Phytolith-occluded organic carbon （PhytOC）， which is a part of the organic carbon encapsulated during the silicification process in grassland plants， constitutes an important component of the grassland carbon sink. The sequestration of PhytOC is important for maintaining the dynamic balance of the carbon cycle within grassland ecosystems. However， the sequestration of PhytOC in grassland ecosystems has not received enough attention and remains insufficiently studied. In this study， we reviewed the current research progress on terrestrial ecosystem PhytOC， analyzed the formation and sequestration of plant PhytOC， the accumulation and stability of soil PhytOC， and the distribution and storage of PhytOC across different grassland types. We also discussed the impacts of human activities and global climate change on grassland PhytOC. Furthermore， the future research directions for PhytOC in grassland ecosystems were also proposed. An in-depth study of PhytOC in grassland ecosystems can provide a theoretical basis for accurately estimating the carbon sequestration potential of phytolith under the background of global climate change， and this could further enhance the carbon cycle model of ecosystems.

Heat shock transcription factor （HSF）， widely found in eukaryotes， are one of the most crucial transcriptional factors families in the plant resistance to heat stress. HSF has highly conserved DNA-binding domain （DBD）， which is involved in complex stress signal transduction and response networks. HSF， as a terminal component of the signal transduction chain， mediated the expression of target genes under abiotic stress. In response to stress， HSF is phosphorylated and ubiquitinated by upstream protein kinases or binds to heat shock elements （HSEs） through ABA signaling pathway to regulate the expression of downstream genes such as heat shock proteins （HSPs）， thereby improving plant stress resistance. In this study， the discovery， structure， classification， regulatory mechanism of HSF and its role in plant response to abiotic stress （extreme temperature， drought， high salinity， heavy metal， et al.） were reviewed， and the future research direction was expected to provide theoretical basis and gene resources for the genetic improvement of crop and forage stress resistance.

Grassland ecosystems， as one of the dominant types of terrestrial ecosystems worldwide， exhibit substantial carbon sequestration potential and play a vital regulatory role in the global carbon cycling and climate change mitigation. This article conducted a bibliometric and visualization analysis of 4，464 publications in the Web of Science Core Collection （WOS） and China National Knowledge Infrastructure （CNKI） database spanning from 1999 to 2022 by VOSviewer and CiteSpace. Current research status and development trends on carbon sequestration functions in grassland ecosystems were examined. The results revealed an increase trend in publication outputs on the carbon sequestration function of grassland ecosystems. Country distribution analysis of publications in WOS database by VOSviewer identified that China and the United States lead this research area. Institute analysis of publication by CiteSpace indicated that Chinese Academy of Sciences， the United States Department of Agriculture， and the University of the Chinese Academy of Sciences emerged as the top three in WOS database. Northwest A&F University， the University of the Chinese Academy of Sciences， and Beijing Forestry University were the most active institutes in the CNKI database. However， there is still potential for improving effective international communication and collaboration among nations and research teams. The bibliometric analysis identified three research hotspots in this field： the driving effects of climate change， human activities， and soil microbial communities on dynamics of carbon sequestration functions in grassland ecosystems；the spatiotemporal variation characteristics of soil carbon storage； and the evaluation of carbon sequestration functions in grassland ecosystems.

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.

Elytrigia elongata is a kind of perennial forage and ecological grass with saline-alkali tolerance， high yield and good quality， which plays an important role in the improvement of saline-alkali land and ecological environment construction in coastal areas in China. However， its biotechnology system is still immature. In this study， 8 germplasm from different sources of Elytrigia elongata were used as experimental materials， tissue culture technology was used to construct the young embryo regeneration system， and excellent acceptor materials suitable for constructing genetic transformation system were screened. The results showed that on the modified induction medium （MS medium+0.5 g/L L-glutamic acid+0.5 g/L L-proline+0.3 g/L enzymatically hydrolyzed casein+30 g/L maltose+2 mg/L 2，4-D+7 g/L AGAR）， a smaller callus was formed on the third day of Elytrigia elongata germplasm culture， and differentiation occurred after 4 weeks of culture. The callus induction rate， differentiation rate， and regeneration time of young embryo of different genotypes were significantly different on the same medium. Among them， the callus induction rate of young embryos of germplasm No.4 was as high as 97.92%， the differentiation rate was 88.33%， the rooting rate was 100.00%， and the regeneration time was relatively short （56.2 d）， which could be used as an ideal chassis material for genetic transformation of Elytrigia elongata.

