Mango leaf analysis survey report 1995/96: laboratory variation, and relationship between leaf nutrient concentration, and fruit yield and quality.
McKenzie C. B.
Author Affiliation: Merensky Technological Services, P.O. Box 14, Duivelskloof 0835, South Africa.
Yearbook - South African Mango Growers' Association 16 : 36-48
Abstract : The survey method was used to determine optimum leaf norms for mango export production in South Africa. Cultivars Sensation and Kent were surveyed for the second season, while Tommy Atkins, Heidi and Keitt were included for the first time. To verify picking dates within November, and to test 2 laboratories, preliminary trials were carried out. Time of sampling within the November period did not appear to be critical for N, Ca, B or Zn. Evidence suggested November was a poor time for K and Mg analysis. Analysis for all elements except N appeared to be reasonably precise. Large variation in N analysis was a problem, as of all the elements, it is the one for which the greatest accuracy and precision is required. Although in its early stages, the survey suggested that N should be kept at the lower end of the norm range for good background skin colour development, except for Heidi where higher levels were acceptable. Concentrations of N, K, Ca and Mg well below industry norms in all cultivars did not appear to have a detrimental effect on yield or quality. Leaf P, Zn and B did not relate well to yield or quality.