Determination of Pistachio Production Function in Pistachio Growing Area of Kerman (Iran)

Pistachio is one of the important non-oil exporting products, however, because of slight precipitation, drought years, and immethodical water resource taking, water resources have reduced. In some areas, besides drought stress, salinity of irrigation water increased more than the tolerance of pistachio rootstocks. Salinity of irrigation water and deficiency of water has caused pistachio tree life to lessen in the last few years. In this research, by estimation of pistachio production function, roles of management tools, resource deficiency and other random factors that have an affect on pistachio production function was evaluated. In this research 100 questionnaires from the Rafsanjan area were provided. For preparing this questionnaire, Rafsanjan pistachio orchards were divided into five pistachio planting areas including Anar, Koshkueieh, western and eastern county of Rafsanjan, Kabotharkhan and Noogh area. In each area based on the amount of cultivated area, the number of questionnaires was recognized. In each selected area one water sample was taken and a soil profile was excavated and evaluated by soil science experts and soil samples were taken simultaneously. Water, soil and leaf samples were analyzed in the laboratory. All results were analyzed statistically by SPSS and SAS software. Data from 65 measured parameters, revealed that 14 of them had priority and explain more than 82 percent of variance. Final investigation introduced three equations as best equation and final equation. First equation: Y-2= 1203.83+110.7X(1)-27.8X(2)-22.7X(6) +54.3X(8) X-1 = Depth of Irrigation Water, X-2 = Irrigation Interval, X6 = SAR (40-80) cm, X8 = TNV (0-40) cm, R-2= 0.44 Second equation: Y-2= -1108.5+104.3X(1)-46.8X(2)+0.18X(3)+556.7X(4) -99.1X(5)+53.63X(6)+216.4X(7)-38.6X(8)- 109.9X(9) +5.15X(10)+59.9X(12)-68.5X(13)+98.3X(14) Third equation: Y = -912.474 + 0.2 X-3 + 52.074X(6) In these equations: X-3 = Total water, X-4 = EC Ave, X-5=P2, X6 = TNV, X-7 = SAR Ave, X-9= Na Ave, X10 = K Ave, X-12= Clay Ave, X-13 = Silt Ave, X-14 = B water