Análise energética de sistemas de produção de soja convencional e orgânica

Abstract

Our experiment was accomplished on the basis of data obtained at Kestring and Agroecology Farms, and pertinent to the soybean cultures implanted in organic (OS) and conventional systems (CS), crops of years 2003 and 2004. Our objective was to make an energy comparative analysis of those two systems, observing the following factors: energy conversion; energy balance and energy efficiency. The CS presented an energy conversion value of 7,81, which was higher than the 4,40 value we found at OS. The energy efficiency found at CS was 130540,80 MJ.ha-1 being 41% higher than the OS value. The monitoring of energy balance at OS showed a total of 41689,04 MJ.ha-1, while the CS presented 113817,37 MJ.ha-1. The energy efficiency consumed by the system for the production of one hectare was 12254,44 MJ (organic) and 16723,43 MJ (conventional). The biggest consumer of energy at OS was the fertilizer, with 5408,63 MJ.ha- 1 - 44,14% of total consumed energy. Regarding the CS, the herbicide spent 8837,73 MJ.ha-1 acting in 52,85% of the consumed energy. The biological component – human labor - participated with just 2,98% of total energy inserted at OS and, with 1,08% at CS.