energy efficiency analysis and modeling the relationship between energy inputs and wheat yield in iran

wheat is the dominant cereal crop constituting the first staple food in iran. this paper studies the energy consumption patterns and the relationship between energy inputs and yield for wheat production in iranian agriculture during the period 1986 – 2008. the results indicated that total energy inputs in irrigated and dryland wheat production increased from 29.01 and 9.81 gj ha-1 in 1986 to 44.67 and 12.35 gj ha-1 in 2008, respectively. similarly, total output energy rose from 28.87 and 10.43 gj ha-1 in 1986 to 58.53 and 15.77 gj ha-1 in 2008, in the same period. energy efficiency indicators, input–output ratio, energy productivity, and net energy have improved over the examined period. the results also revealed that non-renewable, direct, and indirect energy forms had a positive impact on the output level. moreover, the regression results showed the significant effect of irrigation water and seed energies in irrigated wheat and human labor and fertilizer in dryland wheat on crop yield. results of this study indicated that improvement of fertilizer efficiency and reduction of fuel consumption by modifying tillage, harvest method, and other agronomic operations can significantly affect the energy efficiency of wheat production in iran.