Agricultural extension - the power of knowledge in processes of change: Lessons learned and future challenges for Africa. A NORAD funded study

africa south of sahara afrique au sud du sahara agencias voluntarias agriculteur agricultores agricultural sector changement technologique condiciones rurales conditions rurales diffusion de la recherche diffusion of research evaluation extension extension activities farmers indigenous knowledge nongovernmental organizations organisation non gouvernementale organizaciones no gubernamentales privatisation privatization rural conditions secteur agricole sector agrario technological changes tendance tendencias trends voluntary agencies vulgarisation