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

174Table 2. Effects of previous crops on plant population, Striga infestationand incidence, crop damage severity, and grain yield of maizein two villages in northern Nigeria (2002).CroppingsystemsMaizePlant ha -1at 12 WASStriganumberha -1 at 12WASNumber ofmaize plantsinfested ha -1at 12 WASCropdamageseverity*Grainyield(kg ha -1 )Sole maize 21,433c** 1191a 343a 4.08a 1147.6bMaize after 22,954ab 772b 272b 3.50b 1468.4asoybeanMaize after 23988a 1025ab 431ab 3.67b 1384.0acowpeaMaizecowpeaintercrop22513bc 375b 202b 4.17a 782.5cWAS = weeks after sowing.* = Crop damage severity using a scale of 1 - 9, where 1 = healthy plants and 9 = completely dead plants.**Means followed by the same letter(s) within a column are not signifi cantly different at0.05 level of probability (DMRT).Effects of one-year of rotation and intercropping on Striga andmaize in 2002In 2002, plant population at harvest was generally lower than optimalfor all treatments. This is because farmers rushed and planted theircrops with the fi rst rains, which stopped abruptly, resulting in droughtconditions in the early part of the season. The drought caused poorcrop establishment and a lot of missing stands. The overall effectwas relatively low plant population densities. Maize grown aftersoybean and cowpea had similar and higher plant populations thanthe intercropped and continuously cropped maize. The numberof emerged Striga plants was signifi cantly higher in continuouslycropped maize than in maize after soybean, maize after cowpea andintercropped maize (Table 2).Striga incidence was lowered by 218% in intercropped maize,54% in maize after soybean and 16% in maize after cowpea thanin the farmers’ practice of continuous sole cropping of maize for twoyears. Crop damage severity was similar and higher in continuouslycropped and intercropped maize than in maize after soybean andmaize after cowpea. Maize after soybean and maize after cowpeahad higher grain yield than the intercropped and continuously solecropped maize. Maize grain yield was 28% higher after soybeanand 21% higher after cowpea than after the farmers’ practice ofcontinuous sole cropping of maize for two years. Continuouslycropped maize produced 47% higher grain yield than the intercroppedmaize (Table 2).