Small farms best for environment: organic group

In contrast, organic farms could increase output by 10 times by growing many different species of plants at the same time, which helped retain soil and water, she said. "In a one-acre farm in India they can grow 250 species of plants," she said.

FEEDING 9 BILLION PEOPLE

The U.N.'s Food and Agriculture Organization Director General Jacques Diouf said last December there was no reason to believe that organic agriculture can substitute conventional farming systems in ensuring the world's food security.

"You cannot feed six billion people today and nine billion in 2050 without judicious use of chemical fertilizers."

Shiva has began a civil disobedience campaign in India against the patenting of natural seeds, particularly of crops that resist flooding and drought and can better withstand climate change.

"We need this worldwide. Seeds are for everyone," she said.

According to IFOAM, a quarter of greenhouse gases are emitted by industrially farmed crops and livestock. The proportion rises to 40 percent when including the emissions caused by transporting commodities around the world.

IFOAM members also criticized the production of fuel from grains, citing a U.S. university study that it took 1.3 gallons of fossil fuel to make 1 gallon of ethanol from corn.

The United States and Brazil defended their use of corn and sugar cane to make ethanol to fuel cars at the UN food summit saying it was a minor factor in food price inflation.