Soil microorganisms serve as key drivers of biogeochemical cycling processes and are essential for maintaining the structure and stability of terrestrial ecosystems. Although existing studies have made progress in understanding the patterns and mechanisms of microbial responses to warming， there remains insufficient integration of microbial response mechanisms and the scientific application of their trait parameters in ecosystem models. Therefore， this paper focused on five core microbial traits： microbial community structure， biomass， extracellular enzyme activity， respiration， and carbon use efficiency. We systematically expounded the response mechanisms of these core traits driven by warming， clarifying the regulatory effects of relevant environmental variables on them. Meanwhile， this paper outlined current research progress in integrating microbial traits into the carbon cycle models， aiming to enhance the accuracy of assessing changes in ecosystem functioning under climate warming. Based on current research progress， we advocated that future studies should focus on long-term field monitoring and multi-ecosystem， large-scale comprehensive investigation. This would enable accurate prediction of the effects of warming on microbial communities， thereby enhancing model prediction capabilities for microbial-driven ecosystem functions. This will advance mechanistic understanding of soil microbial responses to climate warming and provide theoretical support for sustainable ecosystem management.

To clarify the effects of different grazing intensities on the plant community structure， species diversity， and population niche characteristics in desert steppe， reveal the laws of community species replacement and the niche response mechanisms of dominant species， and provide a theoretical basis for scientific grazing management， this study set up four different grazing treatments to analyze changes in community species composition， diversity， and niche characteristics. The results showed that with the increase of grazing intensity， the community species shifted from perennial forbs and shrubs/subshrubs to perennial grasses； grazing significantly reduced the total aboveground biomass of the community and the biomass of various functional groups， and the Shannon-Wiener index， Simpson index， and species richness index. Stipa breviflora， Cleistogenes songorica， and Convolvulus ammannii maintained a wide niche breadth under all grazing treatments， and the niche overlap among species with high niche breadth was generally high， with the niche overlap between Stipa breviflora and Cleistogenes songorica reaching the highest under the heavy grazing treatment. The study indicated that grazing significantly affected the structure of desert steppe communities by altering the resource competition relationships among species. Therefore， grazing intensity should be controlled in desert steppe management to maintain ecosystem stability.

The development and utilization of saline-alkali land is a key focus for grassland improvement in China， and enhancing the germination capacity of native grass seeds is a crucial step of this process. In this study seeds of Mongolian wheatgrass （Agropyron mongolicum） was used as the material to investigate the effects of nano-iron particle suspensions at different concentrations （25， 50， 75 and 100 mg·L^-1） and different priming duration （4 h and 36 h） on seeds germination， seedling growth characteristics and antioxidant enzyme activities of seedling under 175 mmol·L^-1 mixed salt solution stress （NaCl∶Na₂SO₄=5∶1）. Multispectral imaging technology was also used to rapidly and visually assess seedling vigor and to screen for the most salt-tolerant priming treatments. The results showed that the priming treatment with 4 h significantly outperformed than the 36 h treatment according to the analysis of seed germination and seedling growth indexes （P<0.05）. Nano-iron priming for 4 h at all concentrations significantly improved the germination percentage and germination index （P<0.05）， reduced mean germination time， and increased seedling height， fresh weight， vigor index， and antioxidant enzyme activities （e.g. POD， CAT， APX and MDHAR） in the seedlings （P<0.05）. The nCDA images from multispectral imaging were highly consistent with the trends of these physiological and biochemical changes. Among all the treatments， 50 mg·L^-1 nano-iron priming for 4 h was the most effective， significantly enhancing germinability and growth performance of Mongolian wheatgrass under salt stress and markedly improving its salt tolerance. These findings provide important scientific evidence for vegetation restoration and ecological rehabilitation in saline-alkali lands.

To elucidate the genetic diversity and adaptive evolutionary mechanisms of different geographical populations of the plateau zokor （Eospalax baileyi）， in this study PCR was conducted to amplify and clone the MHC-DRB gene exon 2 in 121 individuals from eight distinct geographical populations. The results showed that the MHC-DRB exon 2 of the plateau zokor exhibits high polymorphism， with significant genetic differentiation among populations. Geographical isolation was identified as the primary factor driving population divergence. Codon usage bias was observed in nucleotide composition. Neutral tests indicated that the plateau zokor population had not undergone recent expansion， and the maintenance of genetic polymorphism was primarily driven by natural selection. The findings of this study will provide a theoretical basis for further investigating the genetic adaptation of MHC genes in Eospalax baileyi and their effective population management.

This study employed conventional chromosome squash techniques to analyze the ploidy levels and karyotypes of eight samples from five Gynostemma species， aiming to investigate their evolutionary trends and phylogenetic relationships. The results revealed that all eight samples exhibited a basic chromosome number of 11. Among them， G.pentaphyllum collected from Fujian Nanjing was tetraploid， while the remaining seven samples were diploid. Satellite chromosomes were observed in two samples. Chromosome types included two categories： m （metacentric） and sm （submetacentric）. Karyotype classifications comprised four types： 1A， 2A， 1B， and 2B. The ratio of the longest to shortest chromosome ranged from 1.48 to 3.26， with an average arm ratio of 1.26-1.45. The karyotypic asymmetry coefficient varied between 55.59% and 58.56%. Based on karyotype evolution， the samples were ordered as follows： GXH， WZ>GXY>AH， FJ>MD， GXB， YJ. These findings provide cytological evidence for the taxonomic classification and phylogenetic analysis of Gynostemma species.

To explore the role of MfWRKY3 in regulating the response of Medicago falcata to stresses， the MfWRKY3 gene was cloned from wild Medicago falcata in this study， and the characteristics of it encoded protein and the expression pattern were preliminarily identified. The results showed that the length of MfWRKY3 ORF （open reading frame） is 1575 bp， encoding a protein with 524 amino acids， predicted molecular mass of 57.36 kDa and an isoelectric point of 6.96. The MfWRKY3 had transcriptional activation activity and was localized in the nucleus， belonging to the WRKY Ⅰ sub-group transcription factor member. Meanwhile， it was found that the MfWRKY3 gene had the highest expression level in the leaves of Medicago falcate， and the its expression in the roots， stems and leaves were regulated by salt， low temperature and ABA treatment. However， the salt stress could significantly induce the expression of MfWRKY3 gene. These findings laid a foundation for further investigating the biological function and molecular mechanism of MfWRKY3 in regulating the response of Medicago falcata to abiotic stresses.

