The content of mineral elements in the leaves of the olive cv. Koroneiki in relation to irrigation and the time of sampling

The changes in the content of P, K, Ca, Mg, B, Mn, Fe and total N in the leaves of irrigated and non irrigated trees of the Koroneiki olive cv, in the course of the yearly growth cycle, were studied in the experimental orchard of the Subtropical Plants and Olive Trees Institute of Chania at Chrisopigi for three successive years. A small but statistically significant increase of the average, i.e. over all samples, content of total N was found in the leaves of irrigated trees. during the first and the third year. In September when N content in the leaves was at minimum for all treatments, the drop in N-content tended to be more pronounced in the dry treatment. Of the other mineral elements the content of P, K, and Mn was distinctly higher in the leaves of irrigated trees whereas the increase in Ca % caused by irrigation was consistent but rather small. Boron and iron were the elements less affected by irrigation while magnesium was the only element which had a higher percentage in the leaves of the non irrigated trees. In winter, when soil moisture is restored to satisfactory levels, the content of mineral elements in the leaves of the "dry" treatment continued to be lower than in the ones which had water during summer, with Mg which was constantly higher in the non irrigated trees being again the only exception.