Determination of optimum leaf nutrient concentration norms for a number of mango cultivars: year I.
Oosthuyse S. A.
Author Affiliation: HortResearch SA, P.O. Box 3849, Tzaneen 0850, South Africa.
Yearbook - South African Mango Growers' Association 18 : 1-5
Abstract : Spot leaf norms were determined from groups of mango trees situated at various locations in the Northern Province of South Africa. Some of the orchards in which the tree-groups were selected have a history of producing fruits of superior quality. The cultivars Zill, Tommy Atkins, Sensation, Heidi, Kent and Keitt were included. In November, leaf samples were taken from each tree for nutrient analysis. After harvesting, ripening and evaluating fruits from each tree, a tree quality index (TQI), based on consumer preference with respect to fruit attributes, was determined for each tree. The trees producing fruits of superior quality were identified. The spot leaf norm was taken as the concentration of a particular nutrient occurring with the greatest frequency in the superior trees. The procedure was independently followed in two tree-sets (each comprising a number of tree groups). In most instances, the difference between the spot norms determined for a particular nutrient was small in terms of the norm-ranges generally declared. TQI and fruit retention or tree yield were always positively correlated.