Reducing losses in small farm grain storage in the tropics

Over two-thirds of all grain produced in the tropics is stored at farm level. Most traditional storage systems are well adapted to their environment and losses are generally low - typically below 5% of grain weight over the storage period.· However, several factors have increased potential losses in farm storage over the past two decades. These include the adoption by small-scale farmers of high-yielding crop varieties which put a strain on existing post-harvest systems, the threat to traditional storage technologies posed by the decreasing availability of important inputs such as construction materials and fuelwood, and, in Africa, the advent of a new storage pest (the larger grain borer). At the same time, recent economic changes in many countries (especially in Africa) have created incentives for farmers to store more grain. This paper critically discusses the main technical approaches to reducing storage losses in the context of the constraints commonly faced by the small-scale farmer. Possible approaches include pre-storage methods (such as timing of harvest), improved drying, better storage structures, appropriate crop varieties, the use of commercial pesticides or locally produced insecticidal materials, and biological pest control. Of these, appropriate varieties (high-yielding and resistant to deterioration in storage) would be the ideal solution, but this is not always feasible. Pesticides are probably the most successful storage technology to date: they are easy to incorporate into most types of storage systems and when correctly used can give high returns to the farmer's investment. The main problems are ensuring an adequate supply of suitable, well-packaged pesticides and in educating farmers to choose and use them correctly and safely. The most difficult technologies to promote to the small farmer are new storage structures and grain dryers, due to their high capital cost; however, small silos have been very successful in some wealthier areas. It is concluded that, although substantial research and development efforts have gone into this area, there have been many cases where 'improved' storage technologies have not been taken up by small-scale farmers. M any of these technologies turn out to be inappropriate for farmer needs, or are not available at the right price and the right time. It is recommended that governments and other organizations wishing to help reduce storage losses work closely with farmers (including women) to design more appropriate technologies, and to help overcome constraints such as poor input supply and lack of finance. Suggestions are made for future research.