Influence of cowpea and melon populations on weed infestation and farmers’ attitude to weed control practice
Small farmers in the humid regions of tropical Africa spend 30–42% of their total farm labour input in controlling weeds. Chemical weed control is normally recommended but high cost of herbicides and environmental pollution are specific problems with chemical weed control. A three year bio-weed control system with three populations of cowpea (20, 33, and 50 x 103 plants ha-1) and melon (5, 10 and 15 x 103 plants ha-1) in a cassava/maize intercrop was conducted to check weeds at 3, 5 and 8 weeks after planting (WAP) in the southeastern humid derived savanna and humid rainforest zones of Nigeria. Cowpea and melon populations at 50 x 103 and 15 x 103 plants ha-1 significantly reduced weed infestation in the cropping system. Since rural women constitute 50–60% of the farming population and are a significant source of labour in weeding operations then a weed control strategy with melon crop which provides oil and protein to farm families may be highly innovating to them. One hundred women farmers were invited to visit the research extension plot at 3, 5 and 8 WAP, before weeding. At 5 WAP, 80% of the farmers and at 8 WAP, 100% of them preferred to adopt 50 x 103 cowpea with 15 x 103 melon plants ha-1 since this combination gave the most effective weed control. Cassava grown as sole crop produced higher root yield ha-1 than when grown with maize, cowpea and melon in the three years and at both locations. Grain yield of maize was significantly depressed in the intercrop system. Cowpea grain yield increased with increase in population, but the increase per unit change in population was much higher in sole cowpea. Similarly, seed yield of melon increased significantly with increase in its population in intercropped and sole cropped melon. The highest net incomes of N83,540, N138,350 and N158,530 for 1989, 1990 and 1991 at Ogoja location and N134,000, N255,590 and N289,240 at Uyo for the respective years were obtained from a four-crop combination of 50 x 103 cowpea and 15 x 103 melon populations and with cassava and maize at 10 x 103 and 20 x 103 plants ha-1. Though sole crop of melon at 50 x 103 ha-1 gave a higher and significant seed yield, it was not profitable and sustainable to small-holder resource poor farmers.
Keywords: Cowpea, melon, weed control, economic analysis, farmers’ attitude