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

Wheat is the dominant cereal crop constituting the firststaple food in iran. this paper studies the energy consumptionpatterns and the relationship between energy inputsand yield for wheat production in iranian agriculture duringthe period 1986 – 2008. the results indicated that total energyinputs in irrigated and dryland wheat production increasedfrom 29.01 and 9.81 gj ha-1 in 1986 to 44.67 and 12.35 gj ha-1in 2008, respectively. similarly, total output energy rose from28.87 and 10.43 gj ha-1 in 1986 to 58.53 and 15.77 gj ha-1 in2008, in the same period. energy efficiency indicators, input–output ratio, energy productivity, and net energy have improvedover the examined period. the results also revealed that nonrenewable,direct, and indirect energy forms had a positiveimpact on the output level. moreover, the regression resultsshowed the significant effect of irrigation water and seedenergies in irrigated wheat and human labor and fertilizer indryland wheat on crop yield. results of this study indicatedthat improvement of fertilizer efficiency and reduction of fuelconsumption by modifying tillage, harvest method, and otheragronomic operations can significantly affect the energyefficiency of wheat production in iran.