Fertilization is a key strategy for restoring degraded grasslands. To identify suitable nitrogen （N） and phosphorus （P） fertilization gradients for enhancing the productivity and soil characteristics of degraded alpine meadows， a lightly degraded alpine meadow in Dangxiong County， Xizang Autonomous Region， was selected for study. A two-factor randomized block design was employed， with four nitrogen levels （N0：0 kg N/hm²， N1：60 kg N/hm²， N2：90 kg N/hm²， N3：120 kg N/hm²） and four phosphorus levels （P0：0 kg P₂O₅/hm²， P1：30 kg P₂O₅/hm²， P2：60 kg P₂O₅/hm²， P3：90 kg P₂O₅/hm²）， resulting in 16 N-P treatments combinations， with N0P0 treatment serving as the control （CK）. Grassland productivity and soil characteristics were evaluated to determine the optimal N-P combinations. The results showed that the combined application of nitrogen and phosphorus fertilizers significantly enhanced aboveground biomass compared with the control， with the N2P2 and N2P3 treatments increasing biomass by 136.9% and 111.9%， respectively （P<0.05）. The combined application also improved soil organic carbon content， particularly in the 0-10 cm soil layer， where the N2P1 and N2P3 treatments reached 15.67 g/kg and 15.26 g/kg， respectively. Available phosphorus content was highest under N2P3 treatment in both 0-10 cm and 10-20 cm soil layers， while total nitrogen content was greatest under N3P1 treatment. Grey correlation analysis of aboveground biomass and soil characteristics （0-10 cm） indicated that N2P3 treatment provided the most favorable comprehensive improvement in productivity and soil nutrient status， followed by N3P3 treatment. Therefore， the combination of 90-120 kg/hm² nitrogen fertilizer with 90 kg/hm² phosphorus fertilizer is recommended as the optimal strategy for the restoration of degraded alpine meadows in Dangxiong County， Xizang Autonomous Region.

Setaria viridis （L.） P. Beauv， a widely adaptable herbaceous plant distributed throughout China， possesses significant ecological and forage value. Due to its notable stress tolerance and its role as an important model plant， Setaria viridis has attracted wide interest in recent years. This article reviews research findings on the biological characteristics， genetic diversity， ecological value， and cultivar development of Setaria viridis， and offers perspectives for further research. It will provide theoretical references for the development， utilization， and breeding of new Setaria viridis varieties.

Plant rhizosheath is the sheath-like structure tightly adhering to the root surface. The unique physical， chemical， and microbiological characteristics of the rhizosheath contribute to vital environmental and biochemical functions including rhizosphere soil aggregation， formation of soil aggregates， enhanced water and nutrient uptake， promotion of microbial colonization， and drought stress resistance. This review provides comprehensive understanding for the research status about rhizosheath in formation and the function and objectively demonstrates current research hot spot. CiteSpace software and bibliometric methods were conducted to retrieve a total of 2812 publications related to rhizosheath from January 1， 2008， to April 30， 2023 in Web of Science （WOS） Core Collection and China National Knowledge Infrastructure （CNKI） database with key words “Rhizosheath”， “Root hair”，“Root exudate”，‘Root sheath’， ‘Root secretion’， and ‘Root hair’. This review illustrates biological， chemical， and physical interactions determining rhizosheath development and plant absorption of water and nutrient from perspectives of plant rhizosheath formation and function. The review aims to provide guidance for further research on molecular genetic mechanisms of rhizosheath development and the application on crop breeding.

Shrub encroachment， which significantly alters structure and function of grassland ecosystems， is a critical ecological issue in China. To obtain a comprehensive and quantitative understanding of the research trends on shrub encroachment research in China， this study conducted a bibliometric analysis using CiteSpace and a meta-analysis based on published literatures on shrub encroachment in China since 1970s. Research on shrub encroachment in China had developed rapidly in recent years， with a primary focus on the drivers of shrub encroachment and its impacts on soil， vegetation， and biodiversity. Studies on shrub encroachment in China had been predominantly conducted in drylands and alpine regions. Major drivers of shrub encroachment included grazing management， climate change， habitat characteristics， and fire. Shrub encroachment was found to have a negative impact on soil quality but a positive effect on community composition， as well as the structure of vegetation and microbial communities in China. The primary management techniques for shrub encroachment included grazing exclusion， grazing management， physical removal， and prescribed burning. This study provides scientific insight into the drivers， impact， and future management strategies for shrub encroachment in Chinese grassland. In the future， it is necessary to strengthen large-scale dynamic assessments of shrub encroachment across diverse grassland types， and integrate remote sensing technology to enhance the scientificity and effectiveness of monitoring and management of encroached landscape in China.

