One Year Residual Effect of Sewage Sludge Biochar as a Soil Amendment for Maize in a Brazilian Oxisol

The thermochemical transformation of sewage sludge (SS) to biochar (SSB) allows exploring the advantages SS and reduces possible environmental risks associated with its use. Recent studies have shown that SSB is nutrient-rich may replace mineral fertilizers. However, there are still some questions be answered about residual effect on soil nutrient availability. In addition, most previous were conducted in pots or incubations. Therefore, properties field conditions remains unclear. This study shows results availability uptake as well maize yield third cropping a three-year consecutive corn system. following treatments compared: (1) control: without fertilizer biochar; (2) NPK: fertilizer; (3) SSB300: produced at 300 °C; (4) SSB300+NPK; (5) SSB500: 500 (6) SSB500+NPK. show has one-year effects by maize, especially phosphorus. Available P contents plots received around five times higher than control NPK treatments. Pyrolysis temperature influenced yield. One year after suspending application, SSB300 increased same level application NPK. stood out promoted grain period (8524 kg ha−1) SSB500 (6886 ha−1). Regardless pyrolysis temperature, boosted resulting exclusive Additional long-term should focused slow-release phosphate fertilizer.