Nutrient composition and seasonal losses of avocado trees.

Abstract

SUMMARY Data are reported for the dry weight and nutrient element content of a bearing, sevenyear-old Mexican seedling avocado tree, for amounts of nutrients translocated from the leaves of Fuerte trees before abscission, and for the amounts of dry matter and nutrient elements lost in abscised leaves and blossoms by two thirteen-year-old Fuerte trees during a two-year period. The data indicate that half or more of the nitrogen and phosphorus and substantial amounts of potassium, magnesium and sulfur are returned to the tree from the leaves prior to leaf abscission. Losses of dry matter and nutrient elements approximately equivalent to 25 per cent of the dry weight of the tree, 40 per cent of the nitrogen, phosphorus and potassium, 60 per cent of the calcium, and 75 per cent of the magnesium may occur each year in the blossoms and leaves that are abscised by an avocado tree. The relationships between these translocations and losses and the number and nutrient composition of the blossoms and the effects on tree growth are discussed.