As a fundamental component of regional water resource planning and management， reference evapotranspiration （ET₀） requires a thorough investigation into the time-lag effects and synergistic interactions of different environmental variables for a comprehensive understanding. However， the response time of ET₀ to vapor pressure deficit （VPD） and temperature and their influencing factors remains unclear. In this study， time-lag effects and their interactions for VPD， temperature （including maximum， minimum， and mean temperatures）， Normalized Difference Vegetation Index （NDVI） on ET₀ were analyzed using data from 107 meteorological sites across Inner Mongolia during 2000—2020. The results indicated： ET₀， VPD， temperature， and NDVI exhibited increasing trends over the study period. Notably， the time lag of ET₀ in response to VPD was longer compared to air temperature， particularly for minimum temperatures in high-altitude regions. ET₀ exhibited a stronger potential sensitivity to VPD compared to mean temperature， whereas the response to extreme low temperatures exceeded that to maximum temperature and VPD. an increase in NDVI was found to shorten the lag time of ET₀ in response to air temperature， whereas it prolonged the lag time of ET₀ in response to vapor pressure deficit.

In this study， alfalfa （Medicago sativa cv. Zhongmu No.1） was used as experimental material under mixed saline-alkali stress at concentrations of 0， 40， and 80 mmol/L （NaCl， Na2SO4， Na2CO3 and NaHCO3 molar ratios of 1∶1∶1∶1， pH 9.3）. The growth indexes， physiological indexes and the expression levels of key genes of the seedlings were measured， which provided a theoretical basis for revealing the mechanism of response to mixed saline-alkali stress. The results showed that the plant height， photosynthetic rate， effective quantum yield of PSⅡ photochemistry and the maximum quantum efficiency of PSⅡ photochemistry （Fv/Fm） in ‘Zhongmu No.1’ alfalfa seedlings were significantly inhibited with the intensification of mixed saline-alkali stress （P<0.05）. The accumulation of hydrogen peroxide， superoxide anion， and malondialdehyde gradually increased， while the activity of peroxidase， proline， and soluble sugar content all significantly increased （P<0.05）. Under 80 mmol/L mixed saline-alkali stress， the expression levels of Na+ transporter encoding genes MsSOS1， MsNHX1， and MsHKT1 were significantly induced （P<0.05）. In summary， ‘Zhongmu No.1’ alfalfa may mainly respond to mixed saline-alkali stress through the following pathways： （1） high expression of Na+ transporter genes such as MsSOS1， MsNHX1， and MsHKT1， promoting Na+ efflux， vacuolar segregation and transfer， and avoiding ion toxicity to plants caused by excessive accumulation of Na+； （2） enhance antioxidase activity and alleviate oxidative damage caused by high pH value.

To clarify the impact of wind turbines on biodiversity and soil properties of grasslands， this study took a wind power area with wind turbines installed and operated for 15 years in the temperate meadow steppe of Inner Mongolia as the research area， and selected a grassland without wind turbines as the control area. The plant community， insect community， soil microorganisms， and soil physical and chemical properties in the area were investigated， and the relationships among these factors were analyzed. The results showed that compared with the grassland in the control area， the vegetation coverage， aboveground biomass， and community diversity of the grassland in the wind power area decreased significantly （P<0.05）. The number of insects in the wind power area increased significantly （P<0.05）， but the diversity of the insect community decreased significantly （P<0.05）. The number of soil fungi and community diversity in the wind power area were all significantly reduced （P<0.05）.Soil moisture content， bulk density， total nitrogen， ammonium nitrogen， alkali-hydrolyzable nitrogen， total phosphorus， and total potassium in the wind power area were all significantly reduced （P<0.05）. Correlation analysis found that there was a significant relationship between soil physicochemical properties and soil microbial communities. Overall， during the operation period of wind power stations， it will cause the degradation of grassland plant communities， the loss of soil nutrients and reduce plant diversity， and lead to a homogenization of the insect community structure.

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.

In this research， effects of three light modes of LED red， blue， and green light spectrum at 23.328 mol/（m²·d） DLI （conventional light with 18 h/6 h， red∶blue∶green=280∶70∶10； continuous light with 24 h/0 h， red∶blue∶green=210∶52.5∶7.5； and alternating light with three light spectra： 24 h/0 h， red∶blue∶green=525∶15； red-green light∶blue light=435∶105； green and blue light∶red light=120∶420） on yield quality， physiological activity， and nitrogen metabolism were determined in an controlled environment plant factory with artificial light. The results demonstrated the adaptability of alfalfa to continuous light. Compared with conventional lighting， healthy morphology and maintained yield were observed in alfalfa under continuous lighting， along with increased soluble sugar and starch content. However， decreases occurred in photosynthetic pigment content， stomatal conductance， and Fv/Fm， without excessive accumulating of H₂O₂ and malondialdehyde. Further data showed that the alternation of red/blue-green light promoted leaf expansion， the alternation of red/green-blue light promoted stem elongation， and the alternation of green/blue-red light shortened the flowering time. In terms of nitrogen metabolism， nitrate nitrogen content was significantly reduced under continuous and green/blue-red light alternation， while ammonium nitrogen content was significantly increased under red/green-blue light alternation. Activity of nitrate reductase was significantly reduced under red/blue-green light alternation， while red/green-blue light alternation significantly reduced nitrite reductase activity. The activity of nitrogen metabolism enzymes was inhibited by continuous and alternating lighting， whereas the content of soluble protein， free amino acids， and crude protein in alfalfa were increased. In summary， continuous lighting and alternating lighting patterns are suitable for the production of alfalfa in plant factory with artificial light.

