Plowing and fertilization are common management practices in alpine meadows， which directly influence plant productivity and species diversity. This study established experimental plots with plowing （Dis）， nutrient addition （NPK）， and their interactive treatment （DisNPK） at the Tianzhu Alpine Grassland Ecosystem Experimental Station of Gansu Agricultural University， with natural grassland as a control （CK）. The objectives were to investigate the effects of plowing and nutrient addition on plant community structure and biomass in alpine meadows and to identify the key driving factors. By measuring soil physicochemical properties， plant biomass， and species diversity， we analyzed the relationships between soil physicochemical properties and vegetation biomass/species diversity. The results showed that all treatments significantly increased the contents of total and available soil nutrients compared to control. The NPK treatment significantly increased aboveground biomass， and the combined effect of plowing and fertilization （DisNPK） had the most significant enhancement on productivity （particularly for grasses and above-ground biomass）. The Dis and DisNPK treatments significantly reduced community diversity. Correlation analysis revealed that soil available nutrients and organic matter were positively correlated with above-ground biomass but negatively correlated with diversity indices （P<0.05）. This study demonstrates that plowing and nutrient addition can alter the community structure and productivity of the ecosystem， providing a theoretical basis for the ecological restoration of alpine meadows.

By collecting 11 forage species from the desert steppe of Siziwang Banner， Ulanqab City， Inner Mongolia， we separately determined and calculated their crude protein， ether extract， crude ash， neutral detergent fiber， acid detergent fiber， total digestible nutrients， dry matter intake， dry matter digestibility， relative feeding value， and relative forage quality. A comprehensive evaluation of the nutritional value of different forages was conducted. The study employed a combined approach utilizing the CRITIC objective weighting method and the GRA-TOPSIS comprehensive evaluation model. The results of the study showed that the three forage grasses in the grass group， in descending order of nutritional value， were Leymus chinensis > Stipa breviflora > Cleistogenes songorica； the five forage grasses in the shrub and semi-shrub group， in descending order of nutritional value， were Bassia prostrata > Krascheninnikovia ceratoides > Caragana microphylla > Artemisia frigida > Caragana stenophylla； and the three forage grasses in the weedy group， in descending order of nutritional value， were Phlomoides umbrosa > Convolvulus ammannii > Astragalus membranaceus.

Elucidating the distribution patterns and driving mechanisms of herbaceous plant diversity provides a critical scientific basis for developing ecological protection strategies. This study conducted a systematic survey of herbaceous plant communities in Yongdeng County， Lanzhou City， using a grid sampling method. We investigated four distinct habitat types-temperate steppe， temperate desert steppe， alpine meadow， and cultivated grassland-to explore the effects of topographic and soil factors on species diversity. The results indicated that： （1） A total of 356 wild herbaceous species belonging to 197 genera and 53 families were recorded. Poaceae， Asteraceae， and Fabaceae were the 3 dominant families， accounting for 38% of the total species richness. （2） The effects of topographic factors on diversity were habitat-specific. The trends of alpha-diversity indices along the elevational gradient differed significantly among grassland types， with the temperate steppe showing the most sensitive response. Species richness exhibited a significant unimodal non-linear response to slope gradient and aspect； notably， species richness peaked on shady slopes and gentle slopes due to favorable hydrothermal conditions. （3） Soil nutrients were identified as key drivers of diversity variation. Species richness was positively correlated with soil total carbon， but it showed significant negative correlations with soil total nitrogen and total phosphorus （P<0.05）. （4） Multivariate analysis further revealed that species richness was primarily driven by soil carbon content （P<0.01）. The Simpson index was significantly correlated with soil phosphorus content （P<0.01）， while the Shannon-Wiener index showed a significant co-variation with the evenness index （P<0.05）.

To investigate the effects of different grazing intensities on soil enzyme activities in a Stipa breviflora desert steppe and the driving factors， this study was based on a Stipa breviflora desert steppe and established four grazing intensity levels： no grazing （CK）， light grazing （LG）， moderate grazing （MG）， and heavy grazing （HG）. The effects of different grazing intensities on the activities of β-D-cellobiohydrolase， β-1，4-N-acetylglucosaminidase， and alkaline phosphatase were analyzed， along with species richness， aboveground net primary productivity （ANPP）， and soil pH， saturated water content， bulk density， organic carbon， available nitrogen， and available phosphorus. The results showed that with the increase of grazing intensity， the three soil enzyme activities， species richness， aboveground net primary productivity， soil organic carbon， available nitrogen， and available phosphorus all significantly decreased （P<0.05）， whereas soil bulk density was significantly increased. The Random Forest model indicated that available nitrogen and available phosphorus were the primary drivers regulating soil enzyme activities. Grazing suppresses soil enzyme activities primarily by decreasing available nutrients. This study provides a theoretical basis for the conservation and ecological restoration of desert steppes. In grassland management and utilization， measures such as controlling stocking rates and implementing seasonal grazing exclusion can be adopted.

