biodiversity and the mechanisms driving their maintenance along an altitudinal gradient. Indicators including plant community composition， species diversity， and soil physicochemical properties were measured to analyze variation patterns in meadow community structure and diversity along altitudinal gradients. The results showed that Carex lancifolia and Polygonum viviparum were dominant at low and mid elevations， while Kobresia humilis became predominant at higher elevations. The relative biomass of Cyperaceae species increased significantly with elevation， whereas forbs decreased markedly， displaying statistically significant differences across altitudes （P<0.05）. Species richness at mid-elevation site （E2） was significantly higher than at both low （E1） and mid-high （E3） elevations （P<0.05）. In contrast， no significant differences were observed in the evenness index， diversity index， or dominance index among elevations. β-diversity also varied across different altitudinal levels （P<0.05）， reflecting distinct community turnover patterns. Further analysis indicated that soil temperature and water content were the primary environmental factors driving changes in plant community composition， while soil pH and carbon and nitrogen nutrients exerted comparatively weaker influences.

To investigate the effects of cellulase and lactic acid bacteria on the forage quality and microbial community of Caragana korshinskii silage. Fresh C. korshinskii forage was ensiled in PVC vacuum bags for 60 days under three treatments: control (CK, no additive), cellulase supplementation (C, 0.1% fresh matter basis), and Lactobacillus plantarum inoculation (L, 1×10⁵ cfu/g). Post-ensiling analyses reveled that the L group exhibited significantly lower pH and higher concentrations of lactic acid, acetic acid, and propionic acid than both the C and CK groups (P<0.05). The C treatments showed significantly reduced ammonia nitrogen and dry matter contents relative to the control (P<0.05). Both additives treatments significantly decreased neutral detergent fiber (NDF) content compared with the control (P<0.05), whereas crude protein (CP) and acid detergent fiber (ADF) contents remained unaffected. Microbial diversity (alpha diversity) was significantly reduced in the L treatment (P<0.05), with Lentilactobacillus emerging as the dominant genus. Collectively, Lactobacillus plantarum effectively enhanced silage fermentation quality and reshaped the microbial community structure, offering practical insights for optimizing Caragana korshinskii silage production.

Alfalfa (Medicago sativa L.) is an important leguminous forage grass, and characterization of its mitochondrial genome (mtDNA) is essential for understanding its evolutionary biology and supporting genetic improvement. In this study, the complete mtDNA sequence of the strain 'Qingda No. 1' was assembled and analyzed. The mtDNA is 290 285 bp in length and contains 35 protein-coding genes, 15 transfer RNA (tRNA) genes, and three ribosomal RNA (rRNA) genes. A total of 56 simple sequence repeats (SSRs) and 48 long repeat sequences were identified. Analysis of synonymous and nonsynonymous substitution rates showed that most protein-coding genes were under purifying selection, with Ka/Ks ratio below 1, whereas rps1 and nad9 exhibited Ka/Ks ratio greater than 1, suggesting possible positive selection. Inverted repeat (IR) boundary analysis indicated that the alfalfa mtDNA was more compact compared with other legumes such as soybean (Glycine max), and tetranucleotide repeats represented the predominant SSR type. Phylogenetic analysis confirmed a close evolutionary relationship between M. sativa and Medicago truncatula. Codon usage bias analysis revealed a preference for codons ending with A or U, and neutrality and ENC-plot analyses indicated that natural selection played a major role in shaping codon usage bias.

