DRIS Approach for Evaluating N, P, K, Ca and Mg Requirement of Sunflower (Helianthus annus)

The Dignosis and Recommendation Integrated System (DRIS) approach was used for foliar diagnosis of N, P, K, Ca and Mg in sunflower. DRIS assessed the nutrient balance in plant tissues and identified not only the most limiting nutrient, but also the order in which the other nutrient become limiting, The DRIS indices elucidate that on the basis of most required nutrient element 54.8, 0.4, 11.5 and 35.0 per cent of the total sunflower area surveyed in Punjab are suffering from the inadequacy of N, P, K and Mg, respectively. The results also show that DRIS indices for N, P and K can be used irrespective of position of leaf sampled, time of leaf sampling and type of cultivar of sunflower plant. According to DRIS indices, the order of secondary nutrient for Ca > Mg was consistent for different leaf positions at bud formation stage, but their order of requirement was inconsistent if taken along with macronutrients as well as for leaf position sampled at full bloom stage.