Efeito do biochar e do lodo de esgoto nos atributos do solo, estado nutricional e produtividade do milho (Zea mays L.)

Abstract

The use of organic waste in agriculture is considered a sustainable practice capable of pro-moting improvement in soil quality. Residues are sources of nutrients and organic matter, capable of increasing the availability of macros and micronutrients, in addition to having a conditioning effect, increasing the retention of ions and water in the soil, benefiting plants and microbiota. In this sense, the study aimed to: a) evaluate changes in physical, chemical and biological attributes after the incorporation of biochar and sewage sludge; b) evaluate the effect of biochar and sludge on the development, productivity and physiology of corn plants. The experimental design was in randomized blocks where the following treatments were applied: 0, 5, 10, 15 and 20 t ha-1 of bio-char; sewage sludge, at a dose of 20 t ha-1 and mineral fertilizer. At 60 days after emergence (DAE) biometric analyzes were performed and diagnostic sheets were collected to determine photosyn-thetic pigments and nutritional assessment. Deformed and undisturbed soil samples, in addition to leaves, were collected at 90 DAE for analysis of chemical, physical, biological attributes, in addi-tion to the determination of macros and micronutrients in the plant. The results in chemical attrib-utes indicated an increase in pH, Total Organic Carbon (COT), Cation Exchange Capacity (CTC), P-available, K+, Fe, Cu, and Mn in the soil after application of biochar and sewage sludge. Regard-ing the physical and biological attributes, it was possible to observe an increase in the following attributes: Total Porosity (PT); pore size distribution; Field Capacity (CC); Permanent Wilt Point (PMP); available water; COT; Carbon of Microbial Biomass (CBM); Metabolic Coefficient (qMIC) and Basal Soil Breathing (RBS), and reduction in Ds and qCO2. Despite the increase in corn productivity caused by the application of biochar, the greatest gains were observed from the application of mineral treatment and sewage sludge, where higher levels of nutrients, photosyn-thetic pigments and grain yield were observed. These results were instrumental in improving soil quality and corn productivity, highlighting the conditioning effects of organic waste, such as bio-char and sewage sludge.