THE STORY OF THE INGA TREE

As narrated by Mike Hands, Founder, Inga Foundation.

For generations, slash-and-burn agriculture has been a way of life for subsistence farmers in rural Honduras, as elsewhere in the tropics, because they know no alternative. Families clear-cut and burn patches of rainforest to create plots of fertile soil for growing their basic food crops. However, the soil fertility does not last. After a few cycles, crops fail and soils erode. This forces families who depend on slash-and-burn agriculture to keep clearing new patches of rainforest every few years just to survive. In some parts of the world, such as localities in mainland southeast Asia, traditional cyclical slash-and-burn practices have been found to be more ecologically sustainable.

Mike Hands, a tropical ecologist from the UK, witnessed rainforest destruction from slash-and-burn and resolved to find out why farm plots in Honduras lost fertility so quickly.

He spent more than 15 years on trials, leading four projects as a Cambridge University researcher investigating which indigenous trees could best withstand climate shocks, anchor and enrich soils, and provide many other benefits to rural farm families living in poverty. Finally, he and his collaborators found what they were looking for: the Inga tree.

Land for Life

The Inga is a genus of tree with outstanding qualities for nourishing tropical soils and restoring soil fertility. While other tree species failed the test of resilience to climate shocks in the original Cambridge University trials, the nitrogen-fixing Inga tree was found to not only stabilize and replenish the soil but also to prevent erosion and protect watersheds and wildlife.

The Inga Foundation, named after the tree, was created to support the application and expanded use of the Inga Alley Cropping method in Honduras and beyond, as a proven effective alternative to slash-and-burn agriculture; and as a way of addressing rural poverty and creating rural wealth through a rejuvenated, agroforestry-based ecosystem.

Mike and the all-Honduran team of foresters, agronomists, field and nursery staff began the Land for Life Project in 2012 to promote the use of Inga Alley Cropping – a fully integrated ecosystem that naturally recreates conditions of the forest floor. The system effectively anchors a family to a single plot of land, allowing the entire family to work together close to home and eliminating their dependence on slash-and-burn agriculture, and helping them to achieve “land for life”

Inga Alley Cropping involves creating alleys lined with nutrient-fixing trees, within which farmers can produce food crops, such as beans and maize, for their families’ survival, as well as cash crops for sale. The trees need to be densely planted (5,000 seeds per hectare) for resilience, to provide all the nutrients needed by the crops, and for soil protection. The method has been demonstrated to provide food and income security and eliminate the need for environmentally destructive slash-and-burn methods that destroy forests. Thanks to demonstration sites, its popularity is now spreading significantly among Honduran farmers, with the potential to spread much wider.

Initial pilots focused on eight local Inga species. A few more were added in the later plantings in Honduras and were outstanding performers, particularly I. oerstediana and I. edulis. Local provenances are always preferred.

The project started with 40 families and has added 40 more families each year; the graduate practitioners of the scheme now exceed 450 families.

The Inga Foundation provides the Inga seeds and cash crop plants (vanilla, turmeric, rambutan, allspice, black pepper, and hardwood trees) at no cost to each new family. The family provides the land, labor, and care on steep, degraded plots close to home, once called “sterile”. Within two years, there is annual pruning for firewood and a protective layer of mulch from the leaves stripped from the branches that protect the soil and prevent erosion. The nitrogen-fixing trees, planted in hedgerows, stabilize and enrich the soil. It is truly a low-input system. The Land for Life Project in Honduras serves as a model for sustainable, organic, regenerative agroforestry in the tropics.

Once farmers hear about the system from friends or relatives, they are eager to visit the Foundation’s demonstration farm and training center at Las Flores. The project has a 12-person full-time team of all Honduran foresters, agronomists, and field and nursery staff. The team all farm themselves, so they understand the challenges.

