Integrating perennials with food crops could restore soil health and increase staple yields. Examples include nitrogen-fixing trees, co-cropping with legumes and other strategies.
"Sub-Saharan Africa's population is expected to reach 1.5–2 billion by 2050. Already the population is ballooning; in many areas, the risk of drought and flood is increasing; most soils are poor; and richer nations are buying up Africa's arable land for their own food or fuel security. African farmers have demonstrated the promise of perenniation. It is time to scale up its use and put it firmly on the research-and-development map."
Via Mary Williams