Select a suitable site that is not on a slope, waterlogged, stony or very shallow.
If the vegetation is an older fallow with trees, shrubs and broadleaves; and too tall to go over with a sprayer, slash the vegetation and plough. If the vegetation is a grass fallow with perennial weeds such as Speargrass, Guinea Grass, Siam Weed, Sensitive Plant or Giant Potato; and too tall to go over with a sprayer, slash the vegetation and wait for two weeks to allow regrowth.
Apply glyphosate (for example RoundUp Turbo, TouchDown Forte) at label rate to deal with the grass regrowing from the slashed grass fallow. Glyphosate should also be applied on a field if it has little vegetation (less than 1 meter tall) with perennial weeds. Thereafter, wait for 14 days to allow total kill by glyphosate.
Tillage operations result in higher cassava yields on productive fields. Ploughing generally increases root yield by at least 5 tonnes per ha. Only invest in ploughing if the revenue expected from 5 tonnes of cassava exceeds the cost of ploughing 1 ha of land. Ridging increases root yield by at least 4 tonnes per ha. Ridge your field if the revenue from 4 tonnes of cassava exceeds the cost of ridging 1 ha of land. Ridging is also recommended if your soil is high in clay content, or you intend to harvest in the dry season, or if weeds are difficult to control.
Plant cassava only when the soil is moist at 1m between rows and 0.8m within rows. Thereafter, apply pre-emergence herbicide such as Primextra Gold at 4 litres per ha or Vigor at 4 litres per ha or Lagon at 1.25 litres per ha within 24 hours after planting. Do not apply pre-emergence herbicide on dry soil. Replace cuttings that fail to sprout after 15-21 days.
When weeds cover 30 percent of your field and they are at 4-6 leaf stage, apply a post-emergence weed control (for example, post-emergence herbicides, mechanical or manual weeding). In grass-dominated fields or in portions of a field that are grass-dominated, apply Fusilade forte at 3L/ha under cassava canopy. For grass and/ or broad leaf-infested fields, glufosinate ammonium (Lifeline, Slasha Gold, Basta, Facinate) may be applied at label rate. But it is important to use a shield on the sprayer nozzle to avoid glufosinate ammonium touching green parts of cassava, which will result in cassava damage. If cassava is less than 8 weeks old and the field is infested with grass and broadleaf weeds, use manual weeding. Do not apply the same herbicides year in year out, because this may promote the development of resistant weeds.