Elytrigia elongata （Host） Nevski， a perennial bunchgrass， possesses outstanding stress tolerance and forage quality. This study aimed to examine the chromosome number， karyotype composition， and gene expression profiles across various ploidy levels within E. elongata germplasm. Three accessions， designated EE030， EE031， and Ae4x， were used as experimental materials. Karyotype analysis was conducted via an enzymatic maceration method， and differences in gene expression among accessions with varying ploidy levels were analyzed through full-length transcriptome sequencing on the PacBio platform. The results revealed that accession EE031 is a diploid （2n=2x=14） with a karyotype formula of K（2n）=2x=10m+4sm， classified as the “1A” type. Accession Ae4x is identified as a tetraploid （2n=4x=28） with a karyotype formula of K（2n）=4x=20m+6sm+2st， classified as the “2A” type. Accession EE030 is a decaploid （2n=10x=70） with a karyotype formula of K（2n）=10x=56m+12sm+2st， also categorized as the “2A” type. In parallel， transcriptome analysis revealed that increased ploidy level was associated with an essential expansion in transcript abundance and functional diversity. Differentially expressed genes in EE031， Ae4x， and EE030 were enriched in 10， 12， and 15 KEGG metabolic pathways， as well as in 39， 38， and 64 GO functional terms， respectively. Furthermore， core functional pathways specific to each ploidy level were identified： （1） EE031 （diploid） was enriched in proteins related to Chromosomes and Chromosome-binding， Stress response， and Signal receptor activity； （2） Ae4x （tetraploid） was enriched in Transporter and Hydrolase activities； （3） EE030 （decaploid） was associated with Metabolism， Transporter， and Transferase activities.

To investigate codon usage bias of Persicaria odorata， we sequenced the chloroplast genome of P. odorata using the Next-Generation Sequencing. The raw sequencing data were quality control filtered， assembled， annotated and constructed a physical map. Furthermore， we systematically analyzed the codon usage bias of 52 protein-coding sequences. Our comprehensive analysis shows that the chloroplast genome was 159 897 bp in length， with a typical quadripartite structure consisting of a large single-copy region （LSC）， a small single-copy region （SSC）， and two inverted repeat regions （IR）. The overall GC content of codons in the P. odorata chloroplast genome was 38.88%， with GC1>GC2>GC3， showing a preference for codons ending with A/U. The effective number of codons （ENC）， the codon adaptation index （CAI）， the codon bias index （CBI） and the frequency of optimal codons （Fop） ranged from 36.29 to 54.14， 0.10 to 0.30， -0.26 to 0.19， and 0.26 to 0.53， respectively. These analysis collectively indicated weak codon usage bias in the chloroplast genome of P. odorata. Neutrality plot analysis， ENC-plot analysis， and PR2-plot analysis revealed that codon usage bias in the P. odorata chloroplast genome resulted from both mutation pressure and selection pressure and was primarily determined by the selection pressure. A total of 10 optimal codons were identified. Our study established a fundamental framework for functional genomics and molecular breeding of P. odorata by providing：（i） theoretical foundations and molecular marker resources for further functional analysis of chloroplast genes， （ii） evolutionary studies， and （iii） molecular breeding within Polygonaceae.

To clarify the basic characteristics of single-copy nuclear gene sequences in Littledalea racemosa and obtain effective single-copy nuclear gene molecular markers， the single-copy homologous genes were identified using OrthorFinder software based on third-generation full-length transcriptome data of L. racemosa in this study. And then through PCR amplification and population testing experiments， 10 pairs of single-copy nuclear gene molecular marker primers for L. racemosa were successfully developed. The results showed that a total of 48 219 CDS （coding sequence） regions were detected in the L. racemosa transcriptome， with an average of 1.57 coding regions per transcript. A total of 301 single-copy nuclear gene sequences were obtained based on the amino acid sequences of transcriptome CDS and finally， 10 pairs of single-copy nuclear gene primers were obtained， which demonstrated effective amplification performance and exhibited intraspecific variation. A total of 64 individuals of L. racemosa were successfully amplified through all 10 pairs of single-copy nuclear genes primers. The gene sequences exhibited extensive variation in polymorphism. The number of segregating sites （S） ranged from 13 to 42， with an average of 24.4. The number of haplotypes （h） ranged from 16 to 32， with an average of 23.7. The average number of nucleotide differences （k） ranged from 2.275 to 16.497， with an average of 7.686. The haplotype diversity （H_d） ranged from 0.776 to 0.896， with an average of 0.841. The nucleotide diversity （π） ranged from 3.05×10^-3 to 15.61×10^-3， with an average of 10.50×10^-3， and the Watterson’s estimator （θw） ranged from 3.27×10^-3 to 9.92×10^-3， with an average of 6.21×10^-3. The genetic differentiation results showed that the genetic variation of 15 populations of L. racemosa mainly existed within populations. Phylogenetic trees constructed using the 10 single-copy nuclear genes demonstrated congruent relationships among five Poaceae species. The 10 pairs of L. racemosa single-copy nuclear gene primers developed in this study， providing abundant candidate markers for future research on phylogeny， and resource conservation and utilization for Littledalea species.

To analyze the genetic diversity characteristics of the phenotypic traits and identify germplasm with superior traits in oats （Avena sativa L.）， this study conducted a comprehensive evaluation of 24 phenotypic traits in 465 oat accessions collected from 26 countries. The results showed that the coefficient of variation for 13 quantitative traits ranged from 13.19% to 46.70%， while the genetic diversity index for 11 qualitative traits varied between 0.12 and 1.00. Correlation analysis revealed significant positive correlations （P<0.01） between plant growth traits （e.g.， plant height， stem diameter） and yield-related or panicle traits， whereas a significant negative correlation （P<0.05） was observed between lodging resistance and thousand-kernel weight. Cluster analysis classified the accessions into six distinct groups： Group I， high-biomass hulled oats suitable for forage breeding； Group II， accessions combining high yield and lodging resistance； Group III， naked oats ideal for grain use； Groups IV-VI， accessions with distinctive characteristics， which can serve as a specialized gene bank. Based on principal component analysis （cumulative contribution rate of 65.05%） and comprehensive evaluation scores （F value）， five elite accessions （174， Y586， Y1062， Y341， 150） with high yield and lodging resistance were identified， demonstrating potential as excellent parental lines or fundamental research materials.