In the alpine pastoral regions of Xizang, sustainable livestock development is severely constrained by the shortage of forage during winter and spring-a shortage resulting from the frigid climate, shallow fertile soil layers, and fragile ecosystems. This study aimed to identify the optimal mixed sowing ratios of rye (Secale cereale L. 'Ganyin No. 1') and common cetch (Vicia sativa L. 'Lanjian No. 3'), along with optimal nitrogen (N) fertilization and irrigation regimes, to provide a scientific basis for high-yield and high-quality cultivated forage production in Naqu, Xizang. A completely randomized design with three factors at three levels was employed, comprising N fertilizer rates (0, 120, and 240 kg/hm²), irrigation levels (0, 10, and 20 mm), and mixed sowing ratios (rye monoculture, and rye-to- common vetch ratios of 1∶1 and 1∶2), resulting in 27 treatment combinations with three replicates each. The results indicated that the mixed sowing ratio significantly influenced both the production performance and nutritional quality of the forage. The treatment combination of a 1∶1 mixed sowing ratio, 20 mm irrigation, and 120 kg/hm² N fertilization achieved the highest hay yield (6 203.60 kg/hm²) and crude protein yield (1 498.73 kg/hm²). Under this optimal treatment, crude protein and ether extract contents significantly increased to 24.13% and 2.37%, respectively. Furthermore, neutral detergent fiber and acid detergent fiber recorded their lowest values (38.81% and 28.41%, respectively), yielding a high Relative Feed Value of 175.72. Therefore, for cultivated forage establishment in the alpine pastoral region of Naqu, Xizang, a 1:1 mixed sowing ratio of rye and common vetch, combined with 20 mm of irrigation and 120 kg/hm² of nitrogen fertilizer, is recommended to achieve high yield and quality.

To investigate the effects of artificial restoration on soil organic carbon (SOC) content and carbon sequestration capability in degraded grasslands, a field experiment was conducted in a degraded desert steppe in Yanchi County, Ningxia. Three reseeding regimes were established: grass mixture (P1), legume mixture (P2), and grass-legume mixture (P3), with a non-reseeded site serving as the control (CK). Soil physicochemical properties,organic carbon (SOC) and its active components, including easily oxidizable organic carbon (EOC), dissolved organic carbon (DOC), and microbial biomass carbon (MBC), were analyzed years after reseeding. The results showed that soil pH and water content significantly increased following reseeding (P<0.05). Soil total nitrogen content increased significantly under P1 and P2, and the electrical conductivity in the 20-40 cm layer under P1 and P3 were significantly higher than that in the CK (P<0.05). SOC content was significantly higher than the CK in the 0-20 cm layer under P3 and in the 20-40 cm layer under P2 (P<0.05). Reseeding generally increased EOC content while decreasing DOC content, with significant changes observed under P1 (P<0.05). Soil MBC content decreased significantly under P2 (P<0.05). The DOC/SOC ratio declined after reseeding, whereas the EOC/SOC ratio under P1 was significantly higher than that under CK, P2, and P3 (P<0.05). In the 0-20 cm layer, the MBC/SOC ratio under P1 was significantly higher than in the CK (P<0.05). Correlation analysis revealed significant negative correlations between EOC and DOC in both soil layers (P<0.05), and between SOC and EOC in the 0-20 cm layer (P<0.05). In conclusion, among the treatments, P3 demonstrated superior performance in promoting SOC sequestration and maintaining carbon pool stability, indicating that grass and legume mixture reseeding is a suitable strategy for restoring degraded desert steppe ecosystems.

Weeds can significantly reduce the yield and quality of Medicago sativa and have become one of the most important pest groups in M. sativa fields. The Yellow River Basin is the core production area of M. sativa in China, where it is of great significance to carry out weed prevention and control in M. sativa fields. To systematically clarify the weed communities characteristics in M. sativa fields in the Yellow River Basin, field weed surveys were conducted in M. sativa planting areas of Shandong, Henan, Shanxi, Shaanxi, Inner Mongolia, Ningxia and Gansu. The results showed that the weeds in M. sativa fields of the Yellow River Basin belonged to 27 species, 25 genera and 12 families. Poaceae, Chenopodiaceae and Asteraceae were the dominant families. Gramineous weed species such as Setaria viridis were overwhelmingly dominant, while Chenopodium glaucum was the predominant broadleaf weed. Weed communities in M. sativa fields across the Yellow River Basin exhibited distinct geographical differences. Overall, the number of weed species in the middle and lower reaches was higher than that in the upper reaches. Specifically, Digitaria sanguinalis and Eleusine indica were the dominant species in the middle and lower reaches, including Shandong, Shanxi, and Henan provinces. S. viridis and other weed species were dominant in the middle reaches (Shaanxi and Inner Mongolia), while Echinochloa crusgalli and Cirsium japonicum were dominant in the upper reaches (Ningxia and Gansu). The priorities of weed control in M. sativa fields vary among regions. Broadleaf weeds should be the main target in Gansu. Gramineous weeds should be primarily controlled in Henan, Shanxi, Inner Mongolia, Shaanxi and Ningxia, while both gramineous and broadleaf weeds need to be managed in Shandong. This study clarified the weed community characteristics and occurrence dynamics in M. sativa fields of the Yellow River Basin, thereby providing a scientific basis for environmentally-friendly weed management in this region.

