Shifting Cultivation.

Shifting cultivation is one of the oldest methods of farming that developed to replace hunting and gathering. It is carried out in forested and sparsely populated areas in Africa.
Shifting cultivation is a system of growing crops on a piece of land for a period of 2-4 years and as soon as the soil loses its fertility. The field is abandoned and another land is cleared and the process continues. This system is also known as slash and burn cultivation meaning that after the vegetation is cleared, it is burnt and the ashes add fertility to the soil.
Shifting cultivation is practised by the Bemba of Zambia who call it Chitemeteme, Azande of North-eastern Congo.