Productivity of water and energy use of potato in sprinkler irrigation systems( Case study: Dehgolan Plain, Kurdistan Province)

Agriculture, while being a supplier of energy, is also its most important consumer. Agriculture is also the largest consumer of water. The optimal use of the two main inputs of agriculture, namely water and energy resources, in the agricultural sector is one of the important priorities of the country's water and agriculture industry (Ahmad & Khan, 2009). One of the most important programs for agricultural development in the country should be to increase the productivity of water and energy consumption. So far, about 2.9 million hectares in Iran have been covered by pressurized irrigation systems, which has led to an improvement in the water productivity index from 0.87 kg/m3 in 2005 to 1.32 kg/m3 in 2015, and the target is 1.6 kg/m3 in 2025. The Dehgolan plain, with an area of 84,982 square kilometers, is located to the east of the city of Sanandaj. The Dehgolan prohibited aquifer is the only source of agricultural water in the region. The solid set sprinkler irrigation system is the most common irrigation system in the region, and in some areas, farmers also use the wheel-move sprinkler irrigation system. In addition, due to the annual decline in the groundwater level, the energy consumption for pumping water has also increased; therefore, it seems necessary to study the water productivity indices as well as the electricity consumption efficiency and the total energy consumption in the mentioned plain. The main objective of this research is to evaluate the water and energy productivity indices of the important potato crop in farmers' fields, with solid set sprinkler and wheel-move sprinkler irrigation systems. In addition, an attempt was made to study both electricand diesel fuel sources.

A study involving 19 farms with a combined area of 177 hectares investigated water and energy use in irrigation systems. The farms were divided into three categories: solid set sprinkler systems with mobile sprinklers powered by electricity (CE), solid set sprinkler systems with mobile sprinklers powered by diesel fuel (CD), and wheel move sprinkler systems powered by electricity (WE). To measure flow rate, an ultrasonic flow meter was used on each farm. Electricity consumption data was obtained from the regional electricity company at the conclusion of the irrigation season. Farms using diesel-powered pumps had their monthly diesel consumption documented. The yield was alsomeasured by sampling method. other necessary and complementary information about the studied farms was collected from farmers, including the amount of potato tuber planted in the farm, fertilizers used, pesticides used, required labor force, and agricultural machinery required in the planting, cultivation, and harvesting stages. At last, to evaluate the productivity of the studied farms, the following indices were used: electricity and energy consumption productivity, water productivity, energy efficiency, and specific energy. 

An analysis of various water and energy efficiency indicators revealed that farms using solid set sprinkler systems with mobile sprinklers powered by diesel fuel (CD farms) performed the worst. These farms exhibited the lowest average water use productivity (1.4 kg/m³), energy use productivity (0.2 kg/MJ), and energy efficiency (0.7), while having the highest average specific energy consumption (5.7 MJ/kg). This suggests that CD farms have a negative net energy input, meaning they consume more energy than they produce. 

This study evaluated water and energy use productivity indices for potato production in farmers' fields of Dehgolan plain, Kurdistan province, Iran. The fields were classified into three groups: CE (solid set sprinkler irrigation system with electric power source), CD (solid set sprinkler irrigation system with diesel fuel energy source), and WE (wheel move sprinkler irrigation system with electric power source). The average energy consumption of CE, CD, and WE farms was 111413, 213931, and 118431 MJ/ha, respectively. The water use productivity indices of CE and WE farms were equal and 17% higher than those of CD farms. The energy use efficiency and productivity of the mentioned farms were also equal and twice those of CD farms. The net energy input of the mentioned farms was 41587, -75931, and 52569 MJ/ha, respectively.In other words, the energy input from CD farms that use diesel engines is negative. In general, based on the studied indices, the status of farms with solid set and wheel move sprinkler irrigation systems that use electric energy is acceptable compared to the national average. However, it is necessary to prioritize the electrification of agricultural wells of farms that use diesel fuel in the country's planning programs.