To screen biocontrol strains with high herbicidal potential， the pathogenic fungus JZ-28 was isolated from naturally infected leaves of Viola philippica in Qinghai Province. Through morphological characterization and multi-gene （ITS， EF-1α， LSU） phylogenetic analysis， the isolate was identified as Clonostachys rosea. Pathogenicity assays demonstrated potent herbicidal activity of strain JZ-28， inducing chlorosis in detached leaves of four dominant broadleaf weed species from the Qinghai-Xizang Plateau（Malva verticillata， Elsholtzia densa， Senecio vulgaris， and Chenopodium album）within 7 days post-inoculation （dpi）. Disease incidence rates in whole-plant assays reached 83%， 95%， 100%， and 70%， respectively. Safety evaluation on six major crops and three cool-season vegetables in Qinghai revealed that JZ-28 was safe for four crops： Zea mays， Vicia faba， Pisum sativum， Brassica napus， and three vegetables： Cucumis sativus， Solanum lycopersicum， and Solanum melongena. Lightly Susceptible was observed in highland barley Hordeum vulgare and Triticum aestivum. These findings indicated JZ-28’s potential as a broad-spectrum bioherbicide against broadleaf weeds in multiple cropping systems. Culture optimization identified sucrose and soybean meal as optimal carbon and nitrogen sources for enhancing mycelial growth and sporulation. This study provided the first evidence of Clonostachys rosea’s bioherbicide potential in alpine ecosystems， addressing a critical research gap in microbial herbicide development and offering sustainable weed management solutions for fragile environments.

To explore the allelopathic mechanism of Euphorbia jolkinii Boiss， a degradation indicator species of mountain meadows in northwest Yunnan， in this study we analyzed its effects on soil phosphorus transformation and related indicators by adding different concentrations of 4-Nitrophenol （4-NP） and 2-Phenethylamine （2-PEA） to the soil. The results showed that both allelochemicals significantly increased soil microbial biomass phosphorus， aluminum-bound phosphorus， calcium-bound phosphorus， and moderately reactive organic phosphorus content， decreased pH and iron-bound phosphorus， occluded phosphorus， moderately stable and highly stable organic phosphorus content （P<0.05）， and promoted the proliferation of bacteria and actinomycetes. 4-NP significantly enhanced phytase activity and reduced acid phosphatase activity. 2-PEA significantly increased acid phosphatase， phytase， and phosphodiesterase activities， while reduced alkaline phosphatase activity （P<0.05）. In summary， the addition of 4-NP and 2-PEA directly affects soil physicochemical properties， changes the content of organic and inorganic phosphorus components， indirectly achieves the accumulation of soil nutrients in its rhizosphere environment， and promotes its further expansion.

The responses of carbon/water cycles in different grassland ecosystems to extreme climatic events and the underlying mechanisms varied. This study， employed the biogeochemical cycle model Biome-BGCMuSo （BGC with Multilayer Soil Module）， integrated with eddy covariance data，conducted sensitivity analysis and parameter optimization to investigate variations in carbon/water fluxes across different grassland types and their responses to extreme climates. The results showed that carbon flux simulations were sensitive to vegetation photosynthetic physiology and carbon allocation parameters， while water flux simulations were sensitive to leaf and root parameters， with variations across grassland types. Optimizing highly sensitive parameters significantly improved carbon flux simulation accuracy， but water flux simulations still require refinement. During growing season heatwaves， all three grassland types remained carbon sinks， though diurnal carbon sequestration decreased by 28.7% and 29.4% in temperate desert steppe and mountain meadows， respectively. Extreme rainfall enhanced carbon and water fluxes across all three grasslands. Drought events increased carbon sequestration by 62.5% in temperate desert steppe but decreased it by 16.3% in mountain meadows. This study reveals distinct response mechanisms of carbon and water cycles in grasslands of arid-semiarid regions to extreme climatic events， providing scientific basis for predicting the evolution of grassland ecological processes under climate change.

