Balanço energético de sistemas de produção na agricultura alternativa

ENERGETIC BALANCE OF FARMING SYSTEMS IN THE ALTERNATIVE AGRICULTURE

Summary

The major purpose of this paper is to obtain the caloric input/output relations for the so called alternative farms, which were analysed as a global farming system. Technical coefficient matrices from a preliminary research concerning profitability of alternative farming systems were applied. Energetic coefficients came either from tables or from specific studies concerning both food and input caloric quantification. It was concluded that biological-origin was the most important source of energy, followed by the fossil-origin ones. Farm energetic efficiency depends on the total amount of calories directly produced, which are closely related to the productive activities and to the applied technology, so the energetic balance ranged widely among farms. Grains and cereals were the products of highest returns per caloric unit invested, while vegetables and livestock products - except honey - showed the lowest rates. The development and improvement of alternative techniques as well as suitable agricultural policies, should contribute to a major absortion of biological energetic contingents which shows minor environmental impacts.