Grassland degradation is a major driver affecting soil structure stability and carbon cycling processes； however， its underlying pathways and regulatory mechanisms under humid climatic conditions remain insufficiently quantified. In this study， a typical montane meadow in Nanshan Pasture， Hunan Province， China， was selected to investigate the characteristics of soil aggregate structure and organic carbon distribution across a degradation gradient， including non-degraded （ND）， lightly degraded （LD）， moderately degraded （MD）， and heavily degraded （HD） grasslands within the 0-30 cm soil layer. The results showed that， with increasing degradation intensity， the proportion of >5 mm macroaggregates decreased by approximately 47%， whereas the proportion of <0.25 mm microaggregates increased by approximately 168%. Meanwhile， the mean weight diameter （MWD） and geometric mean diameter （GMD） of both mechanically stable and water-stable aggregates declined by approximately 46% and 53%， respectively， accompanied by a significant increase in fractal dimension， indicating a transition of soil structure from a stable state to a fragmented state. The breakdown of macroaggregates released organic carbon， part of which was subsequently adsorbed and stabilized by microaggregates， resulting in a shift in carbon distribution from a “macroaggregate-dominated” pattern to a “microaggregate-dominated” pattern. Grassland degradation also led to a decline in total soil organic carbon and induced substantial structural reorganization of soil carbon pools， highlighting the pivotal role of soil aggregates in carbon protection and redistribution. These findings elucidate the structural mechanisms underlying carbon pool dynamics driven by grassland degradation in humid regions and provide a theoretical basis for ecological restoration and carbon sequestration management of degraded grasslands.

Grassland plants achieve species coexistence through differentiated resource utilization， which directly affects the community structure and stability. To explore the impacts of grassland utilization patterns on the coexistence mechanism of community species under the background of nitrogen deposition， four nitrogen addition levels （0，2，5，10 g·m^-2·a^-1） were set up in the moving and fenced grasslands of the Huihe River Basin in Hulun Buir， and the response patterns of plant community diversity， overall interspecific association and niche characteristics to grassland utilization patterns and nitrogen deposition were investigated. The results indicated that mowing grassland was more sensitive to nitrogen addition. Under high nitrogen conditions， species diversity significantly decreased（P<0.05）， and the overall community association weakened and turned negative. The proportion of high niche overlap decreased from 56.06% under N₂ to 31.82% under N₅， while the proportion of low overlap increased to 53.03%. The overall correlation of the fenced grassland was relatively stable； the niche breadth of Leymus chinensis and Stipa baicalensis expanded to 2.77 and 2.67 in the medium nitrogen stage， respectively， but contracted and the overlapping ratio decreased in the high nitrogen stage. Nitrogen addition reshaped interspecific relationships by altering resource availability， while the utilization method of grasslands determined the stability of the community and the ability of ecological niche adjustment； the grassland steppe community exhibited a response of low nitrogen promoting and high nitrogen inhibiting to nitrogen addition.

Basing on the livelihood vulnerability assessment framework， this study constructed a theoretical model of herders’ livelihood vulnerability. Using field survey data from 414 herder households in the pastoral areas of Inner Mongolia， the comprehensive index method was employed to evaluate their livelihood vulnerability. Furthermore， an Ordinary Least Squares （OLS） regression model was applied to analyze the impacts of herders’ climate change adaptation behaviors on their livelihood vulnerability. The results indicated a correlation between herders’ livelihood vulnerability and grassland resource endowments. Furthermore， adaptation behaviors such as purchasing forage and increasing the number of days of stall-feeding were found to exacerbate their livelihood vulnerability. Adaptation measures， such as selling weak livestock， constructing sheds， adjusting livestock composition， and well-digging， had a mitigating effect on herders’ livelihood vulnerability. The impact of grassland ecological compensation and reward policies on livelihood vulnerability exhibited a threshold effect and heterogeneity. Based on the research conclusions， the following recommendations were proposed： creating a pastoral innovation network， providing climate-adaptive technical guidance， and establishing a dynamic adjustment mechanism to formulate regionally differentiated compensation and reward standards. These measures aimed to serve as a reference for the government in formulating effective policies to alleviate herders’ livelihood vulnerability， enhance their capacity to withstand climate change shocks， and promote the sustainable development of animal husbandry.