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.

Against the backdrop of China’s “dual-carbon” strategy and the advancement of ecological civilization， scientific assessment of the ecosystem service values and the realization of ecological product value have becomeacritical approach to harmonize ecological protection and economic development. As the dominant type of grassland ecosystem in China， temperate grasslands play crucial roles in carbon sequestration， water conservation， wind erosion control， and biodiversity maintenance. This article systematically reviews the research progress and methodological framework in economic valuation of temperate grassland ecosystem services， both in China and internationally. The applicability and limitations of major models were compared， and deficiencies in current Chinese research regarding data precision， parameter localization， service coverage， and policy integration were analyzed. This review proposes that future research should focus on constructing multi-scale integrated assessment frameworks， improving model localization and data sharing mechanisms， and strengthening the integration between assessment results and policies such as ecological compensation， GEP accounting， carbon trading， etc.， thereby forming the closed-loop mechanism of “Assessment-Accounting-Compensation-Feedback”. This study aims to provide theoretical foundation and decision support for valuing temperate grassland ecosystem services and realizing the value of ecological products.

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.

In this experiment， 14 bermudagrass germplasms were used as materials. Agronomic traits （erect stem diameter， stolon diameter， stolon internode length， stolon length， branch number， reproductive branch number， leaf width， leaf length， leaf color， grass layer height， reproductive branch height， inflorescence number， inflorescence length， spikelet number， 1000-grain weight， seed length， seed width）， turf quality index （color， texture， density， uniformity， drought resistance， heat resistance ） and growth and regeneration performance indices （stolon and erect stem growth rate， regeneration rate） were evaluated. The results showed that： （1） there were significant differences among 14 germplasms， except for erect stem diameter and stolon diameter. The variation coefficient of 17 agronomic traits ranged from 7.88% to 36.28%， and the variation of leaves and stems was higher than that of inflorescence and seeds. The turf quality scores of 14 germplasms ranged from 4.97 to 6.85， among which C28， C63 and C121 had higher turf quality. From June to September， the growth rate of 14 bermudagrass erect stems was 0.08-0.31 cm/d， the growth rate of stolons was 0.16-0.43 cm/d， and the regeneration rate was 0.07-0.33 cm/d. Among them， the growth rate of germplasm C22 was the fastest， and the regeneration ability of C72 was the strongest. （2） Based on the height of grass layer， leaf length and reproductive branch height with great variability， combined with turf quality， growth and regeneration rate， the tested germplasms were divided into three categories. The first category included germplasm C72， C28 and C22， which had higher plants， wider and longer leaves， faster growth rate， and were suitable for grazing or soil and water restoration. The second category included germplasm C121 and C63， which were low in plant height， slow growth and regeneration， and suitable for turf use. The third category contained the remaining 9 germplasms with intermediate traits.

This study investigated the effects of varying soil salinity levels on the growth and salt transport capacity of Suaeda salsa （L.） Pall. S. salsa was selected as the test species， and a barrel planting experiment was conducted with six salinity treatments： 10.21 g/kg （S1）， 20.92 g/kg （S2）， 30.29 g/kg （S3）， 40.55 g/kg （S4）， 50.36 g/kg （S5）， and a control treatment （CK） with 6.20 g/kg soil salt content. Plant growth parameters and salt transport capacity were assessed at four growth stages to identify optimal salinity conditions for S. salsa cultivation and ecological restoration in saline soils. The results showed that across all growth stages， the treatment with 20.92 g/kg soil salinity （S2） resulted in the most favorable growth performance for S. salsa， as evidenced by significantly higher plant height， stem diameter， fresh weight， and dry weight compared to other treatments. Specifically， at maturity stage， these parameters increased by 29.87%， 47.75%， 33.54%， and 19.45%， respectively， in the S2 treatment compared to CK. Increased soil salinity generally promoted stem and leaf succulence throughout the adult plant， flowering， and mature stages. Across treatments， a trend of decreasing succulence was observed from the seedling stage to the mature stage. Leaf tissue exhibited the highest salt transfer amount across all treatments， followed by stem and seed. As plants progressed through the growth stages， the ash content in all treatments decreased， likely due to dilution by increasing biomass. However， salt transfer amount continuously increased， reaching a peak at the mature stage. The S2 treatment displayed the greatest salt transfer amount （4250.41 kg/hm²）. These findings suggest that a soil salinity level of 20.92 g/kg promotes optimal plant growth status and salt transfer ability in S. salsa.

