It has been established that the post-harvest system of cassava requires more labour than most other staple crops (IITA, 1996). One hectare of cassava containing 10 tons of roots (the average root yield in Africa) needs approximately 721 man-hours to harvest and process: of this labour, 212 man-hours are needed for harvesting, 156 for handling, and 353 for processing.
The Collaborative Study of Cassava in Africa (COSCA) has shown that in 67 percent of cases, cassava processing activities were carried out by women only compared to 6 percent of cases for men only. Women along with children participated in another 19 percent of cases, and in 6 percent of cases women worked alongside men. This represents 92 percent participation by women in cassava processing (Nweke, 1994). However, the number of men involved in cassava processing increases as the opportunities for commercialisation increase (Ugwu and Ay, 1992). Although men are seldom involved in cassava processing operations, they tend to perform more of the heavy-duty farm operations. It was observed that as mechanised processing equipment (such as graters and mills) is acquired, men's participation in cassava processing tends to increase, since they often control and operate these machines. It appears therefore that gender role in cassava processing tends to change as processing becomes more mechanised.
With such a large number of processing steps, the opportunities for food loss in the whole system also become numerous. Major losses occur during processing (23.2 percent), harvesting (13.6 percent) and handling (8.5 percent). Harvesting losses are higher during the dry season because it is more difficult to dig; roots break and remain in the soil. The size, shape, hardness, moisture content and the type of equipment used affect the processing efficiency. Recently, IITA has assembled a technology package for cassava processing in rural areas (IITA, 1996). The package, which is in the form of a village processing centre, contains a chipping and grating machines, a pressing device, a mill, a gari fryer and sifters. Such package has been tested and found to reduce food losses during cassava processing from 22.3 percent to 10.1 percent and the labour input from 295.2 man-hours to 87.6 man-hours per 10 tons of cassava roots (See Figure 6).
Figure 6. Effect of improved cassava processing on labour requirements and post-harvest food loss in the cassava post-harvest system. (Source: IITA, 1996).
A food exchange scheme based on the improved cassava processing technology package was tested in rural Nigeria (IITA, 1996). Using traditional methods, a family normally obtains 12 kg of gari or 18 kg of lafun per 100kg of fresh roots; using the new technology, the yield is 14 kg of gari or 20 kg of lafun. In the food exchange scheme, women bring their cassava roots to the processing centre and receive 12 percent of the roots weight as gari or 18 percent as lafun. They get what they would have obtained should they have processed the cassava by themselves. Moreover, the product they receive is also of better quality. The processing centre keeps the 2 percent of extra product and uses it to cover its processing and maintenance costs. Benefits to women are labour savings and improvement in food quality. They have more time to devote to other chores, to leisure or to self-advancement. The processing centre is also an employment opportunity and source of income for women who are employed there. The food exchange scheme has shown that it can significantly improve the quality of life in a rural community.