Weed control problems in Tanzania; a review team report

This report assesses Tanzanian weed control practices used by seed farms, the National Agricultural and Food Control (NAFCO) farms, selected research institutes, and small farms. The farms visited produced such crops as maize, millet, wheat, barley, and coffee. A wide range of weed control practices were noted such as the use of chemical herbicides, mulch, close ground cover through multiple cropping, and manually pulling up weeds. The most common weeds affecting crop production are Rottboellia exaltata, a grass which grows extremely tall, and Digitaria scalarum, a rhizomatous grass which, if uncontrolled, will spread until infested areas become useless for farming. The former is usually treated with herbicides, the latter by manual and mechanical means. Since there is a shortage of trained scientists specializing in weed control, it is recommended that a cadre of Tanzanian government agronomists be given university training to enable them to conduct research and provide technical advice to NAFCO and seed-farm managers. In addition, short-term training in weed control procedures and research techniques should be offered to researchers, NAFCO farm supervisors, and seed-farm managers. Periodic expatriate weed control consultation should be sought and literature on weed control should be made available to the research institutes. In view of the shortage of farm machinery, minimum tillage techniques not requiring much equipment were suggested as an effective and viable means of controlling weeds. For example, stubble planting, a method of planting directly into existing crop residues with no intervening soil disturbance, controls weeds and delays erosion. Most importantly, the role of sound farm management to determine both the proper balance between weed control methods and the correct time and rate of herbicide application is cited as necessary to establish effective weed control. Suggested references (1968-80) are attached.