In order to explore the effects of alkaline salt stress on the ascorbic acid-glutathione cycle（AsA-GSH） of mitochondria in the radicle and plumule of Bothriochloa ischaemum， this experiment used ‘Taihang’ Bothriochloa ischaemum as material， which was germinated in NaHCO₃ and Na₂CO₃ solutions with Na⁺ concentration of 0（CK）， 10 and 30 mmol·L^-1， and then changes in the activities of AsA-GSH enzymes and lipid peroxidation in their mitochondria of radicle and plumule were analyzed. The results showed that the activities of superoxide dismutase， catalase， glutathione peroxidase and monodehydroascorbate reductase in the mitochondria of radicle increased with the increase of Na⁺ concentration （0-30 mmol·L^-1）， but the opposite phenomenon was observed in the activities of glutathione sulfur transferase， ascorbate peroxidase and glutathione reductase. With the increase of Na⁺ concentration （0-30 mmol·L^-1）， the activities of superoxide dismutase， catalase and glutathione peroxidase in the mitochondria of plumule increased significantly （P<0.05）， but the activities of glutathione sulfur transferase， glutathione reductase and monodehydroascorbate reductase decreased significantly （P<0.05）. There were differences in the effects of type and concentration under alkaline salt on the AsA-GSH in radicle and plumule of Bothriochloa ischaemum， and the sensitivity of mitochondrial AsA-GSH in radicle of Bothriochloa ischaemum to alkaline salt stress was higher than that in plumule.

To investigate the responses of forage growth and grassland soil nutrients to nitrogen fertilizer application， and to promote forage yield enhancement and soil nutrient balance， this study conducted a meta-analysis of 62 selected publications comprising 629 valid data sets. The analysis examined the effects of nitrogen fertilizer application on forage growth and soil nutrients under varying meteorological conditions （climatic zones， mean annual rainfall and mean annual temperature）， soil conditions （alkali-hydrolyzable nitrogen （AN）， total nitrogen （TN）， and organic matter （OM））， as well as the amount of nitrogen fertilizer applied （low， medium， and high）. The results indicated that nitrogen fertilizer application significantly enhanced forage growth and improved soil nutrient status. Specifically， forage height and dry matter yield increased by 25.7% and 58.4%， respectively， while soil TN， AN， and OM contents increased by 21.8%， 19.3%， and 9.0%， respectively. Nitrogen fertilizer application in wet， low-temperature regions most effectively promoted forage growth， whereas nitrogen fertilizer application in wet， high-temperature regions was more conducive to enhancing soil nutrient availability. Nitrogen fertilizer application to nutrient-poor grasslands resulted in a more pronounced increase in forage dry matter yield， and even low rates of N addition produced substantial benefits. Our results demonstrate that nitrogen fertilizer addition exerts positive effects on both forage productivity and soil fertility， providing a scientific basis for grassland fertilization decision-making.

This study was conducted in a Stipa breviflora desert steppe in central-western Inner Mongolia. Based on a long-term （since 2004） fixed-site grazing control experiment platform， four gradients of grazing intensities were set up： ungrazed （Control check， CK）， lightly grazing （LG）， moderately grazing （MG）， and heavy grazing （HG）. Litter and soil samples （0-30 cm depth） were collected to systematically analyze the contents and stoichiometric ratio characteristics of carbon （C）， nitrogen （N）， and phosphorus （P）. The results showed that with increasing grazing intensity， the litter standing crop and its C， N， and P contents decreased significantly， reflecting a reduction in both the quantity and quality of litter. In contrast， the contents of C， N， and P in the soil did not change significantly as grazing intensity increased. However， under moderately and heavy grazing intensities， the coupling relationships among soil nutrients weakened， which indicated that overgrazing led to the “decoupling” of the plant-litter-soil system. This study demonstrates that litter is not only a direct target of grazing impacts but also a key link in the system’s nutrient cycling and feedback regulation. Long-term high-intensity grazing may weaken this regulatory role and exacerbate nutrient limitations. These findings provide important scientific insights for the in-depth understanding of nutrient cycling mechanisms in desert steppe ecosystems and the guidance of ecological restoration and management practices.

