Study of energy indicators and greenhouse gas emissions in wheat production in Golestan province

The significant increases in energy consumption make the continued and accelerated optimization measures on energy supply and demand more critical than ever before (Iranian Ministry of Energy, 2010). Different quantities of energy are consumed per hectare of wheat production by using different inputs such as fertilizers, fossil fuels, electricity, seeds, pesticides and machinery. This leads to greenhouse gas emissions including CO2, N2O and CH4. Increasing the concentration of such gases in the atmosphere can cause global warming. Serious attention to reducing energy consumption and greenhouse gas emissions is therefore necessary. To this end, fuel and energy consumption and greenhouse gas emissions were investigated in all the wheat fields in Golestan Province. Finally, some strategies to reduce consumption and emissions were presented. In order to determine the fuel and energy consumption and greenhouse gas emissions and how to reduce it, 140 wheat fields in Golestan province were investigated through systematic random sampling. The amount of inputs, including fossil fuels was recorded and energy analysis was done based on the consumed inputs amount per unit. Also, the greenhouse gases emission of carbon dioxide, nitrous oxide and methane derived from energy consumption for agricultural inputs and agronomic operations was calculated (IPCC, 1996; Soltani et al., 2013). Finally, energy efficiency, energy productivity, specific energy, net energy and total GWP, GWP in area unit, product weights, input energy and output energy were also calculated. Fuel required to produce wheat was estimated at 123±0.23 L.ha-1 and energy required was 16231.04± 0.34 MJ.ha-1, based on results. Greenhouse gas emissions were calculated at 1414.01±3.17 kg eq- CO2.ha-1. Land preparation and harvesting required higher fuel and energy consumption and produced more emissions than other agricultural operations. Nitrogen fertilizers and fossil fuels were the worst offenders accounting for 70% of total energy consumption and 78% of emissions. Based on the results, using tractors with higher horsepower and equipment with a high working width and penetration depth in soil is preferable because they required fewer operations and less time for land preparation. Using turbo linear sprayers instead of lance sprayers with a tractor, as well as using new engines for irrigation can play an important role in reducing fuel consumption and, consequently, reduce energy consumption and emissions of greenhouse gases in overall agricultural operations. Optimizing the use of nitrogen fertilizers and reducing fossil fuel consumption is critical to reducing energy consumption and greenhouse gas emissions. If wheat production in Golestan is carried out in such a way that the efficiency of using different types of fertilizers, especially urea fertilizer, is increased or by using organic fertilizers that lead to mineral enrichment in soil over a long period of time, the application of a higher efficiency machine which reduces its own use and fuel consumption, it is possible to increase the energy efficiency and the ratio of the output energy to the input per hectare and reduce energy consumption per kg of grain and straw. By applying such management practices, greenhouse gas emissions will also be reduced in land and crop weight unit.