Greenhouse Gas Emission Analysis of Drip Irrigation Systems (A Case Study: Qazvin Province, Iran)

Pressurized irrigation systems are efficient tools for improving agricultural water productivity. Although increasing irrigation efficiency leads to saving water and increasing water efficiency, the implementation and usage of pressurized irrigation systems require energy supply and related tools and equipment, followed by greenhouse gas emissions. In this regard, one of the factors in the degradation of the environment is the phenomenon of global warming due to carbon dioxide emissions. In the present study, drip irrigation systems implemented in Qazvin province during 2010-2020 were randomly selected and evaluated for energy flow and greenhouse gas emissions. In this research, 17 drip irrigation systems, including pistachio, apple, peach, and nectarine crops, were randomly selected and studied in terms of energy flow and emissions of greenhouse gases. According to the energy equivalent coefficients and carbon dioxide emissions coefficient, the total input energy and carbon dioxide emissions for the drip irrigation systems were calculated. The country's agricultural authorities have considered and invested in the development and implementation of pressurized irrigation systems as one of the methods for proper use of water. Due to the phenomenon of global warming, the primary source of which is greenhouse gas emissions, any activity in the production of equipment, energy, and mechanization of irrigation systems leads to the production of greenhouse gases, which in turn increases the air temperature and crop water requirements and climate change. Given the phenomenon of global warming, the main source of which is the production of greenhouse gases, any activity in the direction of the production of equipment, energy, and mechanization of irrigation systems leads to the production of greenhouse gases, which in turn increase the temperature and change the need for water and climate change.

In this research, after collecting data on drip irrigation systems at different stages of equipment supply, we used drilling machines, welding equipment, and manpower based on the equivalent energy extracted from the sources for each of the stages of equivalent energy in terms of Megajoules. The process of implementation and operation of the irrigation system was calculated, and then we used greenhouse gas emission coefficients for three important greenhouse gases: carbon dioxide, nitrogen oxide, and methane, and considered the global warming potential of each gas using the relation "Greenhouse effect =" ∑_"i" ▒"m" _"i" "×" 〖"GWP" 〗_"i" that "i" is The amount of carbon dioxide equivalent to the emitted from the installation and operation of the drip system.

The results showed that the total annual energy consumption and carbon dioxide greenhouse gas emissions in the evaluated irrigation systems averaged 36,2022.68 MJ per hectare and 1974.07 Kg/ha, respectively. The results showed that the highest share contribution of energy consumption and carbon dioxide emissions with 85.27% and 86.15%, respectively, are related to the operation stage of the pumping station system. Besides, the production of system equipment and its transportation to the project site accounted for 12.83% of energy consumption and 10.93% of carbon dioxide emission. The results of energy flow calculations and carbon dioxide emissions using equivalent energy coefficients, global warming potential, and greenhouse gas emissions coefficient showed that the average total energy consumption and greenhouse gas emissions, due to equipment supply, system installation, and the operation of the pumping station, are 534,035 GJ and 29.611 tons of carbon dioxide equivalent per hectare in the period of fifteen years of the economic and useful life of a drip irrigation system. If the irrigation systems are evaluated from an environmental point of view, air pollutants emissions can be considered an influential factor. This issue has been neglected in the country concerning systems evaluation.

The findings of this study show that the amount of energy consumed and carbon dioxide emissions in different stages of drip irrigation systems are very different from each other and the energy consumed in the pumping stage to provide the required working pressure has the largest share. Factors affecting pump power It seems that by applying water consumption management, selecting pumps with higher efficiency, and avoiding imposing additional load on the network, energy consumption in the pumping network can be reduced. On the other hand, due to the efficiency of electricity production in power plants in Iran and its efficiency of transmission and distribution, if the mentioned efficiencies are improved, the equivalent of energy consumption due to electricity consumption in the pumping stage will be reduced. Due to the topographic conditions and geometric shape of farms and their distance from factories producing equipment, energy consumption and subsequent carbon dioxide emissions for different farms will not be a fixed number. The share of all practical steps except pumping energy consumption will be reduced annually.