Most West African farm and garden crops are harvested by hand, using a cutlass, large knife or, for cereal crops, a curved sickle-shaped blade. No special techniques are involved, the main objective being to cut the crop with minimum damage to the harvested product and transport it as rapidly as possible to the farmstead where it is either prepared for home
consumption or for storage.

Mechanised harvesting is still comparatively rare in West Africa, but some crops are being grown on a large scale, where some degree of mechanisation is necessary if the crops are not to be left too long in the field. If this occurs, damage from animals, birds and the natural shedding or dropping of the ripe seeds can considerably reduce the final yield.

Combine harvesters are in use in some areas for harvesting rice and maize and experimental groundnut harvesters have been tested in some parts of West Africa. The mechanised harvesting of cassava, yam and other root crops is a possibility which is being actively explored since the labour requirements for harvesting these major crops are considerable.

Processing and storage: 
Reference to the processing and storage of individual crops is made later in this chapter, but some aspects of these techniques are common to many crops. In general, the losses which occur during the preparation and storage of farm crops are very considerable and
are due mainly to damage by insects and fungi during the storage period.

Processing: This is the term given to those operations which take place after harvesting, and which lead to the production of the commodity which is either used by the farmer, sent to the market or sold to the various agencies which deal with export crops. Many of the basic processing operations such as hulling or decorative milling, grinding, fermenting, starch extraction or latex production may be carried out at various levels, using a range of equipment from farms operated 
machinery such as maize shellers, cassava raspers, cocoa fermenting trays, oil palm presses and fibre decorticators to factory tolerated machinery which involves a high level of technology. The effectiveness of any particular process often depends on the type of machinery available, the level of efficiency at which it is used and, primarily, in the quality and condition of the crop which is being used to produce the final commodity. The use of the correct settings and adjustments on machinery such as palm nut crackers and groundnut decorticators is most important, but it is equally necessary to maintain the equipment in good condition by regular inspection and servicing of the moving parts.

Storage: Storage losses are generally considerable in tropical areas, due to high temperatures and humidity which
encourage the spread of diseases and pests in stored products.
An additional factor, however, is that farm storage facilities are often inadequate to deal with the volume of produce at seasonal peaks and they are frequently not equipped to provide the requirements for more than a limited amount of the crop. This situation can
lead to much of the crop being wasted.

Storage sheds and barns should be kept clean at all times and should be treated with insecticides such as lindane to keep down insect infestation. Containers such as sacks and boxes used for storage should be cleaned and disinfected after use and every effort made to reduce damage by rats and other animals by making storage areas secure against their entry. Good ventilation is important in storage areas, but the roof and side walls should be weather-proof. Wherever  possible, sacks and containers of  produce should be raised above floor
level, on battens, to increase the circulation of air and reduce contact with moisture which may accumulate
on the floor during the wet season. If basic precautions such as these are taken, a significantly greater amount of the produce of the farm will become 
available either for home consumption or for resale.

Seed production and selection:

In temperate countries, specialist seed producers concentrate on producing crops for seed, for resale to farmers through retail suppliers. These seeds are of guaranteed purity, have a high germination capacity, are free from pests and diseases and produce crops of a known high performance. In West Africa, seed production with these objectives is relatively unknown and the responsibility for ensuring that the farmer obtains good seed is often shouldered by the Extension Services of the Departments and Ministries of Agriculture and semi-government organisations and corporations.
New varieties or cultivars of seed are produced by plant breeding. Research Stations are constantly endeavouring to improve the performance of existing
cultivars by hybridisation and  selection.

These new strains, when adequately tested are then usually multiplied for distribution through the Extension
Services. Many new cultivars of maize, sorghum, cowpea and soya bean have been made available to farmers in recent years, through these channels.
Many farm crops, however, are propagated from seeds kept by farmers from their own crops and the following are some of the basic precautions  which should be taken when saving seed from existing crops intended for consumption or sale.

1) Seed should only be saved from plants which are healthy and free from pests and diseases.

2) Any crop from which seeds are to be kept must have shown a good yielding capacity and be well adapted to local environmental conditions.

3) It should be true to type, that is, the majority, if not all of the plants produced should have similar characteristics; only plants which have the characters required in the next generation should be kept for seed.

4) Seeds should not be collected from crops which are likely to have crossed with similar crops grown nearby, cross pollination is likely to produce seeds
which have undesirable characteristics since they will be a combination of those of both parents.

5) Seeds from F, hybrid plants should not be kept for seed since they will produce seedlings which may revert to an earlier parent used in the making of the F, hybrid, which will be inferior.

6) Seeds collected for sowing the following year should be treated with an insecticide and possibly a fungicide to reduce injury from pests and  diseases during storage. They should be adequately dried in the sun and stored in cool conditions. Every effort should
be made to maintain a low level of humidity.

For selecting and storing garden seeds, the same principles should be observed. Particular care should be taken to ensure that only the most vigorous and highs yielding plants are selected for seed production and the first plants to mature are not normally those which are suitable for seed.

Plants produced from early maturing crops are likely to pass on this factor to
the next generation which may result in premature flowering before full stem and leaf development has taken place. In general, a closer control can be kept
over the storage conditions of vegetable seeds, due to the relatively small quantities involved. Whole plants for example, may be uprooted and hung in a dry place, with sheets of paper placed below them to collect any seeds which fall when they are fully ripe and dry.

After thorough drying, seeds may be stored in polythene bags or in airtight glass jars with a material such as silica gel or calcium chloride which will absorb moisture. Many seeds have a period of dormancy through which they must pass before they are capable
of germination. Germination tests, to assess the viability of seeds should therefore only be carried out after.