Xanthium spinosum， a highly invasive plant known for its rapid reproduction and widespread dispersal， significantly impacts the production of food and forage crops. It leads to reduced crop yields， diminished quality， and pasture degradation， making its control crucial for agricultural production. In this study， we investigated the effects of six sand burial depths （1 cm， 2 cm， 3 cm， 5 cm， 7 cm， and 9 cm） on seed germination， seedling growth， and allometric relationships of X. spinosum. The aim was to explore the ecological control of X. spinosum and the crop sowing strategies. The results were as follows： The germination index and emergence rate in the 7 cm and 9 cm burial depth treatments were significantly lower than those in other treatment groups. The plant height， plant weight， number of thorns， and thorn length were all significantly lower than those in the treatments with burial depths of 1 cm and 2 cm. （P<0.05）. The root-to-shoot ratio in the 7 cm and 9 cm burial depth treatments was significantly higher than that in other treatment groups （P<0.05）. The allometric exponent of stem dry weight in the 3 cm burial depth was significantly lower than those in the 5 cm， 7 cm， and 9 cm treatment groups （P<0.05）. Overall， deeper sand burial inhibited the seed germination and seedling growth of X. spinosum. Therefore， this study laid a theoretical foundation for the scientific prevention and control of X. spinosum and crop sowing. It is advisable to conduct deep plowing before crop sowing.

Soil-microbial biomass stoichiometric characteristics serve as a robust indicator of ecosystem nutrient cycling efficiency， yet the mechanisms by which different artificial grassland restoration modes influence these traits remain unclear. This study investigated 3-year-old artificial grasslands dominated by tall-grass species （SF）， short-grass species （XF）， and a mixed planting of tall- and short-grass species （SFXF） in the Three-River-Source Region， with severely degraded alpine grassland （CK） as the control. Soil organic carbon （SOC）， total nitrogen （TN）， total phosphorus （TP）， microbial biomass carbon （MBC）， nitrogen （MBN）， and phosphorus （MBP） in the 0-10 cm layer were measured to analyze their stoichiometric ratios and microbial quotients. The impacts of different restoration modes on soil-microbial stoichiometric balance were further elucidated.The results demonstrated that all three artificial grassland establishment modes significantly enhanced SOC， MBN， and MBP contents. Specifically， the SF treatment increased soil TN， whereas the XF treatment reduced TN and decreased TP by 50.42%. MBN incresed by 24.36% and 35.59% under SF and XF treatments， respectively. The SFXF treatment decreased the microbial C-quotient by 78.40%， while the XF treatment elevated the microbial N-quotient by 49.61%， and the SFXF treatment reduced it by 11.33%. After restoration， the stoichiometric imbalances in soil-microbial biomass （Cimb：Nimb， Cimb：Pimb， and Nimb：Pimb） increased across all treatments， with the most pronounced escalation observed in the SFXF treatment. Redundancy analysis （RDA） revealed that soil N：P and C：P ratios were key drivers of microbial quotient variations. In conclusion， the SFXF mixed planting exerted the most substantial influence on soil-microbial C-N-P cycling. For practical management， supplemental nitrogen fertilization is recommended to optimize plant growth and improve soil quality.

Leymus secalinus plays an important role in improving the ecological environment of the grassland in northern China， the construction of high-yield grassland， the improvement of grassland and the high-quality development of grassland animal husbandry. In this study， 70 wild L. secalinus germplasm resources were used as experimental materials. Based on 19 traits， the principal component analysis （PCA） method， the grey correlation analysis （GCA） method and the distance-based technique for order preference by similarity to ideal solution （DTOPSIS） method were used to comprehensively evaluate the genetic diversity of the germplasm resources of L. secalinus. The results showed that the coefficient of variation of 19 trait indexes of 70 L. secalinus germplasm resources ranged from 0.71% to 97.20%， and the variation degree of stem traits was higher than that of leaves， and the variation degree of phenotypic traits was higher than that of quality traits. There was a significant correlation between the indexes of each trait， and eight phenotypic traits were significantly correlated with fiber content， and plant height and forageyield were significantly correlated with RFV （P<0.01）. LS46 and LS69 performed well in all three different comprehensive evaluation methods. They can provide germplasm material basis for cultivating high-yield and high-quality forage.

