Reducing Postharvest Losses
In the OIC Member Countries
29
maize feed caused water deprivation of 0.3m 3, and the associated PHL account for 21% of the
area under maize.
Sorghum and millet postharvest losses
Sorghums and millets are often collectively referred to as the ‘small grain crops’. Most
sorghum varieties are heat and drought tolerant and thus important foods in arid areas within
Africa, Central America and South Asia. Sorghum is also used to produce alcoholic and non-
alcoholic beverages and biofuel. The millets refer to a number of small-seeded annual grasses
that are cultivated as grain crops, primarily on marginal lands in dry areas of temperature,
sub-tropical and tropics regions. They are grown as food and feed, and globally the largest
producers are India and Nigeria.
These small grains are typically harvested after the rainy season, and therefore by the time
they reach maturity there is less danger from humidity than from birds and other field pests
(e.g. rodents or wild or domesticated animals), especially for broken stalks and fallen ears or
panicles, plus damage from natural dehusking and theft (INPhO, 1999). However, when the
harvest is gathered during the rainy season, fast drying is necessary. Millet and sorghum grains
are traditionally stored still on the ears or panicles by smallholder farmers as this is thought to
better preserve their quality. They are typically then beaten with sticks to obtain the grains as
required by the household, the small grains are easily lost in the soil during threshing. Data in
Grolleaud (2002) suggests mechanical threshing of millet caused higher losses (19.3% losses)
than manual (6.3%) in Gambia, due to breakages and grains remaining on the ears and
panicles. A study by the African Studies Centre in 1987 found storage losses alone ranged from
2-10% in millet, and 4-12% in sorghum across 6 West African countries . Smallholder
farmers in many parts of SSA consider millet a crop that can be stored for 2 years without
protection as few insects tend to attack it, by contrast they view maize and some sorghum
varieties as being far much more likely to be damaged during storage. APHLIS 2012 PHL
estimates range from 8.5-13% for millet across 14 SSA countries, and 11.2-23% in sorghum
across 18 SSA countries. The APHLIS data for Niger suggests for sorghum and millet the losses
are occurring during harvesting/ field drying (4.6%/ 3.5%), threshing (3.6%/ 2%), transport
to farm (2.2%/ 2.5%), farm storage (2.5%/ 1.1%), transport to market (1%/ 1%), and market
storage (2.7%/ 2.7%). A very recent survey of 1293 farmers and traders in southern Niger,
found the most commonly stored commodities in Niger were millet and sorghum, typically
stored for about 6 months by 53% and 80% of respondents respectively (Baoua et al., 2015).
Most respondents took no measure to control insect pests in their stored grains. Some traders
were found to store millet and sorghum for up to 60 months, with some of them keeping up to
400 tons of millet or 500 tons of sorghum. The researchers collected samples during their
survey and kept them in jars in the laboratory for 7 months, finding weight losses then reached
17.1% (millet) and 10.9% (sorghum), although insects were prevented from escaping or
entering, unlike in the field where insects typically disperse once the grain becomes depleted.
Table 7: Sorghum and millet storage losses in traditional granaries in tropical Africa
Country/area Sorghum Millet
form % loss form % loss
Burkina Faso ears 6 ears 10
Northern Nigeria ears 4
Senegal grain + sand 10 ears 2
Northern Ivory Coast ears 11 -12
Mali - - ears 2 – 4
Niger - - ears 3 - 10
Source: African Studies Centre, EHESS, Paris, 1987