Sandy land ecosystems play a critical role in the global carbon cycle， with their internal carbon cycling mechanisms being key to maintaining the global carbon balance. Soil organic carbon （SOC）， as the core component of this system， not only influences the cycling and turnover rates of soil organic matter but is linked to changes in the functional state of sandy ecosystems. It serves as a key indicator for assessing the health and stability to these systems. To gain a deeper understanding of SOC and its stability characteristics in sandy lands， relevant literature from 1998 and 2024 was compiled from the Web of Science （WOS） and China National Knowledge Infrastructure （CNKI） databases for analysis. The results showed that： （1） From 1998 to 2024， the number of publications on SOC in sandy lands showed an increasing trend. Domestic research hotspots focused on "soil nutrients" and "desertification"， while international hotspots were "nitrogen"，"carbon"， and "land use". （2） SOC content， storage， and its composition in sandy lands are influenced by various factors such as land use patterns， microbial activity， vegetation types， and human activities.（3） The stability of SOC in sandy lands results from the combined effects of physical， chemical， and biological protection. Physical protection （e.g.， aggregates） provides a microenvironment for chemical protection （e.g.， mineral adsorption）， while biological protection （e.g.， microbial activity） promotes aggregate various modern technological approaches to achieve long-term， spatially networked observation. In the future， multiple modern technological means should be integrated to achieve intelligent， networked， multi-scale and three-dimensional long-term positioning observations.It is also essential to develop and apply soil carbon sequestration techniques tailored to local conditions. This will help fully reveal the influencing factors and stabilization mechanisms of SOC in sandy lands， laying the foundation for achieving sustainable carbon sequestration goals in these environments.

Alternate partial root-zone irrigation (APRI) is a water saving irrigation strategy that can enhance alfalfa yield but may compromise forage quality. However, it remains unclear whether fixed partial root-zone irrigation (FPRI) can improve biomass allocation and forage quality compared with APRI. A two-year pot experiment was conducted with six treatments: full irrigation (FI), deficit irrigation (DI), FPRI, APRI, alternate partial root-zone irrigation with low water (APRIL), and fixed root-zone irrigation with low water (FPRIL). Biomass allocation and forage quality of alfalfa were evaluated under each irrigation regime. The results showed that compared with FI, FPRI increased crude protein (CP) content of alfafa in the year of planting and two-year-old alfafa by 6.88 g/kg and 3.94 g/kg, reduced neutral detergent fiber (NDF) and acid detergent fiber (ADF) contents of two-year-old alfafa by 46.01 g/kg and 30.10 g/kg, respectively, and increased the root shoot ratio of two-year-old alfafa by 32.76%. Compared with APRI, FPRI increased CP yield of alfafa in the year of planting and two-year-old alfafa by 1.07 g/pot and 0.38 g/pot, reduced ADF yield by 4.70 g/pot and 0.08 g/pot, increased aboveground biomass by 4.75% and 10.96%, increased underground biomass by 3.21% and 18.96%, increased root shoot ratio by 9.12% and 16.89%, respectively. Under further water deficit conditions, FPRIL reduced NDF and ADF yields of alfafa in the year of planting by 0.64 g/plot and 7.07 g/pot, respectively, and increased the root shoot ratio by 62.07%, compared with DI. Overall, fixed partial root-zone irrigation improved forage quality and optimized biomass allocation more effectively than alternate partial root-zone irrigation. These findings provide a theoretical basis for enhancing alfalfa quality and biomass allocation under water limited conditions.

