The application of radio-isotope techniques to fertiliser placement studies in oilpalm cultivation.

Abstract

Pot experiments using Ca(H₂PO₄)₂ labelled with Ca⁴⁵ and P³² showed the content of these nutrients to be highest in the younger leaves and the uptake to be higher from surface application than from placement to 10-20 cm. Field experiments in nurseries and young and adult plantations indicated that the optimal distance of fertilizer application is close to the stem inside the crown diameter of 1-year-old palms, close to the stem or at crown diameter of 2-year-old palms, and at the crown diameter of 3-4-year-old palms; there was no optimal distance for older plantations, though application close to the stem inside the clean-weeded ring was the least favourable. Foliar application resulted in rapid uptake of P, but in less total uptake than from soil applications; difference in the solubility of phosphate had very little effect on P uptake. Since dry periods considerably decrease the P uptake in nurseries and 1-2-year-old plantations, fertilizers to young palms should preferably be applied during the rainy season. (Abstract retrieved from CAB Abstracts by CABI’s permission)