In　this study， the effects of saline-alkali stress on seed germination characteristics of two common Artemisia species from the Songnen grassland-Artemisia sieversiana Ehrhart ex Willd. and A. lavandulifolia DC. were investigated under three groups of different day/night temperature conditions （5/15℃， 15/25℃， and 25/35℃）. Four concentrations （0， 12.5， 25， and 50 mmol·L^-1） of neutral salt （NaCl）， alkaline salt （Na₂CO₃）， and composite saline-alkali solutions （NaCl+Na₂CO₃） were simulated to assess germination percentage， germination rate， and germination potential. The results indicated that seed germination in both A. sieversiana and A. lavandulaefolia was significantly influenced by temperature， saline-alkali stress， species， and the most interactive effects （P<0.05）. The germination percentage rate， and potential of A. sieversiana seeds first decreased and then declined with the increase of temperature， and the optimal germination temperature condition was 15/25℃. A. lavandulifolia exhibited declining germination indicators with the increase of temperature， showing optimal performance at 5/15℃. The germination capacity of A. sieversiana seeds decreased with increase of the concentration of the three saline-alkali solutions under all the tested temperature treatments， and was significantly lower than CK at medium-high concentrations （P<0.05）. The germination characteristics of A. lavandulifolia seeds increased first and then decreased with the increase of the concentration of three saline alkali solutions at low temperature. Treatment with 25.0 mmol·L^-1 single salt solution （NaCl）， 12.5 mmol·L^-1 single alkali solution （Na₂CO₃）， and mixed saline-alkali solutions （NaCl + Na₂CO₃） significantly promoted seed germination compared to the control （P<0.05）. At low concentrations across the three solution types， both species showed no significant differences in germination performance. However， under stress with high-concentration of mixed saline-alkali solutions resulted in markedly lower germination rates compared to individual salt or alkali treatments. Additionally， the interactive effects of saline-alkali stress and temperature exerted dual inhibitory impacts on seed germination.

To investigate the effects of exogenous triacontanol （TA） on the growth and physiological characteristics of sainfoin （Onobrychis viciifolia） seedlings under drought stress， three materials （‘Gansu’ sainfoin， new line P1， and 2049） were subjected to -1.0 MPa polyethylene glycol 6000 （T₁） simulated drought stress using a nutrient solution sand culture method. Foliar sprays of TA at 0（CK）， 2.5（T₂）， 5.0（T₃）， 7.5（T₄）， 10.0（T₅）， and 12.5（T₆） μmol·L^-1 were applied， and 21 morphological and physiological indicators were measured to identify the optimal TA concentration. Results demonstrated that all TA concentrations alleviated drought stress， with 10.0 μmol·L^-1 TA （T₅） exhibiting the greatest efficacy. Under T₅ treatment， shoot height， biomass， and photosynthetic parameters increased by 19%-454% compared to T₁， while root-shoot ratio， osmoregulatory substances， and antioxidant enzyme activities decreased by 15%-89%. Principal component analysis identified stomatal conductance， chlorophyll a， and carotenoids as key regulatory indicators. Comprehensive drought resistance evaluation ranked treatments as T₅ > T₆ > T₄ > T₃ > T₂ > T₁， with varietal responsiveness ordered as GS > P1 > 2049. These findings indicated that TA enhanced sainfoin drought resistance by modulating physio-biochemical traits， with 10.0 μmol·L^-1 （T₅） being the optimal treatment， providing a theoretical basis for TA application in drought management during sainfoin cultivation.

Soybean residue， a primary by-product of soybean processing， can undergo aerobic fermentation to enhance its nutritional value and palatability. Water activity may emerge as a key determinant of the nutritional quality of soybean residue during aerobic fermentation. The aim of this experiment was to investigate the effects of aerobic fermentation on the fermentation quality of soybean residue feed under different water activities （Aw）， providing a theoretical basis for the production process of soybean residue feed. A soybean residue feed material with water activity as a single variable was constructed by recombining the raw material substrate and microorganisms through microbial transplantation technology. Three water activity treatment groups were established： low （Aw1=0.9868）， medium （Aw2=0.9880） and high （Aw3=0.9912）. Microbial quantity， nutrient composition， and fermentation quality were analyzed after fermentation for 12 h， 24 h， 36 h， 48 h， and 60 h under aerobic conditions. The results showed that the soluble carbohydrate content was higher in the Aw2 group （P<0.001）， and Enterobacter and yeast showed greater adaptability. Crude protein content， organic acid content， and lactic acid bacteria quantity were higher in the Aw3 group （P<0.001）， and the growth of mold and aerobic bacteria was significantly inhibited. Under medium and high water activity conditions， microbial metabolism was more active and utilized substrates more efficiently. In conclusion， the fermentation quality of soybean residue feed in the medium and high water activity treatment groups （Aw2 and Aw3） were superior， and the quality of aerobic fermentation could be effectively improved by reasonably adjusting water activity.

To screen out high-quality salt-tolerant Lolium multiflorum germplasm resources， the salt tolerance of 50 accessions of Lolium multiflorum with different ploidy levels were evaluated in this study. Under different NaCl concentration treatments of 0， 50， 100， 150， 200 and 250 mmol·L^-1， the root length， shoot length， germination rate， germination potential， germination index， and vigor index after seed germination were measued. Salt tolerance of the experimental materials was assessed by using correlation analysis and other methods. The results showed that the D values of the 50 materials ranged from 0.037 to 0.972. At a Euclidean distance of 13.5， the 50 accessions were classified into 1 salt-tolerant accession， 9 moderately salt-tolerant accessions， 15 moderately salt-sensitive accessions， and 25 salt-sensitive accessions. Salt stress treatment of the screened extreme materials with different ploidy at the seedling stage showed that both plant height and biomass were inhibited， while relative water content and chlorophyll content were decreased， indicating that plant growth and physiological processes were suppressed under salt stress. Comprehensive comparison between the seed germination and seedling stages revealed that tetraploid Lolium multiflorum germplasm exhibited better salt tolerance than diploid materials. The findings provide theoretical support for breeding salt-tolerant Lolium multiflorum materials.