As microbial metabolites, lipopeptide-type lipids exhibit significant potential in sustainable agriculture. This study conducted a multi-scale experiment approach, including pot, plot, and field trials to investigated the regulatory effects of a Bacillus subtilis-derived lipopeptide-type lipid on alfalfa (Medicago sativa) growth and soil nutrients. The results showed that the combined application of lipopeptide-type lipid through seed coating and root irrigation significantly improved the emergence rate of alfalfa from 40.90% in the control group (CK) to 57.70%. Plant height and fresh weight were enhanced by 14.23% and 20.93%, respectively. In the field trials, increases under treatments were found in plant height and fresh weight by 15.31% and 55.88%, respectively, compared with control, while the leaf relative chlorophyll content (SPAD values) and crude protein content were also promoted by 9.76% and 16.76%, respectively. In terms of soil nutrient regulation, treated with fertilizer containing lipopeptide-type lipid significantly enhanced microbial biomass nitrogen, available phosphorus, and readily available potassium compared to the control group. This study demonstrates the dual function of lipopeptide-type lipid in simultaneously improving alfalfa yield and quality as well as enhancing soil health in semi-arid regions. These findings provide a theoretical basis and practical guidance for the application of microbial-derived lipid as green fertilizer and development of sustainable agricultural technologies in ecologically fragile areas.

Pennisetum centrasiaticum is a typical pioneer species on the abandoned farmlands of the Loess Plateau. Based on ten years of continuous field monitoring data, the responses of P. centrasiaticum population dynamics to the abandonment duration and climatic factors were analyzed. The results showed that with increasing abandonment duration, the plant height and canopy diameter of P. centrasiaticum decreased significantly by 2.26 cm and 6.01 cm, respectively, after ten years of abandonment compared to the first year. Reproductive branch density and tiller density exhibited an initial increase followed by a decline, in which tiller density peaked in the fifth year of abandonment. Tiller density reduced by 2.31 tillers/ m² in the ten years of abandonment compared to the peak. Seedling density decreased by 4.00 plants/m² after ten years abandonment compared to the first year. Population density and aboveground biomass showed significant decreasing trend with abandonment duriation, with annual average reductions of 0.82 plants/m² and 1.92 g/m², respectively, by the tenth year relative to the first year. The abandonment duration was identified as the dominant factor affecting plant growth, reproductive characteristics, and biomass accumulation of P. centrasiaticum populations, independently explaining 33% to 79% of the variation in each of the indictors. Structural equation modeling further revealed that the abandonment duration not only directly suppressed the aboveground biomass of P. centrasiaticum, but also exerted an indirect negative effect by limiting seedling density. Furthermore, the abandonment duration indirectly reduced the proportion of P. centrasiaticum aboveground biomass within the community by suppressing plant height, canopy diameter, seedling density, and population density.

This study systematically investigated the floral traits， flowering dynamics， and breeding system of Galega orientalis Lam populations in Hutubi County， Xinjiang， China. The results showed that G. orientalis flowers from May to June， with population-level， individual-plant， and single-flowering durations lasting approximately 45 days， 15 days， and 2 days， respectively. The flowers are perfect， blue-violet， with stamens and pistils maturing simultaneously （homogamous）. During anthesis， the stigma remain positioned above the anthers， creating spatial separation. Pollen viability peaked on the day of anthesis， with a maximum recorded value of 81.07%. The outcrossing index （OCI） was 4， the pollen-ovule ratio （P/O） was 2 329.9， and the natural fruit-set rate was 64%. Based on artificial pollination experiments， the breeding system was determined to be primarily outcrossing， partially self-compatibility， pollinator-dependent， and lacking active selfing capability. The flower possesses the typical piston-type pollen release mechanism characteristic of the subfamily Faboideae. Bees were identified as the primary effective pollinators， and root sprouting （root suckering） serves as an effective pathway for reproductive compensation.

