WEED MANAGEMENT-SYSTEMS BASED ON ANIMAL-DRAWN CULTIVATORS FOR MAIZE PRODUCTION IN THE SOUTHERN HIGHLANDS OF TANZANIA

Experiments on weed management techniques for maize production were ca rried out at the Uyole Agricultural Centre and on farmers' fields in M bozi district, Tanzania, using the inter-row cultivator (Cossul), over -the-row cultivator (MOP) and hand-weeding. There were no significant differences in field capacities between the two cultivators, although the MOP cultivator tended to have slightly higher capacities. Field ca pacities tended to be higher when the maize was 45 cm high. The use of cultivators alone reduced labour inputs for weeding by 80%, and the u se of cultivators combined with hand-weeding reduced labour by 40%, co mpared with hand-weeding alone. Hand-weeding alone, or in combination with cultivator weeding gave the best control of weeds, and similar hi gh maize yields (5 t ha-1 compared with 2 t ha-1 with no weeding). The use of cultivators alone gave significantly poorer weed control and a yield of 3.3 t ha-1. The use of cultivators plus within-row hand-weed ing gave marginal rates of return greater than 1.0, indicating a reaso nable return on the investment in labour. The results emphasize the im portance of weeding for higher maize yields in the Southern Highlands of Tanzania. Higher yields can be obtained by manual weeding alone but at the cost of high labour inputs, representing high levels of family drudgery or high labour hiring costs. Those farmers who have access t o ox-drawn systems are advised to arrange additional within-row manual weeding to ensure higher yields. Ox-drawn cultivators alone for weedi ng are only suitable for situations where labour is scarce.