Grazing and topography are key factors influencing the structure and function of alpine shrub ecosystems， but their effects on shrub populations and communities remain unclear. For this purpose， this study explored the effects of topography （three types of slope positions） and grazing （three distances from livestock enclosure） on the dominant species of alpine shrubland Caragana jubata and the companion species Thalictrum alpinum in the Qilian Mountain Grassland Agricultural Demonstration Area. The results showed that： 1） The distance from livestock enclosure explained the plant height and height-to-crown ratio of the Caragana jubata as 45.10% and 46.80% （P<0.01）， and the plant height， height-to-crown ratio and density of the Thalictrum alpinum as 46.50%， 40.60%（P<0.01） and 55.30% （P<0.001）. The topography only affects the population coverage of the Caragana jubata， which can explain that the coverage of the Caragana jubata is 22.30% （P<0.05）. 2） The overlap degree of the ecological niches of the Caragana jubata and the Thalictrum alpinum is the lowest at a distance of 400 meters between the livestock enclosure and the highest at 1200 meters. 3） The plant height， crown breadth and density of the population of Thalictrum alpinum significantly affected the community coverage， with an interpretation rate of 35.3% （P<0.05）. The community coverage significantly affected the population density of Thalictrum alpinum， with an interpretation rate of 25.1%（P<0.01）. The plant height， density and importance value of the population of Caragana jubata significantly affected the community coverage， with an interpretation rate of 57.6%（P<0.01）. This study reveals the role of grazing and topography in influencing the shrub-herbaceous competitive balance in alpine shrublands by regulating population growth and its population-community relationship， providing a scientific basis for grazing in complex topography.

Studying the altitude distribution pattern and driving factors of plant community diversity in subalpine meadow is helpful to reveal the mechanism of plant community species coexistence and diversity maintenance under the background of coastal elevation gradient. In this study， the plant community in Gongnaisi mountain area was taken as the research object， and the distribution law of plant community diversity along the elevation gradient and environmental influencing factors were discussed to reveal the plant community construction mechanism in this area. The results showed that： （1） With increasing the altitude， Pielou index， Simpson index， Shannon-Wiener index， Functional Evenness Index （FEVE）， Functional Divergence Index （FDIS） and Rao’s second entropy index all showed a single-peak change pattern， and the system development structure changed from divergence to aggregation； （2） PD index was significantly positively correlated with species richness and Margalef index， and positively correlated with Pielou index and Rao second entropy index. In addition， except FDis， there was a positive correlation between species richness index and functional diversity index； （3） Community diversity was mainly affected by environmental factors such as soil organic matter， total nitrogen， pH， average annual temperature， average annual precipitation and soil moisture. The plant community diversity in Gongnaisi subalpine meadow changed regularly along the elevation gradient， and its distribution pattern was mainly driven by environmental factors such as soil organic matter， total nitrogen， pH， annual average temperature， soil moisture content and annual average precipitation.

Grasslands play a vital role in safeguarding ecological security and sustaining ecosystem functions. Xinjiang hosts some of China’s most abundant grassland resources. However， under the combined impacts of climate change and human activities， grassland degradation has become increasingly prominent in recent years. To comprehensively assess the current status and degree of ecological restoration in the Xinjiang “Grazing Withdrawal and Grassland Restoration” project areas， we evaluated ecosystem structure， ecosystem quality， and ecosystem services by integrating the InVEST and RUSLE models to quantify restoration outcomes. The results show that： （1） In terms of ecosystem quality， net primary productivity （NPP） increased from 190.96 g·m^-2·a^-1 in 2003 to 205.34 g·m^-2·a^-1 in 2021， and fractional vegetation cover （FVC） continued to rise， with improving areas accounting for 69.78% of the total areas. （2） Regarding ecosystem services， water conservation increased from 98.2 mm during 2003-2015 to 121.1 mm during 2015-2021. Soil retention increased from 273.74 to 283.61 t·hm^-2， while windbreak and sand-fixation capacity changed from 2.82 to 3.62 t·hm^-2. （3） The ecological restoration index （ERI） indicated that high-restoration areas （ERI>0.5） accounted for 19.08% of the study areas， whereas low-restoration areas （ERI≤0.2） represented only 0.02%. These findings provide quantitative evidence to support ecological protection and management in the project areas， facilitating zoned， graded， and differentiated ecological restoration strategies.