This study aimed to evaluate the salt-alkali tolerance of Elymusdahuricus accessions during germination and early seedling stages. Three preliminary accessions were first screened under gradient salt-alkali stress （NaCl∶NaHCO₃=3∶1） to determine appropriate treatment levels； 100 and 150 mmol·L^-1 were selected for subsequent experiments based on germination rate. Ten wild accessions originating from diverse regions and habitats were then subjected to these two stress concentrations in a pot trial， with water as the control. Germination and agronomic traits were measured to comprehensively assess salt-alkali tolerance.Salt-alkali stress significantly inhibited seed germination and seedling growth， and the inhibitory effects intensified with increased concentration. Under 100 mmol·L^-1 stress， accession E5 exhibited the highest values for all germination parameters and was identified as the most tolerant one， whereas E6 showed the poorest performance， with 0% germination at 150 mmol·L^-1， indicating lowest tolerance. The ten accessions were consequently ranked as E5>E2>E9>E1>E10>E4>E3>E7>E8>E6， and classified into five categories： highly tolerant， tolerant， moderately tolerant， weakly tolerant and non-tolerant. These results provide valuable germplasm resources and a theoretical basis for breeding salt-alkali-tolerant E. dahuricus cultivars and for elucidating the molecular mechanisms underlying salt-alkali tolerance.

This study focused on 194 Agropyron cristatum （crested wheatgrass） germplasm resources from diverse geographic origins. To assess phenotypic diversity and screen elite germplasm， we employed a suite of analytical methods including coefficient of variation （CV）， genetic diversity index， cluster analysis， principal component analysis （PCA）， correlation analysis， and grey relational analysis， based on 28 key phenotypic traits. Additionally， we used QGA software to analyze genetic distance， sampling proportion， and clustering methodologies， aiming to identify the optimal strategy for constructing a core germplasm collection. The reliability and representativeness of the resulting core set were rigorously verified. The results demonstrated that：statistical analysis of 28 phenotypic traits in 194 accessions of Agropyron cristatum （crested wheatgrass） revealed substantial phenotypic variation. The coefficient of variation （CV） ranged from 17.02%-87.85%， and the genetic diversity index （Shannon-Wiener index， H'） varied from 0.500-2.103. For qualitative traits （e.g.， spike shape， glume color）， the CV spanned 24.43%-52.75%， with an average H' of 0.869—indicating moderate diversity. For quantitative traits （e.g.， plant height， spike length）， the CV was broader （17.02%-87.85%）， and all H' values exceeded 1.524 （average： 1.962）， which reflected high genetic diversity. The results demonstrated that A. cristatum possesses rich genetic diversity， providing a solid foundation for elite germplasm selection and breeding programs.The grey relational analysis （GRA） demonstrated that spike length， spike width， spikelet number， length of the first rachis internode， spikelet color， flag leaf width， leaf sheath length， plant color， and other morphological traits served as key indicators for the comprehensive evaluation of Agropyron cristatum （L.） Gaertn. germplasm resources. A set of elite germplasm accessions （B61， B1， B37， B83， B164， B193， B48， and B85） were identified through screening. All of the accessions are incorporated into the core collection， thereby providing a scientific basis for the construction of a representative core germplasm set. Multivariate analysis integrating principal component analysis and QGA software optimization demonstrated that the combination of Euclidean distance metrics， multiple clustering priority sampling， single linkage method with a 25% sampling proportion constituted the optimal strategy for core germplasm construction in Agropyron cristatum （L.） Gaertn. （MD=0%， CR=100%， VD=25%， VR=113.474%）. The resultant core collection comprising 48 accessions exhibited a significantly higher cumulative contribution rate （75.54%） compared to the original population ， while maintaining 100% of the original genetic diversity. This scientifically validated core set provides a robust foundation for germplasm utilization and genetic improvement in crested wheatgrass.

The objective of this study was to reveal the effects of different forms of nitrogen fertilizers on perennial alpine cultivated grassland plant communities and soil properties. A 4-year-old perennial mixed-seeded grassland established in 2019 at Qinghai University’s comprehensive experimental demonstration base of plateau specialty agriculture and animal husbandry was used as the research object. Four treatments of control （CK）， amide nitrogen fertilizer （U）， ammonium nitrogen fertilizer （A） and nitrate nitrogen fertilizer （N） were set up to determine and analyze treatment effects on the plant community structure， soil physicochemical properties and microbial biomass. The results showed that application of different forms of nitrogen fertilizers significantly affected plant productivity， soil physicochemical properties and microbial biomass of artificial grassland， while the effect on plant diversity was not significant. Different forms of nitrogen fertilizers showed U>N>A in promoting plant productivity， with an increase of 62.60%， 53.71% and 25.85% over control. respectively. Application of amide nitrogen fertilizer significantly increased soil water content and soil conductivity and significantly decreased soil bulk density and pH value. Application of ammonium nitrogen fertilizer significantly increased total phosphorus and decreased soil microbial biological carbon to nitrogen ratio. Application of nitrate nitrogen fertilizer significantly increased soil quick phosphorus， total nitrogen， microbial biochar and microbial biochar-phosphorus ratio. Redundancy analysis showed that soil pH value and bulk weight were key soil factors influencing perennial alpine cultivated grassland plant communities. In summary， it is recommended that amide nitrogen fertilizers should be given priority in the development of nitrogen application programs for perennial alpine cultivated grassland productivity maintenance and soil improvement.

