By Joshua Kato
Cassava roots should be harvested at peak of maturity or the right age, size and tenderness required for fresh market (use of roots as a snack or home cooking).
Fully matured cassava roots should be harvested for processing.
Cassava roots may lose the valuable starch, rot or become woody if not harvested at maturity. They are exposed to rodents and the land cannot be put to productive use in the next season if the roots are not harvested.
This contributes to the general agriculture outputs in smallholder systems and can cause a shortage of land and increase production costs, especially in places where land is scarce.
- Harvest cassava roots when they are mature to have accumulated enough starch but have not yet become fibrous.
- The optimum age when the starch and dry matter yields are highest is 9 –12 months after planting, depending on the variety and the climate. Some varieties mature in 15 – 18 months. The extended cold season may delay the maturity of cassava.
- Harvesting too early results in a low yield while delayed harvesting could reduce yield.
- Harvest cassava when the soil is slightly soft but has no excessive water so that you can easily remove soil from the roots. Harvesting in soft soil is easier than when the soil is harder. Roots harvested in soggy conditions get soil stuck between them and this can lead to inaccurate weight records. Also, the roots may be very dirty and highly contaminated when peeled, thereby requiring a large volume of water and extended time to wash the peeled roots thoroughly.
How to harvest cassava
Cassava roots are harvested by pulling the stem which carries the roots out of the ground. Harvesting could be done manually or by mechanical methods.
Manual method
- Cut the plant at about 30 –50 cm above the ground; use the stem to lift the roots.
- Pull the plant gently and do not drag the roots. Dragging can cause bruises and cuts which may lead to early deterioration.
- If the soil is compact, loosen it but take care not to damage the roots.
- Separate the roots from the stem using a sharp knife or cutlass. Cut each root near the stem. Do not break the roots from the stump by hand. This will cause injuries which lead to root rot.
- After harvesting, do not leave the roots under the sun. Too much heat causes weight loss and early deterioration. m Manual method of harvesting usually requires 40-60 persons, depending on the season, to harvest 1 ha of cassava in 1 day
Postharvest handling
Cassava tubers attached to the main stem can remain safely in the ground for several months. However, after harvest, the roots start deteriorating within 2 – 3 days and rapidly become of little value for consumption or industrial use.
Transporting cassava roots
To avoid root deterioration and loss of quality, transport to the homestead, market or processing plant immediately after harvesting.
- Use wheelbarrows or any other suitable container to transport roots in small quantities and short distances, such as from the farm to the roadside or bulking centre where they will be loaded on a vehicle for long-distance transportation.
- Gently offload the roots from the wheelbarrow or container without causing bruises or damage to the roots
- Vehicles transporting cassava a long distance should be covered with tarpaulin to avoid rapid moisture loss from the roots.
- Use oxen-cart for transportation especially in rural areas where there are no paved roads or the roads are not passable to vehicles
- Carefully sort and arrange roots neatly in the vehicle or cart to save space
- Do not seat or put heavy objects such as vehicle tyres on roots after loading.
