Reducing Postharvest Losses
In the OIC Member Countries
27
formally and informally each year (Ahmad, 2009). While in neighbouring India, there have
been several studies of wheat damage and weight loss during storage, Rahman et al., (1945)
reported 6-73% of wheat kernels damaged during a storage season, Prasad et al ., (1977) found
15% damaged kernels during a few months storage, equating to a weight loss of 2.6%, and
seed viability loss of 24%. Khan and Kulachi, (2002) found weight losses of 3.4-6.5% within 5
months storage, and high levels of discoloured and shrivelled grains and foreign matter.
Maize postharvest losses
Maize (also commonly known as corn) is also widely grown throughout the world, its high
genetic variability enables it to be produced in tropical, sub-tropical and temperate climates.
More maize is produced than any of the cereals. It is an important staple food in many
countries as well as being used in animal feed and various industrial applications.
When grown by smallholder farming households, a very small proportion of the maize is
harvested as green maize, for boiling and consumption or small sales, the rest is harvested
once mature and following a short period of drying on the standing plant. The maize cobs are
then transported home (by head-load, cart, bicycle, motorbike), dried either in their husks or
de-husked, on platforms or a mat on the ground or on the bare ground (although this increases
the risk of contamination). Once dry the cobs will be shelled, and the shelled grain usually
further dried on mats or cow-dung plastered ground, and then treated to help protect it
against insect attack during storage, prior to loading it into the storage container (maize grain
is now commonly stored in sacks which are then kept indoors, as opposed to in granaries).
Much of the smallholder maize marketing occurs within a few months of harvesting, with
traders or aggregators typically moving through the villages and purchasing it. Households
tend to regularly take some maize grain to the local mill for grinding into flour which is then
often used in producing staple stiff porridges. In urban areas, maize is milled and often packed
before retailing. Some of the purchased maize grain is also made into livestock feed.
Many studies have focused on maize PHL particularly in sub-Saharan Africa. Much of that data
has been used to create the APHLIS data set. In APHLIS the PHL figure can be further analysed
to provide a rough comparison of what loss is occurring at each stage in the PH chain. As an
example data from Kaduna state, Nigeria (2013) and for Eastern region, Uganda (2012) is
shown in Table 6. This data shows the heaviest maize PHL occurring during harvesting and
field drying, and storage. The studies which the estimates are partially based on are shown in
the final column.
However, it must be remembered that due to the complexity such a long-term multi-spatial
multi-actor study, few, if any, studies have quantitatively assessed and compared losses all
along the different stages of a maize (or other cereal) value chain. It should also be
remembered that such figures would be both highly contextual and relatively subjective in
nature. Whilst such figures might be used to target loss reduction investments, some types of
loss may be easier than others to reduce. Given the various investments (e.g. time, financial,
natural resources) that farming households need to make to reduce PHL, it is important to
consider what incentives would help drive these changes and these are explored (see Hodges
& Stathers, 2013 for discussion).