Development of Diagnostic Leaf Nutrient Norms and Identification of Yield Limiting Nutrients Using DRIS in Rose Grown under Protected Conditions

Leaf samples collected from protected cultivation units of rose around Bangalore (Karnataka) and Hosur (Tamil Nadu), when flower buds were at pea size, were processed and analyzed for various nutrients and thus, the data bank was established. By using Diagnosis and Recommendation Integrated System (DRIS), nutrient expressions, which have shown higher variance and lower coefflcient of variation, were selected as norms viz, N/P(13.02), K/N(0.85), N/S(11.10), P/S(0.853), K/P(11.0), N/Ca(2.18), N/Mg(7.18) etc. In addition, five nutrient ranges have been derived using mean and standard deviation as low, deficient, optimum, high and excess for each nutrient to serve as a guide for diagnostic purpose. The optimum N ranged from 2.53 to 2.96% , P from 0.19 to 0.23%, K from 2.23 to 2.72%, Ca from 1.15 to 1.59%, Mg from 0.41 to 0.55% and S from 0.21 to 0.27%. Among the micronutrients, the optimum Zn ranged from 28 to 64 ppm, Fe from 176 to 240 ppm, Mn from 107 to 175 ppm and Cu from 13 to 21 ppm for roses under protected conditions. The diagnosis of nutrient imbalance (DRIS indices) indicated that the most common yield limiting nutrients were potassium and magnesium among the macronutrients and iron and zinc among the micronutrients in protected cultivation units of rose.