The environments represented by agro ecological zones are often associated with distinct farming systems and land-use and settlement patterns. Maps of agro ecological zones have been used in many countries for different agricultural planning applications ranging from the physical location of research stations; the introduction of particular crops, cultivars and technologies to suit the conditions in different areas; the allocation of water resources to agriculture; fertilizer recommendations; policies and regulations for rural land use; inputs and technology subsidies; and others. These applications illustrate the attractiveness of the AEZ concept to planners and decision-makers of different stripes and colours: the bird’s-eye view of agricultural potential and constraints offered by integrating the key components of the agricultural environments is much easier to understand than a stack of single-theme maps.