To investigate the effects of Carboxymethyl cellulose （CMC） on the physiological characteristics of Cynodon dactylon under Salt Stress in vegetation concrete， a controlled simulation experiment was conducted. The experiment utilized Cynodon dactylon as the test material， with four salinity gradients [normal salt level （0 g·kg^-1）， mild Salt Stress （3 g·kg^-1）， moderate Salt Stress （6 g·kg^-1）， and severe Salt Stress （9 g·kg^-1）] and four CMC concentration treatments （0%， 0.1%， 0.2%， 0.4%），The study examined the impacts of CMC on the physiological characteristics of Cynodon dactylon under varying Salt Stress intensities. The results showed that with the intensification of Salt Stress and the extension of stress duration， the physiological performance of Cynodon dactylon decreased. Carboxymethyl cellulose （CMC） treatment effectively enhanced the plant height， biomass， net photosynthetic rate， transpiration rate， stomatal conductance， and proline content of Cynodon dactylon， reduced the intercellular CO₂ concentration and malondialdehyde content ，and enhanced its ability of salt stress. Specifically， under normal salt conditions， mild salt stress， and moderate salt stress， the application of 0.4% CMC yielded the best promoting effect on the growth of Cynodon dactylon； whereas under severe Salt Stress， 0.2% CMC showed the optimal growth-promoting efficacy.

To investigate the effects of shrub introduction on soil moisture， C-N-P stoichiometry， and their trade-off relationships in a desert steppe， this study was conducted in the desert steppe of eastern Ningxia. The research compared sites with shrubs introduced for different durations （8， 17 and 27 years） with a site enclosed for grassland restoration for 17 years. Soil water， soil organic carbon （SOC）， total nitrogen （TN）， total phosphorus （TP） contents， and their stoichiometric ratios in the 0-100 cm soil layer were analyzed. The root mean square deviation （RMSD） was used to quantify the trade-off between soil water and nutrients. The results showed that soil water content significantly decreased with increasing shrub introduction years （P<0.05）. Soil TN showed a significant increasing trend （P<0.05）， while TP initially increased and then decreased； both were consistently higher than those in the enclosed grassland. SOC and TN exhibited a strong coupling relationship. The soil N∶P and C∶P ratios fluctuated and decreased with increasing soil depth. Trade-off analysis revealed that the mean RMSD was 0.55 in the enclosed grassland， compared to 0.39 in the sites of shrub introduction. As soil water decreased， the synergistic effect between soil water and nutrients disappeared in the 0-100 cm layer. In summary， nearly 30 years of shrub introduction improved the nutrient content in the 0~100 cm soil layer while maintaining relatively stable soil stoichiometric ratios. However， water stress might emerge as a consequence.

Low-temperature stress is a critical factor regulating plant growth in alpine meadows on the Tibetan Plateau. This study selected common forage species from four functional groups in alpine meadows in North Tibet， measured their cold-tolerance-related physiological indicators， and explored the impact pathways of livestock grazing exclusion， climatic conditions， soil nutrients， and plant community structural regimes. The results showed that （1） cold tolerance-related physiological indicators were significantly different among species and plant functional groups （P<0.05） without significant differences between inside and outside of the fences for grazing exclusion； （2） at the community level， malondialdehyde （MDA）， peroxidase （POD）， and catalase （CAT） activities were positively correlated with growing season precipitation （GSP）； superoxide dismutase （SOD） activity was positively correlated with growing season temperature （GST）； soluble sugar （SS） and SOD were negatively correlated with soil total nitrogen （STN）； SS and soluble protein （SP） were negatively correlated with soil total phosphorus （STP）； proline （Pro）， SS， and CAT were negatively correlated with species richness and the Shannon-Wiener index； Pro was negatively correlated with the Simpson's diversity index； and aboveground biomass （AGB） was negatively correlated with MDA and CAT （P<0.05）； （3） the structural equation modeling （SEM） revealed that AGB was directly affected by temperature and antioxidant enzyme activity， with path coefficients of 0.39 and -0.41， respectively. Soil nutrients and community structure indirectly affected antioxidant enzyme activity through osmoregulatory substances， with effect sizes of -0.13 and -0.18， respectively. Precipitation affected AGB indirectly through antioxidant enzyme activity， with an effect size of -0.30. It is recommended to elucidate the mechanisms underlying interactions between cold tolerance-related physiological indices and environmental variables on plant survival in alpine meadows in further studies.

Plant hormones play important regulatory roles in crop growth， but the relationship and mechanism by which exogenous hormones induce the growth and development of Caucasian clover root tillers are still unclear. In this study， the effects of indole acetic acid （IAA）， cytokinin （CTK） and kinetin （KT） on the growth and development， endogenous hormone content and expression of related genes in Caucasian clover root tillers were compared. The results showed when the concentration of IAA was 8.0 mg·L^-1， exogenous IAA treatment had the strongest effect on the growth of Caucasian clover root tillers. And when CTK concentration was 100.0 mg·L^-1， exogenous CTK treatment had the strongest inhibitory effect on the growth of Caucasian clover. Exogenous KT treatment had the greatest effect on the growth of Caucasian clover root tillers while KT concentration was 0.5 mg·L^-1. Compared with the control group， exogenous hormone treatment had a significant effect on BRI1， AP2/ERF， KNOX， MAPK gene family， PAL， POD and other related genes. In conclusion， 8.0 mg·L^-1 IAA and 0.5 mg·L^-1 KT work best. This study provides a practical guidance for the artificial propagation and rapid grassland planting of Caucasian clover.

The changes in the carbon pool of alpine grasslands of the Qinghai-Tibet Plateau play an irreplaceably significant role in promoting regional ecological balance and sustainable development. This study focused on the alpine grasslands of the Qinghai-Tibet Plateau and analyzed the effects of winter warming， clipping， and their interactions on soil organic carbon components and the stability of carbon pool. The results indicated that winter warming significantly increased the content of easily oxidisable organic carbon in the soil. Clipping significantly increased the content of soil particulate organic carbon and decreased the content of mineral-bound organic carbon （P<0.05）. The interaction between winter warming and clipping significantly reduced the content of mineral-bound organic carbon （P<0.05）. Winter warming significantly enhanced soil carbon pool activity， the carbon pool activity index， and the carbon pool management index （P<0.05）. Soil moisture content showd a highly significant positive correlation with the content of mineral-bound organic carbon （P<0.01）， while it exhibited a significant negative correlation with the carbon pool activity and the carbon pool activity index （P<0.05）. Redundancy analysis and hierarchical partitioning revealed that soil moisture content and nitrate nitrogen concentration significantly influenced the components of soil organic carbon and the stability of the carbon pool. This study provides fundamental data for understanding the changes in soil organic carbon pools under the effects of climate change and human activities in the alpine grasslands of the Qinghai-Tibet Plateau.