To explore the amelioration effect of intercropping salt-tolerant forage grasses with halophytes on saline-alkali soils， a field experiment was conducted with four treatments： CK （monoculture of Echinochloa frumentacea）， T₁ （intercropping E. frumentacea with Suaeda salsa）， T₂ （intercropping E. frumentacea with Atriplex aucheri） and T₃ （intercropping E. frumentacea with Salicornia europaea）. The synergistic effects of intercropping different halophytes on soil quality and E. frumentacea yield were investigated. Compared with CK， all the intercropping treatments significantly reduced bulk density （BD）， pH and total dissolved salts （TDS） in the 0~40 cm soil layer. The largest reductions （8.84%， 7.19% and 19.86%， respectively） were observed under T₁. Soil total porosity （STP）， soil organic matter （SOM）， alkali-hydrolyzable nitrogen （AN）， available phosphorus （AP） and readily available potassium （AK） were markedly increased， with T₁ showing the greatest increments （13.38%， 26.02%， 60.01%， 26.46% and 22.13%， respectively）. Activities of soil urease （UE）， invertase （INV） and catalase （CAT） rose by 48.86 %， 45.51% and 54.11% under T₁， providing a favorable soil environment for seedling emergence and growth of E. frumentacea. Grain yields under T₁， T₂ and T₃ were significantly higher than that of CK， with increases of 55.71%， 40.01% and 20.95%， respectively. E. frumentacea yield was positively correlated with STP， soil fertility indices and enzyme activities， and negatively correlated with BD and salinity-alkalinity indicators. The soil quality index （SQI） calculated from the full dataset ranked the treatments as T₁>T₂>T₃>CK. In conclusion， intercropping E. frumentacea with S. salsa is the optimal pattern for improving saline-alkali soil quality and crop productivity， and can serve as an effective biological amelioration measure in the Ningxia Yellow River irrigation district and similar ecological regions.

This study implemented no-till reseeding of alfalfa （Medicago sativa） with irrigation （applied only in the establishment year） to restore degraded grassland in Yuyang district， Shaanxi Province. By investigating vegetation characteristics of enclosure， irrigation， the first year and the fourth year of alfalfa reseeding grasslands， the effects of restoration measures were evaluated to provide technical supports for the restoration of degraded grasslands in this region. The results showed that： （1） irrigation， as well as the first year and the fourth year of reseeding， significantly increased vegetation biomass and plant diversity compared to enclosure alone， while irrigation alone significantly increased the dry weight proportion （DWP） of annual grass and forb in the vegetation and decreased that of perennial grass， posing a potential threat to grassland ecosystem stability； （2） compared to irrigation alone， reseeding in the first year significantly increased the DWP of legume and decreased that of annual grass in the vegetation， indicating an optimized community structure； （3） as for reseeding in the fourth year， the community biomass reached 5321 kg·hm^-2， which was 5.58 and 2.63 times that of the enclose and irrigation， respectively， and there was 67.78% of the biomass contributed by the reseeded alfalfa， demonstrating high production potential while maintaining plant diversity. In conclusion， the reseeded alfalfa could be maintained in the improved grassland over the long term and reseeding alfalfa with irrigation （applied only in the establishment year） can be served as a primary measure for restoring the degraded grassland in this region.

Soil salinization restricts the development of agriculture in the Hexi Corridor. In this study， the saline-alkali soil in Guazhou County was taken as the object， and four treatments were set up as no modifier （T₀）， straw granular fertilizer （T₁）， no-tillage （T₂） and Hekang （T₃） to explore the effects of different modifiers on the growth of forage maize， soil nutrients and salt ions. The results showed that soil organic matter， available nitrogen， phosphorus， potassium， Ca²⁺，Mg²⁺， pH and total salt decreased first and then increased under different treatments. Na⁺ increased first and then decreased， K⁺ increased， Cl^-，SO₄^2- and HCO₃^- decreased. With the deepening of soil layer （0-100 cm）， pH， total salt， Na⁺，Cl^-，SO₄^2- increased， while K⁺，Ca²⁺，Mg²⁺and HCO₃^- decreased. In the 0-20 cm plough layer， T₃ had the best effect on reducing pH， total salt and HCO₃^-， and T₂ had the best effect on inhibiting Na⁺ and SO₄^2- accumulation. T₁ significantly increased the contents of soil organic matter， available nitrogen， available phosphorus and available potassium （increased by 13.76%， 29.42%， 244.59% and 11.61%， respectively）， and had the best effect on maize stem diameter， plant height and fresh grass yield （increased by 33.47%， 56.02% and 72.28%， respectively）. In summary， straw granular fertilizer （T₁） is the best choice for the improvement of saline-alkali land in this area.