Tropical Soils: less is more in fast carbon pathways, but only with standing forest
posted by Ariella Jew on May 7th, 2010
The Amazon rainforest is one of the most amazing displays of symbiotic relationships one can experience in the world. This complex and layered eco-system thrives through the many systems and cycles that interweave through the layers of canopy, creating one of the most bio-diverse displays of life on the planet. Nature designs the most magnificent Permaculture systems – it is quite an experience to spend time in this magical place and humbly observe her teachings.
Observing the thriving and abundant rainforest, it is hard for some to comprehend why the neighboring agriculture in the region experiences quite the opposite affect, but the answer is quite simple – it’s all about the soil.
In simplistic terms, due to constant high temperature and moisture levels, and associated microorganism, fungal and insect life – the degradation of organic matter in these regions are extremely rapid. In a healthy forest, this thin layer of organic matter is quickly cycled. In the Amazon, 80-90% of the biomass lives above ground. In the temperate regions of the world this ratio is reversed.
Root systems are shallow and widely spreading, allowing the biomass above ground to grab the nutrients from this thin surface layer. Massive amounts of organic matter produced by the forest allow this cycle to be maintained as the forest is constantly mulching itself and recycling. In addition the thick canopy serves the dual role of protecting the delicate and thin soil on the forest floor from the heavy rain.
Once this biomass above ground is removed for traditional agriculture purposes, a rapidly soil depleting chain of events follow. Without the humus build up due to the rapid decay, there is nowhere for nutrients to hold in the soil and structure is poor. Heavy rains, now pounding the exposed earth, leach nutrients and wash away the tiny layers of fertility that do exist. The infamous swidden (�slash-and-burn�) practices are a result. Farmers cut and then burn the forest in order to add minerals into the soil, but due to the reasons explained above, the land will only support cultivation for 1-3 years, after which time, the fertility is gone and the land is left to fallow for up to 10-20 year. Farmers will continue to clear and burn land on cycles eventually returning to their first plot too burn and plant again. Such patterns are arguably sustainable by small populations over vast areas of forest, particularly if Terra Preta practices are incorporated, however, when time cycles between cultivation shorten, the net result is forest and soil degradation.
To further aggravate the problem, when chemical or organic fertilizers are applied to these unstable tropical soils, these nutrients have no organic matter to attach to and are thus leached in to the ground water at an even higher rate, thus throwing off the delicate balance of the neighboring forest that are still intact. With populations increasing and forest rapidly decreasing (largely due to these techniques) this is clearly not a sustainable model. There’s got to be a better way and the solutions we find will be crucial to the health of our planet.
“This difference between temperate and tropical soil fertilities is often seen as the reason why nations in temperate climates tend to be more advanced than tropical nations. Some tropical soil types cannot support anything but the most simple civilizations. This difference in soil fertilities, in combination with the higher population growth rates in tropical nations, probably explains why the bulk of the world’s hunger is found in tropical nations. Today about 75% of the world’s human population resides in tropical climates. This population (about 4.5 billion) is growing significantly faster than human populations in temperate climates, and about 0.8 of these 4.5 billion do not have enough to eat, and many more are malnourished.”
-Bruce Sundquist – http://home.windstream.net/bsundquist1/tpgw.html)
The forest demonstrates the systems that work. Inspired by the abundant designs in nature, we have plans to develop Forest Garden techniques to create abundant systems on a recently acquired 40 acres of degraded land in the Amazon about 60km outside of Iquitos. The Permaculture Education Center is being established in collaboration with Peruvian based Non-Profit, The Institute for the Preservation of the Amazon Rainforest and Indigenous Traditions which will soon be based on this land.
The project will launch, and start up cost funded through a Permaculture Design Certificate Course June 22 – July 6th lead by Andrew Jones where students will have the opportunity to collaborate in the design of the centers early planning and at the same time immerse in the cultural treasures of the region made possible through the 10 years of shamanic apprenticeships and work by co-founder Roman Hanis. View course Details >>
We seek to create a model for carbon negative living, which provides abundance for the living communities on all levels. The vision is to implement a multi-layered agro-forestry model, which also incorporates and nurtures the preservation of ancestral shamanic traditions, medicinal plant, as well as exploration on ancient techniques of Terra Preta (“black earth”) where ancient cultures successfully developed large areas of thick fertile soil. These� ancient traditions hold the keys in both quite literally creating a sustainable foundation and then nurturing the life stemming from it.
It is crucial that we spend our energy creating small living models that are able to explore and evolve organically as we learn and live. It is through these living models that we will truly be able to collaborate with indigenous communities and pool our wisdom together. And it is through these living models that we connect to the languages of nature and develop our own intuitive knowing.