Last year, a group of West African countries set out a roadmap to supercharge rice farming. At least $20 billion of investment would be needed to boost yields, irrigation and logistics, they calculated.
That plan has already hit some stumbling blocks.
Production is struggling to close the gap with imports that are needed to meet growing demand, and farmers are facing fresh setbacks.
Take Nigeria, Africa’s top rice producer. To help curb food inflation, the nation in January received its first major shipment of brown rice in a decade after waiving import 

