Comparison of DRIS ratio norms of selected fruit crops

Diagnosis and recommendation integrated system (DRIS) ratio norms were developed for major fruit crops grown in peninsular India was complied and the relative ratios of different nutrient elements were compared. The mean nutrient values of different fruit crops showed wide variation for various nutrients. Thirty six nutrient expressions were compared. Based on physiological role the imbalances of certain nutrient ratios were found more important compared to others. The ratio served as guide in identification of common yield limiting nutrients of selected fruit crops in peninsular India. Among different forms of expression Zn/Ca, N/K, Fe/Ca were found more important as the deficiency of these nutrients have become more common in recent past. The ratio of K/N was widest in case of Anab-e-Shahi grape at bud differentiation stage. Overall the K/N ratio among different fruit crops showered greater uniformity when compared to P/N ratio indicating greater balance in N and K application compared to N and P application of nutrients. The wide range noticed in different ratios indicated the need for developing crop specific and region specific nutrient management strategies in fruit crops to realized high yield potential. The P/Zn ratio was as wide as from 1.023 to 14.49 indicating mutual interaction among nutrients and thereby emphasising the need for developing multivariate diagnostic norms with higher diagnostic sensitivity.