Investigation the energy indices and greenhouse gases emission in soybean production, Golestan Province

Inputs such as chemical fertilizers, fossil fuels, electricity, seed, and machinery consume energy in soybean production. This energy consumption is expected to cause Greenhouse Gases Emissions (GHG). Increasing the concentration of these gases in the atmosphere could lead to Global Warming. The purpose of this study was to investigate the energy consumption and GHG in soybean production in Golestan Province, Iran.  

In this study, 140 farmers were selected to investigate the soybean production systems in Golestan Province in northeastern Iran. The data of consumed energy (machines, seeds, fertilizers, fuel, pesticides, human labor, and electricity) were collected by a questionnaire. Then fuel, input and output energy, energy indices, and global warming potential (kg eq-CO2/ha) were calculated by related coefficients.  

Based on results, fuel and energy requirements for soybean production were estimated 210.83±0.09 L/ha and 19036.08±2.53 MJ/ha, respectively. Also, GHG emissions were calculated 2306.85±3.17 kg eq-CO2/ha. Fossil fuel and electricity consumption had the highest energy consumption and GHG emissions values, respectively, so that 62% of the total energy consumption and 75% of the total GHG emission belonged to electricity and fossil fuel consumption, respectively. Energy output derived from soybean was 42124.95±0.73 MJ/ha. The output-input ratio was estimated 2.21±0.01. Net energy gain was raised by increasing the seed yield and decreasing the input consumption such as electricity, fossil fuel, and N-fertilizer. Energy productivity was calculated 0.147±0.01 Kg/MJ. On average, 2306.85±3.17 kg eq-CO2/ha greenhouse gases were released into the atmosphere for soybean seed production.  

Focusing on optimal consumption of fossil fuels and decreasing the electricity consumption in irrigation is essential for reducing the energy consumption and greenhouse gas emissions for soybean production in Golestan Province, Iran.