Implications of the rainfall climate of southern Somalia for semi-mechanized rain-fed crop production

Abstract

Ten years of climate and yield data were used to evaluate semi-mechanized rain-fed farming practices on vertisols in southern Somalia. Median rainfall totals for the main rainy season varied between 384 and 432 mm, and maize production was reasonably successful, with a rainfall water use efficiency for grain of 9 kg ha −1 mm −1. Estimated probabilities of crop failure varied between 0.1 and 0.3, and of reasonable yields between 0.5 and 0.67. The local cowpea variety proved to have a low yield potential, with a water use efficiency of only 1 kg ha −1 mm −1, but a low minimum water requirement, resulting in low yields but a low frequency of crop failure. Rainfall during the short rainy season was low and insufficient to justify cropping. Analysis of the relations of yield with current and preceding fallow rainfall indicated that fallow soil management failed to increase yields. Cumulative probabilities of planting rains did not reach 0.5 until the latter part of April which, together with the rapidly decreasing probabilities of rainfall during June, indicates that short-season maize varieties may be better adapted to the environment. The probabilities of too much rainfall hampering crop and soil management activities and causing crop waterlogging damage are sufficiently high to warrant investigations on methods of improved surface drainage.