In Sub-Saharan Africa, the bulk of agricultural output is produced by small holder farmers who continue to depend on rainfall. As such, agricultural economists often use average rainfall as a summative environmental indicator in estimating agricultural production function. This methodology is flawed. A close scrutiny of agricultural practices /agronomic sciences reveals that agricultural output is more determined by rainfall distribution than average rainfall. This relationship is explored in the Togolese context. The conclusion reached is that, between 1965 and 1992, intra-annual rainfall distribution measured by its standard of deviation has not been relevant in explaining the variation of food production in Togo due to the continuous degradation of the ecosystems. This result provides additional information for improved decision making and calls for urgent account of environmental aspects in the formulation of sustainable agricultural policies in SSA.