Dr. Dennis Garrity spoke today at SENR about how agroforestry is transforming entire landscapes in Africa. Dr. Garrity detailed a number of ways farmers are growing more crops by cultivating trees in their field. The details differ, but usually involve a leguminous tree that can provide both fertilizer for the field and fodder for livestock. One such tree, Acacia (Faidherbia), has the amazing added benefit of loosing its leaves during the wet season when farmers grow crops. This is basically the perfect tree, providing timed inputs of fertilizer, light, and forage at just the times the crops, farmer, and livestock need them.
According to Dr. Garrity, Faidherbia does not grow in the wild and is dependent on human cultivation. But until 10 years ago, no one knew how to propagate the tree: farmers tended them when they found them, but attempts to plant seeds or take cuttings had failed. Once researchers from the World Agroforestry Centre developed a cheap and easy way to propagate Faidherbia, its use has been rapidly adopted, especially in the Sahel region of Africa, where millions of hectares have been transformed.
Many of the questions from the audience focussed on possible problems and objections to this agronomic technique. What if pests wiped out the tree, or used the tree as refuges? If it was so good, why hadn't farmers adopted it before? What would happen when commercial farms replaced small holders? Some of these questions had initially occurred to me as well, but after reflection, the question I was most interested to ask would have focussed on what this example of agroforestry innovation could teach us to look for in the future. How can we learn from this example to look for other species in other parts of the world that might become essential components of new agricultural systems that can increase diversity, resilience, and production for the 21st century?
The real insight of this talk is that productivity is not set in stone: humans can and should manage their environments to improve them over and above what is "natural".
This presentation has in-depth information on the spread of agroforestry in Niger.
This is a great agroforestry organization: http://www.plant-trees.org/about.htm