Site classification of commercial eucalypt plantations in the Congo. Use of layer depths and microelement deficiencies as productivity indices

Abstract

Since 1978, 42,000 lia of clonal eucalypt plantations have been established in the Pointe-Noire region for pulp production. l'lie soils are sandy, acidic, very poor in reserves of available nutrients, and the benefît of applying NPK to the plantations has been shown. However, despite NPK fertilization, marked différences of production (10--) 25 m' ha" year-1 at the end of stand rotation) can bc observed between sites with comparable soil characteristics: texture, pli, some of cations, cation exchange capacity, phosphorus, total carbon and total nitrogen. So, a need of relevant site classification indices exists and has conducted to set up a pot experimentation in order to assess, in particular, macroelement deficiencies. (Résumé d'auteur