Story about the soybean boom in South America. Includes worries about damage to the rainforest.

BBC NEWS | Business | Soybean fever transforms Paraguay

What's not mentioned is that soya farmers have also used illegal GM soya, and then presented the Brazilian government with a fait accomplis : "hey, we grew this stuff, and if you force us to destroy it, we'll go bankrupt." which the government has pretty much caved-in to.

This matters because there are real (ie. not mere technophobic, anti-science) reasons to be sceptical about GM.

The basic pattern is this :

The GM in soya is designed to make crops more resistant to strong herbicide (weed-killer).

GM crop is more productive, because farmers can now blast the land with stronger herbicides to kill off all the weeds, while the GM crop resists.

After 5 - 10 years, those few weeds which did survive the herbicides, having been selected for in this tougher environment, come back, resistant to the herbicide.

The weed problem resumes, and now you need even stronger herbicide which you then have to create even more resistant crops to.

Now you have further problems.

- can you find a crop strong enough to resist an even stronger herbicide?

- the stronger herbicide is finding its way into the food chain (and rivers, and us)

- you can't do crop-rotation, because the land is now so poisonous that only the single GM crop (and the super-weeds) can survive there. GM forces you into a monoculture.

- because you can't do crop-rotation, you need to use more fertilisers to put back the nutrients back into the land.