Inga

25 October 2020

Sipapu looks to nature for inspiration as we begin our first steps to sustainable food security 

The question of how to achieve sustainable farming in the tropics is a huge one,  considering how much deforestation in the Amazon is driven by traditional slash and burn agriculture. We’re grappling with the question, albeit on a smaller scale.

Food security is essential for a functioning community, but how do we go about it? It needs to be organic, low-maintenance, low-tech, relatively easy to do, produce all the food needed and be sustainable in the long-run.  It’s a challenge, and the solution as ever is found in nature itself. 

So how does nature do it? 

Tropical forests are the most productive in the world, producing 15-25 tonnes of biomass per hectare, compared to 2 tons of maize an agricultural plot of the same area. And you’ll be surprised to learn that the tropical forest has some of the world’s poorest soils.

So what’s the secret? In a word: recycling.

Nutrients are precious and the object of tough competition. Nothing is wasted. Walking through the jungle you might fight yourself covered in butterflies or bees desperate to get the salt from your sweat. Or you might find dung beetles rolling away some precious caca or a fallen tree covered in fungus. Everything is adapted to finding, producing and managing nutrients. All of which comes together to create the finely tuned web of complex ecological relationships that is the neotropical rainforest .  

Slash and burn it 

This complex and highly evolved system disappears when a farmer looking for food security for his family or a little income from cash crops, picks up his machete and starts to chop. The debris is burnt away, leaving behind empty land ready for planting.

A popular crop these days is papaya. It’s planted in high density and sprayed with every chemical imaginable and for two years, maybe three, big bags of papaya are taken to the market. It all comes to a halt when the soils, drained of nutrients, finally give up and the papaya stops producing. The land is left for dead and it all begins again when the farmer picks up his trusty machete and heads for the next patch of jungle. 

Kind of easy, but not so sustainable, at least, not on human timescales. 

Nature’s Solution 

When the aim is to achieve a more harmonious relationship between people and nature, the solutions are never simple. The list of requirements for alternative systems is almost endless; it must be able to be productive on degraded soils, provide food security and/or income, not be too complicated, require little economic input and of course be organic, especially in the sense of not using chemical fertilisers or pesticides (tempting though the latter might be!)

Luckily, we have an incredible system of sustainable abundance to draw from: the jungle itself. 

Looking at how  plants within this system are so productive is key. They’re full of adaptations to poor soils, e.g. is buttress roots of many Amazonian trees. As the scant nutrients that exist in the soil are limited to the top few centimetres, plants develop shallow root systems. Trees need support, hence the long winding roots across the surface of the soil.  

Inga, a species of guava, has many adaptations that enable it to grow quickly on degraded soils. It’s a pioneer species. Inga recruits other symbiotic organisms to bring in the all-important nutrints. Bacteria in the roots fix nitrogen from the atmosphere in the soil. Fungi do the same for phosphorus. These systems deliver the two most important nutrients for growth.  

Sure, Inga deploys these nutrients for its own growth, but it also recycles them via leaf fall and mulch. Decomposing leaves release nutrients into the soil, while the constant cover encourages roots systems and protects the soil from the harsh tropical sun. 

As part of an agricultural system, inga is able to regenerate degraded soils and keep them productive consistently for years without the use of fertilisers and pesticides.

Analogue Forestry: Inga AlleY CROPPING

Now for the food! 

Inga Alley Cropping involves planting long rows of inga at 2m intervals, with a 6m wide “alley” in between.

The space in the middle benefits from the pioneering soil enriching and maintaning of inga. By pruning  the inga twice a year, there’s a huge input of leaves to create mulch. It helps prevent weeds, retains soil-moisture in the dry season and assists in pest control. Once the system is established  in 2-3 years, there’s minimal maintenance, no inorganic inputs, little economic investment.

Inga Alley Cropping is not particularly difficult to set up, and it can provide  food security for years to come.  It’s a tried and tested permaculture method pioneered by Mike Hands, with more than 20 years of research at Cambridge University and Kew Gardens in the UK.

The Inga Foundation set up by Mike Hands has worked successfully with many communities in Latin America and tropical Africa’.  

We’re so excited to initiate this project. Food security is a key component of our Phase 1 Sustainability Plan.  So far, we have been planting seeds and replanting seedlings. Next, we’ll be digging our first alleys. 

Follow us here and on Instagram for further updates!

THANKS TO

Laura Coomber and Hannah Woolhouse for research, project initiation, and words and pictures. Plant drawings by Hannah Woolhouse

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