An agro-ecological zone is a land resource
mapping unit, defined in terms of climate,
landform and soils, and/or land cover, and
having a specific range of potentials and
constraints for land use (FAO 1996). An agroecological
zones (AEZ) map is an essential tool
for agricultural planning. There are three regional
classification schemes of AEZ commonly used
in Rwanda. These were defined based on
differences in soils, altitude and rainfall, and as
such also show marked differences in cropping
patterns, farm size, livestock ownership
and other important household and regional
characteristics. The most used in Rwanda is that
of Clay and Dejaegher (1987), who defined five
AEZ with emphasis on agronomic and socioeconomic
homogeneity within AEZ among
farmers and their farming systems (Figure 13.1).