Paper presented at the 19th 1UFRO World Congress, August 1990, Montreal, Canada

The Influence of Site Factors on the Foliar Nutrient Content of Eucalyptus grandis in Natal

Published in: South African Forestry Journal
Volume 156, issue 1, 1991 , pages: 28–34
DOI: 10.1080/00382167.1991.9629084
Author(s): M.A. HerbertInstitute for Commercial Forestry Research, South Africa

Abstract

Although foliar analysis is commonly used to diagnose the nutritional status of trees and their ability to respond to fertilising, it is also a measure of site type and quality. The availability of nutrients in the soil varies with climatic and biotic as well as edaphic factors, while uptake by the plant may depend on more than the nutrient status of the soil. This paper examines the foliar nutrient concentrations of Eucalyptus grandis as expressions of climatic and edaphic factors for a wide range of sites, in order to test and quantify these relationships. Preliminary results show foliar nutrients to be strongly correlated to topsoil organic carbon, extractable P, exchangeable Ca, Mg, K, exchangeable acidity and pH. Highly significant multiple regressions accounted for 78 to 96 % of the variation in foliar nutrients. Climatic factors were correlated with fewer foliar nutrients, the most important variable being temperature, which in turn was correlated with topsoil organic carbon. There is a need to stratify sites for relational site factor studies possibly on the basis of organic carbon content and exchangeable acidity and develop separate foliar norms for E. grandis on different site types.

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