The Africa Soil Health Consortium (ASHC), managed by CABI, produces extension material for growers in Africa. ASHC published a guide to integrated soil fertility management, written by a team of experienced soil scientists and agronomists and edited by Thomas Fairhurst. You can download it here.
ASHC produced a field guide that provides details of coffee banana cropping methods. The guide outlines good agricultural practices that promote integrated soil fertility management. You can download it here.
There are many other extension materials available on the project materials archive.