Heat shock transcription factors （HSFs） play crucial roles in plant growth and development， as well as in responses to biotic and abiotic stresses. In this study， we identified the MruHSF gene family in Medicago ruthenica using genomic data and conducted bioinformatic analyses. The expression patterns of MruHSF gene under drought stress were comprehensively analyzed through transcriptomic data and quantitative real-time PCR （qRT-PCR）， preliminarily exploring their potential roles in drought stress responses. The results showed that 27 MruHSF family members， with encoded proteins ranging from 97 to 505 amino acids （aa）， isoelectric points （pI） between 4.64 and 8.72， and molecular weights of 10 998.3 to 55 296.45 Da. Except for three unassigned gene， the remaining MruHSF genes were distributed across eight chromosomes. Phylogenetic analysis classified them into three evolutionary clades. Conserved motif analysis revealed that all MruHSF proteins except MruHSF02， MruHSF03， and MruHSF27 contained Motifs 1， 2， and 4， which were highly conserved in M. ruthenica HSF protein. Additionally， multiple cis-acting elements related to hormone response， light response， and abiotic stress were identified in the promoter regions of MruHSF genes. Expression analysis shows that MruHSF01， MruHSF08， MruHSF13， MruHSF16， and MruHSF22 exhibited significant differential expression under drought stress， suggesting their potential roles in the drought response mechanism of M. ruthenica.

As an important leguminous green manure crop， Astragalus sinicus plays a crucial role in improving soil physicochemical properties and enhancing crop yield and quality. To investigate the diversity of seed-borne fungi associated with A. sinicus， this study conducted isolation and identification analyses on seeds from three varieties： Xiangzi No. 1 （XZ）， Xinzi No. 2 （HX）， and Yijiangzi （YJ）. Using traditional isolation and culture methods， a total of 13 fungal species belonging to 13 genera were identified. Among them， Penicillium sp. was predominant， accounting for 42.5%， 27.0%， and 17.5% of isolates from XZ， HX， and YJ， respectively. 3 species were uniquely isolated from XZ and HX， and Fusarium oxysporum and Mucor circinelloides from both XZ and YJ. High-throughput sequencing showed that the dominant fungal taxa associated with the seeds of the three A. sinicus varieties were Ascomycota， Basidiomycota， and unclassified fungi， collectively comprising 90.29% of the total fungal community. A total of 72， 53， and 64 genera were detected in XZ， HX， and YJ， respectively， with Alternaria and Fusarium being among the common genera. Notably， several genera identified through high-throughput sequencing （Penicillium， Fusarium， Chaetomium， and Cladosporium） were also detected by traditional culture methods， validating the consistency between the two approaches. Compared with traditional isolation， high-throughput sequencing greatly expanded the detected diversity of seed-associated fungal. In conclusion， A. sinicus seeds harbor a highly diverse fungal community， including common pathogenic genera such as Penicillium， which can cause storage mold， and Alternaria， which is known to cause field diseases.

In this experiment， 13 quantitative traits and 7 qualitative traits of Caucasian clover （Trifolium ambiguum Bieb.） as the maternal parent， white clover （T. repens L.） as the paternal parent， and 8 F₁ generations bred from distant hybridization between them were investigated， to study the phenotypic relative heritability and heterosis of F₁ hybrids. The results showed that the phenotypic genetic diversity of 13 quantitative traits was abundant， and the coefficient of variation of 11 traits was more than 10%. The genetic diversity index of 7 quality traits was low. The phenotypic inheritance of the F₁ was mostly positively dominant， and the highest relative heritability a₁ can reach 1.92. The relative heritability of female parent to F₁ was higher than that of male parent. The most obvious heterosis of F₁ was the number of florets and fruited florets， and the heterosis rates of 65.03% and 80.96%. Cluster analysis showed that 8 F₁ generations were close to Caucasian clover and far from white clover.

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.

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.

In this study， the bibliometric software CiteSpace was used to visually analyze and systematically organize literature data in the field of grassland soil from CNKI （1992-2021） and WOS database （1995-2021）. The findings revealed that in CNKI database， Pratacultural Science， Acta Prataculturae Sinica， Acta Ecologica Sinica， and Chinese Journal of Applied Ecology published more grassland soil research results. Long Ruijun and Zhang Fawei of high centrality are the connecting authors. The University of Chinese Academy of Sciences ranked first in the number of documents published in the database. According to the characteristics of the number of publications， the research progress of grassland soil in China was divided into three stages： the initiation phase （1992-2002）， the stable development phase （2003-2012）， and fluctuating development phase （2013-2021）， and the early germination research stage and the corresponding themes of each stage were discussed. In the WOS database， there were many grassland soil research results published in journal of Agriculture Ecosystems & Environment， Rangeland Ecology Management， Plant and Soil， Journal of Arid Environments. Bai Yongfei and Han Xingguo of high centrality are the frontier authors. The Chinese Academy of Sciences ranked first in the number of database publications. China had a large number of papers， but centrality was less than that of The United States of America and Germany. Finally， the hot spots and frontiers of grassland soil research were analyzed comprehensively， and it was pointed out that soil carbon and nitrogen budget under the background of global climate change was the main research direction in the future.

