More than 70% of the rice in Africa is harvested by hand using a sickle, knife or machete. This requires a lot of labor, mostly provided by women in rainfed upland and lowland areas, and by men in irrigated environments.
Hand harvesting is fraught with problems, including the time required that could be used in other activities and delays in harvesting, leading to both quantitative and qualitative losses. These losses occur through shattering, attack by rodents, birds and insects, grain germinating in panicle due to rainfall or lodging (panicles touch the soil).
Mechanized harvesting may involve the use of small reapers in combination with mechanical threshers, mini combine-harvesters and large combine-harvesters.
Reapers: Reapers are machines that cut and gather rice panicles at harvest. They have been introduced for use in the rainfed and irrigated lowland environments in sub-Saharan Africa (SSA). Reapers can be either hand-driven or mounted on tractors. They can be easily manipulated under wet and dry conditions. A reaper with a cutting-width of 1.5 m can operate at a rate of 2−4 ha per day.
Reapers are more appropriate for use on medium-sized farms (5–25 ha) and may be affordable for farmer cooperatives. Reapers are commonly used in the Office du Niger (Mali) and northern Senegal.
Mini-combines: Since 2000, small combine-harvesters have been introduced from Asia. While they can harvest 2–5 ha/ day, their introduction has not been successful in SSA, because of the higher level of sophistication of the technology, lack of trained operators, poorly prepared and unlevelled field conditions, lack of spare parts and maintenance, and the high initial investment required by small-scale farmers.
These challenges are now being addressed by introducing smaller and cheaper ‘mini-combines’ with less sophisticated technology that may be fabricated and maintained locally. The major parts that need to be imported are the gearbox and drive belts. The local fabrication of these mini-combines will help ensure employment and incomes for the fabricators or local artisans, maintenance-service providers, spare-part fabricators, and others.
Large combine-harvesters capable of harvesting 5–10 ha/day are mostly used in the large irrigation schemes in Egypt, Mauritania and Senegal. They are suitable for large farms but need well-levelled fields to function efficiently. These combines are very expensive, often costing more than $100,000, tend to break down often, and spare parts are not readily available.
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