Diagnosis and recommendation integrated system (DRIS) ratio norms and identificantion of yield limiting nutrients in rose grown under open field conditons

A survey was conducted in Karnataka and Tamil Nadu where rose crop is being cultivated in a large area and collected leaf samples from 60 different gardens when flower buds were at pea size. The samples were processed and analyzed for various macro and micro 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 coefficient of variation, were selected as norms viz, P/N (0.073), N/K(1.529), N/S(15.904), S/P(0.883), Mg/K(0.178), Fe/K(82.97), Ca/Mg(2.814) etc By using mean and standard deviation, five nutrient ranges have also been derived as low, deficient, optimum, high and excess for each nutrient to serve as a guide for diagnostic purpose. The optimum N ranged from 2.23 to 2.51%, P from 0.16 to 0.19%, K from 1.51 to 1.97%, Ca from 0.76 to 1.13%, Mg from 0.27 to 0.39% and S from 0.14 to 0.17%. Among the micronutrients, the optimum Zn ranged from 26 to 36 ppm, Fe from 122 to 159 ppm and Mn from 61 to 98 ppm. The DRIS indices indicated that the most yield limiting nutrients were potassium, nitrogen and zinc uder open field cultivation of roses.