The farmer-to-farmer sharing of Inga seed takes place spontaneously as families plant several Inga seed trees. They have seen that Inga alleys produce food even during seven-month droughts and after eight inches of rain during deluges – and that all the Inga alleys survived the November 2020 back-to-back hurricanes with little to no damage. This farmer-to-farmer initiative ensures the natural expansion and lasting success of the system. The Foundation is in the twelfth year of the Land for Life Project. They have demonstrated, at landscape scale, and for the first time in the humid zones of Central America, a practical and sustainable alternative to slash-and-burn methods, which reverses environmental and soil degradation, as well as eliminating poverty and food insecurity. Families are empowered while protecting, enhancing, and restoring environments.

Over 5.5 million trees have been planted in Honduras under the Inga Alley Cropping scheme. The work of the Inga Foundation has created 100% sustainable food security for families whose Inga Alley Cropping plots are established for 18 months or more. Food security here means the stark difference between a good crop produced in a system that is resilient to climate violence and a poor crop from the previous unproductive slash and-burn agriculture system. Families’ nutrition is also enhanced: the Inga trees retrieve, retain, and recycle essential plant nutrients from the mineral mixture added at the outset.

Laboratory data showed much higher agricultural yields from plots with rock-phosphorus added, but also higher phosphorus content in the grain itself, better for nutrition. This principle applies to other nutrients and micro-nutrients.

Rural livelihoods are improved, as participants do not have to take on debt via loans. Women, young people, and older farmers are full participants, with some modifications as needed. The Inga Foundation works with family units or households on their land. About 6–8% are single-parent families, usually headed by widows. Extra manual labor is provided to help such families establish their Inga Alley Cropping system. The same is true for elderly people of either gender: provisions are made to lend them extra “muscle” to establish the system.

"There are no loans, debt or microloans – the program is by and for the families as they are trained at their plot and make all planting decisions. Slash-and-burn agriculture stops as soon as families plant their basic grain alley of hedgerow plantings of Inga tree species. All have 100% food security in 18–24 months and none have gone back to slash-and-burn agriculture. The Inga Tree Model is a grassroots program by and for the families."
- Mike Hands, Founder, Inga Foundation

The system eliminates chemical fertilizers, herbicides, fungicides, pesticides, fossil fuel intensive inputs, GMO seeds, and heavy equipment (with only a small supplement of mineral rock phosphate/lime required). Therefore, agrochemical run-off is stopped, promoting watershed integrity and biodiversity protection. The Foundation sees far more biodiversity in the Inga plots themselves, and in the secondary vegetation which has been spared burning; in comparison with the fire-climax grass-scrub vegetation of the original degraded sites. In the future, these observations will be strengthened by professional biodiversity surveys.

Stems and branches from annual pruning of the Inga trees are also a source of renewable firewood – which means that families do not have to harvest forest trees. Excess Inga wood may be traded or sold. An overall observation from the program sites is that the Inga Alley Cropping system has reduced migration to Honduran cities by creating more viable rural livelihoods. Its steady uptake by rural farming families can be explained by the fact that it provides what they need most: food security in basic grains.

"Tree-based systems are resilient to climatic violence, whether as drought or hurricanes. Enhanced soil organic matter acts as a sponge, retaining water and releasing it slowly. Thick mulch reduces evaporation from the soil to almost zero."
- Mike Hands, Founder, Inga Foundation

How Challenges are Addressed

Farmers need to be convinced to change behaviors from the old slash-and-burn ways, it was all they ever knew. It takes demonstration to convince a family to change practices – the demonstration site and leadership of the local Honduran farmers (all using the method themselves) have been pivotal.

At the start of the program, demonstrations were indispensable; now, farmers’ first encounter with the system is often with an Inga-farming neighbor. Nonetheless, the Foundation still uses the demonstration facilities.

With the benefit of these refinements over years of trials locally in Honduras, the Inga Foundation believes the Inga Alley Cropping system could be trialed more widely throughout the humid tropics.