Leaf Diagnosis and the Interpretation of Fertilizer Requirements of Plants

Abstract
The principles proclaimed by Lagatu and Maume during the course of study of the physiology and metabolism of the apple were tested. Dwarf apple trees were grown in pure quartz sand cultures and were supplied with nutrient solutions containing a constant and optimal concentration of P, N, and K. At appropriate periods, leaves and twigs were analysed for total N and K. Total omission of either N or K in no instance resulted in an increased K or N content of leaves. With a decrease of N in the nutrient medium there was a decrease in K concentration of the leaves and with a decrease in K there was a decrease of N. The relative concentration of N and K in twigs was exactly of the same order but of different magnitude.