To investigate the effects of grazing and topography on alpine shrub populations， in this study the effects of topography and grazing on population growth， inter-species relationships in alpine scrub in the Qilian Mountains were analyzed by using the populations of Potentilla anserina and Poa subfastigiata as the research objects， through setting up three kinds of terrain， namely， valley， shady slopes， and sunny slopes and five different distances from livestock pens for each terrain type as grazing plots. The results showed that grazing and topography jointly regulated the growth of two plant populations. The increase in grazing pressure gradient （reduced distance from the livestock pens） inhibited the vertical （plant height） and horizontal （crown width） growth of the two species， and increased the population density and vegetation cover. The valley was characterized by a balance of water and heat resources， and the two species coexisted in the highest density， with shady slope has better humidity conditions and stable water supply， which was conducive to the growth and reproduction of moisture-loving Potentilla anserina. The sunny slope had ample sunlight and suitable thermal conditions， favoring the dominance of Poa subfastigiata in their ecological niche. The topography indirectly influenced the competition of the populations by altering the heterogeneity of microhabitats， while grazing directly influenced the competition through trampling. Topography indirectly affected population competition by altering microhabitat heterogeneity， grazing directly affects population dynamics through trampling and foraging. Topography and grazing influenced the competitive landscape of moisture-loving and drought-tolerant species， thereby affecting their status in the community. This study quantified the pathways of topography and grazing on the growth and interspecific relationships of alpine shrub populations， which can provide a scientific basis for the sustainable utilization of the alpine ecological barriers.

To advance the application of near-infrared （NIR） spectroscopy in assessing the quality of mulberry （Morus alba L.） silage， a total of 105 silage samples were collected. Interval Partial Least Squares （iPLS） was employed to extract informative spectral intervals， and rapid NIR prediction models were subsequently developed using Partial Least Squares （PLS）. The results indicated that the models for crude protein， acid detergent fiber， neutral detergent fiber， and pH exhibited the best performance and were suitable for practical prediction （R²cv， R²p>0.8； RPDcv， RPDp>2.5）. Models for dry matter， lactic acid， and condensed tannins demonstrated moderate performance and were adequate for approximate estimation （2<RPDcv<2.5； 2<RPDp<2.5）. In contrast， the model for hydrolyzable tannins required further refinement （RPDp<2）. Collectively， these findings suggest that models constructed based on characteristic spectral intervals offer enhanced stability and predictive accuracy. This approach provides a theoretical basis and technical support for the efficient production and utilization of mulberry silage， while also offering valuable insights for the development of NIR analytical instrumentation.

This study aimed to identify the optimal intercropping ratio of sweet sorghum （Sorghum bicolor） and sesbania （Sesbania cannabina） in the Chengdu Plain region and to clarify its effects on forage productivity and interspecific interactions. Five intercropping ratios （3∶1， 2∶1， 1∶1， 1∶2 and 1∶3； sweet sorghum ： sesbania） were established， with monocultures as controls. Agronomic traits， forage yield and nutritional quality were evaluated to assess the overall performance of the intercropping system. The results showed that intercropping significantly reduced plant height and stem diameter of both species. However， the nutritional quality of the mixed forage was significantly improved compared to sweet sorghum monoculture. Crude protein， total digestible nutrients and comprehensive quality indicators increased with the increas of sesbania proportion. Sweet sorghum monoculture produced the highest fresh and dry matter yields， while the 3∶1 intercropping ratio achieved the highest yield among the intercropping treatments. Interspecific interaction analysis indicated a facilitative effect when the sowing ratio exceeded 1∶1， whereas sesbania inhibited sweet sorghum growth at lower ratios. Based on TOPSIS and membership function evaluation， the optimal sowing ratio in the Chengdu Plain was determined to be 2∶1， corresponding to 14.67 kg·hm^-2 of sweet sorghum and 30.00 kg·hm^-2 of sesbania. These findings provide a scientific basis for optimizing the sweet sorghum–sesbania intercropping system in the Chengdu Plain.

This study took Medicago sativa as the research object to explore the impacts of irrigation and biochar application on the actual production benefits of Medicago sativa from the perspective of nutritional quality and economic benefits. Four irrigation gradients （W₁ reduction of 30%： 450 mm， W₂ reduction of 15%： 550 mm， W₃ conventional irrigation gradient ： 650 mm， W₄ increment of 15%： 750 mm） and two biochar application levels （C₀：0 t·ha^-1，C₂：20 t·ha^-1） were set to determine the nutrient quality and annual hay yield of Medicago sativa and screen the best irrigation amount and biochar application amount. The results showed that under the condition of biochar application， the crude protein content of Medicago sativa showed an increasing trend， the neutral detergent fiber was significantly lower than that under C₀ treatment， and the dry matter intake rate and relative feeding value were significantly improved. The annual yield in W₂C₂ treatment was significantly higher than that in W₂C₀ treatment， superior to other treatments， and the annual net profit was the best， 22 422.93 CNY·ha^-1， which was 2148.53 CNY·ha^-1 higher than W₃C₀. Comprehensive evaluation showed that W₂C₂ treatment was the optimal irrigation and biochar application scheme to achieve the synergistic improvement of Medicago sativa yield， quality and economic benefits.