The magic bean

The magic bean

Julian Pettifer travels through Guatemala, Honduras and Brazil to investigate the story of a plant which could feed the world, the magic mucuna bean.

I am inclined to be sceptical about agricultural revolutions. About 40 years ago, we heard so much about "the Green Revolution" that would banish hunger and usher in an age of plenty.

That revolution was the exact opposite of what today would be considered "green". It was industrial and technological: a revolution in food production using chemical fertilisers, herbicides, pesticides and a range of so-called "miracle" crop varieties.

It certainly achieved several decades of rapidly increasing food production, but there are still hundreds of millions of people who are under-nourished and the outlook for them is gloomy.

Grain being planted in unploughed ground in Brazil

Professor Jules Pretty, Director of the Centre for Environment and Society at Essex University argues that poor producers cannot afford expensive technology, and therefore must find solutions based on existing resources.

The mucuna bean

One of those existing resources is the mucuna bean. It is cheap, effective and easy to use.

On Professor Pretty's advice, I went to Guatemala and Honduras where mucuna has been widely promoted by non-government organisations working among the rural poor.

Mucuna provides the best solution to their biggest problems: how to improve crop yields on steep, easily eroded hillsides with depleted soils.

When the peasants cut down and burn the forest, the land begins to lose its productivity. As the soils lose their ability to absorb water, they are easily washed or blown away.

This is where mucuna provides all the answers.

Farmers first plant the beans which produce masses of vigorous growth. Then, maize is planted into the residues of the beans which are left to rot on the surface of the land. Subsequently, beans and maize are grown together.

As the soil improves, yields of grain are doubled and even trebled. Mucuna produces 100 tonnes of organic material per hectare, creating rich soils on rocky hillsides in just two or three years.

It also produces fine compost and almost wholly suppresses weeds. The land never needs to be ploughed.

75% of terrain in Central America is mountainous

Moreover, mucuna produces its own fertiliser. Like many leguminous plants, the magic bean takes atmospheric nitrogen and stores it in the ground where it can be utilised by other plants. This is enough to triple maize yields.

As I saw in Honduras, results like that can turn abject poverty into modest prosperity.

New hope

I visited the small town of Guinope, two hours' drive from the capital Tegucigalpa.

Twenty years ago, Guinope was a dying community, as many of its small farmers gave up the struggle to feed their families and fled to the cities.

Today, some of those fugitives are returning to their abandoned land and are making it fertile and productive.

Nodules in which bacteria fix nitrogen

I spent a day with Elias Zelaya, a pioneer of sustainable farming who has spread the message of the magic bean to scores of other small-holders in the area.

As I walked the hillsides, visiting neighbours with him, there was a refreshing absence of that sense of despair that pervades too much of Central America.

Even farmers with the poorest soils are able to increase their yields dramatically with very little investment other than knowledge.

Brazil at the forefront of sustainable farming

But mucuna is just one of a number of crops which are transforming farming in Central and South America.

I was astonished to discover that Brazil is in the very forefront of sustainable farming.

Fourteen million hectares of arable land is never ploughed.

Elias Zelaya

Using the "zero tillage" system, it is in permanent cultivation, using a wide variety of cash crops, cover crops and green manures.

In Santa Catarina State, government agricultural policy is increasingly radical.

"The government has thrown down a challenge to make Santa Catarina the first Brazilian state to be free of the use of agrochemicals," said local government adviser Jose Cesare Pereira.

In the state of Rio Grande du Sul, 95% of arable land has become zero-tillage in the past decade and sustainable farming is promoted with evangelical zeal. Brazil, that was so recently the by-word for environmental destruction, is now setting the agenda for sustainable management of its natural resources.

That's good news for Latin America and for all of us.

The magic bean: Sunday, June 10th at 18.15 BST on BBC 2.

Reporter: Julian Pettifer
Producer: Suzanne Campbell Jones
Deputy Editor: Farah Durrani
Editor: Fiona Murch