Compost from pruning residues: nutrient dynamics and influence on the microbiological community, an in-depth study

European viticulture is one of the agricultural sectors that, due to its high yields, requires abundant amounts of fertilizers. The intensive use of chemical fertilizers causes a decrease in organic matter in soils, a general impoverishment of their quality, as well as a significant environmental impact. In addition, the global energy crisis has led to a reduction in fertilizer availability, driving winegrowers and researchers to look for alternative solutions for vine nutrition, such as compost. Compost from pruning waste represents a smart solution to close the loop in the vineyard. To date, this particular amendment is still little studied and, above all, the dynamics of nutrient release or how it affects microbial activity are poorly known. Moreover, given the fundamental role of fungi in the soil, an innovative strategy to address current challenges appears to be the use of fungal inoculated compost. This study compared three types of fertilization to elucidate their effect on soil: NPK, mineral fertilizer; PWC, compost from pruning residues; iPWC, the same compost inoculated with fungi (Trichoderma and Glomus). The trial was carried out for 5 months in a growth chamber. Fifteen pots were filled with inert soil and assigned to the above treatments. Humidity, temperature and light/dark period were monitored. During the trial, the dynamics of key nutrient release, the enzyme activity in soils and the effects on microbial communities were investigated. The preliminary results showed that compost, especially when inoculated with fungi, clearly influenced the enzyme activity in soils. The microbial communities had a higher activity in the fungal consortium and simple compost treatments, while the functional diversity was higher in the treatment with mineral fertilizer.