The effect of Irrigation system type on the amount of irrigation water, yield and water productivity of wheat in farmers conditions (case study: Hamadan province)

Water scarcity and the recent droughts have multiplied the necessity of proper and optimal use of limited water resources. Drip irrigation is one of the new methods of irrigation that is used with the aim of optimal use of water and increasing water productivity in many agricultural products including wheat. This research was conducted in order to investigate the drip irrigation systems (Tape) implemented in the wheat fields of Hamedan province and compare it with other common systems during 2016-2018. In this research, first, farms were selected and evaluated by random sampling method. The measured parameters included the amount of irrigation water, yield, water productivity, water salinity and soil salinity changes. The volume of irrigation water in fields with drip irrigation varied from 2716 to 5760 m3/ha and was determined as 4153 m3/ha on average. The average volume of irrigation water in sprinkler and surface irrigation systems was determined as 4090 and 5918 m3/ha, respectively. The highest amount of yield was determined as 5581 kg/ha in the drip irrigation. The average yield in sprinkler and surface irrigation systems was estimated to be 4381 and 3000 kg/ha, respectively. The highest average water productivity (irrigation+ effective rainfall + leaching) related to the drip irrigation system and is 0.88 kg/m3 , and it was determined as 0.8 and 0.39 kg/m3 in sprinkler and surface irrigation system, respectively. Therefore, drip irrigation has increased water productivity by 10% and 125.6% compared to sprinkler and surface irrigation systems. Also, the results of this research showed that the salinity of the soil in the drip irrigation system increased at the end of the growing season compared to the beginning of the spring season. Therefore, leaching water requirement should be added to the amount of applied water (irrigation water + effective rainfall) in the drip irrigation system.