"Soil and vegetation are being lost at an alarming rate around the globe, which in turn has devastating effects on food production and accelerates climate change," Iceland's President Olafur Ragnar Grimsson said in a statement.

The planet will need to produce ever more food with the world population set to rise to nine billion by 2050 from 6.1 billion in 2000 and 1.7 billion in 1900.

"With a rising world population and biofuels, more land is needed," said Andres Arnalds, Icelandic head of the meeting's organising committee.

He said that land degradation and desertification was a "silent crisis" -- according to some estimates, an area the size of Iceland loses it vegetation every year.

UN reports this year say that global warming will shift rainfall patterns and cause more frequent floods or droughts, adding to desertification that may mean more hunger for hundreds of millions of people in Africa and Asia.

VIKINGS

The experts will debate ways to improve soil productivity, use water more efficiently and safeguard plants and animals vital to renewing soils. Iceland is now virtually barren, for instance, but forests covered up to 40 percent of the island before Viking settlers arrived and felled trees for fuel. "By protecting the soil we're addressing climate change, aiding biodiversity and improving livelihoods," said Zafaar Adeel, head of the UN University's Canadian-based International Network on Water, Environment and Health.

"We should be irrigating only the most productive soils, and then sparingly," said Andrew Campbell, Australia's first National Landcare Facilitator, of ways to confront the worst drought in Australia since at least the 17th century.

He also said that measures such as enforcing existing laws on land use or better food labelling could help. "If you buy a steak in a supermarket you can't tell if it's from a property that's overgrazed or one that's well managed," he said.