The comparison of surface irrigation systems with two different frequency in pistachio orchards

This research carried out on 30-years-old Ohadi cultivar in Kerman research station from 2002-2005. The soil texture was sandy loam and electrical conductivity (Ec) of irrigation water was 3 ds/m. This study was based on randomized compelet block design in split plot layout, with three replications and three irrigation methods including: border irrigation with border width one and two meters (M1 and M2 treatments) and flood irrigation (M3 treatment). Experimental treatments were irrigated with 30 and 60 days irrigation intervals (F1 and F2 treatments). Irrigation water amount was calculated based on the modified penman by FAO. In the end of each season some factors was measured included: nut fresh and dry weight, percentage of blank and unsplit pistachios, and number of nuts in ounce. MST A TC package used for statistical analysis. For evaluation of salinity distribution in root zoon, Ec measured in different distance and depth of soil and salinity curve draw with Winsurf software. The results indicated M2F (traement with 8.44Kgltree and 2.4lKgltree fresh and dry yield respectively, was the best treatment. Three-years average of fresh and dry yield for the irrigation at 30 days interval was more than 60 days interval. The (M1F1and M1F2) treatments had the minimum of yield. Our data related to amount of water saving in different treatment showed that with decreasing in width of irrigation border to lm and 2m, 30% and 60% water saving happen in compare to flood irrigation respectively. The most and least water use efficiency was for M1F1, 0.266 Kg/m3 and M3F2, O.l19Kg/m3. However between irrigation border of lm and 2m there was no significant difference. Salinity accumulation in middle of tree row and in below of mounds in irrigation border of I m was more severity, however, in irrigation border of 2m not only there was not any salinity accumulation but also because of suitable irrigation and in base of water requirement and leaching requirement had a better condition in soil and root zoon of trees in compare to condition of before treating in control. Therefore with regard of all evaluated factor in this research irrigation border of lm, although of significanting of some factors such as percentage of blank pistachio, nut indehiscence percentage, number of nut per ounce and more water saving in compare to control but because of salt accumulation in close to trees and below of mounds, it is not recommended. Regarding to the treatment of irrigation border of 2m not only about all of evaluated factors in compare to the control have not significant difference but also in some factors such as fresh and dry yield and salt accumulation have a better conditions and in point of view of water saving had 30% economy so was the best treatment and recommended to all of growers.