Nya rön om bladanalysens användning

Authors

• Hjalmar Selenius Ålands försöksstation, Jomala

DOI: https://doi.org/10.23986/afsci.71831

Abstract

This study, which is part of a more extensive investigation in resistance to drought, has through special circumstances led to a method of obtaining through leaf analysis a proportion between nitrogen and potassium which is characteristic for every species and variety. This proportion depends on the colour of the leaf, graduated according to the shade of blue-green yellow-green and dark light, which again depends on whether chlorophyll a, blue-green, or chlorophyll b, yellow-green, is the dominant substance that gives its colour to the leaves. The N/K proportion varies from about 3.20 in pine and juniper needles to about 1.00 in certain oats varieties. Analyses of samples from a combined nitrogen fertilizing and irrigation experiment with spring cereals, 1964—67, showed that irrigation as well as nitrogen fertilizing constantly increased the N/K proportion. In an experiment arranged in 1971 by spraying strawshortening substance (CCC, 4 kg/ha) on winter and spring wheat, oats and barley varieties, it was proved that this treatment, which generally brings about a changing of the colour of the leaves in the direction from yellow-green to blue-green also generates an increase in the N/K proportion.