Nitrogen

Abstract

An experimental plot of 280 lychee trees of the three commercial cultivars grown in Israel, Mauritius, Bengal, and Floridian was planted in autumn 1978 on a sandy loessial soil in the northern Negev region. In spring 1980 an experiment was started, with four levels of N (25, 50, 75 and 100 ppm), supplied in the irrigation water as a composite liquid fertilizer: “Nutricol‐3”;.

The effect of N fertilizer on vegetative growth was examined by measuring the tree size and trunk diameter in the autumn of each year. Analyses were carried out to determine the level of various nutrient elements in the leaves.

During the four years 1980–1983, an unexpected significant effect of the fertilizer on the vegetative growth was found: the higher the fertilizer level, the smaller the height and diameter increments. It should be pointed out that all of the trees were healthy and no differences were found among the cultivars as to the effect of N level.

Key words:

• Lychee
• nitrogen fertilizer
• vegetative growth