Exploring the effects of grazing on ecosystem multifunctionality （EMF） in long-term enclosed grasslands is of great significance for sustainable grassland management. A 4-year grazing experiment with four intensities （control， light， moderate， and heavy） using Cervus elaphus kansuensis was conducted in the long-term enclosed grasslands of Yunwushan， Ningxia. Plant traits， species diversity， functional diversity and 11 grassland functional indicators were measured， and correlation analysis， linear regression and random forest models were employed to investigate the impacts of grazing intensity on grassland EMF.Results showed that compared with heavy grazing， moderate grazing （light and moderate intensities） significantly increased the coverage and density of gramineous and leguminous plants， as well as leaf nitrogen content， Shannon-Wiener index， species richness， Pielou evenness index， functional divergence index， soil total phosphorus content and EMF. Correlation analysis indicated significant positive correlations between EMF and community coverage， density， leaf carbon and nitrogen contents， and multiple diversity indices. Grazing intensity， community structural characteristics， leaf functional traits and species diversity indices were confirmed as important predictors of EMF.In conclusion， EMF in long-term enclosed grasslands is significantly enhanced by moderate grazing through the improvement of community structure， optimization of leaf functional traits and promotion of community species diversity.

To clarify the community structure， distribution pattern of wild vascular plants in wetlands of the National Nature Reserve for Black-necked Cranes in the Lhasa River Basin and their relationship with environmental factors， the study conducted field surveys on 23 typical plots in the reserve from 2022 to 2023， using methods such as TWINSPAN classification， CCA ordination， and diversity index analysis， to systematically investigate community type classification， spatial distribution characteristics， environmental driving mechanisms， and the coupling relationship with black-necked crane habitats. Results showed that a total of 114 species of wild vascular plants belonging to 83 genera and 34 families were recorded in the study area， with dicotyledonous herbs as the main components； TWINSPAN classified the communities into 7 types， among which the communities were mainly composed of herbaceous plants， with fewer arbor plants. CCA ordination indicated that longitude， mean annual precipitation ， slope gradient ， and slope aspect were the key environmental factors driving community distribution. Diversity analysis showed that the Shannon-Wiener index （1.31-2.95） and Simpson index （0.37-0.99） were significantly different among communities （P<0.05）， and the Mantel-test confirmed that mean annual precipitation had the most significant impact on the Pielou evenness index and Shannon-Wiener index . Further quantification by RDA analysis showed that longitude， mean annual precipitation， slope aspect， and slope gradient were the core factors regulating community diversity. Among them， the Shannon-Wiener index and Pielou index were positively correlated with mean annual precipitation， and the Simpson index responded significantly to the longitude gradient. The results revealed the adaptation patterns of plateau wetland plant communities to hydrothermal gradients， providing a theoretical basis for the protection of black-necked crane habitats and wetland ecosystem management.

To reveal the characteristics and spatial differentiation mechanisms of soil fertility at different degradation stages of alpine marsh wetlands， 84 plots were selected in this study， including non-degraded， lightly degraded， and moderately degraded wetlands in Qilian Mountain National Park， Qinghai. An improved Nemerow index and principal component analysis were used to evaluate soil fertility， and the geographical detector model was employed to quantify the influence of environmental factors on its spatial heterogeneity. The results showed that soils at all degradation stages were within the fertile level. The comprehensive fertility index was the highest in non-degraded wetlands （2.03）， slightly decreasing in lightly （1.87） and moderately degraded wetlands （1.83）， with total nitrogen being identified as the main limiting factor. As degradation intensified， soil organic matter， cation exchange capacity， total nitrogen， and total phosphorus gradually decreased， whereas total potassium increased. Except for total potassium， all indicators declined with soil depth. Geographical detection revealed that mean annual precipitation （q=0.741）， altitude （q=0.403）， and mean annual temperature （q=0.402） were the dominant factors influencing the spatial differentiation of soil fertility. Among the multi-factor interactions， the combinations of mean annual precipitation and temperature （q=0.897）， and temperature and NDVI （q=0.870） showed the strongest explanatory power for the spatial pattern of soil fertility. These findings provide a theoretical basis for degradation diagnosis and ecological restoration of alpine marsh wetlands.

The Qaidam Basin is a typical inland arid saline basin in China， characterized by high soil salinity and harsh plant growth conditions. Soil amendment is therefore of great significance for the rational development and utilization of saline-alkali land. This study focused on oat （Avena sativa） grown with the application of four soil amendments （single superphosphate， potassium humate， cattle manure+desulfurized gypsum， and attapulgite） to analyze oat production performance and nutritional quality， aiming to identify the ideal soil amendment for saline-alkali soils in the Qaidam Basin. The results showed that oat treated with single superphosphate achieved greater plant height， stem diameter， and forage yield， measuring 107.57 cm， 3.47 mm， and 1001.00 g·m^-2， respectively. Oat treated with potassium humate exhibited higher crude fat and water-soluble carbohydrate content， at 3.15% and 25.40% respectively， while its acid detergent fiber and neutral detergent fiber content were lower. Piecewise Structural Equation Modeling （SEM） analysis indicated that the soil amendments affected nutritional quality by influencing forage yield and stem diameter. The TOPSIS multi-criteria decision model demonstrated that oat treated with single superphosphate had superior production performance and nutritional quality， which is the ideal soil amendment for application in saline-alkali soils of the Qaidam Basin.

