How does it work and why does it matter?
Here are five short films which tell the story of how and why Inga Alley Cropping was invented.
What is slash and burn?
Slash and burn is a subsistence farming method used by millions of families in the tropics. Farmers cut down and burn a patch of forest in order to create an area of fertile soil on which they can grow their food. However, the soil fertility is short lived. Once cleared of trees and exposed to the strong tropical climate, the bare soil is rapidly stripped of nutrients. The first year following the slash and burn method often gives a good crop, the next year less so and, by the 3rd year, crops often fail completely. In order to survive using such an ineffective method, families must clear fresh areas of rainforest every few years.
What is Inga Alley Cropping?
Mike Hands developed the revolutionary method of Inga Alley Cropping through a decade of research alongside Cambridge University. After researching a number of alternative methods, the only truly sustainable system to emerge was Inga Alley Cropping. The Inga species are nitrogen-fixing trees capable of maintaining soil fertility and good harvests year on year. Breaking the cycle of slash and burn allows families to gain long term food security on one piece of land.
A year in Inga Alley Cropping
Once the Inga alleys have developed, the Inga trees are pruned at chest height. Their role at this stage is to provide shade that will inhibit the growth of weeds. Next the branches are stripped of leaves and are laid on the floor to break down and provide mulch, thus protecting the soil and preventing further weed growth. Larger branches are used as firewood, allowing families to obtain all the wood they need for cooking from the Inga plots and avoiding further deforestation.
The crop is then planted through the mulch within the pruned alleys. As it grows, the Inga also recovers, providing the crop with some shade and protection from the sun. Once fully matured, the crop is harvested. The Inga is then left to grow until the next planting season arrives, by which time they have fully recovered and the whole cycle is ready to be repeated.
This system delivers huge benefits by ensuring a reliable harvest year on year from the same plot of land with minimal labour required. By recreating the conditions naturally found on the forest floor, Inga out-competes the aggressive invasive grasses which normally dominate the farmers’ plots.
This biological weed control is hugely important as it removes the need for extensive weeding by hand or chemical means. In fact, it is often the combination of this takeover by weeds, as well as the loss of fertility, that forces farmers to abandon their plots and clear new areas of forest.