Investigation of optimal economic water/land ration in pistachio producing areas in Anar and Rafsanjan Townships.

Determination of economic optimal of water/land ratio in different conditions is too important, in management and policy making areas. In this study, this ratio was determined in pistachio producing areas of Anar and Rafsanjan cities. Using stratified random sampling method, a sample of 100 farmers was selected. As, more than 1 orchard were considered for each farmer, final sample size was 286. Water/land ratio was determined in two different conditions. The results showed that, in the first assumption, when there is enough water, using more water, pistachio yield can be increased twofold in the study area. But, this assumption is unreal and there is not unlimited water in district. In contrast, water is scarce and pistachio orchards are abundant in relation to water. Thus, in second assumption, water is considered limited and pistachio orchards were considered unlimited. In this condition, optimal consumption of water was estimated 8468 cubic meter per hectare per year. Investigation of water/land ratio frequency among farmers showed that some of them use more than and some less than optimal. Pistachio producers who use less than optimal ratio (44 percent) are able to increase their profit by increasing water/land ratio. In contrast, farmers who used water more than optimal ratio can decrease water/land ratio to optimal point in condition which water is unlimited (19200 cubic meters per hectare per year). They can do this by eliminating water surplus and switching off their pumps and so enhance their profit per hectare by decrising pumping costs and increasing water productivity. In this study, in addition to pistachio yield, other germination and reproduction characteristics such as shoot length and thickness, the number of germination and reproductive buds, and the ratio of lost buds to total buds were considered as dependent variables. In other words, when it is not possible to estimate pistachio yield, optimal consumption of water is determined by using germination and reproduction characteristics. At last, a production function was estimated in which pistachio yield was dependent variable and independent variables were germination factors. This production function can be used for determination of pistachio yield, using germination factors every time during the year. So, using this function, without estimating yield, optimal water/land ratio can be calculated and surplus orchards can be determined. Thus, it is recommended that these functions are formulated as a computer package and introduced to responsible persons.