A simple agro-ecological zonation for fertilizer recommendations in Mozambique

A practical and simple agro-ecological zonation of Mozambique is presented to facilitate the identification of production conditions and to serve as a basis for agricultural recommendations. The zonation is based on: FAO Major Soil Groupings, altitude and mean annual rainfall. The rationale of the zonation is evaluated by correlating these criteria with other climatic variables and the maize growth cycle. The effectiveness of the zonation was tested with maize yield data from fertilizer trials. The results show that FAO Major Soil Groupings explain a significant part of the total variation in N and organic C contents, Olsen P, exchangeable K, pH and CEC. Altitude relates significantly with temperature, maize growth cycle, radiation and rainfall reliability. Mean annual rainfall relates significantly with rainfall reliability and radiation. Grouping the maize fertilizer trials according to the zonation criteria explained 39% of the variation in unfertilized yields and yield responses to NPK fertilization, and 51% of the variation in fertilized (NPK) yields. The agro-ecological zonation on the basis of soil, altitude and mean annual rainfall proved to be a sound and practical way to identify land areas sufficiently homogeneous to be served by the same fertilizer recommendation.