Dichondra （Dichondra repens） is a warm-season perennial ground cover plant belonging to the Convolvulaceae， which is widely utilized in landscaping， soil and water conservation， and orchard ground cover. Low-temperature stress is a main limiting factor restricting its promotion and utilization. In this study， we evaluated turf performance and cold adaptability of 12 dichondra genotypes， including nine wild materials which were collected from Southwest China， two nationally certified cultivars， and one widely-used introduced cultivar. The results found significant variations in leaf area， uniformity， leaf color， green period， canopy height， and establishment rate among the 12 genotypes. A comprehensive evaluation of turf performance by using the subordinate function values analysis indicated that the wild Dr5 exhibited superior characteristics including fast establishment， short canopy height， dark green leaf color， high uniformity， and the longest green period， demonstrating high lawnscape value. In contrast， wild Dr17 showed the poorest turf performance. Under consecutive two-year low-temperature stress， all genotypes showed significant declines in chlorophyll content and fluorescence parameters （Fv/Fm and PI_ABS）， but electrolyte leakage and malondialdehyde content exhibited varying degrees of increase. Notably， Dr5 demonstrated the lowest semilethal temperature， lower EL and MDA content， and higher chlorophyll content， Fv/Fm， and PIABS. These findings indicated that Dr5 had significantly lower oxidative damage to cell membrane， enhanced membrane stability， and superior photosynthetic performance under cold stress. Based on a comprehensive evaluation of cold tolerance using the subordinate function values analysis over two years， cold tolerance of 12 genotypes was ranked in descending order as follows： Dr5>Dr21>Dr1>Dr32>Dr2>Dr33>Dr30>Dr3>Dr4>Dr15>Dr11>Dr17. Dr5 exhibited the strongest cold resistance， and Dr17 had the weakest cold tolerance. Given its excellent turf quality and exceptional cold tolerance， Dr5 could be used as a superior germplasm for landscaping and a key candidate for breeding cold-tolerant dichondra cultivars. These findings also lay a foundation for further research into the low-temperature adaptation mechanism of different dichondra genotypes.

The restoration of saline grasslands relies on effective soil amelioration， precise seeding timing， and successful seedling establishment. In this study， the pioneer grass species Leymus secalinus was used as test material， and low， medium， and high salinity levels of salt stress were set up using a 1∶2 ratio of NaCl and Na₂SO₄. The effects of salt stress and its interaction with seedling age on root system phenotypic plasticity were investigated. Our results showed that salt stress made roots grow shallower. Seedling age was the main factor controlling root biomass distribution （P<0.001）. Salt alone and its interaction with age were only significant in some cases. Salt and age both reduced root length， surface area， and volume （P<0.01）. Their interaction had the strongest effect on root volume （F=36.878）. Salt damage increased nonlinearly as the seedling grew. Root tip number decreased with higher salt. Older seedlings were more sensitive to salt. Root angle significantly reduced at the two- and three-leaf stages. Also， root fractal dimension showed a nonlinear response， and increased under low salt but decreased under medium and high salt （P<0.05）. This study revealed the phased adaptation strategies of Leymus secalinus seedlings under salt stress， providing a basis for enhancing the application potential of Leymus secalinus in ecological restoration of saline grasslands.

The identification and characterization of phenotypic traits are the foundation for understanding crop germplasm resources for breeding new cultivars. The sorghum germplasm from Central Asia demonstrated unique genotypes. It is of great significance to fully understand these materials for sorghum breeding in China. This study focused on 44 sorghum germplasm resources introduced from Central Asia. Precise characterization of phenotypic traits was systematically conducted， combined with multivariate statistical methods （including correlation analysis， cluster analysis， and principal component analysis） for systematic evaluation. Data analysis revealed that the tested accessions exhibited high heterogeneity at the phenotypic level， possessed diverse genetic backgrounds， and demonstrated complex interrelationships among traits. Cluster analysis grouped the 44 sorghum accessions into five clusters. Based on different breeding objectives， suitable germplasm resources can be selected. Principal component analysis （PCA） and comprehensive evaluation were performed on the sorghum resources. Based on F-values， the top 10 accessions with the best overall performance were identified. Among them， 7 germplasm materials belonged to Cluster II， and their phenotypic characteristics were significantly superior to that of the other clusters （e.g.， with mean plant height reaching 286.33 cm and panicle weight at 102.50 g）. They showed particularly outstanding performance in stalk lodging resistance and grain yield potential， making them valuable core parental materials for germplasm innovation and the development of hybrid combinations. This study analyzed the phenotypic diversity of sorghum germplasm resources and classified them based on similar phenotypes. This study provides a theoretical foundation for sorghum cultivation in semi-arid and arid regions， and also lays a foundation for the efficient utilization of sorghum germplasm resources and the development of new varieties.

