Read this fascinating article outlining how a private company in Brazil has transformed vast savannahs of crappy, acidic dirt into productive soil that produces mountains of food, without chopping down the Amazon jungle: http://www.economist.com/node/16886442
Here are some snippets from the article:
[quote]In a remote corner of Bahia state, in north-eastern Brazil, a vast new farm is springing out of the dry bush. Thirty years ago eucalyptus and pine were planted in this part of the cerrado (Brazil’s savannah). Native shrubs later reclaimed some of it. Now every field tells the story of a transformation. Some have been cut to a litter of tree stumps and scrub; on others, charcoal-makers have moved in to reduce the rootballs to fuel; next, other fields have been levelled and prepared with lime and fertiliser; and some have already been turned into white oceans of cotton. Next season this farm at Jatobá will plant and harvest cotton, soyabeans and maize on 24,000 hectares, 200 times the size of an average farm in Iowa. It will transform a poverty-stricken part of Brazil’s backlands.
Embrapa is short for Empresa Brasileira de Pesquisa Agropecuária, or the Brazilian Agricultural Research Corporation. It is a public company set up in 1973, in an unusual fit of farsightedness by the country’s then ruling generals. At the time the quadrupling of oil prices was making Brazil’s high levels of agricultural subsidy unaffordable. Mauro Lopes, who supervised the subsidy regime, says he urged the government to give $20 to Embrapa for every $50 it saved by cutting subsidies. It didn’t, but Embrapa did receive enough money to turn itself into the world’s leading tropical-research institution. It does everything from breeding new seeds and cattle, to creating ultra-thin edible wrapping paper for foodstuffs that changes colour when the food goes off, to running a nanotechnology laboratory creating biodegradable ultra-strong fabrics and wound dressings. Its main achievement, however, has been to turn the cerrado green.
When Embrapa started, the cerrado was regarded as unfit for farming. Norman Borlaug, an American plant scientist often called the father of the Green Revolution, told the New York Times that “nobody thought these soils were ever going to be productive.” They seemed too acidic and too poor in nutrients. Embrapa did four things to change that.
First, it poured industrial quantities of lime (pulverised limestone or chalk) onto the soil to reduce levels of acidity. ... Embrapa scientists also bred varieties of rhizobium, a bacterium that helps fix nitrogen in legumes and which works especially well in the soil of the cerrado, reducing the need for fertilisers.
Second, Embrapa went to Africa and brought back a grass called brachiaria. Patient crossbreeding created a variety, called braquiarinha in Brazil, which produced 20-25 tonnes of grass feed per hectare, many times what the native cerrado grass produces and three times the yield in Africa.
Third, and most important, Embrapa turned soyabeans into a tropical crop.
Lastly, Embrapa has pioneered and encouraged new operational farm techniques. Brazilian farmers pioneered “no-till” agriculture, in which the soil is not ploughed nor the crop harvested at ground level.[/quote]
The Cerrado is NOT a giant wasteland. Its a very diverse ecosystem that is just as important to the entire biosphere as any rainforest. Small farm holders are neither hobbyists nor inefficient. They are more productive per square foot than any mega-farm. They are also more efficient at using resources, maintaining biodiversity and soil fertility.
Large farms growing only two or three cash crops on tropical soils is doom to failure. They cannot handle industrial agriculture...period. After a decade or two the whole system will collapse.