Full Length Research Paper
Achmad Arivin Rivaie
Abstract
Most of trials in New Zealand radiata pine (P. RADIATA) plantations were conducted on Podzol Soils and Mapua sandy loam soils. Few trials were conducted on Allophanic Soils in the country. A better understanding on change in P chemistry and tree growth due to the application of P fertiliser on an Allophanic Soil is important to determine appropriate management practice for the P fertiliser. A glasshouse trial was carried out to investigate changes in the soil available P, the P nutrition, growth of P. RADIATA seedlings, and to determine relationships of soil plant-available P with plant P on an Allophanic Soil, following the application of three rates of triple superphosphate (TSP) in a glasshouse. The results showed that the application of P fertilizer enhanced the P availability in the soils of radiata seedlings as measured by the Bray-2 P concentrations. The dry matter yield and the P concentrations in needles, stem, and roots of radiata pine increased also with increased rates of triple superphosphate application to a P-deficient Allophanic Soil. Furthermore, P concentration in the new shoot needles had significant logarithmic relationship with Bray-2 P concentration in the soil under the radiata seedlings. This curvilinear relationship suggests that the P concentration of new shoot needles diminishes with an increase in the plant-available P concentration (Bray-2 P) in this high-P fixing Allophanic Soil.