Addition of silicate rock in the composting of poultry manure: Effects on chemical, enzymatic, and microbial properties

Composting is a simple and sustainable technique that produces a nutrient-rich organic amendment. This compost can be further enriched with low-cost materials such as silicate rock (SR) powder, offering several benefits for crops like rice, which has the ability to accumulate silicon in its tissues. This study aimed to evaluate the dynamics of chemical, enzymatic, and microbial parameters during the composting of poultry manure (PM) with the addition of SR, and its subsequent application to two rice cultivars under field conditions. Overall, the main properties that varied during the composting process were nitrogen (N), phosphate (P₂O₅), potassium oxide (K₂O), calcium (Ca), magnesium (Mg), and pH. Firmicutes was the most abundant phylum in both treatments, and the addition of SR did not significantly alter the bacterial community composition. Field results showed that fertilization with SR-enriched compost increased the yield of the BRSMG Caçula cultivar, reaching 2.5 t/ha compared to 1.76 t/ha in the treatment without SR.