Energy flow evaluation of soybean fields in Golestan province

In this study, the energy flow was analyzed in soybean fields of Golestan province. For this purpose, some indexes such as energy use efficiency, net energy, specific energy, energy productivity, direct energy, indirect energy, renewable and non-renewable energy, total energy input and total energy output were calculated. Primary data were obtained through field survey and personal interviews with agricultural specialists and farmers of Golestan province and filling in questionnaires. The data obtained were converted to secondary usable data using energy equivalents from available literature. Analysis of data showed that the greatest contribution to input energy belonged to energy from electricity (43.74%) followed by energy from fuels and chemical fertilizers. In addition, in these fields energy use efficiency was calculated as 2.31. In this study, the average energy productivity was 0.09 Kg MJ-1.This means that 0.09 kg of seed was obtained per unit energy in Golestan soybean fields. Variables of seed, labor force and chemicals were the least demanding energy input for soybean production in this region. Results indicated that 60.78% and 39.22% of total energy input were in renewable and non- renewable forms, respectively.