EFFECTS OF PHOSPHORUS APPLICATION ON PRODUCTTVITY AND NUTRIENT ACCUMULATION OF A EUCALYPTUS UROPHYLLA PLANTATION

Abstract

Application of superphosphate at establishment as basal fertilizer increased tree growth and survival of Eucalyptus urophylla in a 4.5-year-old trial near
Gaoyao, Guangdong, China. It also increased P and N concentrations in young fully expanded leaves at one year and biomass in all tree components. The addition of 20, 50 and 200 kg P ha^-1 increased stand volume by five to seven times of the mean annual increment of trees without P. The more P applied, the higher the percentage of stemwood and the lower the relative allocation of biomass belowground. The low P concentrations in leaves and roots at 20 kg P ha^-1 at year 4.5 suggested the withdrawal of P from the biomass, through internal cycling. The addition of P increased N, P, K Ca and Mg uptake. The 200 kg P ha^-1 treatment was optimal both for wood chip production and economic return.