The role of Inga alley-cropping in two of the five major components of the "Guama" (..or "8-hectare") Model in a sustainable, low-input rural livelihood for the humid tropics.

The first point that must be made is that the model is a flexible response to the individual family's needs and aspirations; it is not a rigid prescriptive formula.

The model reflects a demographic fact in Honduras  :  We are told that the average area of degraded (usually steeply sloping) land available to such a family for the purposes of slash-and-burn agriculture is about 8 hectares.  This, formerly forested land, will almost invariably, be covered in, at best, secondary scrub vegetation; more commonly, in fire-climax grassland.  It will be degraded in fertility and structure; and, because of its dominance by the perennial grasses, will be exceedingly hard to keep weed-free during crop growth.

Normally, several hectares will be slashed-and-burned annually; solely to satisfy the family's basic food requirements.  No alternative use of any of the 8 ha. can be contemplated because all of it will be subsumed into short-rotation burning at perhaps 2-3 year intervals.  This is insufficient, by a huge margin, to replenish the the soil's fertility.  Nutrients are leached out of the soil with every burn; yields decline year-on-year; and weeding becomes increasingly, and inescapably laboursome.  (>60 man-days. ha^-1. yr^-1 are common; the figure can easily exceed 100 md.).

In contrast, we are finding that 2+ years under a developing and closing Inga canopy, before first pruning, achieves the virtual 100% elimination of the grasses from the site.  Thereafter, the mulch from the annual or biannual prunings smothers any weed regeneration.  We have documented case-histories of maize crops being taken after zero weeding inputs in an Inga a-c plot.

These, and other factors, coalesce to form the foundations of a sustainable subsistence system.  Food-security is the indispensible pre-condition for any sustainable low-input rural livelihood:

A  single hectare of Inga a-c has been found sufficient to achieve this; in place of the 8 ha. of unsustainable slashed-and-burned scrub/grass that it replaces.

Taking the model at its simplest, the vital factor of food-security liberates 7 ha. for other uses; and the land-use pattern might appear thus:

1 ha. of Inga a-c for basic grains.
1 ha. of Inga a-c for cash-crops.
1 ha. of low-maintenance fruit trees (eg. citrus) as a low-input cash-crop.
5 ha. of degraded land for reforestation and carbon-capture.

....or in whichever combination of components; on whatever area of land, that the particular family sees fit to deploy.  All of these components have been proven individually on the ground.

The "Guama" (...or "8-hectare") Model of land use  :  Schematic table