Effets des jacheres a Acacia mangium, auriculiformis et Chromolaena odorata sur la fertilite du sol et les redements de l'igname ( Dioscorea SPP.) en zone forestiere de C&#244te d'Ivoire

Abstract

An agroforestry trial, using legume trees for fallow improvement, was conducted from 1990 to 1993 at the CNRA experimental Station of Oume, in the semi-deciduous forest zone of Cote d'Ivoire. The study aimed at characterizing changes in soil fertility induced by 1-year-old fallows (Acacia mangium, Acacia auriculiformis and Chromolaena odorata) and to show the effects of these legumes on post-fallow crop yields. After field clearing and cultivation, yam (Dioscorea alata) yields were obtained from tubers. The results showed that one-year old fallows did not result in significant rise in soil chemical parameters, except for a slight increase in cation exchange capacity under A. mangium. However, yields showed the superiority of A. mangium (8.83 tonnes/ha) and A. auriculiformis (5.22 tonnes/ha) over Chromolaena odorata fallows (2.67 tonnes/ha). In spite of important potentials, the legume tree fallows required more time to improve soil fertility status.