This study was carried out to evaluate the agronomic potential of elephant grass biomass (Pennisetum purpureum Schum) biochar obtained through slow pyrolysis using a semi-continuous pilot screw reactor in the absence of a carrier gas, and under different conditions. The biomass was pyrolyzed with temperature ranging between 400 and 600 °C. The products (biogas/biochar/bio-oil) yields were evaluated. With increasing temperature, there was a decrease in biochar yield, however, the bio-oil yield was relatively constant. Different physicochemical properties of the biochar were evaluated, and the biochar was incubated in the soil for 60 days. After the incubation period the mixture of soil and biochar underwent analysis to determine soil fertility. The biochar produced presented an elevated content of micro and macronutrients, as well as high pH. Agronomic tests showed that biochar presented great potential to be used as an auxiliary liming agent, and as a fertilizer.