The use of roots to test n, p and k deficiencies in eucalyptus nutrition

Bioassays have been developed which can provide diagnostics of the nutritional status of trees. They measure the flux of N, P or Rb for K into roots from standard solutions where the rate of influx is inversely related to nutrient supply. The bioassays have been applied in the study of nutrient deficiencies in Eucalyptus grandis in both pot and field trials, and showed greater sensitivity than foliar analysis in detecting nutrient deficiencies and interactions between elements which may influence growth and wood production. The way in which these bioassays could be used as a management tool is discussed.