Quemada!

Jeremy asked recently whether shifting agriculture ((Also called slash-and-burn and swidden cultivation, and tavy in Malagasy.)) can really support growing populations. I’ve just come across (via the PLEC newsletter) a paper from Madagascar ((E. Styger, H.M. Rakotondramasy, M.J. Pfeffer, E.C.M. Fernandes and D.M. Bates 2007. Influence of slash-and-burn farming practices on fallow succession and land degradation in the rainforest region of Madagascar.  Agriculture, Ecosystems and Environment 119: 257-269.)) which says maybe.

Its objectives

were to analyze jointly with the Betsimisaraka farmers how slash-and-burn practices influence fallow species succession, and how current fallow/cropping regimes influence agricultural productivity and upland degradation dynamics.

The researchers conclude, from discussions with farmers and botanical surveys, that fallow periods have been cut by up to two thirds — to 3-5 years — in the past 30 years. This means that fallow land goes from having plentiful pigeon wood trees on it to bare, dry unproductive grassland in 5-6 rice cropping cycles, after which agriculture is no longer possible. After each cycle, the land needs to be left fallow for increasing lengths of time in order for the soil to recover fertility: “already with the third cycle after deforestation, vegetation starts to degrade quickly in parallel with agricultural productivity decline.”

The findings of this paper indicate that the tavy system with its currently short fallow periods is collapsing.

The main culprit is fire. As fallows become more herbaceous, fire is more difficult to control, and wildfires escape more easily, often “eliminating a productive plot of land for agriculture without getting any benefits of production.”

So what can be done? Try to take fire out of the equation, certainly. “The restoration of soil fertility should build on the biological potential of the system, by optimizing nutrient cycling (e.g. through residue and weed recycling, mulching) and by producing and recycling of high quality organic matter (e.g. through improved fallows and cover crops).” The key to the adoption and success of these practices will be engagement with the young, according to the authors:

The careful development of alternative agricultural practices should especially be done in collaboration with young farmers. If the young obtain a real interest in agricultural intensification, they may not feel the need anymore to leave their native villages and migrate to the forest border to undertake tavy.

Down on the levee

A riverine trifecta today, describing threats to the biodiversity — including agrobiodiversity — associated with major rivers around the world…

From Italy, news that students and teachers from the University of Gastronomic Sciences at Pollenzo (founded in 2004 by Slow Food guru Carlo Petrini) — over 150 of them —  will travel down the Po River watershed by bicycle and boat in September and October. They’ll be giving the river and its valley a source-to-delta checkup, they say, diagnosing their ills but also identifying their abiding strengths — ecological, cultural and, presumably, agricultural.

Further east, Hubert von Goisern, an Austrian musician, has done something similar — but in his own way — for the Danube. He’s spent the summer giving a series of concerts down the river for a WWF campaign to raise awareness of the damage that planned development projects will do to the habitat of the Danube sturgeon. Plans to straighten and deepen the course of the river to facilitate shipping are expected to affect a thousand-kilometer stretch, destroying a unique natural and cultural heritage.

And further east still, Nguyen Huu Chgiem, the son of a Mekong delta rice farmer, reflects on how climate change, deforestation and saltwater intrusion are affecting Vietnam’s “rice basket.” And what he can do about it now that he’s a professor of environment and natural resources management.

Lose the farmers, lose the environment

Banaue Rice Terraces2 Further to Luigi’s thoughtful article on how hard farming is becoming, and how the skills needed to farm effectively are being lost as young people abandon rural life for the city, news that a farming environment often considered the eighth wonder of the world is under threat. The Banaue Rice Terraces of Luzon in the Philippines are beyond words. But they are apparently being destroyed by giant earthworms and edible snails, among other pests. But honestly, if the people are introducing snails to supplement their diet, how sustainable can the terraces possibly be? Only human labour can sustain such artifice, and only human need can command and coordinate that much labour. The President of the Philippine Senate has called for a “comprehensive study”. But what is it likely to recommend? That maintaining the terraces be a government-funded job to keep a tourist attraction in a state that will attract tourists, and their cash? Or can the communities that have inherited the Banaue terraces somehow be shown ways in which they can benefit directly from the tourist cash?

Photo from Wayfaring Travel Guide (because Flickr doesn’t work too well here in China.)

Disappearing languages, disappearing agrobiodiversity

There are about 7,000 languages currently spoken around the world. By 2100, there will half that, if we’re lucky. That’s according to Harrison and Gregory Anderson of the Living Tongues Institute for Endangered Languages in Oregon, who “traveled the world to interview the last speakers of critically endangered languages as part of the National Geographic Society’s Enduring Voices Project.” Here’s a telling quote from Harrison Anderson:

Most of what we know about species and ecosystems is not written down anywhere, it’s only in people’s heads.

Just compare the map of hotspots of language loss with those of centres of crop origin and diversity. When the last native speakers of those 3,500 doomed languages go in the next century or so, they’ll be taking with them irreplaceable knowledge of agricultural biodiversity. Knowledge which we’ll need to make the most of that agrobiodiversity, and indeed to conserve it in situ (should we wish to) ((Or, indeed, should we be able to, given what climate change is going to do. Anyway, thanks to Ola for pointing out the article.)).