This research evaluated 18 accessions of Echinochloa frumentacea (Roxb.) Link germplasm in a pot experiment under 150 mmol / L NaCl stress at the seedling stage to screen for salt tolerance and establish a corresponding evaluation system. Twenty-four phenotypic traits, encompassing biomass, antioxidant enzyme activity, chlorophyll fluorescence parameters and photosynthetic indices, were measured. The comprehensive salt tolerance index (D-value) of each accession was subsequently calculated. Principal component analysis (PCA), correlation analysis, membership function analysis, cluster analysis, and a comprehensive evaluation were then undertaken to systematically assess and classify the salt tolerance of the accessions. A predictive regression model for salt tolerance was developed using stepwise regression analysis. The results revealed significant differences between the salt-treated and control groups for all traits, with varying degrees of correlation among the 24 indicators. Based on the D-value-based hierarchical cluster analysis, the 18 accessions were classified into four groups: two highly salt-tolerant accessions, ten salt-tolerant accessions, five moderately salt-tolerant accessions, and one salt-sensitive accession. Among the highly salt-tolerant group, accession CF033297 exhibited superior salt tolerance and was identified as an elite germplasm resources for breeding salt-tolerant Echinochloa frumentacea Stepwise regression analysis further identified q_P, K⁺, Pn, F_v/F_m, Proline content, O₂^-, aboveground biomass, and root length as reliable indicators for evaluating seedling-stage salt tolerance in Echinochloa frumentacea.

Shrub branch mulching and sheep manure addition have shown potential in degraded grassland restoration practices for improving soil moisture and nutrient availability, respectively. However, the mechanisms and effects of these two measures, whether individually or combined, on soil water and nutrient regulation and dominant forage growth in desert steppe remain unclear. Therefore, a two-factor split-plot experiment was conducted in the desert steppe of Yanchi, Ningxia. The main plots consisted of three levels of Caragana korshinskii branch mulch treatments: no mulch, short-branch mulch (5-10 cm), and long-branch mulch (70-130 cm). The subplots included four sheep manure addition levels of 0 kg/hm², 4 000 kg/hm², 8 000 kg/hm², and 16 000 kg/hm². Their effects on soil moisture, temperature, nutrients, and dominant forage growth were investigated. The results showed that: (1) Compared with no branch mulch, both short-branch mulch and long-branch mulch reduced soil temperature and increased soil water content, whereas sheep manure addition had no significant effect on soil moisture or temperature; (2) Both branch mulch and sheep manure addition significantly decreased soil pH and increased the contents of soil organic carbon, nitrogen, and phosphorus; (3) Branch mulch and sheep manure addition significantly promoted the growth of dominant forages. All growth indices of Agropyron mongolicum were highest under the short-branch mulch and 8 000 kg/hm² sheep manure addition treatment, while Lespedeza potaninii performed best under the long-branch mulch and 8 000 kg/hm² sheep manure addition treatment; (4) Redundancy analysis indicated that soil water content, temperature, and nutrients were key environmental factors influencing forage growth, with particularly pronounced effects on Agropyron mongolicum. In summary, branch mulch mainly improved soil hydrothermal conditions, whereas sheep manure addition primarily enhanced soil nutrient supply. Their combination effectively promoted the growth of dominant forages in desert steppe, providing a scientific basis for grassland ecological restoration and sustainable management.

This study investigated the effects of exogenous hormones on seed germination and seedling growth of Bromus inermis X12 under drought stress. PEG-6000 was used to simulate drought conditions, and a gradient test determined that 25% PEG represented the semi-lethal concentration. On this basis, the alleviating effects of melatonin (MT), methyl jasmonate (MeJA), and gibberellin (GA₃) were comparatively evaluated. The results showed that all three exogenous hormones could effectively alleviate the inhibitory effects of drought on seed germination and seedling growth. As hormone concentration increased, the germination percentage, germination potential, germination index, and vigor index first increased and then decreased, whereas leaf length and root volume continued to increase. After treatment with the highest concentration of MT and GA₃, the activities of antioxidant enzymes in leaves and roots reached their peak, and MDA content decreased to the lowest level. As MeJA concentration increased, the activity of antioxidant enzymes initially increased and then decreased. The comprehensive evaluation based on the membership function approach showed that GA₃ had the best promotion effect during the germination stage at 288.70 μmol/L and 144.35 μmol/L. The optimal concentrations at the seedling stage were 200 μmol/L for MT, 0.05 μmol/L for MeJA, and 577.41 μmol/L for GA₃.

