Square root and quadratic equations for the study of leaf diagnosis in wheat

Abstract

Difficulties in the use of diagnosis in annual plants have led the authors to explore the quadratic and square‐root functions as models for nutritional status in wheat. These equations were chosen to explain more readily the physiological aspects that lie behind the relationship between nutrient content and yield. Ninety‐one equations were fitted using the results from five sets of experiments. In all equations x‐values were the mineral concentrations in the leafs and y‐values the dry weight of leaves, grain or aboveground matter. Although both equations represent the relationship well, the square‐root function is considered more suitable because its asymmetry reflects the observed behavior of growth with respect to nutrition.