Energy input for tomato production what economy says, and what is good for the environment

The central Fars province is the main tomato producer region in Southwest Iran. This study was undertaken to evaluate the energy consumption patterns of tomato production, corresponding GHG emissions, and relationships between inputs and output by a Cobb-Douglass econometric model. The changes in GHG emissions were also investigated to display if the result is in favor of the environment as well as economy. The non-hierarchical cluster analysis determined three groups of tomato farmers with respect to the energy inputs and tomato yield; C1, C2 and C3 including 90, 46 and 20 farmers, respectively. The findings showed that around 40-60 GJ/ha energy is needed to produce 54-70 ton/ha tomato. Although, the C1 farmers consumed around 20 Gllha higher energy than C3, they also had a higher output input energy ratio; 1.15 and 1.12, respectively. The GHG emission index (I-GHG) disclosed that energy efficiency indices cannot represent the environmental risks of energy inputs since some higher energy efficient groups also emitted higher carbon. The econometric analysis revealed that some energy inputs significantly correlates with the yields of C1 and C2 farmers. The highest marginal physical productivities (MPPs), however, indicated that tomato yield is most sensitive to machinery and chemicals energy inputs in the C1 and C2, respectively, which should be considered first to increase in order to achieve productivity enhancement. The result displayed that higher energy consumption according to the econometric models and MPPs may lead to much higher CO2 emissions compared to the current average emissions particularly when MPP is low. Hence, it is suggested that production types with the highest MPPs should be considered if change in energy inputs is desired. In addition, it is recommended that green econometric models are needed to evaluate balanced energy use consumption together with other agronomical, economical and the environmental sustainability impact assessment criteria. (C) 2014 Elsevier Ltd. All rights reserved.