Effect of maize intercrop plant densities on yield and β-carotene contents of orange-fleshed sweetpotatoes

Abstract

Despite efforts to demonstrate the value of orange-fleshed sweetpotato (OFSP) (Ipomoea batatas L.) and quality protein maize (Zea mays L.) in combating vitamin A and protein malnutrition, small land holdings by rural poor farmers still limit the crops’ overall production in Africa. As such, intercropping and optimum plant density in cropping systems will help farmers to improve productivity of the crop, and hence, improve household food and nutrition security. This study determined the effect of maize plant population, in a sweetpotato-maize intercrop, on yields and β-carotene content of two popular OFSP cultivars, Ejumula and NASPOT 9 O (Kabode). Each variety was intercropped with maize variety Longe 5, at three plant densities (i.e. 41,666, 55,555 and 88,888 plants ha^-1), at Ngetta Zonal Agricultural Research and Development Institute in Uganda. While 55,555 plants of each OFSP cultivar were used for both sole and intercrops, the sole maize plot was 44,444 plants ha^-1. Maize and sweetpotato were harvested at 120 and 135 days after planting, respectively. β-carotene content and yield in sweetpotato roots were significantly (P<0.05) reduced by high maize density. Irrespective of maize density, NASPOT 9 O produced more root yields than Ejumula. Land Equivalent Ratios of >1.2 were obtained at maize intercrop densities of 41,666 and 55,555 plants ha^-1.

Keywords: Ipomoea batatas, land equivalent ratio, Zea mays