The lower tillage intensity in Africa may simply reflect the abundance of land: in order to maximize labor productivity, people work thinly over a large area. Under the substitution view, the profitability of mechanization and its contribution to economic growth depend on the opportunities available to workers (and sometimes draft animals) released from their tasks.
Primary tillage is one of the first operations to be mechanized when a new source of mobile power becomes available. Secondary tillage operations often continue to be performed by the old power source for a long period. Transport.