In this study， Poa pratensis var. Qinghai was used as the research subject. The changing trends in leaf stoichiometric ratios and nutrient resorption efficiency under six phosphorus （P） addition levels （30， 45， 60， 75， 90， and 105 kg·hm^-2， sequentially labeled as P₁， P₂， P₃， P₄， P₅， and P₆） were investigated. The results indicated： （1） The leaf carbon （C）， nitrogen （N）， and P contents generally exhibited the pattern of senescent stage < full ripeness stage < milky ripeness stage， with the highest accumulation of leaf nutrient contents observed under the P₃ level. （2） Leaf C/N and C/P ratios generally followed the pattern of senescent stage > full ripeness stage > milky ripeness stage， while the N/P ratio generally showed full ripeness stage > milky ripeness stage > senescent stage. （3） The Nitrogen Reabsorption Efficiency （NRE） was the highest under the CK （control， no P addition） treatment， whereas the Phosphorus Reabsorption Efficiency （PRE） was the highest under the P₂ addition level. （4） A generally positive correlation was observed between leaf NRE and stoichiometric ratios， while PRE exhibited a generally negative correlation with stoichiometric ratios in mature leaves and a generally positive correlation with stoichiometric ratios in litter leaves. This study suggests that the appropriate P addition amount is P₂-P₃ （45~60 kg·hm^-2）. This research provides practical guidance for precision fertilization and scientific management of artificial grasslands in alpine regions.

Nitrogen deposition intensification influences nutrient cycling in grassland ecosystems， yet plant nutrient responses under grazing and enclosure remain unclear. This study conducted a two-year multi-level nitrogen addition experiment in an alpine steppe in Qinghai to investigate the responses of nitrogen （N） and phosphorus （P） contents at both the plant functional group and community levels to nitrogen addition under enclosure and grazing conditions. The results showed that N addition significantly increased the N concentrations in grasses， sedges， forbs， and the community as a whole （P<0.001）， but had no significant effect on legumes （P>0.05）； N addition significantly enhanced the P concentrations in grasses， sedges， and the community （P<0.001）， while significantly reducing that in legumes and forbs （P<0.05）. Management practices further regulated the nutrient response pathways： under enclosure condition， nitrogen addition primarily induced a phosphorus dilution effect， thereby increasing the N∶P； while under grazing condition， it promoted nitrogen absorption and altered phosphorus dynamics， leading to an elevated N∶P， with the overall N∶P being higher in enclosed grasslands. The study demonstrated that grazing and fencing， as distinct management approaches， were key factors regulating the response of plant nutrients to nitrogen deposition in the alpine steppe， holding significant implications for understanding regional nutrient limitations and guiding sustainable grassland management.

To explore the effects of nitrogen （N） deposition on interspecific associations and niches of grassland plants， this study was conducted in the Horqin typical steppe. Nine treatments were set up， including the addition of inorganic N （I） and organic N （O） at three rates （0， 4， and 8 g·m^-2·a^-1） and their combinations（I₀O₀， I₄O₀， I₈O₀， I₀O₄， I₀O₈， I₄O₄， I₈O₄， I₄O₈， and I₈O₈）. The results showed that the plant community exhibited a random distribution under the treatments without inorganic N addition， a positive association under the I₄O₀ treatment and a negative association under the I₈O₀ treatment. Niche responses were species-specific： the niche breadth of Bassia prostrata in the I₈O₄ treatment was 58.3% higher than that in the I₄O₈ treatment （P<0.05）； Agropyron cristatum maintained a relatively high and stable niche breadth （0.32~0.36） across all treatments， and the proportion of high niche overlap of this species reached 87% under the I₈O₈ treatment. The ecological response rate （R=2.65-2.97） and niche overlap index （ΔO_ik=0.120~0.138） of A. cristatum were relatively stable； the R value of Artemisia scoparia surged to 140.50 under the I₈O₀ treatment； the R value of Lespedeza davurica remained negative （-1.62 to -0.66） with ΔO_ik<0. In conclusion， N addition enhances the negative interspecific associations of the community and niche differentiation， leading to variations in resource use efficiency among species.

Spatial patterns of soil water content are fundamental to regional ecosystem stability and the sustainable use of water resources. Focusing on the Qinghai Lake Basin， this study integrated field measurements and remote-sensing imagery with statistical and geospatial analyses to investigate the spatial distributions of soil water content and soil water storage at multiple depths. Machine-learning models—Random forest （RF） and Extreme gradient boosting （XGBoost）—were applied to simulate soil water content and storage at varying depths across the basin. The results indicated that soil moisture content in the Qinghai Lake Basin gradually decreased with increasing soil depth （32.06%， 27.17%， and 24.99%， respectively）， while soil water storage increased with depth （29.72 mm， 32.07 mm， and 32.34 mm， respectively）. Spatially， soil moisture in the basin exhibited a general pattern of high values in the north and east and low values in the south and west， with higher values in the upper reaches of rivers than in the lower reaches， and higher values in the mountainous areas surrounding the lake than in the lakeshore zones. Across different vegetation types， alpine meadows had the highest soil moisture content and water storage. Model simulation results revealed that air temperature， precipitation， and the Normalized Difference Vegetation Index were the primary influencing factors of the soil moisture spatial model. This study elucidates the spatial distribution patterns and environmental response mechanisms of soil moisture in the Qinghai Lake Basin， providing a scientific basis for regional ecological restoration and water resource management.

