In the mid '80s, the traditional farming system in southern Benin had collapsed because extensive tilling affected soil fertility. The problem was aggravated by the spread of a grass weed Imperata cylindrica. When advised by researchers of the International Institute of Tropical Agriculture, Nigeria, farmers were apprehensive about planting Mucuna pruriens, an annual leguminous creeper, which has no food value. But Mucuna, when it dies in the dry season, leaves behind a lot of nitrogen-rich organic matter and helps the soil retain rainfall. Mucuna also helps in eliminating Imperata grass by cutting off its requirement of sunlight. Corn yields have trebled when planted after Mucuna (Ceres, The FAO Review, Vol 28, No 158).