Diagnosis and Recommendation Integrated System (DRIS) Approach for Diagnosing the Nutrient Status of Kinnow Fruit Trees

The Diagnosis and Recommendation Integrated System (DRIS), which uses nutrient indices as indicator of nutrient deficiency was used to evaluate macro-and micro-nutrients status of kinnow hybrid fruit trees. The DRIS norms were computed from 471 sets of data on leaf mineral composition and corresponding fruit yield collected from 87 kinnow fruit orchards of submontaneous areas of Punjab, N-W India. The data were divided into two sub-populations on the basic yield: sub-population B in which yield exceeded >200 fruit number per plant, and sub-population A in yield lower than <200 fruit number per plant. The mean concentration of 2.38, 0.107, 0.901, 3.747, 0.444 per cent and 20, 6.8, 40 and 28.6 ppm for N, P, K, Ca, Mg, and Zn, Cu, Fe, and Mn, respectively in the leaf tissues of high yield population of kinnow fruit trees were taken as the DRIS norms to compute DRIS indices by computer DRISPB program. The DRIS approach assessed the nutrient balance in plant tissues and identified not only the most limiting but also the order in which the other element would become limiting. The DRIS approach can be used to measure nutrient status of kinnow fruit trees irrespective of position of leaf tissue sampled. The DRIS indices computed from the mineral composition of leaf tissues data showing single nutrient deficiency symptoms of N, P, K, Zn, Co and Mn inferred that DRIS approach can be effectively employed to diagnose nutrient deficiency in kinnow fruit trees in different orchards. On the basis of DRIS indices, 7, 21, 15, 20, 20, 16 and 5 per cent of total samples of kinnow collected from different regions of Punjab were found to be inadequate in N, P, K, Mg, Zn, Cu and Mn, respectively.