In order to research the effects of different stocking rates on the age-structure and ecological niche of Stipa breviflora population， the study was conducted on the Stipa breviflora steppe desert in Siziwang Banner， Ulanqab City， Inner Mongolia， China. A single factor random complete block design was adopted， and a comparative analysis was conducted using static life tables， ecology niche width， and ecology niche overlap index. The results showed that the age-structure of the population of Stipa breviflora changed with changing in stocking rate. With an increase in stocking rate （below the level of moderate grazing stocking rate）， individuals in the Stipa breviflora population increased from C03 level （diameter of bunch 1.1-2.1 cm） to C08 level （diameter of bunch 6.1-7.1 cm）， thereby ensuring that individuals achieve their expected physiological lifespan； Heavy grazing led to “fragmentation” and “juvenilization” of individuals of Stipa breviflora， and the mortality rate of Stipa breviflora was evenly distributed among all age groups. Below the level of moderate grazing stocking rate， the ecological niche width of the middle and elderly age groups of Stipa breviflora was relatively small， and the competition intensity among individuals was relatively weakness； The ecological niche overlap among young and middle-aged individuals was relatively high， and there was intense competition among individuals； However， heavy grazing not only led to “aggregation” and “juvenile” of Stipa breviflora individuals， but also increased the intensity of competition among individuals， resulting in intensified competition between young and middle-aged individuals. In summary， Stipa breviflora resisted grazing disturbance by transitioning from high individual age groups （young and middle-aged） to middle and elderly groups below moderate grazing stocking rate， but heavy grazing resisted grazing disturbance by “aggregation” and “juvenile” of middle and elderly individuals， thereby ensuring that the population is in an absolute dominant position in the community.

In order to reveal its effectiveness as an ecological restoration measure and the state of community succession， this study took the vegetation of a desert steppe in Inner Mongolia enclosed for 22 years as the research object. And the effect differences of long-term enclosure on plant community species diversity， species niche characteristics， and interspecific associations were compared and analyzed between the enclosed site and the control site. The main results showed that under the enclosure treatment， the number of plant community species， the Margalef diversity index， the Shannon-Wiener diversity index， the Simpson richness index， and the Pielou evenness index all increased significantly. The important value and niche breadth of perennial herbs increased significantly， while the important value and niche breadth of degradation indicator species such as Neopallasia pectinata decreased significantly. The number of plant species pairs with niche overlap values greater than 0.2 and 0.5 increased to varying degrees. Interspecific association analysis based on the Pearson correlation coefficient， the interspecific association coefficient AC test， and the Spearman rank correlation test indicated that the overall interspecific association in the plant community of the enclosed site showed a non-significant negative correlation and the interspecific associations were weak. In conclusion， long-term enclosure significantly increased plant diversity in the desert steppe， optimized species composition， and improved plant utilization efficiency of environmental resources. However， the weak interspecific associations and the non-significant negative overall correlation indicate that the community is still in an unstable successional stage after 22 years of enclosure， and its long-term stability and restoration effectiveness require further attention.

This study focuses on the niche characteristics， interspecific association， and community stability of dominant species in the herb layer under extreme cold and arid conditions on the Ngari Plateau， aiming to provide a research basis for the ecological restoration of alpine desert steppes. The results showed that Stipa purpurea had the widest niche breadth （12.41）. Some species exhibited an asymmetric phenomenon between niche breadth and importance value， with obvious niche differentiation. The average values of the niche overlap index and similarity index were 0.14 and 0.05， respectively， indicating a low overall competition intensity， and species adopted a low-intensity competition survival strategy. Most interspecific associations were not significant， and the average values of the Jaccard index and Ochiai index were relatively low， with species coexisting in a weak interaction mode. The M. Godron model showed that the intersection point of community stability was close to the theoretical stable point （20， 80）， and the herb layer was in a stable successional stage. The study indicates that the community maintains stability through the dominance of wide-niche species， the differentiation of narrow-niche species， and weak positive associations. It is suggested that species with similar ecological habits should be preferred in ecological restoration to maintain interspecific balance.

In alpine meadows， the surface soil heaves to form hummocks under the influence of frost heaving， transforming the originally relatively homogeneous habitat into a heterogeneous one. In this study， 9 sampling plots were established along a soil moisture gradient in the alpine meadows of the Western Sichuan Plateau. We compared and analyzed the differences in plant communities and species diversity between hummocks and inter-hummock meadows under different soil moisture conditions. The results showed that： Soil physical properties and soil chemical properties exerted effects on the plant diversity of hummocks and inter-hummock meadows， respectively. The plant community on hummocks gradually transitioned from Kobresia （sedge）-dominated vegetation to shrub-dominated vegetation， while the plant community in inter-hummock meadows gradually shifted from Carex （sedge） and Kobresia-dominated vegetation to grass-dominated vegetation. The abundance of weedy plants and occasional species in hummocks was significantly higher than that in inter-hummock meadows. Habitat aridification increased the dissimilarity in species composition between hummocks and inter-hummock meadows， and the dissimilarity in species composition of hummocks was higher under different soil moisture conditions. In conclusion， hummocks tend to aridify the microhabitat and provide favorable conditions for the invasion of occasional species. Although hummocks increase plant diversity， they have a negative impact on the stability of alpine meadow vegetation. This research holds significant implications for guiding the conservation and management of alpine meadow vegetation.

To investigate the effects of biochar combined with nitrogen fertilizer on vegetation， soil physicochemical properties， and extracellular enzyme activities in artificially restored bare-land grasslands in the Qilian Mountains， a randomized block design was conducted in 2021. The treatments included a basal fertilizer （biochar 0.5 t·hm^-2 + organic fertilizer 1.5 t·hm^-2） with nitrogen additions of 50， 100， 150， and 200 kg·hm^-2 （CN₁， CN₂， CN₃， CN₄）， as well as CN₀ （basal fertilizer only）， CN₅ （200 kg·hm^-2 nitrogen without basal fertilizer）， and CK （no fertilization）， totaling seven treatments. The results showed that biochar-nitrogen application significantly increased aboveground biomass （AB）， belowground biomass （BB）， and root/shoot ratio （R/S） （P<0.05）. Specifically， CN₃ significantly enhanced soil water content （SWC）， total nitrogen （TN）， soil organic carbon （SOC）， and nitrate nitrogen （NO₃^--N）， while CN₃ and CN₄ significantly promoted the activities of β-1，4-acetylglucosaminidase （NAG）， leucine aminopeptidase （LAP）， and cellobiose hydrolase （CBH） （P<0.05）. Piecewise structural equation modeling （SEM） indicated that biochar-nitrogen application improved vegetation performance and soil fertility by stimulating extracellular enzyme activities and nutrient supply. In conclusion， CN₃ （basal fertilizer + 150 kg·hm^-2 nitrogen， C∶N≈12∶1） showed the optimal effect， providing a theoretical reference for the restoration of bare-land artificial grassland in alpine regions.