In order to explore the effects of spraying brassinosteroid （BR） on the growth and physiological characteristics of alfalfa （Medicago sativa） seedlings under low temperature stress， the new cold-resistant alfalfa line （P4） and Longdong alfalfa （Medicago sativa ‘Longdong’） were used as the research objects in this study. After 13 days of low temperature stress （4℃）， different concentrations of exogenous BR （0.00， 0.25， 0.50， 0.75， and 1.00 mg·L^-1， representing T₀， T₁， T₂， T₃， T₄ treatment， respectively） were sprayed on the leaves. After 5 days， the morphological and physiological indexes of the seedlings were measured. The results showed that low temperature stress significantly inhibited the growth of alfalfa seedlings. However， after applying different concentrations of BR， the plant height， leaf length， leaf width， leaf area， aboveground and underground biomass， root shoot ratio， total root length， total root surface area， root diameter， root volume， root tip number， root activity， phenylalanine ammonia lyase， cinnamic acid-4-hydroxylase， 4-coumaric acid coenzyme A ligase and total flavonoid content of alfalfa seedlings were significantly higher than those of T₀ （P<0.05）. The content of malondialdehyde decreased significantly （P<0.05）. The comprehensive evaluation of membership function showed that different concentrations of BR treatments were in the order of T₂>T₁>T₃>T₄>T₀， indicating that spraying 0.25-1.00 mg·L^-1 BR could alleviate the effects of low temperature on the growth of alfalfa seedlings， while the 0.5 mg·L^-1 （T₂） BR treatment was the best. The results provided a theoretical basis for the rational use of BR to solve the problem of chilling injury in alfalfa cultivation.

To investigate the effects of biochar and manure on the growth and nutritional quality of silage maize （Zea mays）， the experiment was conducted to determine the agronomic traits of silage maize at different growth stages， yield and nutritional quality by setting up 8 fertilization treatments of single or combined application of biochar， manure and inorganic fertilizer with no fertilization （CK） as the control. The results showed that biochar and manure could promote the growth of silage maize and improved its nutritional quality， and the combined application of biochar and manure was more effective than single application. Compared with no fertilization （CK）， single application of biochar （B） increased the fresh and hay forage yield of silage maize by 33.5% and 29.7%（P<0.05）， respectively. Under the condition of no chemical fertilizer， the content of ether extract， relative feeding value， total potassium and zinc in biochar combined with manure （BM） treatment was the highest， and the total phosphorus content of plants was significantly increased， while the neutral detergent fiber was reduced by 20.5% （P<0.05）. Under the condition of applying inorganic fertilizer， compared with the treatment of applying inorganic fertilizer （F） alone， the fresh forage yield， hay forage yield and zinc content of biochar combined with manure （BMF） treatment were the highest， and the acid detergent fiber decreased by 9.6% （P<0.05）. In summary， biochar combined with manure can significantly improve the production performance of silage maize， and provides theoretical guidance for promoting forage yield increase and farmland improvement in arid and semiarid areas.

To address the current status of soil phosphorus deficiency， this study aimed to develop novel， safe， and efficient microbial fertilizers. Polygonatum cirrhifolium from Tibet was used as the test material， and the streak plate method was employed to isolate and screen phosphorus-solubilizing strains. Their phosphorus-solubilizing capacity was determined， and the culture conditions were investigated. The results showed that a total of 9 phosphorus-solubilizing bacterial strains were isolated. Among them， 5 strains with a phosphate solubilization index （PSI）>2.0 were screened， with phosphorus-solubilizing capacities ranging from 29.603 to 41.730 mg·L^-1. The strains were identified as follows： JYHJ-1 as Pseud-omonas yamanorum， JYHJ-2 as Pseudomonas koreensis， JYHJ-3 as Serratia proteamaculans， JYHJ-4 as Pseudomonas azotoformans， and JYHJ-5 as Microbacterium oxydans. Strain JYHJ-3 exhibited the strongest phosphorus-solubilizing ability， and it could secrete 7 types of organic acids as well as possess capabilities such as siderophore production， potassium solubilization， nitrogen fixation， and indole-3-acetic acid （IAA） production. In the single-factor experiments， the optimal phosphorus-solubilizing efficiency was achieved when lactose was used as the carbon source， ammonium acetate as the nitrogen source， initial pH was 5.5， inoculation volume was 2%， and NaCl concentration was 1%. Based on the single-factor experiments， response surface methodology （RSM） was applied to optimize the initial pH， inoculation volume， and NaCl concentration. The final optimal culture conditions were determined as follows： lactose as the carbon source， ammonium acetate as the nitrogen source， initial pH 5.5， inoculation volume 3%， and NaCl concentration 1%. In conclusion， the rhizosphere of Polygonatum cirrhifolium was rich in phosphorus-solubilizing bacterial resources. This study provided strain resources and a theoretical basis for the sustainable cultivation of medicinal Polygonatum cirrhifolium and the development of microbial fertilizers.

