By Mara Schechter
This post is part of a series where Nourishing the Planet asks its readers: What works? Every week we’ll ask the question and every week you can join the conversation!
Africa’s declining soil fertility has already caused yields to drop by 15 to 25 percent in six African countries, including Malawi, Zambia, Kenya, Uganda, Mali and Niger, according to Dr. Roland Bunch, Director of Sustainable Agriculture and Rural Livelihoods at World Neighbors, in his chapter of State of the World 2011.
Dr. Bunch suggests using green manure/cover crops, or living trees, bushes and vines, to improve soil health and avoid a potential famine. In Mali, the Dogon people have developed a multi-layered system, where they plant leguminous trees, such as acacias, and trim them annually to provide shade and fertilize their fields. Many Dogon farmers now have yields that are three times higher than the average yield of other Sahel areas with similar rainfall.
In other parts of the Sahel, farmers are reviving traditional management practices. Farmer-Managed Natural Regeneration (FMNR) is a process that involves pruning the stems of indigenous trees to cultivate and regrow trees. This revegetation is helping restore the area’s land: the trees release nitrogen into the soil and protect the soil from erosion.
To increase the use of FMNR, the Web Alliance for the Re-Greening in Africa (W4RA) has created web-based information exchanges between farmers, and the organization, SahelEco, has started Trees Outside the Forest and the Re-Greening the Sahel Initiative to effect policy changes that support FMNR.
Integrating trees with crops is part of an approach known as agroforestry. The World Agroforestry Centre is helping farmers use a combination of agroforestry and conservation farming methods, known as Evergreen Agriculture. Evergreen agriculture can help not only improve soil moisture and nutrients, but also reduce agricultural inputs–leguminous trees, for example, add nitrogen to soils naturally–and enhance food security. In Malawi, intercropping acacia trees with maize increased yields by up to 280 percent.
One important element of conservation farming is conservation tillage, which leaves the residue from prior crops on fields. According to IFPRI’s Millions Fed: Proven Successes in Agricultural Development, in Argentina, soybean cultivation using zero tillage has led to a total gain of US$4.7 billion dollars since 1991. Conservation tillage saves money and time spent in preparing soil, and can lead to improved production.
As drought and over-farming decrease soil quality, farmers in Africa are using conservation agriculture to increase yields while healing the land.
Mara Schechter is a media and communications intern for the Nourishing the Planet project.
These are only some of the innovative projects working to improve soil health—do you know of any others? Tell Nourishing the Planet what works and have your answers featured on the blog. Comment below, email Danielle Nierenberg at Dnierenberg@Worldwatch.org, or tweet your response to @NourishPlanet.
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