To investigate the effects of different intercropping methods of lablab bean （Dolichos lablab L.） and silage maize （Zea mays L.） on grass production performance and forage quality， a randomized block design was adopted in this experiment， and two mixed sowing methods were set up， peer mixed sowing （T₀： Mono-cropping of maize； T₁： silage maize+1 seed of lablab bean hole sowing； T₂： silage maize+2 seeds of lablab bean hole sowing； T₃： silage maize+3 seeds of lablab bean hole sowing） and inter row mixed sowing （X₀： Mono-cropping of maize； X₁： silage maize+15 kg·hm^-2 lablab bean； X₂： silage maize+22.5 kg·hm^-2 lablab bean， X_3： silage maize+30 kg·hm^-2 lablab bean）. The results showed that the stem diameter of silage maize under peer mixed sowing （T₁， T₂， and T₃） was significantly increased by 13.9%， 15.0%， and 26.4%， respectively， compared to that of maize monoculture. For total dry matter， there was no significant difference in peer mixed sowing T₁ compared to maize monoculture， while both mixing treatments （T₂ and T₃） were significantly lower compared to maize monoculture. There was no significant difference in inter row mixed sowing of X₁ and X₂ compared to maize monoculture， while X₃ treatment was significantly lower than maize monoculture. In inter row mixed sowing， the crude protein content of X₁ and X₂ was significantly increased by 27.5% and 57.0%， respectively， compared to that of X₀. In summary， it is recommended that silage maize inter-row mixing of 22.5 kg·hm^-2 （X₂） lablab beans can be used as a suitable mixing method in the northern part of Shaanxi Province.

Aiming at low utilization efficiency of corn and broom sorghum straw raw materials in rural Balin Left Banner， Chifeng， and beef cattle malnutrition caused by farmers' lack of dietary knowledge， this study explored changes in nutritional quality，fermentation characteristics，in vitro digestibility and microbial community of total mixed rations（TMR）with different straw ratios during room-temperature storage，to provide basis for straw feed utilization and beef cattle feeding. Five groups with corn straw：broom sorghum straw raw ratios of 9∶1，8∶2，7∶3，6∶4，5∶5 were set，mixed with concentrate to prepare TMR with 50%moisture content，sealed in ethylene plastic bags.Samples were collected at 0，2，5，7，10，15 days（3 replicates per group）for index determination and sequencing. with prolonged storage， dry matter（DM），crude protein（CP），water-soluble carbohydrates（WSC），neutral detergent fiber（NDF），and acid detergent fiber（ADF）of all groups decreased（P<0.05），and DM loss was lower in high broom sorghum straw raw groups； pH increased with trace detected propanoic acid and butyric acid （P<0.05）；after 2 days， bacteria were dominated by Pantoea（increasing pH）and Bacillus（promoting DM loss），while fungi were dominated by Alternaria and Clavispora（causing mildew，positively correlated with nutrient loss）. TMR decays within 2 days at room temperature；low broom sorghum straw raw groups are prone to deterioration due to WSC depletion，while high-ratio groups delay decay but have insufficient acidification. Proliferation of aerobic bacteria and molds is the key for the decay. It is suggested to select high broom sorghum straw raw formula for short-term feeding， and to use airtight packaging and control storage time.

This study aimed to explore intercropping of Hunan millet and soybean in saline-alkali soils. By assessing the photosynthetic characteristics and agronomic performance， the optimal intercropping pattern was identified， providing new solutions for the development and utilization of saline-alkali land. The study included six planting patterns： Hunan millet sole crop （HS）， soybean sole crop （DS）， 2∶2 （H₂D₂）， 2∶4 （H₂D₄）， 4∶2 （H₄D₂）， and 4∶4 （H₄D₄）. The photosynthetic characteristics， agronomic performance， and nutritional quality of Hunan millet were comprehensively evaluated to determine the best intercropping configuration. The results showed that intercropping significantly promoted the growth of both Hunan millet and soybean. Among the intercropping patterns， the land equivalent ratios （LER） of H₂D₄， H₄D₂， and H₄D₄ were greater than 1， with H₂D₄ showing the highest LER of 1.18. Under the H₂D₄ treatment， the net photosynthetic rate （Pn） of Hunan millet was 45.6 μmol·m^-2·s^-1， stomatal conductance （Gs） was 0.0518 mol·m^-2·s^-1， and transpiration rate （Tr） was 3.36 mmol·m^-2·s^-1， all of which were superior to those of the sole crop. Additionally， Hunan millet under the H₂D₄ treatment showed optimal nutritional quality， crude protein content reaching 10.03%， and other indicators such as crude ash， crude fat， acid detergent fiber， neutral detergent fiber， and relative feed value all performed well. Principal component analysis further confirmed that the H₂D₄ pattern performed the best overall. This intercropping configuration promoted an ideal light environment within the plant canopy， leading to enhanced both yield and quality of Hunan millet and soybean.

The purpose of this study was to investigate the effects of different additives on the fermentation quality， nutrient composition and in vitro fermentation of stylo silage. Fresh stylo was ensiled with addition of 1.00% tea polyphenols （TPP）， coconut shell activated carbon （CSAC） or calcium lignosulfonate （CL）， along with additive-free control group （CK）. After 42 days fermentation at room temperature， fermentation quality， nutritional components and in vitro rumen fermentation were determined. The results showed that compared with the CK group， the addition of TPP and CSAC significantly reduced （P<0.05） the silage pH value and in vitro rumen gas production， significantly increased （P<0.05） soluble carbohydrate， true protein， lactic acid content and Flieg’s score comprehensive score， and the addition of TPP significantly reduced （P<0.05） ammonia nitrogen content and proportion， but CSAC led to a higher number of yeasts and molds in Stylosanthes silage. The addition of CL increased （P<0.01） lactic acid bacteria population， in vitro rumen fermentation gas production and 30 h dry matter digestibility of the silage， and decreased （P=0.01） its neutral detergent fiber content. In conclusion， the results indicated that all the three additives had certain effects on the quality of stylo silage， with the comprehensive effects of tea polyphenols was superior. Adding 1.00% tea polyphenols could reduce protein degradation of stylo grass during ensiling fermentation， increase the lactic acid concentration， improve the silage fermentation quality and nutritional value.

