Effects of variety, crop arrangement and period of weed interference on the performance of maize grown in mixture in northern guinea savannah of Nigeria

Field trials on the effects of variety, crop arrangement and period of weed interference on the performance of maize grown in mixture were conducted at the Institute for Agricultural Research farm, Samaru (11011 N; 07038' E and 686m above sea level) in the Northern Guinea Savanna ecological Zone of Nigeria during the wet season of 2000 and 2001. Extra early maize TZEE-W was used as test crop, two cowpea varieties (Kanannado and Sampea 7): two crop arrangements (alternate row and alternate stand arrangements) and ten periods of weed interference (weed free till 3, 6, 9, 12 weeks after sowing (WAS) and harvest and a corresponding set that were kept initially weed infested till 3,6,9,12 WAS and harvest. Two treatments were left weed free or weed infested throughout the crop life cycle. The treatments were evaluated in a split-plot design with varieties and crop arrangements allotted to main plot and period of weed interference to sub-plot. Varieties, crops arrangement and period of weed interference had significant effect on weed growth and yield parameters of maize. Maize grown in mixture with Kanannado gave lower weed dry matter (WDM), higher crop vigour score (CVS), higher grain yield and 100-grain weight. Maize in alternate row arrangement performs better than maize in alternate stand arrangement. Keeping the crop weed free till 6 WAS and beyond gave better crop performance.