Common grassland management practices affect plant and soil element stoichiometry, but the primary environmental factors driving variation in plant C/N ratios for different species in different types of grassland management remain poorly understood. We examined the three dominant C/N stoichiometric responses of plants to different land uses (moderate grazing and mowing) in the temperate meadow steppe of northern China. Our results showed that the responses of the C/N ratio of dominant plants differed according to the management practice. The relative abundance of N in plant tissues increased due to increased soil NO₃⁻, with a consequent decrease in plant C: N in the shoots of Leymus chinensis, but the C/N ratio and nitrogen concentration in the shoots of Bromus inermis and Potentilla bifurca were relatively stable under short-term moderate grazing management. Mowing reduced the concentration of soil NH₄⁺, thus reducing the nitrogen concentration of the roots, resulting in a decrease in the root C/N ratio of Potentilla bifurca. Structural equation model (SEM) showed that the root C/N ratio was affected by both root N and soil inorganic N, while shoot C/N ratio was only affected by the soil inorganic N. Our findings provide a mechanistic understanding of the responses of plant C/N ratio to land use change. The species-level responses of plant stoichiometry to human-managed grasslands deserve more attention.

Cotton waste, a growth medium for Volvariella volvacea, has significant commercial and nutritional value. Under controlled environmental conditions, substrate nutrient composition and microorganisms affect the growth of V. volvacea. In this study, the changes in the nutrient content of the substrate at different stages of fruiting body development were compared based on an 86% waste cotton substrate, and microbial diversity was studied via 16S rRNA analysis. The results indicated that there were significant differences in nutrient content in the substrate at different stages of fruiting body development. The total contents of carbon, nitrogen, and phosphorus initially increased but then decreased due to nutrient absorption and utilization by V. volvacea. It was also found that large amounts of organic nitrogen decomposed into more readily utilizable inorganic nitrogen. The nutritional content and microbial community structure of the substrate during the egg stage significantly differed from those during the other four stages, making the egg stage the most critical period in cultivation. Through correlation analysis between nutrient content and microbial differences, it was found that differential microbial taxa (Beijerinckiaceae, Burkholderiales, Chitinophaga jiangningensis, etc.) with nitrogen fixation, denitrification, and cellulose decomposition functions were significantly related to carbon- and nitrogen-related indicators such as nitrate nitrogen, microbial biomass carbon, and alkali-hydrolyzed nitrogen. These microorganisms play important roles in determining the variation in the nutritional profile of the substrate. This study provides a theoretical basis for promoting the absorption and utilization of nutrients by V. volvacea by altering the structure of the microbial community of the growth substrate.

Volvariella volvacea were grown on an abandoned cotton-based substrate, which was divided into two conditions: a group with added nutrients (N3P3) and a control group (CK). Using metagenomic sequencing technology, the study investigated the effect of nutrient addition during the growth process of V. volvacea on the microbial community and metabolic pathways of the substrate. The study found that the main bacteria in the N3P3 group were Proteus and Microsporidium, while in the CK group, Bacillus marinosus and Microsporidium globosa were more common. At all stages of V. volvacea growth, Proteobacteria and Firmicutes dominated. Metabolic function analysis showed that the N3P3 group significantly increased amino acid metabolism, nitrogen metabolism, genetic information processing, and cellular processes, while reducing the contents of pathogenic and saprophytic symbiotic fungi. Nitrogen metabolism, phosphorus metabolism, and carbon metabolism were closely related to the growth of V. volvacea, and nutrient addition significantly improved microbial community diversity and metabolic levels, which can be used as a substrate optimization formula. This is of great significance for the development of sustainable agriculture.

Using waste cotton as substrate for straw mushroom production has great nutritional support value and commercial value. The production of Volvariella volvacea depends on the physicochemical and microbial properties of the substrate. Due to the strong influence of microorganisms and the complexity of substrate culture, Volvariella volvacea production was finally induced under controlled environmental conditions. The interaction of microorganisms in the process of substrate fermentation has greatly affected the production and colonization of Volvariella volvacea. In this study, the characteristics and production performance of bacterial microbiota in Volvariella volvacea substrate (fermentation period) were compared, and the microbial community in Volvariella volvacea substrate was identified. The growth of Volvariella volvacea changed the microbial composition and structure of substrate. 16S rRNA was used to study the microbial diversity of Volvariella volvacea culture material at different stages and its effect on substrate.The results showed that: in the whole fermentation cycle, the total number of bacterial species in the substrate was negatively correlated with time, and the abundance of Proteus in the substrate was high (accounting for 40%), which decreased first and then increased with the fermentation time. In all samples, at the species level, the relative abundance of amino acid metabolism and sugar metabolism was high, which reflected that the substrate played a great role in nourishing Volvariella volvacea.The technology used in this study provides the overall and detailed characteristics of microbial composition changes in Volvariella volvacea substrate. Analyze the influence of substrate microorganisms on Volvariella volvacea culture, determine the most suitable substrate environment, improve resource utilization, understand the optimal fermentation conditions corresponding to substrate formula, effectively use different substrates in different regions as substrates for Volvariella volvacea culture, and reduce the transportation cost of raw materials. Improve the profits of edible fungi industry. The knowledge generated will help to improve matrix formulation (selection of base materials) and accelerate matrix production, for example, through biotechnology interventions in the form of customized biostimulants and the design of environmentally sustainable bio based materials.