PREPARATION OF THE LAND
When cassava is grown as the first crop in forest land. no further preparation is required than the clearing of the forest growth. When cassava is grown after other crops. it often can be planted without further preparation of the soil, once the preceding crop has been harvested or the soil has been ploughed two or three times until free from grass and other plants.
Clearing of forest land is done to let in more sunlight to the ground and to remove weeds and undergrowth which might otherwise compete with economic plants. The practice in tropical southeast Asia is to clear the forest soil completely, including the removal of all roots and other obstructions beneath the soil, by cutting and burning the forest cover; the land is then deeply ploughed. African practice is to burn the land cover only. Burning removes only small branches and underbush but does not consume all of the trunks and branches. It also destroys soil parasites, and the layer of ashes increases the amount of potassium salts available to the growing plants. However, some reports have indicated that complete clearing of the soil in certain parts of Africa caused deterioration due to the leaching out of nutrients.
Cassava culture varies with the purposes for which it is grown.
Cassava is either planted as a single crop or intercropped with maize, legumes, vegetables, rubber, oil palm or other plants. Mixed planting reduces the danger of loss caused by unfavourable weather and pests by spreading the risk over plants with different susceptibilities.
For agricultural purposes, cassava is propagated exclusively from cuttings. It is raised from seed only for the purpose of selection Seeds produce plants with fewer and smaller roots than those of the parents and as many as half of the seeds may fail to germinate. On the other hand, cuttings taken from the stalks of the plant take root rapidly and easily, producing plants identical in character with the parent plants.