Energy Consumption Analysis and Environmental Impact Assessment of Grape Production in Hazavah Region of Arak City

Introduction Today, grapes are cultivated in a vast zone worldwide. Grapes are among the major horticultural produced in Iran and the country is ranked 10th in the world for the grape production. Therefore, efficient use of energy from this crop is very important. Energy is one of the principal requirements for the economic growth and development of agriculture. Scientific forecasts and analysis of energy consumption will be of great importance for planning the energy strategies and policies. The enhancement of the energy efficiency not only helps in improving competitiveness through cost reduction but also results in minimized greenhouse gas (GHG) emissions and environmental impacts. In other hand, energy analysis in the crop production systems enables to identify the effective farming system in different farm size with respect to energy parameters. Based on mentioned points, the objective of this study was to evaluate the energy flow of grape production in three sizes (small, medium and large) of land and then, the life cycle of the production in Hazavah Region of Arak city, Iran. Materials and Methods In this study, data were obtained from 58 growers using face-to-face questionnaires in Arak county of Iran. Orchards were selected using stratified random sampling. Investigation of the energy flow in a production system necessitate calculating input–output energies. In order to deal with this part, energy coefficients were taken into account to convert all agricultural inputs to their energy equivalent. In other words, each input was converted to its energy equivalent by multiplying the application rate of agricultural inputs used within the system by its energy coefficient. In order to evaluate how efficient, the system under study is, some well-known indicators have been introduced and widely applied when a production system is appraised. In this study, a life cycle approach was used for assessment of environment impacts of the grapes production. Life Cycle Assessment (LCA) refers to the process of compiling and evaluating the inputs, outputs and the potential environmental impacts of a product system throughout its life cycle. Goal and scope definition, inventory analysis, life cycle impact assessment and life cycle interpretation are four mandatory steps, which should be followed in a full LCA study. The characterization factors used in this study were adapted from Simapro software which is linked to EcoInvent database. Results and Discussion On average, the values of consumed and produced energies were 1854 MJ ton−1 and 11800 MJ ton−1, respectively. Among all input energies, chemical fertilizers held the first rank with an amount of about 704 MJ ton−1. It accounted for 38% of the total energy used in the production season.  Energy use efficiency, which is a ratio between output and input energy, was calculated as 5.75. Also, the energy productivity was estimated as 0.48, meaning that 0.48 kg grapes is produced when one MJ energy is consumed. The total Global Warming (GW) was calculated as 508.63 kg CO2 eq. ton−1. The farm size had an influential effect on the GW and other impact categories. An increase in the farm size led to reduction in the environment impacts. It means that the value of GW for large farms fell at 498.68 kg CO2 eq. ton−1 and the value of GW for small farms fell at 698.69 kg CO2 eq. ton−1. The upshot was that GW and other impact categories for large farms were significantly less than its counterpart in small farms due to the high value of grapes produced in large farm groups. Impacts of manure played a more important role on GW. Also, direct emissions of chemical fertilizers made high contribution to acidification and eutrophication. Management of using chemical fertilizers can be an appropriate way to reduce the acidification, eutrophication and other environmental impacts on the grape production.   Conclusions Chemical fertilizers (38%), demonstrated their pivotal roles in total energy consumption. The direct emissions in the grape production resulted from high application of chemical fertilizers contributed considerably to some environmental impacts. It suggested establishing a sustainable and environmental friendly grape production system in the region with application of efficient fertilizers by integrated nutrient management.