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.
Grazing is one of the effective strategies for managing weed dynamics in grassland ecosystems. However， the regulatory mechanisms governing forage production and weed dynamics under grazing disturbance remain poorly understood. Therefore， this study investigates the effects of grazing management on the forage productivity of Bothriochloa bladhii （Retz） S.T. Blake， a perennial grass species， and its relationship with weeds in a cultivated grassland in Lubbock County， Texas， USA. Results indicated that： （1） Grazing enhanced the sensitivity of forage productivity， fibers and CP to weeds. （2） Grazing remarkably decreased the weed coverage （61.9%-81.4%， P<0.05） and species richness （23.2%-49.9%，P<0.01）. The inhibitory effects accumulated over time. Consequently， grazing enhanced the community stability and weed competitiveness of Bothriochloabladhii. （3） Grazing increased the forage equivalent unit of Bothriochloabladhii， and improved its quality. The findings provide a theoretical basis for developing appropriate grazing and weed management strategies for integrated crop-livestock production systems.
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.
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.
This study investigated soil nitrogen mineralization responses to precipitation changes during the anthropogenic grassland-shrubland transition in the eastern desert steppe of Ningxia. A controlled litter-water manipulation experiment was conducted， including three litter treatments （grass， shrub， CK） and two precipitation treatments （+40% and -40%）， to assess soil nitrogen mineralization patterns under different simulated precipitation regimes. The results showed that compared with grass litter， the soil microbial biomass nitrogen in desert grassland and grassland edge soils were more sensitive to shrub litter under high precipitation conditions， and in shrubland the soil microbial biomass nitrogen was more sensitive to shrub litter under reduced precipitation （P<0.05）. Under increased precipitation， shrub litter led to an increasing trend in soil ammonium nitrogen and net ammonification rates significantly increased during the transition （P<0.05）， whereas soil microbial biomass carbon， microbial biomass nitrogen， and nitrate nitrogen along with its mineralization rate declined. Under reduced precipitation， soil nitrate nitrogen and net nitrification rates increased， and microbial biomass carbon and nitrogen in shrubland were significantly higher than those in desert steppe （P<0.05）. Throughout the transition process， the soil inorganic nitrogen and its mineralization rate were significantly affected by both litter type and precipitation （P<0.05）. Among these factors， the positive effect of increased precipitation on ammonium nitrogen was greater than that of litter， whereas nitrate nitrogen and net nitrification rate were primarily regulated by litter type （P<0.05）. In conclusion， shrub litter exerted a markedly stronger stimulatory effect on soil nitrogen mineralization than grass litter， thereby playing a dominant role in soil nitrogen cycling during grassland-shrubland transition. Specifically， under higher precipitation， shrub litter mainly enhances soil ammonification （NH accumulation）， while under reduced precipitation， nitrogen mineralization shifted toward a nitrification-dominated pathway （NO generation）.
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.
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.
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.
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.
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.
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.
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.
