Senegal Cereal Postharvest Losses
The smallholder farmers in all 14 provinces of Senegal cultivate maize and sorghum, all but Dakar cultivate millet, 11 cultivate rice and four harvest fonio. The climate of the four southern provinces (Kédougou, Kolda, Sédhiou and Ziguinchor) is tropical savannah (Aw of the Köppen code) while the others are hotter and dryer, Saint-Louis, Louga and Matam are hot desert (Bwh) and the remainder are hot semi-arid (Bsh). APHLIS makes no distinction between Bsh and Bwh. In Senegal there is a single rainy season from July to October, with more rainfall in the south than the north. In most parts there is a single cereal harvest, except in the valley of the River Senegal and Anambé basin in Kolda where some areas have irrigation that may allow a second harvest.
In 2012, total cereal production was about 1.1 million tonnes of which an estimated 14.7% (or 0.166 million tonnes) was lost in postproduction activities. Most of this loss is contributed by millet in absolute terms because it has by far the largest production, but in relative terms it suffered a lower proportion of losses than other grains (Fig. 1). There may be damp weather at harvest time that prevents good drying and so increases losses. In 2012, this was observed in the millet crop of five provinces. The Larger Grain Borer, a pest of maize, is known to be present in three provinces but the losses caused are no greater than the usual damage by weevils (Sitophilus spp).
Figure 1: Weight loss maps for the provinces of Senegal in 2012
The density of losses in millet and rice, the two crops with greater production, is shown in Figure 2. This contrasts strongly with the % weight loss estimates (Fig. 1), since provinces with greater % weight losses do not necessarily have greater absolute losses (tonnes of loss). In the case of millet, Kaolack province has amongst the lowest % weight loss (5-10%), not least because there was no rain at harvest, whereas it has the highest loss density (15-20 MT/km2) because for its land area it produces an exceptionally large millet crop. This suggests that it may be a good target for loss reduction measures. Similarly for rice, Saint Louis province is among the lowest for % weight loss (10-15%) but is the highest for loss density (15-20 MT/km2).
Figure 2: Loss density (MT/km2) for millet and rice in Senegal 2012 (see Fig. 1 for key to provinces)
The postharvest loss profiles (PLPs), used by the APHLIS calculator to estimate losses, are strongly specific to the situation in Senegal in the case of maize and rice, reasonably specific for millet and sorghum, but much less so for fonio. Specific PLPs give more reliable loss estimates.