Evaluation nutritional status of watermelon with deviation from optimum percentage (DOP) method in Poldasht, West Azerbaijan

Deviation from optimum percentage (DOP) can be used as an efficient method to interpret the results of plant analysis and the nutritional requirements of agricultural and horticultural crops. To determine the DOP norms and evaluation nutritional status of watermelon, leaf samples were collected from 150 fields of watermelon in west Azerbaijan; and N, P, K, Ca, Mg, Fe, Mn, Zn, Cu and B were determined. The fields were divided into high-yielding (23% of fields, ≥ 40.5 ton ha-1) and low-yielding (77% of fields; K> Mg> P> Ca for macronutrients and as Zn> Fe> B> Cu> Mn for micronutrients. Plants have high nutritional balance index (NBI) indicating relatively imbalance of absorbed nutrients by watermelon and imbalance fertilizer application in the studied fields.