To identify the optimal combination of sowing rate and row spacing for oat (Avena sativa) production in the alpine arid and semi-arid regions of Xinjiang, a field experiment was conducted using a two-factor randomized complete block design. The cultivar Longyan 5 was used as the experimental material, with four: 150 kg/hm²(S1), 180 kg/hm² (S2), 225 kg/hm² (S3), and 270 kg/hm² (S4), and two row spacings treatments: 15 cm (L1) and 30 cm (L2). The effects of different sowing rate and row spacing combinations on the growth, forage yield, and nutritional quality were evaluated using correlation analysis and principal component analysis. The results showed that the interaction between sowing rate and row spacing had highly significant effects on plant height, stem diameter, number of effective tillers, and leaf-stem ratio among the eight treatment combinations (P<0.01). When maximizing fresh forage yield was the primary object, the S2L1 treatment produced the highest fresh yield, reaching 82 340 kg/hm². For the coordinated improvement of yield and quality, the S2L2 treatment exhibited the best overall performance, with fresh forage yield, crude protein content, and relative forage quality reaching 81 986.67 kg/hm², 11.26%, and 104.11, respectively. Correlation analysis revealed that stem diameter and fresh forage yield were extremely significant positive correlation with crude protein content and relative forage quality (P<0.01). Principal component analysis further showed that S2L2, corresponding to a sowing rate of 180 kg/hm² and a row spacing of 30 cm, achieved the highest comprehensive score and was therefore identified as the optimal combination for high yield and high-quality oat production in the study area. These findings provide a theoretical basis and technical support for optimizing oat cultivation practices and ensuring forage supply for animal husbandry in the alpine arid and semi-arid regions of Xinjiang.

Astragalus dahuricus （Pall.） DC.， a high-quality native plant in Inner Mongolia， is widely used in ecological restoration. However， research on its cultivation remains limited. To promote the conservation-based development of native grass seed resources and optimize the breeding technical system in Inner Mongolia， this study adopted a three-factor， four-level orthogonal experimental design to investigate the effects of row spacing （40， 50， 60， 70 cm）， sowing rate （10， 15， 20， 25 kg/hm²）， and nitrogen-phosphorus-potassium （The ratio of N∶P₂O₅∶K₂O is 18∶18∶18） compound fertilizer application rate （105， 210， 315， 420 kg/hm²） on seed yield and its component. The results demonstrated that the highest seed yield was achieved under a row spacing of 50 cm， a seeding rate of 10 kg/hm²， and a fertilization rate of 210 kg/hm². Among these factors， the impact on seed yield followed the order： row spacing > fertilizer rate > seeding rate， with the seeding rate having no significant effect. Grey correlation analysis of the seed yield components showed the following order of relational degree： number of pods per inflorescence > number of inflorescences per unit area > thousand-seed weight > number of seeds per pod > number of florets per inflorescence.

To investigate the effects of long-term annual mowing at different stubble heights on community characteristics and temporal stability in rainfed legume-grass mixed pasture, a mixed sward composed of Leymus chinensis, Medicago varia Martin. cv. Caoyuan No. 2, and Bromus inermis was established as the experimental system. Five treatments were implemented: No mowing and stubble heights of 0, 6, 10, and 14 cm. Mowing was conducted annually in late August beginning in 2008, and by 2018 the pasture had undergone ten consecutive years of mowing, representing long term management. Community characteristics and temporal stability were analyzed for the period from 2018 to 2021. The results showed that long term annual mowing significantly increased the height of L. chinensis, the density of grasses (L. chinensis and B. inermis), the aboveground biomass of the community and individual forage species, and the community stability index (P<0.05). At a stubble height of 6 cm, the density of B. inermis and the community stability index were significantly higher than those under other stubble height treatments (P<0.05), and the aboveground biomass of M.varia was significantly higher than that under treatments with stubble heights of 10 cm, 14 cm and no mowing (P<0.05). At a stubble height of 10 cm, the height of L. chinensis was significantly higher than that under other stubble height treatments (P<0.05), and the proportion of weed biomass was the lowest. Moreover, the interaction between stubble height and annual precipitation significantly enhanced community productivity and temporal stability (P<0.05). Overall, a stubble height of 6-10 cm is optimal to maintaining community productivity and temporal stability in rainfed legume-grass mixed pastures of Inner Mongolia under long term mowing management.