To screen the optimal Arbuscular mycorrhizal fungus （AMF） for Berberis poiretii Schneid. and B. sibirica Pall. and thereby accelerate commercial propagation of the genus， seedlings of both species were inoculated with Funneliformis mosseae （Fm）， Claroideoglomus etunicatum （Ce）， a 1∶1 mixture of both （Mix）， or left non-inoculated （CK）. Mycorrhizal colonization， growth and physiological parameters， and berberine concentration were subsequently quantified. Colonization peaked under Mix in B. poiretii and under Ce in B. sibirica. Root architecture responded similarly： Ce produced the greatest root-tip number and total root length in both species （significantly so in B. sibirica）， whereas Mix maximized mean root diameter and root volume， root surface area did not differ among treatments. Soluble-protein content and superoxide dismutase （SOD） activity were highest after Ce inoculation and the lowest in CK for both taxa. Peroxidase （POD） activity was also the highest under Ce in B. poiretii， but under Fm in B. sibirica. In conclusion， AMF inoculation consistently stimulated growth， antioxidant capacity， and berberine biosynthesis in the two Berberis species， providing a practical pratical referances for their large-scale cultivation.

Drought stress inhibits seed germination of alfalfa （Medicago sativa L.） and reduces its yield. This research studied the effects of cerium oxide nanoparticle priming on seed germination and physiological characteristics of alfalfa under drought stress. Alfalfa seeds were used as materials and primed with different concentrations of cerium oxide nanoparticle （CeO₂NPs） solutions （0， 50， 100， 150， 200 mg·L^-1） in the dark for 24 hours. Drought stress was simulated with 15% PEG to explore the mitigating effect of CeO₂NPs on seed germination. The results showed that 15% PEG significantly inhibited seed germination， while priming with 150 mg·L^-1 CeO₂NPs increased the germination rate to 77% （P<0.05）， which was 5% higher than the non-primed treatment. It also shortened the average germination time， increased the germination index， and enhanced the fresh weight of germinated seedlings. At the physiological level， the 150 mg·L^-1 CeO₂NPs priming treatment increased the activities of α-amylase and β-amylase， and significantly reduced the contents of reducing sugar （P<0.05）； the 100 mg·L^-1 treatment significantly improved the activity of antioxidant enzymes； the 50 mg·L^-1 treatment effectively reduced the ROS content； all concentrations of CeO₂NPs priming treatments significantly decreased the malondialdehyde content （P<0.05） and the proline content， and increased the soluble protein content as osmotic adjustment substances. Comprehensive analysis indicated that 150 mg·L^-1 CeO₂NPs priming had the best mitigating effect on alfalfa seed germination under drought stress.

To investigate the regulatory effects of exogenous ammonium sulfate on the silage quality and hydrogen cyanide （HCN） degradation of regrowth waxy sorghum [Sorghum bicolor （L.） Moench]， a 60-day silage experiment was conducted with three addition levels of ammonium sulfate （0%， 0.3%， and 0.5% of dry matter）. Fermentation characteristics， nutritional composition， feeding value， and HCN dynamics were continuously monitored. Principal component analysis （PCA） and redundancy analysis （RDA） were employed for comprehensive evaluation. The results showed that ammonium sulfate significantly improved both nutritional quality and silage safety. The 0.5% ammonium sulfate treatment increased crude protein by 12.3%， while neutral detergent fiber （NDF） and acid detergent fiber （ADF） decreased to 43.82% and 27.60%， respectively. Lactic and acetic acid concentrations increased by 35.7% and 28.4%， accelerating acidification （pH<4.2 within 7 days） and suppressing undesirable microorganisms. HCN degradation rate increased by 40% between 7 and 15 days， with final residual content below 170 mg·kg^-1 and a degradation rate of 53% after 60 days. Feeding performance was also enhanced， with relative feed value （RFV） and relative forage quality （RFQ） reaching 160 and 180， respectively. Overall， ammonium sulfate at 0.4%-0.6% of dry matter effectively improved silage fermentation， nutritional quality， and safety， meeting the standards for high-quality forage （RFV>145， HCN<200 mg·kg^-1） and providing a scientific basis for developing the “grain-forage dual-purpose” sorghum production model.