The search for a sustainable alternative to slash-and-burn agriculture in the World's rain forests: the Guama Model and its implementation

Abstract

This account describes the context, history and outcomes of a series of studies into the ecology of slash-and-burn (S-B) agriculture in the world's humid tropics. These studies, which began in the mid-1980s, identified promising lines of research and continued to field trials, in Central America, of candidate agricultural systems as possible sustainable alternatives to the practice. The only system to emerge from 7 years' comparative trial with any promise of sustainability, in this context, was the agroforestry technique known as alley-cropping; but only with trees of the genus Inga . Inga alley-cropping then underwent field trials with subsistence farming families in northern Honduras. The system was aimed at the twin objectives of achieving food security in basic grains, on minimal inputs, and of providing the means of eliminating further S-B in the region. Since then, Inga alley-cropping has become the heart of a sustainable and integrated rural livelihood model (the Guama Model) which is being implemented successfully in northern Honduras with some 300 families. These families had been attempting to subsist on a few hectares of land degraded by decades or centuries of S-B. The development of Inga alley-cropping, supplemented by rock phosphate and other mineral supplements, as a sustainable subsistence and cash crop alternative means that land previously being held in reserve for subsequent S-B operations can now be planted to permanent forms of agroforestry. Entire landscapes can be re-greened by productive agroforest vegetation. Achieving this at scale will require the investment of huge extension effort and funds. However, the environmental, social and economic returns are also huge; and they are sustainable. In this programme,we are seeing the vitality and goodwill of hundreds of families focussed on the raising, planting and management of trees in ways that feed the living organisms of the soil and, hence, feed themselves. In so cheerfully planting out their own futures, they plant and reshape the future of their own country. Replicating this at scale, as Rattan Lal outlines below, could reshape the future of this planet. In the mid-1980s, progress on sustainable alternatives to S-B, especially in rain forests, was frustrated by a lack of conclusiveness in the literature as to why soil fertility fails so rapidly post-burn; but also by a degree of contradiction on the impacts of the burn on certain plant nutrients. Hands (Hands 1988 The ecology of shifting cultivation. MSc thesis, University of Cambridge) concentrated on the role of soil phosphorus and attempted to resolve these contradictions. The Cambridge Alley-cropping Projects (1988–2002) continued this theme and threw light on the question of sustainable food production in rain forest environments.

Structural equation model was used to evaluate the effects of soil chemical environment, fertility and enzyme activity on eucalyptus biomass

“…Consistent with the findings of previous studies [ 40 ], soils showed a trend of acidification after multi-generational succession, but soil OM and TN were significantly elevated in sprouted second-generation stands, but fast-acting nutrient elements generally showed a decreasing trend. The soil was exposed due to violent soil disturbance (slash and burn) during the new plantation process, which destroyed the soil structure and caused a large loss of SOM and nutrient elements in the T0 and T1 stands [ 41 , 42 ]. After mature felling of newly planted forests, the sprouting and re-growth operation was adopted, which does not require clearing of harvesting residues, so nutrients were gradually accumulated within the soils of second- and third-generation stands [ 43 ], while the accumulation of nutrient elements is also promoted by heavy fertilization.…”

senderos productivos de la bioeconomía: El caso Honduras

“…spp.) en la región del bosque húmedo del país; sobre todo, en el Departamento de Atlántida (Hands, 2021). Este cultivo permite la recuperación de terrenos al fijar grandes cantidades de nitrógeno (N 2 ), generar hojarasca que evita la proliferación de malezas y evitar la erosión; además, sirve de sombra intermedia en sistemas agroforestales con cacao (eobroma cacao) y/o café (Coffea arabica), y es clave para mejorar la seguridad alimentaria de la población, ya que su fruto es comestible.…”

RENDIMIENTO DE BANANO DÁTIL EN SISTEMA DE CALLEJONES DE Inga spp., A DIFERENTES DOSIS DE FERTILIZANTES DE POTASIO Y FOSFORO

“…This combination of plants brings about an equilibrium in the productive system favouring food security, strengthening resilience of socio-ecological systems and carbon fixing as a strategy to mitigate climate change (Colon-García, 2021). On the other hand, the Guama Model, is an agricultural production system in alleys, using Inga trees, this system is an option for achieving sustainable rural development in the humid tropics (Hands, 2021) because it increases water storage in the soil, improves soil fertility, increases cation exchange capacity (CEC) of the soil, decreases soil temperature due to litter accumulation on the surface and blocks the growth of weeds. Even though these systems offer advantages, they require external fertilization, such as in maize (Catari-Yujra et al, 2022), coffee (Sanchez, 2017), and cacao (López, 2015).…”