This study aimed to investigate the differences in plant community characteristics and soil nutrient stoichiometry among three grassland types： temperate desert， temperate steppe， and mountain meadow on the northern slope of the Tianshan Mountains in Xinjiang， China， as well as the relationships between them. Field sampling and laboratory analysis were conducted to determine plant community traits， soil carbon （C）， nitrogen （N）， and phosphorus （P）contents， microbial biomass carbon， nitrogen， and phosphorus （MBC， MBN， MBP）contents， and soil enzyme activities. Redundancy analysis （RDA） was used to identify the key environmental factors driving plant community composition. The results showed that： From temperate desert to mountain meadow， plant community height decreased significantly （P<0.05）， while the coverage， density， and diversity indices （except for evenness） increased. The highest contents of soil organic carbon， total nitrogen， total phosphorus， MBC， MBN， and MBP were found in mountain meadow， whereas the soil N∶P ratio was lowest in temperate desert. The activities of β-glucosidase and alkaline phosphatase were highest in mountain meadow， while the activities leucine aminopeptidase and N-acetyl-β-D-glucosaminidase were highest in temperate steppe. From temperate desert to mountain meadow， soil nutrients accumulated， and vegetation trended to be shorter and denser. Among three types， temperate desert grasslands were nitrogen-limited. RDA indicated that MBC∶MBN ratio and MBP were key factors driving plant community characteristics （cumulative explanation rate： 66.7%）. In conclusion， this study provides a theoretical basis for understanding of nutrient cycling and guiding the restoration of degraded grasslands in arid ecosystems.

To reveal the response of microbial communities of generalized and specialized species to different grazing intensities in mountain meadows in the middle section of the northern slope of Tianshan，the changing characteristics of generalized and specialized species in light grazing，heavy grazing，and control samples（with fenced-in meadows serving as the control） were studied，and the association of generalized and specialized species communities with soil factors under grazing interference was explored. The results showed that light grazing significantly enhanced both alpha and beta diversity of microbial generalists and specialists relative to heavy grazing. Proteobacteria，Actinobacteria，and Acidobacteriota dominated bacterial generalist and specialist communities，while Ascomycota，Basidiomycota，and Chytridiomycota were predominant in fungal communities across all grazing treatments. Co-occurrence network metrics（node number，edge number，average degree，and robustness） initially increased and subsequently declined with escalating grazing intensity，whereas vulnerability showed an inverse trend. The relative contribution of deterministic assembly processes to bacterial and fungal community assembley increased with grazing intensity； however，stochastic processes remained the dominant assembly mechanism. Functional prediction using Tax4Fun2 and FUNGuild revealed that grazing altered metabolic capabilities of bacterial functional groups and shifted the abundance profiles of fungal functional groups. Mantel tests and random forest analyses confirmed significant relationship between soil factors and microbial communities under grazing disturbance，with soil variables exhibiting lower explanatory power for generalists than for specialists.

Sucrose synthase (SUS) is a key regulatory enzyme in plant sugar metabolism and plays a central role in plant responses to abiotic stresses. This study employed an integrated bioinformatics and transcriptomics approach to systematically identified the SUS gene family (designated as MsSUSs) in Medicago sativa ‘Xinjiang Daye’ and elucidated their transcriptional regulatory mechanisms under drought stress. The results showed that the genome of M. sativa ‘Xinjiang Daye’ contains 31 SUS genes distributed across 25 chromosomes, which are classified into three subfamilies: SUS Ⅰ, SUS Ⅱ, and SUS Ⅲ. The MsSUS proteins are predominantly hydrophilic and acidic, with most localized in the cytoplasm. Proteins interaction analysis revealed that MsSUSs interact with members of the glycoside hydrolase (GH) family. Expression analysis revealed that ten MsSUS genes were significantly upregulated under drought stress, among which MsSUS7 and MsSUS24 exhibited the greatest increases, with expression levels under severe water deficit (soil moisture content at 20%-50% of field capacity) reaching 3.74 and 8.34 times that of the control, respectively. The promoter regions of MsSUSs contain abundant abiotic stress-responseve elements, such as ABRE and MBS, as well as numerous binging sites for MADS transcription factors. Among them, 15 MsMADS genes were highly expressed under drought stress, with MsMADS33 showing sustained up-regulation following stress treatment. Molecular docking analysis suggested that the MADS-box domain may bind to the promoter regions of MsSUS9 and MsGH5 via hydrogen bonds. In summary, this study predicts that MsSUSs may cooperate regulate sucrose metabolism with MsGHs under drought stress, thereby enhancing osmotic balance and cell wall stability to improve the drought tolerance of M. sativa ‘Xinjiang Daye’, a process potentially positively regulated by MsMADS33.

