Dear FSN,
I am Mike Hands, a Founder/Trustee of Inga Foundation in UK. I was a Researcher in the University of Cambridge for 16 years, but based mainly in Central America (1986-2002). We were researching the Ecology of slash-and-burn agriculture in an acid-soil rain forest environment; and particularly conducting long-term trials of different cropping systems for the production of basic grains.
I would like to draw the Forum's attention to Inga Foundation's Land for Life Program in Honduras which has been implementing the findings of the four Cambridge projects since 2012.
The context here is highly-degraded soils on steep, rocky hillsides in the Cordillera Nombre de Díos. Many of these sites have been subject to slash-and-burn episodes repeated over a period of more than a century, in most cases. The farmers who now own these small farms describe them as "estéril" (Sterile); they are generally dominated by invasive fire-climax grasses and/or scrub vegetation.
By planting Inga trees in dense alley-cropping (a-c) configuration; and by adding mineral supplements (Rock-P, Dolomitic Lime and K-Mag), we have been able to restore the fertility and moisture-holding capacity of these soils within 2-3 years.
Around 500 families are currently, and successfully, implementing Inga a-c which is at the heart of a broader agroforestry model known there as the Guama (Inga) Model. Inga a-c is a mulching system that generates its own Nitrogen inputs to the soil. These families have achieved food-security in basic grains in the face of climatic extreme conditions. In the prolonged droughts of 2016, 2019, 2023 and this year, the only farmers to take in grain crops were those using the Inga a-c system. The key to its success is that the soil is never exposed to the full force of the sun; it is protected, firstly by the dense Inga canopy; and secondly, following annual pruning, by a deep mulch of Inga leaves. This retains residual moisture within the soil, making it available to the crop.
The system is being replicated in 15 other humid tropical countries.
Once the families have achieved food-security in basic grains on permanent Inga-c plots, they can remove residual land from the slash-and-burn cycle and can plant more extensively-managed agroforest systems; the remaining three components of the Guama Model. They produce a wide diversity of cash-crops, fruit crops and, eventually, fine tropical timber. The model has transformed the families' economies; it is regenerating springs of fresh water and is re-greening the landscape.
Here is the point regarding resilience: Tree-based systems, like forests, are resilient to both drought and violent storms because the roots anchor the soil, which can receive and retain massive volumes of rainfall without erosive damage. Soil Organic Matter (SOM) under forest acts as a sponge, releasing water slowly. As outlined above, the canopy, litter layer and/or mulch resist violent rainstorms.
The model is outlined in a recent publication by The Royal Society Open Science platform:
Hands, M. R. 2021: The search for a sustainable alternative to slash-and-burn agriculture in the World's Rain Forests: The Guama Model and its Implementation.
Royal Society Open Science. Vol. 8: Issue 2.
The Royal Society. London.
https://doi.org/10.1098/rsos.201204
and is better described on: www.ingafoundation.org
Thank you for your kind patience if you have read this far
Mike Hands
Inga Foundation
M. Mike Hands