Norms establishment of the Diagnosis and Recommendation Integrated System (DRIS) for nutritional diagnosis of Onion (Allium cepa L) in Western Azarbaijan Provice, Iran

Diagnosis and recommendation integrated system (DRIS) can be used as efficient methods to interpret the results of plant analysis and the nutritional diagnosis in crops and fruit trees. To establish DRIS norms in onion (Allium cepa L) leaf samples were collected from 50 fields and N, P, K, Ca, Mg, Fe, Mn, Zn, Cu and B concentrations were determined. On the bases of yield, the studied fields were divided into two groups low and high yield groups. DRIS norms were established for the different nutrient ratios. DRIS indices were calculated to evaluate nutrients balances and order of nutrients requirements. On the bases Means of DRIS indexs, the respective for requiremen of nutrients were Ca>K>P>Mg>N for macro nutrients and Cu>Mn>B>Zn>Fe for micro nutrients. Sufficiency ranges of macro and micro nutrients were derived by DRIS technique. DRIS-derived sufficiency ranges were 2.9-3.68, 0.21-0.39, 3.7-6.4, 1.38-2.6 , 0.23-0.33 % for N, P, N, Ca, Mg, and 86-154, 9-32, 44-65, 9-18, 23-35 mg/kg for Fe, Zn, Mn, Cu, B respectively. The nutrient balance index (NBI) of DRIS was much more than zero in all low-yielding farms.