Eucalypt dieback and nutritional management of plantation forest: physiological aspects

Abstract

In order to investigate the effects of P and Ca under water stress conditions on the development of die-back symptoms, seedlings of eucalypt were cultivated in soils fertilized with P and Ca and submitted to water stress. The increase of Ca and P in the medium with a simultaneous water deficit caused a decrease in stomatal resistance and an increase in the P content of the plants. An increase in the levels of P and Ca in the soil caused significant increases in leaf area and the accumulation of total dry matter effects, that were overriden by the water deficit. In general, P concentrations were higher in stressed plants; the opposite was observed for Ca, which was found to be higher in irrigated plants. It could be concluded that the development of die-back symptoms was more closely associated with high P doses and water stress than with Ca doses.