Increases in population thus arise from large youthful cohorts, the product of past high fertility, making their way through the population structure. Hence, the combination of slowing natural growth and net out-migration from rural areas will soon lead to falling rural populations; as already in evidence in parts of Latin America, East and Southeast Asia (Keats & Wiggins 2016).

The future of agriculture in the developing world is that of farming with less labour. Given that this has been the reality of agriculture in high-income countries for a century or more, technical options to do this are well known. Increasingly farm operations that can readily be mechanised, at modest cost, will be. This does not mean large tractors and combines: more likely it means two-wheel cultivators at first. Neither does this mean sudden conversion to the almost-fully-mechanised operations seen, for example, in the US Midwest. Plenty of operations will continue to require manual work: harvesting of most fruit and vegetables, picking coffee, for example. 

Two economic issues thus arise for policy-makers.