DAR ES SALAAM, April 30 -- Across Tanzanias agricultural heartlands, growth is visible. Fields are fuller, output is rising and farmers are producing more than ever before. Yet for all this effort, much of the value slips away before it reaches those who worked hardest to create it. The real gap is not in production. It lies in what happens after.

From farm to market, value is lost at every stage. Crops move quickly, but without processing. Goods travel long distances but without efficient logistics. Markets exist but remain fragmented. As a result, Tanzania produces more yet earns less than it should. This is the quiet cost of not moving up the value chain.

The leak begins at harvest. Limited storage and aggregation facilities mean a s...