Returning spent mushroom substrate (SMS) to the field is an effective way to dispose of it. However, given the substantial nutrient consumption associated with Volvariella volvacea SMS, their effects on soil properties and crop performance warrant further investigation. By analyzing the effects of three different application rates of SMS on soil nutrients and lettuce (Lactuca sativa L.) quality, the results showed that the group with 1.5 kg m−2 SMS addition improved the total nitrogen (+21.2%), and organic content (+27.9%) in soil, and it demonstrated particularly outstanding performance in enhancing the survival rate (+21.9%), average weight (+71.7%), chlorophyll content (+45.6%), and total phenolic content (+25.2%) of lettuce. By comparing the soil microbial communities in the control group, the SMS (1.5 kg m−2) treatment group, and the organic fertilizer treatment group, it was found that they were mainly composed of Group S1, S2, and S3 microorganisms, respectively. The microbial community evenness in the treatment groups was greater than that in the control group. Furthermore, the results also revealed that the microbial conversion efficiency of nitrogen and phosphorus in the SMS treatment group was higher than the control group, which promoted nutrient cycling and improved the quality of lettuce. Our analysis provides an environmentally friendly way for Volvariella volvacea SMS disposal.
Yang et al. (Tue,) studied this question.