To provide high-quality strain resources for specialized microbial fertilizer applying in arid regions， strains were isolated with characteristics of nitrogen fixation， phosphorus solubilization， plant hormones secretion， and drought tolerance from plant rhizosphere by selective medium on three plant species from arid areas. 16S rRNA identification was applied for molecular distinguish and effects of growth-promoting was tested by paper germination test. Results of this research revealed 35.1% of 37 strains isolated from three plant rhizospheres had the characteristics of phosphorus solubilization， nitrogen fixation， and plant growth-promoting. The nitrogenase activity of the strains ranged from 17.92 to 169.74 nmol C₂H₄/（h·mL）. The concentration of dissolved inorganic phosphorus ranged from 13.39 to 363.31 μg/mL， while dissolved organic phosphorus ranged from 58.69 to 99.37 μg/mL. Twelve of the strains with better nitrogen fixation and phosphorus solubilization were picked for further testing of plant hormone secretion and drought tolerance. Secreting results demonstrated that 2.86 to 27.60 μg/mL indoleacetic acid was produced by all 12 strains. Meanwhile， zeatin and abscisic acid were produced by most of the strains， with the volume of 1.75 to 7.78 μg/mL and 1.98 to 4.61 μg/mL， respectively. Five superior PGPR strains through phylogenetic analysis were identified： strain YB6 was Bacillus subtilis， HC7 was Microbacterium oxydans. Additionally， strains HL7， HC9， and HC3 were categorized under the genera Achromobacter sp.， Ochrobactrum sp.， and Phyllobacterium sp.， respectively. For the results of germination test on paper， five selected PGPR strains both improved seed germination and alleviated the inhibition of drought stress on seed growth. Notably， strains YB6 and HC9 had the most significant effect on seed germination and growth， indicating their potential as valuable microbial fertilizer resources in arid regions.

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.

Grassland ecosystems play a vital role in maintaining biodiversity and environmental integrity. However， inappropriate grazing practices and climate-related disturbances can lead to irreversible damage. Understanding the impact of grazing on plant populations is essential for realizing the ecological and economic benefits of these ecosystems. The bibliometrics examined global and domestic literature on the effects of grazing on plant populations. Using CiteSpace software， we analyzed publication trends， research topics， characteristics， limitations， and potential future directions. The results showed that the number of publications globally and within China had steadily increased over time from 1999 to 2022. In the Web of Science （WOS） database， China ranked fourth globally in terms of publications， and the Chinese Academy of Sciences was the second-most prolific institution worldwide. Chinese scholars had made significant contribution， with researchers like Wang Deli and Hou Fujiang being particularly active in recent years （2020-2022）. Research on the impact of grazing on plant populations is primarily published in ecological journals， including the Journal of Applied Ecology and the Journal of Ecology. In the China National Knowledge Infrastructure （CNKI） database， the main publishing institutions were regionally concentrated， with institutions in the Inner Mongolia Autonomous Region holding a significant advantage within China. Related research is predominantly published in the Chinese Journal of Grassland and Acta Agrestia Sinica. International research primarily focused on population-level characteristics （dynamics， protection， growth， and response）， while domestic studies often adopted a broader perspective， encompassing diversity， ecosystems， and alpine meadows. Despite recent growth， Chinese research output in this field flag behind the United States. Although there had been a gradual increase in publications in recent years（2019-2022）， the range of publishing institutions was narrow， the journals were scattered， and the research scope was limited. Strengthening regional cooperation， deepening research， and making breakthroughs can enhance China's influence in this area.

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).

