Sustainable agricultural development requires a systematic effort towards the
planning of land use activities in the most appropriate way, apart from
several other institutional and policy programmme initiatives. Agro-ecological
zoning (AEZ) is one of the most important bases for agricultural developmental
planning because survival and failure of particular land use or farming system
in a given region heavily relies on careful assessment of agro-climatic resources.
A practical zoning approach thus arises because climate represented by thermal
and moisture regimes forms small geographic areas, resulting in a variable
mosaic of specialized areas, capable of supporting varied land use systems (Troll,
1965). The approach is used to categorize agroclimatically uniform geographical areas for agricultural developmental planning and other
interventions. A framework of agro-ecological zoning describing concepts,
methods and procedures was conceptualized for the first time by FAO (1976).
Agro-ecological zoning refers to the division of an area of land into land
resource mapping units, having unique combination of landform, soil and
climatic characteristics and or land cover having a specific range of potentials
and constraints for land use (FAO, 1996). The particular parameters used in
the definition focus attention on the climatic and edaphic requirements of
crop and on the management systems under which the crops are grown. Each
zone has a similar combination of constraints and potentials for land use and
serves as a focus for the targeting of recommendations designed to improve
the existing land use situation, either through increasing production or by
limiting land degradation. The addition of further layers of information on
such factors as land tenure, land availability, nutritional requirement of human
and livestock populations, infrastructure and costs and prices, has enabled the
development of more advanced applications in natural resource analysis and
land use planning. AEZ can be regarded as a set of core applications, leading
to an assessment of land suitability and potential productivity. An output of
AEZ studies includes maps showing agro-ecological zones and land suitability,
quantitative estimates on potential crop yields and production. Such
information provides the basis for advanced applications such as land
degradation assessment, livestock productivity modeling, population support
capacity assessment and land use optimization modeling