Effects of Hypsizygus marmoreus spent substrate on prevention and control potential of continuous cropping obstacle in Dictyophora indusiata cultivation

Background Continuous cropping poses a significant challenge to the sustainable cultivation of Dictyphora indusiata , often leading to soil degradation, microbial imbalance, and the accumulation of soil-borne pathogens, which severely compromise yield and quality. Conventional mitigation strategies, raise environmental and safety concerns. This two-year study investigated the efficacy of using fermented Hypsizygus marmoreus (seafood mushroom) spent substrate (SMS) as a sustainable, biocontrol-based approach to remediate soil, suppress pathogen communities, and alleviate the continuous cropping obstacles affecting D. indusiata. Results By varying SMS application timing, we assessed it effects on yield, nutritional quality, soil physicochemical properties, enzyme activities, and microbial community diversity. Applying SMS three months before planting (S3-24) stabilized soil pH in the second year. Soil available phosphorus increased by 87.34%, total nitrogen by 14.14%, and organic matter declined less (14.14% decrease vs. 29.95% in control). Soil microbial diversity increased within 1-2 months, with phosphate-solubilizing bacteria reaching 7.52%. Soil phenolic acids increased, especially p -coumaric acid (up 179.14% in S3-24). In vitro tests showed that at 250 mg/L phenolic acids, both D. indusiata mycelium and pathogens grew faster, but pathogens had a stronger growth advantage. Fruiting body weight peaked at 19.61 g per fruit in S3-24, and fresh yield reached 12,758.4 kg/hm², representing a 745.07% higher than control. Crude polysaccharide and protein increased by 32.42% and 1.60%. Phenolic acid also increased mycelial diameter to 2.4-4.8 μm, improving mycelium structure and supporting higher yield. Moderate phenolic acid levels benefit both D. indusiata and pathogens, but pathogens competitiveness may drive cropping obstacles. PLS-PM showed that S3-24 strengthened key pathways-from soil properties to enzyme activity (path coefficient: 16.29) and fungal communities (4.77)-and the enzyme-phenolic acid-microbe cascade effect (19.58), improving coordination and stability in the soil microecological network (GoF=0.78) and alleviating continuous cropping obstacles. Conclusions Appropriate SMS use mitigated these challenges, stabilizes yield, and improves quality. This approach recycled agricultural waste and offers practical solutions for future D. indusiata continuous cultivation.