Enhanced soil ecosystem multifunctionality and microbial community shifts following spent mushroom substrate application in vineyards

Abstract

Soil multifunctionality and microbial diversity in agricultural ecosystems are influenced by fertilization. Spent mushroom substrates (SMS) have recently been used as organic fertilizers, but their effects on soil and microbial functions in orchard ecosystems remain understood. A two-year field study was conducted to compare the different types (Agaricus bisporus and Pleurotus eryngii substrates) and application rates (equal to 975, 1575 and 2250 kg N ha⁻¹ yr⁻¹) of SMS on soil multifunctionality and microbial community properties in vineyard soils. The application of Pleurotus eryngii substrate at a N input rate of 2250 kg ha⁻¹ yr⁻¹ significantly increased soil multifunctionality by 48.04 % compared to non-fertilized soil, due to reduced soil bulk density, increased soil nutrient content and enhanced soil enzyme activity. Additionally, SMS application significantly improved bacterial diversity and altered bacterial and fungal community structures, with changes positively correlated with soil organic matter content. Furthermore, SMS amendment primarily increased the relative abundances of keystone species categorized as module and network hubs in the bacterial co-occurrence network. Compared to Agaricus bisporus substrate, the application of Pleurotus eryngii substrate increased the relative abundances of organisms involved in aromatic compound degradation (38.63–71.18 %) and saprotroph (3.14–4.40 %), while significantly reducing pathotrophic fungi by 59.96–64.76 %. It is noteworthy that Cu and Cd accumulations were increased by 7.92–52.54 % in vineyard soils treated with SMS. However, the type and application rate of SMS had divergent effects on Cr and Pb accumulations, suggesting that the better microporous structure of Pleurotus eryngii substrate helps bind and passivate heavy metal ions depending on the element type. The contents of Pb, Cd and Cu significantly influenced the diversity and composition of soil microbes. Overall, the proper use of SMS improves soil multifunctionality, and Pleurotus eryngii substrate application could further enhance microbial network structures and ecosystem functions in vineyard soils.