To get a proper energy consumption pattern and an increase in energy productivity, determining a relationship\r\nbetween energy inputs and outputs is necessary. In this study, the equivalent energy of inputs and outputs data used in wheat\r\nproduction in Abyek town of Ghazvin province, Iran was collected from farmers over three years. The energy ratio was\r\nobtained as 2.11, 2.08 and 2.03 and energy productivity was obtained as 0.15, 0.14 and 0.14 (kg MJ-1) for 2010, 2009 and 2008,\r\nrespectively. It was found that the contributions of indirect and non-renewable energies on wheat yield were more than the\r\nimpacts of direct and renewable energies. To determine the effects of energy inputs on wheat yield, the Cobbââ?¬â??Douglas\r\nproduction function was used. Model 1 was composed of individual energy inputs: labor, machinery, electricity, diesel fuel,\r\nwater for irrigation, fertilizer, chemicals and seed energies In Model 2 energy inputs divided to direct and indirect energies\r\nand in Model 3 they divided to renewable and non-renewable energies. The R2 values in all three models were more than 0.98\r\nand showed that the models can estimate well. The sensitivity analysis results for Model I showed that the major marginal\r\nphysical productivities (MPPs) were water for irrigation, human labor and water for irrigation in 2010, 2009 and 2008,\r\nrespectively. In Model II, the major MPP belongs to for renewable energy in the same years.
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