Grassland ecosystems constitute a major terrestrial carbon pool, and their carbon source and sink dynamics play a critical role in regulating the global carbon cycle. To systematically assess the research status, emerging hotspots, and future trends in grassland carbon source and sink studies, a bibliometric analysis was conducted using CiteSpace based on 3 215 publications indexed in the Web of Science database from January 1st, 1995 to May 14th, 2025. The results showed a steady increase in the number of publications over the past three decades, reflecting growing attention to this field. China, the United States, and Germany were identified as the leading contributors, with a relative stable group of high-productivity authors and collaborative research networks. The evolution of research topics closely aligned with international and national policy agenda. Research hotspots were concentrated in representative regions such as the Qinghai Xizang plateau, and eddy covariance technology emerged as a dominant methodological approach. Major themes included carbon source and sink estimation, soil carbon pool dynamics, vegetation productivity, litter decomposition, and soil respiration processes. Future research priorities include addressing data gaps in underrepresented regions through multi-scale studies, clarifying complex driving mechanisms and interactive effects among environmental factors, quantifying the carbon sequestration potential of restored grasslands, assessing agricultural emissions and mitigation strategies, and exploring the integration of pastoral industry transformation with carbon market mechanisms. Overall, continued policy guidance, sustained attention to emerging research frontiers, and expansion of interdisciplinary and multi scale studies are essential to strengthen the role of grassland ecosystems in responding to global climate change.

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.

Soil organic carbon （SOC）， with its critical ecological functions， is a key indicator for assessing the effectiveness of ecological restoration in grassland surface mining areas. This review focused on the effects of ecological restoration on SOC， considering vegetation， soil， and soil microbial restoration. Plant， soil， and soil microorganism all influenced SOC dynamics in grassland surface mine， with soil microorganisms likely playing the most significant role in SOC changes. Additionally， this review identified existing challenges and proposed potential strategies to address issues related to plant， soil， and microbial restoration in these areas. The review also emphasized the importance of investigating the interactive effects between plant， soil， and soil microorganisms on SOC. This review provides theoretical insights to guide the rational implementation of ecological restoration practices and support further research development， technical advancement， and application on this field.

Functional microorganisms are essential for promoting plant growth in the desert steppe ecosystem of Inner Mongolia， offering valuable theoretical support and a scientific foundation for grassland ecological restoration and sustainable management. However， comprehensive research on the species diversity and plant growth-promoting mechanisms of these microorganisms within the rhizosphere and endosphere of forage grasses in this region remains limited. This study employed high-throughput sequencing technology to provide a preliminarily analysis of the rhizosphere bacterial community composition associated with 12 dominant forage grass species in the desert steppe. Five bacterial strains （A1-A3 and B1-B2， respectively）were isolated from endosphere and rhizosphere and screened using nutrient-modified selective media based on the soil nutrient conditions of the experimental site. These strains were identified as Bacillus sp. （B1 and B2）， Promicromonospora sp. （A1）， and Streptomyces sp. （A2 and A3）. Functional characterization revealed these strains exhibited strong nutrient-solubilizing capabilities. Strain A2 demonstrated a soluble phosphorus content of 164.51 mg/L in inorganic phosphorus fermentation broth， while strain A3 showed a soluble phosphorus content of 17.43 mg/L in organic phosphorus fermentation broth. All strains exhibited significant potassium-solubilizing activity. Furthermore， they produced plant growth-promoting hormones and displayed ACC deaminase activity. Strain B1 produced auxin at 26.08 μg/L. ACC deaminase activity ranged from 32.20 to 40.05 U/L for strains A1， A2， A3， and B1. All five strains promoted the growth of Neopallasia pectinata seedlings， particularly in enhancing radicle growth.

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.

Nitrogen (N) is a key limiting factor for plant growth, and the increase in N deposition has become a crucial driver influencing the soil-plant nutrient cycle in grasslands. However, the mechanisms underlying the effects of different N addition rates and frequencies on soil-plant stoichiometric relationships remain unclear. A field experiment was conducted in a temperate typical grassland to examine the effects of three N addition rates: 0, 10, and 20 g N/(m²·a) and two N addition frequencies (twice a year and twelve times a year) on the nutrient stoichiometric characteristics of surface soil and on the relationship between plant biomass and carbon (C), nitrogen (N), and phosphorus (P) contents in the dominant plants Leymus chinensis and Stipa grandis. Results showed that N addition significantly increased soil C and N contents while decreasing soil P content, thereby reducing the C∶N ratio and increasing the C∶P and N∶P ratios. Under the high-frequency addition, the decrease in soil P content and the increases in C∶P and N∶P ratios in the 20 g N/(m²·a) treatment were lower than those in the 10 g N /(m²·a) treatment. In addition, increasing the N addition rates elevated plant N content while reducing plant P content, resulting in a decreased plant C∶N ratio and increased plant N∶P and C∶P ratios. However, N addition frequencies had no significant effects on plant or soil nutrient contents or their stoichiometric ratios. Partial least squares path model revealed that N addition rates indirectly regulated plant stoichiometric ratios by modifying soil and plant nutrient contents, thereby promoting increases in the aboveground and belowground biomass of the two dominant plant species. In contrast, N addition frequencies had no significant impact. This study demonstrated that N addition transitions plants from N limitation to N saturation and further intensifies P limitation, which may become a critical process constraining the productivity increases in grassland ecosystems.

