Nations in Sub-Saharan Africa may be unable to feed 60 percent of a projected population of 1 billion by 2025 unless dramatic steps are taken to improve the fertility and quality of soil in the region, according to a report by the U.N. Food and Agriculture Organization released on Saturday, World Food Day. The capacity of the land to support food production is being compromised by overgrazing, deforestation, and inefficient agriculture, among other forces. Developed nations will need to pitch in hundreds of millions of dollars to forestall a major food crisis, the report says. It calls for work to halt erosion, improve water supplies, and develop farming techniques better suited to the region.