Evaluation of Nutritional Balance for Grape Orchards of Sisakht Region in Kohgiluyeh-Va-Boyerahmad Province by Deviation from Optimum Percentage Method

Nutritional balance is an important factor in improving the yield and quality of horticultural products. Leaf analysis is a suitable method for determining the nutritional status of orchards. The method of deviation from optimum percentage(DOP) is a new and easy method with regard to the interpretation of leaf analysis as compared to other methods. In this method ,an index for individual nutrients is calculated by the equation: DOP=[( C× 100)/Cref ]-100. In this equation, (DOP) is the desired index for a given nutrient, C is the leaf concentration of the nutrient in question, and Cref is the desired concentration of that nutrient as found in high performing plant samples. In this study, soil and leaf samples were taken from 40 orchards and analyzed by standard methods. The optimal concentrations of nitrogen, phosphorus, potassium, calcium and magnesium in grape leaf were determined to be 5.05% , 0.7%, 1.42%, 1.7% and 0.4%, respectively, and for iron, manganese, zinc, copper and boron were 206.5, 110.3, 61.5, 14.6 and 33.9 mg/kg, while the DOP indices, for low yielding orchards, calculated, similarly showed that nutritional elements were imbalanced; more specifically iron, manganese, copper, potassium, zinc and boron deficiencies were prevalent in 91, 82, 82, 67, 59 and 54.5 percent of low yielding grape orchards, respectively.