The assessment argues that modest outlays on rain-fed agriculture, in particular, could drastically improve the productivity of farming in poor countries and so help both to raise farmers' incomes and also to cut the need for an expansion of agriculture elsewhere.

ECONOMIST: Financing water projects

Irrigated rice-farming, which is two or three times more productive than the rain-fed sort, is growing rapidly throughout the basin, albeit from a low base.

ECONOMIST: The Mekong river