To evaluate the effects of habitat factors on plant communities and biological soil crusts (BSCs) across different restoration stages of alpine meadows patches, field investigation was conducted in Henan Mongolian Autonomous County (3 615-3 681 m), Maqin County (3 673-3 904 m), and Maduo County (4 245-4 282 m) in Qinghai Province. The influences of altitude and slope (i<7°, 7°<i<25°, i>25°) on plant communities and BSCs were analyzed across different patches, including active patches, inactive patches, restored patches, and non-patchy areas, as well as restored patches of varying sizes (S<1 m², 1 m²<S<5 m², S>5 m²). The results showed that species richness and diversity of plant communities in patchy alpine meadows initially increased and then declined with rising altitude, decreased with increasing slope, and gradually increased during patch restoration. The abundance of BSCs generally declined with increasing slope. No BSCs were detected in active or inactive patches, whereas they occurred in restored patches, and their abundance increased with patch size. In patches larger than 5 m², BSC abundance did not differ significantly from that in non-patchy alpine meadows. Correlation analysis indicated that the abundance of lichens, mosses, and algae was negatively correlated with slope and altitude, and significant positively correlation with vegetation diversity and patch restoration stage (P<0.05). Structural equation modeling demonstrated that patch type significantly enhanced vegetation species diversity (path coefficient 0.87, P<0.001), which in turn promoted BSCs development (path coefficient 0.69, P<0.001), with additional positive effects of patch size (path coefficient 0.21, P<0.05). Slope (path coefficient -0.34, P<0.001) exerted indirect negative effects on BSCs by reducing vegetation species diversity. In summary, higher altitudes, steeper slopes, and smaller restored patch areas constrain BSCs development. As degraded meadows recover and plant diversity increases, BSCs abundance gradually improves. These findings provide a scientific basis for the ecological restoration of degraded alpine meadows on the Qinghai-Xizang Plateau.

Enclosure is an important management practice in grassland ecosystems. To clarify the effects of enclosure duration on the niche characteristics and interspecific associations of plants in desert steppe, this study employed methods including importance value, niche breadth, niche overlap, Chi-square test, Ochiai index, and Percentage of Co-occurrence (PC) to investigate the niche characteristics and interspecific associations of dominant plants species in a Stipa breviflora steppe under different enclosure durations (1, 10, 19, and 25 years). The findings reveal that enclosure duration significantly influenced the importance values and niche breadths of the main plant species. In the early stage of enclosure, Cleistogenes songorica was the dominant species in the community. As enclosure duration extended to 10 and 19 years, the dominance species shifted, and Convolvulus ammannii became the most important species. By 25th year of enclosure, the perennial plant Cleistogenes songorica had regained its status as the absolute dominant species. With increasing enclosure duration, the niche overlap index of the main plant species exhibited a pattern of decrease-increase-decrease, indicating intense interspecific competition. Under different enclosure durations, interspecific associations among the main species in the steppe were predominantly negative. Chi-square analysis revealed that negatively associated species pairs accounted for a large proportion, while the Ochiai index and PC values were generally low, indicating weak species associations. Overall, with increasing enclosure duration, a trade-off pattern was observed between annual and perennial species, leading to shifts in the status of dominant species within the community. The overall species association remained negative, suggesting considerable community fluctuations and strong interspecific competition, reflecting an unstable community structure.