Intercropping for the improvement of sorghum yield, soil fertility and Striga control in the subsistence agriculture region of Tigray (northern Ethiopia)

Striga hermonthica is a major biotic constraint in the dry and less fertile areas of northern Ethiopia. Emphasis is being placed on improved cropping systems to address the interrelated problems of Striga and soil fertility decline. The potential benefits of intercropping were investigated at two sites representing different environments for crop yield improvement, soil fertility maintenance and Striga control. Ten food legume and oilseed crop species were compared in inter-row arrangement with sorghum under non-fertilized conditions. In most cases, there was no significant negative impact of intercropping on sorghum growth and development. Among the intercrops, two cowpea varieties - cv. TVU 1977 OD and cv. Blackeye bean - produced the highest supplemental yield of up to 329 and 623 kg ha(-1) grain and 608 and 1173 kg ha(-1) biomass at Adibakel and Sheraro respectively. Treatment differences on Striga infestation and measured soil fertility indicators were not significant. Nevertheless, valuable grain and biomass obtained from the legume intercrops, without seriously compromising sorghum yield, could offer multiple benefits as a source of protein, additional income, feeds for animals and manure in the subsistence agriculture regions of northern Ethiopia.