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.

Nutrient enrichment is a key driver of plant diversity loss in grassland ecosystems. However， the specific pathways and mechanisms underlying species diversity reduction under different nutrient additions influence remain insufficiently understood. This study investigated the effects of nitrogen （N）， phosphorus （P）， and combined nitrogen and phosphorus （N+P） additions on alpine meadows located on the eastern edge of the Tibetan Plateau， using the natural community as a control. The main objective was to examine changes in species richness， biomass， and light transmission， and to elucidate the direct and indirect mechanisms contributing to species richness decline under these experimental treatments. The results showed as follows：（1） N was identified as the primary limiting nutrient for aboveground biomass. Both N and N+P additions significantly increased aboveground biomass （P<0.05）， primarily due to an increase in the biomass of grasses； （2） N and N+P additions significantly reduced species richness （P<0.05）， whereas P addition alone had no significant effect； （3） The mechanisms underlying the reduction in species richness under N and N+P treatments were consistent and involved both direct effects of nitrogen and indirect effects via increased aboveground biomass， which in turn reduced light availability.

Grazing is a primary utilization of grassland ecosystems， where livestock behaviors， specifically feeding， trampling， and excrement deposition， directly or indirectly alter soil physicochemical and biological properties. These alternations， in turn， differentially affect biogeochemical processes within the grassland ecosystem. However， the mechanisms by which these behaviors influence soil greenhouse gas （GHG） emissions remain poorly understood. To address this knowledge gap， this study systematically explored the emission mechanism and key influencing factors of carbon dioxide （CO₂）， methane （CH₄）， and nitrous oxide （N₂O） in grassland soil by analyzing the interactions between major grazing behaviors and soil environmental conditions. The results showed that feeding behavior can alter vegetation biomass and regulate vegetation community structure， thereby modifying exogenous carbon inputs to influencing soil CO₂ emissions. Trampling behavior impacts soil physical structure and microenvironmental conditions， which in turn affect soil aeration and microbial activity， leading to variable effects on soil respiration and associated CH₄ and CO₂ emissions. These effects are closely dependent on grassland type and trampling intensity. In contrast， dung and urine deposition increase nitrogen input to the soil and enhance N₂O emissions， primarily by altering soil chemical properties and microbial dynamics. The characteristics of the excreta， grassland type， and environmental conditions all play important roles in regulating nutrient availability and GHG emission in pastoral systems. These findings elucidate the distinct processes and potential mechanisms through which livestock behaviors affect soil GHG emissions in grassland and provide a theoretical basis for optimizing grazing management to mitigate emissions in pastoral ecosystems.

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{}_{\mathrm{4}}^{+} accumulation）， while under reduced precipitation， nitrogen mineralization shifted toward a nitrification-dominated pathway （NO{}_{\mathrm{3}}^{-} generation）.

This study investigated the combined effects of biochar and phosphorus fertilizer application on the growth and physiological characteristics of alfalfa （Medicago sativa L.） grown in saline-alkali soil from the Yellow River Delta. A two-factor completely randomized design was employed with four biochar application rates （B0： 0 g/kg， B5： 5 g/kg， B15： 15 g/kg， and B25：25 g/kg） and five phosphorus fertilizer rates （P0： 0 mg/kg， P5： 5 mg/kg， P10： 10 mg/kg， P20： 20 mg/kg， and P50： 50 mg/kg） in a coastal saline soil substrate. Plant growth parameters and physiological indicators （biomass accumulation， osmotic pressure regulating substances， and antioxidant enzyme activity） were measured to assess alfalfa performance under various treatment combinations. The results showed that under constant biochar application， increasing phosphorus fertilizer rates initially stimulate plant growth and physiological parameters （plant height， stem diameter， root length， root surface area， relative water content of leaves， chlorophyll content， and antioxidant enzyme activity）. However， these parameters decreased at higher phosphorus levels. Conversely， leaf proline， soluble sugar， and malondialdehyde contents exhibited an opposite trend. The B15 treatment appeared to be more effective in mitigating the negative effects of saline-alkali stress on alfalfa growth. The combination of biochar and phosphorus fertilizer significantly enhanced both aboveground and underground biomass accumulation， especially under B25 treatment. With increased phosphorus fertilization， the effect on alfalfa yield was significantly enhanced. The results of subordination function showed that the comprehensive impact of biochar treatment on alfalfa was in the order： B15>B25>B5>B0. The growth and physiological indices of alfalfa were optimal under the B15P20 treatment， with total biomass increasing by 159.5% relative to the B0P0 （control） treatment. In conclusion， a biochar application of 15 g/kg combined with 20 mg/kg phosphorus fertilizer resulted in the most favorable growth and physiological responses for alfalfa grown in this saline-alkali soil.