Nutrient Diagnosis of ‘Valencia’ Oranges by DRIS

Abstract

Abstract Reference values were derived from field data for use in evaluating the N, P, K, Ca, and Mg status of ‘Valencia’ orange ( Citrus sinensis [L.] Osbeck) trees by the Diagnosis and Recommendation Integrated System (DRIS). DRIS diagnoses generally agreed with diagnoses made by the sufficiency range method, with the advantage that DRIS reflects nutrient balance, and identifies the order in which nutrients are likely to become limiting. DRIS diagnoses were affected by the type and age of the tissue sampled. DRIS reflected changes in nutrient concentrations due to alternate bearing or crop load effects and agreed with the sufficiency range method when concentration changes were sufficient to affect the latter method.