Though the Loess Plateau dryland region in northern Shanxi is a key oat-producing area in China， its forage productivity remains low due to limited rainfall and a lack of suitable oat varieties. To identify high-quality， high-yield forage oat （Avena sativa） cultivars， we evaluated 38 widely promoted domestic and imported varieties， assessing their growth periods， agronomic traits， yields， and nutritional quality. The results showed that there was significant variation in maturity time （86-127 days）， with late-maturing types predominating （21/38）. ‘Molasses’ and ‘Tianyan No.3’ achieved the highest fresh （27 100 and 23 500 kg·hm^-2） and dry forage yields （11 700 and 11 500 kg·hm^-2）. Five cultivars-including ‘Magnum’-had the highest soluble sugar content （16.4%-18.1%）， while ‘Shooter’‘Longyan No.2’ and ‘Longyan No.1’ had the greatest crude protein content （8.7%-8.8%）. Seventeen varieties exhibited premium forage quality， with Relative Forage Value values of 113.7-126.1. Based on the “Quality Classification of Oat Hay” standard， 13 cultivars were classified as Type A hay and 9 as Type B （all Grade III）. Overall， ‘Molasses’ ‘Magnum’ ‘Tianyan No.3’ ‘Jiayan No.2，’ and ‘Monida’ demonstrated superior performance and are recommended for priority adoption in eastern dryland areas of northern Shanxi’s Loess Plateau.

To explore the influence of urban grassland types on soil DOC and its characteristics， this study took the urban green space ecosystem in Beijing as research object. Four treatments were established： bare land， cool-season grassland， warm-season grassland， and urban understory ground cover. The soil DOC content was measured， and the spectral characteristics of soil dissolved organic matter （DOM） were analyzed by using ultraviolet-visible spectroscopy and three-dimensional fluorescence spectroscopy. The results showed that compared to the bare land， the DOC content of the cool-season grassland surface soil was significantly decreased by 30% （P<0.05）， but there was no significant difference from warm-season grassland and urban understory ground. The UV spectra showed there was no significant difference between the aromaticity and the hydrophobicity of the DOM among the treatments. The fluorescence spectra showed that the DOM of urban grasslands had mixed source characteristics. In compared with the bare land， the humization process of the urban grasslands was enhanced but self-source contribution was decreased， with strong microbial activity but weak bio-availability. The results showed that the dynamic of DOC in urban grassland was regulated by vegetation type， management measures and microbial activity. The optimization of fertilization management and the consideration of carbon sequestration type of grass species could enhance the function and stability of urban soil carbon sequestration， which provided theoretical support for the improvement of urban green space ecological function.

In this study， we used S. transiliense seedlings as a research object and conducted a pot experiment with continuous drought stress to systematically investigate the dynamic changes in root system morphology， physiological response and anatomical structure. The results showed that with the increass of drought stress intensity， root system morphology changed significantly， with a decrease in topological index and fractal dimension， and a shift in root branching patterns towards a more efficient “dendritic” structure. At the physiological level， there was a significant accumulation of reactive oxygen species （ROS）， increase in membrane lipid peroxidation and enhanced ability to regulate osmosis. Antioxidant enzyme activity showed a trend of increasing first and then decreasing. The anatomical structure analysis revealed that the root tip epidermal and endodermal cells thickened to enhance water-holding capacity， while the cortical parenchyma， vascular system and root tip diameter all showed a decreasing trend to optimize water transport efficiency. This study revealed the adaptive strategy of S. transiliense by integrating root system configuration plasticity， physiological regulation， and anatomical structure optimization， providing a scientific basis for studying the drought resistance mechanisms of desert plants and also offering an important reference for ecological restoration and breeding in arid areas.

The mechanism of the influence of vegetation restoration on soil characteristics in the loess hilly landslide area is unclear， in this study we selected the typical landslide area in the loess hilly and gully region of central Gansu in the upper reaches of the Yellow River as the experimental site. Through field sampling and indoor analysis， combined with fractal theory， the differences in soil particle size characteristics and physical and chemical properties under three ecological restoration measures， namely natural restoration， honeysuckle planting， and corn planting， were compared. The results showed that： （1） Under different ecological restoration measures， the composition of soil particles was mainly composed of sand grains （34%~37%）， fine sand grains （27%-28%）. （2） Compared with natural restoration， the pH in the honeysuckle area decreased significantly， and the moisture content in the corn area increased significantly. The contents of soil organic matter， total nitrogen and total phosphorus in artificial restoration were all higher than those in natural restoration. （3） The range of the single fractal dimension was 2.44 to 2.72， specifically corn （2.72）> honeysuckle （2.65）> natural recovery （2.44）， and the recovery of corn leads to better soil quality. Under different ecological restorations， the single fractal dimension of soil showed an increasing trend as the soil texture changes from coarse to fine. The nutrient content and moisture content of soil restored artificially were higher than those restored naturally， that was， artificial restoration measures were more conducive to enhancing the soil's water retention capacity and nutrient fixation capacity. The study shows that in the process of landslide control， appropriately adopting auxiliary measures of artificial restoration can effectively improve soil structure， increase vegetation coverage of the landslide site， and reduce soil erosion.