Biosolid and sugarcane filter cake in the composition of organomineral fertilizer on soybean responses

Purpose Organomineral fertilizers formulated from different organic sources have been studied for the fertilization ofseveral crops. Filter cake is currently one of the most used sources of organic matter; however, sewage sludge also presentscharacteristics of agronomic interest, being one of the major environmental problems in Brazil. In this sense, the efficiencyof pelletized organomineral fertilizers produced with both sources were evaluated for the development of soybean underdifferent fertilization levels.Methods The experiment was carried out in greenhouse conditions. The soil was characterized as Red Eutrophic Oxisol. Theexperimental design was randomized block design in a 2 × 4 + 2 factorial scheme, corresponding to two sources of organicmatter (sugarcane filter cake and treated sewage sludge), in four doses (50, 75, 100 and 125% of recommendation for soybeancultivation), as well as a mineral fertilization and no-fertilization treatments. The plant development was evaluated (stemdiameter, plant height and chlorophylls a and b) at 30, 60 and 90 days after sowing.Results Organomineral fertilizers formulated from sanitized sewage sludge or sugarcane filter cake promote a higher soybeanplant height in relation to mineral fertilizer, especially after the middle of the crop cycle. The level of fertilization referringto 75% of the recommended dose for soybean, when made with sanitized sewage sludge or filter cake, resulted in large stemdiameter in relation to mineral fertilization.Conclusion Organomineral fertilizers based on sanitized sewage sludge or filter cake promote increases in soybean characteristicsup to 90 days.