عنوان مقاله [English]
Pistachio is one of the most valuable agricultural products, and it has a special position among the agricultural products in Iran. Overall water use for Pistachio is high relative to other tree crops, but they are extremely tolerant to salinity and water shortage in arid and semiarid regions of Iran. Due to the high water requirements of pistachio trees, lack of water for proper production is one of the most important problems in Iran and due to the reduction of water resources and increased irrigated agricultural lands in Iran; it suffers from severe water deficits.
Phene et al. (1985) used irrigation treatments of 25, 50, 75, and 100% of standard evapotranspiration by trickle irrigation. Their results showed that pistachio yield and qualities profoundly decreased in treatments of 25 and 50% of full irrigation and there were no significant differences of its yield and qualities among treatments of 75% and 100% of full irrigation. They did not recommend full irrigation for pistachio trees. Goldhamer (1993) examined the effect of deficit irrigation on pistachio trees and showed that mature trees are resistant to water stress between the formation of the exterior shells until the fast growth of their seed, so, irrigation could be reduced about 50%. Monastra et al. (1996) in an experiment used four drip irrigation regimes of 0, 25, 50, and 75% of standard evapotranspiration and showed that trunk diameter was significantly affected by irrigation water and volume and trunk section was the highest at treatment of 75% for five to seven years after planting. Other researchers also found that deficit irrigation at a stage of plant growth resulted in saving irrigation water in arid and semi-arid areas without any yield reduction (Sedaghati and Hokmabadi, 2015; Memmi et al., 2016).
Because of limited water resources in Iran, it is required to use deficit irrigation for obtaining acceptable yield and quality of pistachio. The main objective of this research was to study the deficit irrigation level of pistachio (Akbari cultivar) without decreasing quantity and quality of yield compared to conventional irrigation in the selected region.