Demand-Driven Technologies for Sustainable Maize ... - IITA

172It is necessary to validate that these technologies work effi cientlyunder farmer-managed conditions and are indeed appropriate forAfrican farmers (Fisher 1999). The study reported in this paper wasdesigned to evaluate the effects of one and two-year rotations withlegume trap-crops.Materials and MethodsThe trials were established on 12 Striga-infested farmers’ fi elds selectedin two neighboring villages in Kaduna State, northern Nigeria, from2001 to 2003. The fi elds are located in the northern Guinea savannazone, which is characterized by a sub-humid climate with monomodalrainfall of 900-1200 mm. Rainfall distribution extends over an annualgrowing period of 5-6 months. Total rainfall was 1322 mm in 2001,1007 mm in 2002 and 1135 mm in 2003.The following treatments were evaluated:i. cowpea-maize intercrop for three years,ii. one year of soybean followed by maize for two years,iii. one year of cowpea followed by maize for two years,iv. two years of soybean followed by one year of maize,v. two years of cowpea followed by one year of maize, andvi. continuous farmers’ practice of sole cropping of maize for three years.An improved Striga-tolerant open-pollinated maize variety (Acr. 97TZL Comp1-W), an Alectra-tolerant, high N-fi xing soybean variety(TGX1448-2E) and an early maturing cowpea variety (IT 93K 452-1)were used in the study. The two legume varieties have been foundto cause suicidal germination of Striga in screen house experiments(Berner et al. 1996).The trials were successfully established on eight farmers’ fi elds atUngwa Shamaki and four at Tashan Kaya. Each farm with the six plotsconstituted a replicate. The gross plot size was 400 m 2 and the net sizewas 340 m 2 . In 2001, each crop was planted on ridges as a sole cropexcept for the maize-cowpea intercrop. Maize was sown at 3 plants hill -1at a spacing of 75 x 50 cm. Two weeks after sowing (WAS), the maizewas thinned to two plants per stand. Soybean was drilled at a spacingof 5 cm on ridges 75 cm, apart. In the sole cowpea, two seeds wereplanted on ridges at a spacing of 75 x 25 cm without thinning but in theintercrop one stand of cowpea was planted between two maize stands.The fi eld operations performed in 2001 were all repeated in 2002 and2003. All crops were hoe weeded at 3 and 6 WAS followed by a carefulhand-pulling of weeds other than Striga. Fertilizer was applied to maizeat the recommended rate of 100 kg N ha -1 , 40 kg P 2O 5ha -1 and 50kg K 2O ha -1 using NPK (15:15:15) and urea. The nitrogen fertilizer was