A Simple and Rapid Test, Using the Ninhydrin Method, For the Determination of The Nitrogen Status of Fruit Trees

Abstract

AbstractShoots, stem bark and roots from 13 fertilizer trials on apple, peach and orange trees growing in commercial orchards in Victoria (Australia) were sampled during winter and their content of free amino-nitrogen determined by a simple colorimetric ninhydrin method.The values thus obtained from trees growing under different levels of nitrogen showed wider differences than those obtained by conventional leaf analysis for total N. The largest differences in nitrogen levels were present in the roots rather than in the above-ground parts of the trees sampled.The ninhydrin method is simple and rapid and can be carried out during winter on root or bark pieces in advance of the normal time of applying fertilizers.