Energy use pattern and greenhouse gas emission of wheat production: a case study in Iran.

Wheat is one of the most important staple foods in the world and modern wheat productions heavily depend on fossil and other energy resources. Sufficient amount and efficient use of these energies are requirements for sustainable wheat production. This study therefore focuses on estimating energy consumption and greenhouse gas (GHG) emission in rainfed wheat production in Kohgilouye-BoyerAhmad province of Iran during the years 2008-2010. The input farm resources and output wheat yield were transformed to forms of energy by multiplying them with their corresponding energy coefficient. To evaluate performance of wheat production, energy indices such as energy ratio, energy productivity, specific energy and net energy were calculated. GHG emission was calculated by multiplying the application rate of inputs by its corresponding emission coefficient. Analysis of energy indicators in wheat production revealed that energy use efficiency, energy productivity and net energy had increasing trend during the studied years. The average value of energy use efficiency, energy productivity and net energy were 2.13, 2.15 kg MJ -1 and 8585.87 MJ ha -1 in 2010. Analysis of GHG emission showed that total emission in wheat production was 280.57 kg CO 2 eq ha -1 and nitrogen fertilizer, diesel fuel and phosphate fertilizer had the highest contribution in producing GHG emission, respectively. This study indicates that management of intensive-energy consumption resources such as chemical fertilizers and diesel fuel are possible pathways to improve energy efficiency and decrease total GHG emission in wheat production.