Using of Hydrus 2D model for proposing suitable irrigation scheme and simulating soil salinity (Case study of Semnan pistachio orchards)

Due to the lack of water resources (quantitatively and qualitatively) and application of different irrigation management in terms of interval and depth of irrigation water (irrigation scheduling) in agriculture and orchards, it is necessary to apply proper irrigation management to prevent the accumulation of salt in the root zone. Pistachio trees are resistant to drought and can produce an average yield even with low amounts of water. The irrigation interval of pistachio trees depends on factors such as soil texture, evapotranspiration, water and soil salinity, irrigation method, tree age and available water amount. Various irrigation methods are used for pistachio trees, the most important of which are surface irrigation, surface drip irrigation, subsurface drip irrigation, and bubbler irrigation. Given that there is no comprehensive information on irrigation management and quality of irrigation water for pistachio orchards in the drip irrigation method of main pistachio growing areas of Semnan (Damghan), identifying different pistachio irrigation managements provides this possibility by using different irrigation scenarios and valid and practical models, suitable irrigation management can be performed in order to increase yield and simulate soil salinity. Three orchards were selected from Damghan city of Semnan province (with a focus on pistachio orchards and surface drip irrigation systems) in order to investigate performance, irrigation management and soil salinity changes. In this regard, information including longitude and latitude, area of orchards, number and arrangement of drippers, irrigation scheduling and soil sampling performance for measuring salinity was done.