Studies on the leaf nutrient standards in kinnow

Sand culture studies were carried out to develop the deficiencies of single nutrient elements in Kinnow. The treatments included the plants grown on complete nutrients solution and single omission or restriction of N, P, K, S, Zn, Fe, Mn and Cu from the culture. The mature leaves from the middle of shoots were analysed for nutrients when deficiency symptoms just started, and when deficiency symptoms developed fully. The nutrients levels in the plants receiving complete solution have been designated as ‘optimum’ and the ones below the levels when deficiency symptoms started to appear as ‘deficient’. Thus, the optimum levels were 2.8, 0.15, 1.57, 0.33 per cent; 62, 103, 38 and 10 ppm for N, P, K, S, Zn, Fe, Mn and Cu, respectively. The deficient level for the respective element was below 2.30, 0.09, 0.72, 0.17 per cent and 19, 61, 21 and 4 ppm. The leaves of severely N-deficient plants contained the highest levels of P (0.32%), K (2.98%), S (0.56%) and Zn (86.3 ppm). Similarly, the leaves of S-starved pints had the highest concentration of N (5.07%). K deficient Kinnow plants had accumulated N, Sand Mn in their leaves. The nutrient deficiencies also adversely affected the growth of plants.