Abstract:
Experiments were conducted at Serere Agricultural and Animal Production Research Institute
(SAARI) in 1996 and 1997 to determine the time of initiation and number of cultivations to
optimise returns and the cost of weed control. Weeding was started either early (30 days after
planting, (dap)) or late (45 dap). In both cases, plots were cultivated four times at fortnightly
intervals but where cultivation was initiated early, some treatments were cultivated five or six
times. The herbicide (Tomen) was also tested. Reduced weeding from both late initiation and
reduced number of cultivations reduced plant height, numbers of branches, fruiting positions,
number of bolls and seed cotton yields. Weeding costs increased with higher number of
cultivations but was optimized with early initiation and five cultivations. Non-weeded controls
gave no yield while Tomen was ineffective against some dicotyledonous weeds species.