Dados do Trabalho

Título

GRANULATION OF BIOSOLID AND INORGANIC SOURCES AS ORGANOMINERAL FERTILIZERS TO REDUCE NUTRIENT LEACHING

Resumo

Combining biosolid and mineral sources of phosphorus and potassium to produce organomineral fertilizers (OMF) can be used to reduce the environmental impact of sewage residues. This approach enhances nutrient management by simultaneously incorporating organic matter and promoting nutrient retention. Our study evaluated the effect of different NPK formulations of granulated OMFs on the leaching losses of nutrients compared to their individual components [biosolid, potassium sulfate (PS), and rock phosphate]. Two forms of isolated N, P, and K sources (granulated and non-granulated), five OMFs with different NPK proportions (1-2-0, 1-4-0, 1-0-2, 1-2-2, 1-2-4), and a control (unfertilized) were evaluated over 10 weeks in a leaching column filled with soil collected from a Planossolo háplico. Fertilizer rates were applied based on N recommendations for corn and the lowest proportions of P and K in OMFs. Fertilizers did not influence N leaching, which averaged 18 mg L-1 for NH4+ and 98 mg L-1 for NO3-. Phosphorus was not detected in the leachate samples during this trial. Potassium sulfate had the highest K leaching (90 mg L-1), which did not differ from the other fertilizers containing potassium (granulated PS, 1-0-2, 1-2-2, and 1-4-2). Among the treatments with K application (excluding potassium sulfate), leaching values ranged from 20 to 31 mg L-1, with the highest values being recorded under the 1-0-2 treatment and the lowest with granulated PS. Despite not being statistically different, the association of potassium sulfate with granulation or OMFs decreased cumulative K leaching by 4.5 and 3.0 folds, respectively. Planned contrasts between granulated and non-granulated fertilizers showed that granulation significantly reduced K leaching by 70% compared to non-granulated potassium sulfate. Hence, OMFs can change nutrient leaching dynamics due to granulation, making it key to consider the physical composition of fertilizers when using them for nutrient management.

Palavras-chave

potassium sulfate, potassium leaching, leaching losses

Instituição financiadora

FAPERJ - Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro