Role of vermicompost in improving soil enzyme activity and crop yield in organic farming systems

Abstract:

A data gap exists in the understanding of how vermicompost influences the enzymatic machinery of Russian chernozem soils, which are among the world's most fertile yet increasingly degraded by decades of intensive mineral fertilization. This research compared the effects of vermicompost at 2.5 and 5 t/ha, Farmyard Manure (FYM) at 10 t/ha, and a combined vermicompost + FYM treatment against an unfertilised control on five soil enzyme activities, microbial biomass carbon, and crop yield in an organic wheat-sunflower rotation at the Volga Institute of Agricultural Sciences, Saratov, during 2021-2023. A RCBD with four replications was used. Vermicompost at 5 t/ha raised dehydrogenase activity by 124%, phosphatase by 120%, and beta-glucosidase by 177% over the control after two years. Crop yield under vermicompost 5 t/ha (3.87 t/ha wheat, 1.92 t/ha sunflower) was comparable to FYM at 10 t/ha (3.74, 1.84) despite the lower application rate. The combined treatment gave the highest yields (4.08, 2.14 t/ha). A stepwise regression identified dehydrogenase and phosphatase as the best predictors of yield variation (R2 = 0.81). These findings confirm vermicompost as an effective tool for restoring soil biological function in degraded chernozems.