This study aims to explore the effects of exogenous ABA on the accumulation pattern of differential metabolites in the roots of wild medicinal-edible plants Sphallerocarpus gracilis of Qilian Mountains. Ultra-high liquid phase system and ultra-high performance liquid chromatography-electrospray-triple quadrupole linear ion trap-tandem mass spectrometry （UPLC-ESI-QTRAP-MS/MS） extensive targeted metabolomics technology was used to detect and analyze the changes of metabolites in roots by applying with 20 μg·L^-1 exogenous abscisic acid （ABA） as well as 2000 mg·L^-1 sodium tungstate. The results showed that two kinds of carotenoids were detected in the roots of Sphallerocarpus gracilis for the first time， they were β-carotene and lutein， respectively. Furthermore， a total of 537 differential DAMs in 7 categories were identified， among them shikimic acid and phenylpropionic acid （206 species）， terpenoids（93 species）， alkaloids （92 species）and amino acids （84 species） accounted for a relatively high proportion. Pathway enrichment analysis was performed on differential metabolites based on Kyoto Encyclopedia of Genes and Genomes. The differential metabolites （DAMs） were distributed in 15 metabolic pathways in 5 categories， which were mainly enriched in phenylalanine metabolism， thiamine metabolism and tyrosine metabolism. In summary， exogenous ABA and its inhibitor sodium tungstate can affect the metabolic pattern of Sphallerocarpus gracilis， which is expected to be applied to the development of targeted regulators on key metabolic pathways.

In this study， there were 163 selected sampling sites with a total of 489 sampling plots in the grassland of Qinghai Lake Basin. And the spatial distribution characteristics of soil total carbon （TC）， soil organic carbon （SOC）， total nitrogen （TN） content and density （ TCD， SOCD and TND ） in different grassland types were studied by means of field sampling and experimental analysis， mathematical statistics and spatial analysis methods. Results showed that the soil average TC content in the 0-10 cm， 10-20 cm and 20-30 cm layers were 5.60%， 4.72% and 4.30%， respectively. Corresponding SOC content averaged 4.40%， 3.70%， and 3.34%； TN content were 0.46%， 0.37%， and 0.30%. The average values of TCD in the corresponding soil layers were 5.75 kg·m^-2， 6.07 kg·m^-2 and 6.01 kg·m^-2， respectively. The average values of SOCD were 4.53 kg·m^-2， 4.75 kg·m^-2 and 4.67 kg·m^-2， respectively. The average values of TND were 0.46 kg·m^-2， 0.46 kg·m^-2 and 0.42 kg·m^-2，respectively.Alpine meadow soils exhibited the highest carbon and nitrogen contents， whereas alpine desert soils showed the lowest. Spatially， the content and density of soil TC， SOC and TN were lower in the northwestern of the basin， on the northern shore of Qinghai Lake， in the headwaters of Buha river and Shaliu river， and higher in the middle reaches of all rivers. Soil cumulative SOC and TN contents and densities in the 0-30 cm depths were collectively influenced by annual mean precipitation， vegetation coverage， and ecosystem gross primary productivity.

In order to explore the changes of community vegetation characteristics and stability before and after different grassland restoration， this study took three main types of grasslands （alpine meadow， mountain meadow and temperate grassland） in the eastern Qilian Mountains as the research objects. According to the methods of community investigation， paired sample T-test and curve fitting， the structural characteristics， diversity and stability of communities before and after ecological restoration were analyzed. The results showed that： Comprehensive restoration measures could effectively improve the vegetation coverage， density and biomass of grassland， which showed an upward trend and significant difference （P<0.05）. After restoration， the important value of dominant species Kobresia humilis in alpine meadow increased to 32.76， the important value of dominant species Stipa bungeana in mountain meadow increased from 25.69 to 32.74， and the important value of dominant species S. breviflora in temperate grassland increased to 31.20. Cyperaceae and Gramineae played an important role in the restoration of three types of grassland. The implementation of restoration measures led to the increase of species number and biomass， which changed the grassland population structure and reduced the uniformity of species distribution， so that the Margalef， Shannon-Wiener and Simpson indexes increased， and the pielou evenness index decreased. After restoration， the Euclidean distances of alpine meadow， mountain meadow and temperate steppe were 6.29， 8.85 and 5.39， respectively， and the stability of M.Godron was further improved. In summary， ecological restoration can effectively improve the characteristics and stability of grassland communities in the eastern Qilian Mountains， but the responses of each grassland to restoration effects are inconsistent. It is necessary to pay more attention to grassland changes after restoration to prevent grassland degradation again after restoration.