Análise energética da produção de soja em sistema de plantio direto

Abstract

This work aimed to estimate the energy balance of the soybean crop under no tillage system on farm in Medianeira, Paraná, Brazil. Two energy inputs types was considered in the system: the direct and the indirect energy. As direct energy the biological (labor, seeds and organic fertilizer) as the fossil (diesel fuel, lubricants and grease) were considered. The indirect energy (industrial) includes machinery and implements, fertilizers, insecticides and herbicides. The energy coefficients were obtained from specific papers about caloric quantification of the operations and inputs. The soybean yield recorded was 3.798.78 kg ha-1 . The highest energy consumption was from the industrial type (36.52%) followed by the fossil energy (29.79%) and the biological energy (27.74%). Energy efficiency means to optimize the energy source use, resulting in a low energy input to provide de same amount of energetic value to the final product. Energy efficiency of 18.64% was verified. It was attributed to the reduced mechanization and the biological energy used through the organic fertilizer, seeds and labor. However, despite of the high efficiency the system showed high dependence of the fossil energy use (diesel fuel consumption and herbicides), corresponding to 51.69% of the total energy consumption.