Composting food waste relieves pressure on landfills while producing an inexpensive, nutrient-rich soil amendment that farmers use to improve soil fertility. Compost adds organic matter to the soil, increasing the water-holding capacity of its structure, facilitating root penetration and making nutrients available to crops over time.
Subsistence farmers have traditionally relied on composting and livestock manure to improve soils. The Ibo tribe of Nigeria, for example, used branches from trees for mulching, applied goat dung to individual plants, and composted human waste as early as the 1970s. In Zimbabwe, farmers traditionally graze cattle during the day and contain them in pens at night so that they can collect the manure and spread it over farmland.
A number of projects have been teaching farmers across the continent how to compost and improve the quality of compost produced. A participatory radio show in the Zégoua region of Mali resulted in a 64 percent increase in household adoption of composting. In Kenya, a demonstration project turned waste from households, vegetable markets, and an avocado processing plant into compost that farmers could use to increase crop yields or sell. And farmers in Pelungu, Ghana, are building goat shelters with sloped floors that transport dung into a central location using gravity. The manure is then composted and used on farms.