Ashkan Nabavi-Pelesaraei - Department of Agricultural Machinery Engineering, Faculty of Agriculture, University of Tabriz, Iran.
Ahmad Sadeghzadeh - Technical and Vocational University, Tehran, Iran.
Mir Hossein Payman - Department of Agricultural Machinery Engineering, Faculty of Agriculture, University of Guilan, Iran.
Hassan Ghasemi Mobtaker - Young Researches Club, Tabriz Branch, Islamic Azad University, Tabriz, Iran.

The objectives of this research were to investigate influences of energy inputs and energy forms on output levels and evaluation of CO2 emissions for hazelnut production in Guilan province of Iran. Moreover, the sensitivity analysis was done by marginal physical productivity (MPP) method for energy inputs and energy using linear regression. Initial data were collected from 120 orchardists in September and October 2012. The total energy of 2862.62 MJ ha-1 was calculated for gardening in one year. The results of energy forms analysis revealed the share of non-renewable and indirect energy was more than renewable anddirect energy, significantly. The ratio of energy output to energy input was approximately 3.93. Total CO2emissions of hazelnut production was calculated as 77.66 kgCO2eq. ha-1. Also, the diesel fuel had the highest share of emissions among all inputs with 33.84%. Econometric model estimation indicated that the impact of human labor, machinery, diesel fuel and pesticides energy inputs were significantly positiveon hazelnut yield. The sensitivity analysis was presented that the marginal physical productivity (MPP) value of pesticides, farmyard manure and diesel fuel energy were the highest with 9.43 and -4.86 and 0.97, respectively. In energy forms econometric models, impact of direct, indirect and renewable energies were significantly. Furthermore, direct and renewable energies was the most sensitive groups in energy forms with MPP value of 0.98 and 1.19, respectively.

Energy consumption; Hazelnut production; CO2 emissions; Cobb-Douglass function;Sensitivity analysis