Abstract
In a glasshouse study, early competition for nitrogen (N) was seen between the pepper (Capsicum annuum L.) and the weeds thorn apple (Datura stramonium L.) and barnyardgrass [Echinochloa crus-galli (L.) Beauv.]. This competition affected the growth and fruit yield of the pepper. Thorn apple competed more intensely with pepper than did barnyardgrass, and caused damage to the crop by earlier stages of the growth season than barnyardgrass. The presence of either weed until the 6-leaf growth stage of pepper was sufficient to reduce significantly the fresh fruit yield of the crop. The longer the weeds remained the worse were their effects on crop growth and productivity. Reduced fruit yield was more the result of reduced number of fruits rather than reduced mean fresh fruit weight. The reproductive parts of the pepper were more seriously affected by the presence of the weeds than were their vegetative parts.