PREDICTED OUTPUT LEVELS
Let us assume that 0.6 kWh of mechanical energy per operator per day is available, and that specific energy for threshing of sorghum is 3.2 kWh/tonne. Therefore the thresher should be able to thresh 750 kg per day with 6 men operating.
If we assume 30 days threshing at the end of the growing season, then thresher output can be 22.5 tonnes per growing season (assuming single shift operation only). That corresponds to the output from 45 hectares with yields of 500 kg per hectare per growing season, or 22.5 hectare for 1000 kg per hectare yield.
Incidentally, average cereal consumption in societies where cereals are the staple food, and are not used in significant quantities for conversion to animal protein, is in the region of 200 kg per adult per year, providing an average daily food energy intake of 2055 kilocalories (2.4 kWh) per adult on a zero-loss basis.
Thus as an indication, one thresher could serve, on the basis of one growing season per year, a community whose number was around 110 adult equivalents, assuming that sorghum or millet was their only staple, and that no trade was conducted in that crop.
For Milling, from Omar (1977) and from standard milling textbooks, then 25 kWh / tonne is a reasonable figure for the production of fine flour from low moisture content maize, sorghum or millet. If we assume that 4 pedallers can produce 0.6 kWh per pedaller per day and that milling can be done 320 days per year, then one machine could mill 30.7 tonnes of fine flour per year, serving a community of 154 adult equivalents.