In order to fully utilize the by-products of safflower （Carthamus tinctorius） and explore the best ratio of mixing silage in different proportions with forage oats （ Avena sativa ） and safflower stems and leaves， six treatments were designed in this study. Oats and safflower stems and leaves were mixed with fresh weight， and the mixing ratios were 10∶0 （CK）， 9∶1 （H₁₀）， 8∶2 （H₂₀）， 7∶3 （H₃₀）， 6∶4 （H₄₀） and 5∶5 （H₅₀）. Each treatment was repeated in three groups. After sealing and fermentation for 60 days， the samples were taken and analyzed. The fermentation quality， nutritional value and bacterial community structure were determined. The results showed that the sensory evaluation results of the experimental group were still good or above. The pH values of CK group and H₁₀ group were significantly higher than those of other experimental groups （P<0.05 ）. There was no significant difference in ammonia nitrogen content among the experimental groups. The contents of lactic acid and acetic acid in H₃₀ group were significantly higher than those in other experimental groups （P<0.05）， and the contents of acid detergent fiber and neutral detergent fiber were the lowest. There was no significant difference in acid detergent fiber content among the experimental groups. The contents of propionic acid and butyric acid in CK group were significantly higher than those in other experimental groups （P<0.05）. The dry matter content and soluble sugar content increased with the increase of the proportion of mixed silage， while the crude protein content was decreased in the opposite direction. Combined with the comprehensive evaluation of the membership function method， it was concluded that the silage fermentation quality of the H₃₀ group was the best， in terms of microorganisms， at the phylum level， the dominant bacteria in each test group were Firmicutes. At the genus level， except for the unidentified-Chloroplast in the H₄₀ group， the dominant bacteria in the other test groups were Weissella. The results of comprehensive analysis showed that the optimal mixing ratio of oats and safflower stems and leaves was 7∶3， and the fermentation quality and nutritional quality were significantly improved.

Grasslands disturbed by mining activities in alpine regions exhibit slow recovery under natural conditions. Although organic amendments have been demonstrated to improve soil structure and water retention， their medium- to long-term effects on soil nutrient dynamics and microbial community composition remain unclear. This study investigated the regulatory effects of an organic amendment on the physicochemical properties and microbial community structure of grassland soils in high-altitude mining areas. The results showed that the organic amendment significantly enhanced soil moisture retention and nutrient accumulation. After three years of restoration， soil water content， particulate organic carbon （POC）， and total nitrogen （TN） at a depth of 25 cm increased by 17.07%， 22.86%， and 24.72%， respectively. Despite the gradual decomposition of the organic amendment in surface soil over time， its beneficial effects persisted in deeper layers. Additionally， the organic amendment improved bacterial community composition by increasing the relative abundances of Proteobacteria， Actinobacteria， and Acidobacteria. Mantel tests and redundancy analysis （RDA） further revealed that the organic amendment enhanced the positive correlations between soil nutrient parameters and microbial community structure， thereby facilitating microbial succession and ecological functional recovery.

This study was designed to systematically investigate the effects of different hybrid Pennisetum varieties and microbial additive treatments on the silage quality of hybrid Pennisetum. A total of six hybrid Pennisetum genotypes were employed， with each genotype assigned to a control group （CK）， Lactobacillus paracasei （LP） group， Bacillus subtilis （BS） group， and Lactobacillus paracasei + Bacillus subtilis （LP+BS） group. The inoculation dosages for both L. paracasei and B. subtilis were standardized at 1×10⁶ CFU·g^-1 fresh weight （FW）. Following a 30-day fermentation period， nutritional parameters and fermentation indices were quantified， with comprehensive evaluation conducted via Flieg scoring system and principal component analysis （PCA）.Results demonstrated that probiotic amendments significantly enhanced crude protein （CP） content in‘PI_587000’and‘536321’genotypes， while markedly reducing neutral detergent fiber （NDF） content in ‘536321’and‘103’genotypes. Supplementation with LP and LP+BS notably decreased the ammonia nitrogen ∶ total nitrogen （NH₃-N∶TN） ratio in‘Sunongke No.2’‘ 536321’‘102’and‘103’ （P<0.05）， whereas all BS-treated groups exhibited significantly higher NH₃-N∶TN ratios than LP+BS treatments （P<0.05）. Genotypes‘102’and‘103’showed elevated lactic acid （LA） accumulation. Integrative analysis of Flieg scores and NH₃-N∶TN ratios indicated that ‘late-maturing Pennisetum’displayed optimal fermentation performance， with LP+BS demonstrating the most pronounced improvement in forage silage quality. PCA yielded five principal components with a cumulative contribution rate of 86.558%， confirming‘late-maturing Pennisetum’as the top-performing genotypes and LP+BS as the most effective additive treatment. Conclusively，‘late-maturing Pennisetum’is preferable as silage substrate for hybrid Pennisetum， and the LP+BS consortium represents the optimal probiotic additive for enhancing silage quality.

In this study， alfalfa（Medicago sativa L.）was used as the experimental material. Through field control experiments and randomized block design， the effects of irrigation water temperature （surface water and groundwater） and irrigation amount （65%-75% field capacity， 55%-65% field capacity， 45%-55% field capacity） on yield， quality and irrigation water use efficiency of alfalfa were studied. Hay yield， irrigation water use efficiency， crude protein， ash， acid detergent fiber content and relative feeding value of alfalfa were analyzed， and the irrigation methods with high yield， high quality and high water efficiency of alfalfa were determined， in order to provide theoretical basis and practical guidance for optimizing irrigation management and efficient production of alfalfa. The main results are as follows， compared with groundwater irrigation， surface water irrigation significantly increased hay yield （17.36%-21.72%）， crude protein content （4.98%-7.07%）， crude ash content （0.47%-1.25%） and relative feeding value （3.61%-5.53%）， and decreased acid detergent fiber content （1.06%-2.98%） and neutral detergent fiber content （1.97%-4.42%）. Under mild drought stress， crude protein （20.33%）， crude ash （8.22%）， acid detergent fiber （22.48%）， neutral detergent fiber （39.96%） and relative feeding value （168.75） reached the optimal value. The irrigation water use efficiency of surface water treatment was the highest （2.73 kg·m^-3） under severe drought stress. Groundwater and severe drought stress synergistically inhibited root physiological activity， aggravated the decrease of yield and quality， and reduced water use efficiency.