June 14, 2010
Slash and burn agriculture is in some ways merely an intensification of a more sustainable form of agriculture practised for many years by indigenous people and referred to as shifting cultivation. However, slash and burn agriculture differs in one crucial aspect: whereas the shifting cultivators would burn an area of forest, grow crops on it for one to three years and then leave it fallow to allow it to regenerate into secondary forest for perhaps as long as 20 to 40 years before repeating the cycle, the unfortunate slash and burn farmers of today, due to population pressures on the land, are often only able to leave it fallow for as little as five years. This means that the land is incapable of restoring its nutrients and may eventually become so degraded that it becomes virtually unfarmable. This then leads to farmers attempting to farm on steeper and steeper slopes and burning more and more of the rainforest.
Hillsides denuded by continuous slash and burn agriculture – Photo Copyright FUPNAPIB, Honduras.
Mike Hands' research provides evidence that a new farming technique could mitigate environmental impact and aid impoverished farmers. Research found that vital nutrient phosphorous was leaching out of the soils of a typical slash and burn plot at a devastating rate. However, Hands showed that by using the leaves of a common tropical tree Inga edulis (which also fixes nitrogen) as a mulch this process could be dramatically diminished. Thus by planting rows of Inga edulis, and then after two years pruning them and sowing maize seed in the resulting mulch of leaves, not only would a good harvest be achieved but also the fertility of the soil would be maintained. Here was a system of agriculture that would allow the tropical farmer to farm in one place for many, many years, instead of having to move on every two or three years and burn more tropical rainforest.
The new system was tried out with tropical farmers in neighbouring Honduras, where farmers were rapidly denuding and destroying the slopes surrounding the Pico Bonito National Park. The results were impressive. One of the farmers Victor Coranado claims that he’s able to achieve a maize harvest that is four times greater than he used to achieve by the old slash and burn methods.
Honduran Farmer with his bumper crop of maize grown in the Inga alley system. Photo Copyright Anthony Melville.
Back in Honduras the CURLA University at La Ceiba has also successfully set up trial Inga plots and has been impressed with the yields obtained. They are now running courses to teach their students about the benefits of the new system and will shortly be helping local farmers to change to the new system. A new charity Rainforest Saver Foundation is currently helping to fund this important work. They have also helped fund a small NGO in Cameroon in West Africa to see if this new technique can be just as successful on a different continent. They have already planted trees for a seed orchard and the local NGO has persuaded ten farmers to trial the technique on small plots of land.
It is not a system that can be established overnight as it takes two or three years for the Inga trees to grow large enough to produce the first mulch that can be sown into, but the rewards once the plot is established are worth the wait. Results have shown that not only can the farmer continue farming on the same plot without the need to burn more and more rainforest but also his yields are likely to be consistently higher. The farmer also has the benefit of an easily available supply of firewood, once the Inga trees have been pruned. There is also far less erosion so less silt to damage the rivers and surrounding coastline.
If enough farmers can be persuaded to give up their destructive slash and burn agriculture and take up this more sustainable and productive technique, I believe there is an opportunity not only to raise food production levels in impoverished rainforest margins and give poor farmers a better livelihood but also to save millions of acres of rainforest from the incursion of slash and burn agriculture.
Charles Barber is with the Rainforest Saver Foundation.
How an agricultural revolution could save the world's biodiversity, an interview with Ivette Perfecto
(05/04/2010) Most people who are trying to change the world stick to one area, for example they might either work to preserve biodiversity in rainforests or do social justice with poor farmers. But Dr. Ivette Perfecto was never satisfied with having to choose between helping people or preserving nature. Professor of Ecology and Natural Resources at the University of Michigan and co-author of the recent book Nature’s Matrix: The Link between Agriculture, Conservation and Food Sovereignty, Perfecto has, as she says, "combined her passions" to understand how agriculture can benefit both farmers and biodiversity—if done right.
Could agroforestry solve the biodiversity crisis and address poverty?, an interview with Shonil Bhagwat
(09/24/2009) With the world facing a variety of crises: climate change, food shortages, extreme poverty, and biodiversity loss, researchers are looking at ways to address more than one issue at once by revolutionizing sectors of society. One of the ideas is a transformation of agricultural practices from intensive chemical-dependent crops to mixing agriculture and forest, while relying on organic methods. The latter is known as agroforestry or land sharing—balancing the crop yields with biodiversity. Shonil Bhagwat, Director of MSc in Biodiversity, Conservation and Management at the School of Geography and the Environment, Oxford, believes this philosophy could help the world tackle some of its biggest problems.
Farmers have poor understanding of role of wildlife in protecting crops
(08/10/2009) Environmental conservation depends, to a large degree, on public acceptance. Understanding people’s opinions on ecosystems and wildlife can be very helpful in designing programs that aim to benefit both the environment and society. A new study, published in Tropical Conservation Science, interviewed organic shade-coffee farmers in Cuetzalan, Mexico, to understand how they perceive the wild animals that live in their fields, as well as their knowledge of the ecological roles these species play in maintaining ecosystem services.