Mineral nutrition of slash pine in subtropical Australia. II. foliar nutrient response to fertilization

Abstract

In the previous paper, we reported the stand growth of slash pine (Pinus elliottii) during the first 11.5 years of plantation in response to (1) initial fertilization at plantation establishment with P rates of 11, 22, 45 and 90 kg P ha⁻¹ which were either banded or broadcast in the presence or absence of basal fertilizers containing 50 kg N ha⁻¹, 50 kg K ha⁻¹ and 5 kg Cu ha⁻¹ and (2) application of additional 40 kg P ha⁻¹ at age 10 years. Here we present the responses in foliar nutrient concentrations of slash pine in the first 11.5 years to the initial fertilization and the additional P applied at age 10 years.

Foliar N and K concentrations in the first 9.6 years of plantation decreased with the initial P rate. Application of the basal fertilizers improved foliar Cu concentration. Foliar Ca and Mg concentrations increased linearly with the initial P rate. The initial fertilization did not affect foliar Mn concentration in the first 9.6 years. Foliar P concentration increased quadratically with the initial P rate, which accounted for 77–86% of the variation in foliar P concentration. Most of the explained variation in foliar nutrient concentrations was attributable to the plantation age except for foliar P concentration. In the case of foliar P concentration, 53% was explained by the initial P rate, 31% by the plantation age and 2% by the positive interaction between the initial P rate and the plantation age. Foliar P concentration of slash pine at age 11.5 years increased quadratically with the initial P rate and linearly with the additional 40 kg P ha⁻¹ applied at age 10 years, accounting for 81% of the variation in the foliar P concentration. Foliar nutrient analysis indicated that P was the major limiting nutrient affecting the stand growth of slash pine in the first 11.5 years.