Integrated weed management systems in sorghum based cropping system in Nigeria

Sorghum (Sorghum bicolor (L) Moench) is the fifth most important staple food crop after wheat, rice, maize and barley. Sorghum is consumed by more than 70% of the population. Striga hermonthica is a serious biotic constraint to cereal production in the dry savannas of sub-Saharan Africa. Striga infestation in sorghum is reported to be higher in Nigeria than in other West African countries with about 80% (8.7 million ha) of land cropped to sorghum infested by this weed. Field trials were conducted in 2012 and 2013 to evaluate the effect of seed treatment, sowing date and trap crop in the management of S. hermonthica. During the investigation in two sorghum (resistance and susceptible) which involved intercropping with soyabean, seedtreatment with parkia biglobosa pulp and sowing at different dates (June and July), these were found to reduce the infestation of sorghum by S. hermonthica. The results showed that the effect of shading by soyabean, putative allelopathic mechanism effect of parkia material and high relative humidity due to established rainfall in July showed some benefits against S. hermonthica infestation. Growth of S. hermonthica was almost completely suppressed and yield increased with the resistant sorghum intercropped with soyabean, primed at 66 g/L parkia and planted in July. Key words: Shading, soyabean, allelopathy, Parkia pulp, sorghum, Striga.