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D.E. Angeles, M.E. Sumner and N.W. Barbour

Diagnosis and Recommendation Integrated System (DRIS) norms for pineapple [Ananas comosus (L.) Merr.] were developed from 1185 observations of previously published leaf nutrient composition and yield. The data were divided into high-yielding (> 60 t·ha-1, 650 observations) and low-yielding (< 60 t·ha-1, 535 observations) sub-populations and the norms derived by standard DRIS techniques. The validity of the norms was tested using independently published sets of data from factorial experiments in which yield responses to N, P, and K had been obtained. In the case of most data sets, the new DRIS norms were able to make correct diagnoses where critical values failed to make any diagnoses for N, P, and K. Thus, the DRIS approach revealed nutrient deficiencies in the range normally considered to be sufficient. Increased precision is found in the evaluation of nutrient balance in the DRIS approach, which is ignored in the case of critical values.