The study revealed the mechanism of different agricultural wastes to improve the yield and quality of Morchella.

Morchella spp.is a high value-added rare edible fungus, and the optimization of its cultivation substrate is a key link to achieve efficient production and eco-friendly agriculture. In recent years, the resource utilization of agricultural waste has become an important direction of sustainable development. The reuse of waste such as tomato matrix, mushroom bran and coconut shell can not only reduce production costs, but also reduce environmental pollution, which has significant ecological and economic benefits. Morchella is a kind of edible fungus that depends on soil cultivation. In order to clarify the characteristics of soil microbial community and its influencing factors under different cultivation substrates of Morchella, Illumina NovaSeq high-throughput sequencing technology combined with ecological and statistical analysis methods were used to analyze the relative abundance, inter-group differences, soil physical and chemical properties, yield and quality of bacteria and fungi communities in Morchella original soil, 5 % tomato substrate soil, 5 % mushroom bran soil and 5 % coconut shell soil. The results showed that agricultural wastes such as mushroom bran, waste tomato matrix and coconut shell had a synergistic mechanism for Morchella cultivation :In terms of yield and quality, the yield of mushroom bran group was the highest ( soil nutrient enrichment ), followed by tomato matrix ( water holding capacity + peat nutrition ). All three promoted early fruiting, and significantly increased the contents of polysaccharide, crude protein and potassium, and reduced crude fat and crude fiber. The addition of each material on soil improvement optimizes the physical structure ( reducing bulk density, increasing water holding capacity ) and chemical properties ( enriching nitrogen, phosphorus and potassium, regulating nitrogen forms and medium and trace elements ) ; in terms of microbial regulation, the abundance of beneficial bacteria such as Actinomycetota, Gemmatimonadota and Devosia was significantly increased, and the function of nitrogen fixation / nitrification / decomposition was enhanced. The abundance of Bacillaceae in the spent mushroom substrate group was positively correlated with the yield. At the same time, it inhibits pathogenic fungi such as Mortierella and Trichoderma, and reduces fungal diversity to reduce ecological competition. Fungus chaff has the dual advantages of nutrient release and microbial regulation. Tomato substrate and coconut shell are new and efficient resources, and the three promote yield increase through the ' physical-chemical-microbial ' synergistic path. In the future, it is possible to regulate functional microorganisms and optimize waste pretreatment technology to achieve sustainable development.