Proposal: Critical Nutrient Ranges for Crop Diagnosis¹

Abstract

Abstract The concept of critical nutrient concentration (CNC) as a basis for diagnosing nutritional problems is well established. The CNC implies a single point on a curve that relates nutrient concentration with yield. However, a single point is difficult to establish experimentally and, in addition, the critical point may vary under different conditions. Therefore, it seems desirable to deal with a critical nutrient range (CRN) of concentration rather than with a single concentration. Critical nutrient range is defined as: that range of nutrient concentration above which we are reasonably confident the crop is amply supplied and below which we are reasonably confident the crop is deficient. If “seasonal monitoring” of crop nutrition is to be useful, CNR values must previously be established at various growth stages during the season. Data are cited to illustrate the need for the CNR approach and for seasonal monitoring of CNR values.