WASHINGTON (AP) — Science has provided the souped-up seeds to feed the world, through biotechnology and old-fashioned crossbreeding. Now the problem is the dirt they're planted in.

As seeds get better, much of the world's soil is getting worse and people are going hungry. Scientists say if they can get the world out of the economically triggered global food crisis, better dirt will be at the root of the solution.

Soils around the world are deteriorating with about one-fifth of the world's cropland considered degraded in some manner. The poor quality has cut production by about one-sixth, according to a World Resources Institute study. Some scientists consider it a slow-motion disaster.

In sub-Saharan Africa, nearly 1 million square miles of cropland have shown a "consistent significant decline,'' according to a March 2008 report by a worldwide consortium of agricultural institutions.

The cause of the current global food crisis is mostly based on market forces, speculation and hoarding, experts say. But beyond the economics lie droughts and floods, plant diseases and pests, and all too often, poor soil.

A generation ago, through better types of plants, Earth's food production exploded in what was then called the "green revolution.'' Some people thought the problem of feeding the world was solved and moved on. However, developing these new "magic seeds'' was the easy part. The crucial element, fertile soil, was missing.

"The first thing to do is to have good soil,'' said Hans Herren, winner of the World Food Prize. "Even the best seeds can't do anything in sand and gravel.''

Herren is co-chairman of the International Assessment of Agricultural Knowledge, Science and Technology for Development, a collection of scientists sponsored by the United Nations and World Bank. It produced a 2,500-page report last month which, among other recommendations, emphasized a need to improve the world's soil.

Genetic improvements in corn make it possible to grow up to 9,000 pounds of corn per acre in Africa. But millions of poor African farmers only get about 500 pounds an acre "because over the years, their soils have become very infertile and they can't afford to purchase fertilizers,'' said Roger Leakey, a co-author of the international report and professor at James Cooke University in Australia.

Soil and water issues "have been taken for granted,'' said Ohio State University soil scientist Rattan Lal. "It is a problem that is not going to be solved. It's going to get worse before it gets better.''

In Africa, farmers are forced to use practices that rob nutrients from the soil, not put it back, said Herren, who heads an Arlington, Va., nonprofit. Fertilizer is a quick, short-term fix, but even that isn't being done, he said.

The current crisis could have been avoided "if we, the world, had promoted fertilizer in Africa and we have known for ages it works,'' said Pedro Sanchez, Columbia University tropical agricultural director.

In that way, the problem with soil is a prime example of a larger failing of agriculture science, said Sanchez, who has won both the World Food Prize and a MacArthur genius grant. Scientists have the knowledge to feed the world right now, but that is not happening, Sanchez said. "It's very frustrating, especially when you see children dying.''

The fruits of biotechnology and the staples of modern agricultural scientific techniques include irrigation, crop rotation, reduced tilling, use of fertilizer and improved seeds. It's a way of farming differently instead of just using better seeds that requires extra money up-front that many African farmers don't have, scientists said.

Fixing soil just isn't "sexy'' enough to interest governments or charities, said Robert Zeigler, director general of the International Rice Research Institute in Manila, Philippines.

Zeigler's center last week planted its 133rd crop of rice in the same land since 1963, trying to pinpoint the right combination of nitrogen and fertilizer. Better seeds worked wonders. But finding money for soil health is difficult and because of that, less work is accomplished, he said.

But there are success stories, Sanchez said, pointing to the small African country of Malawi. Three years ago, the country's new president invested 8 percent of Malawi's national budget in a subsidy program to get fertilizer and better seeds to small farmers. Each farmer got two bags of fertilizer and 4 1/2 pounds of seeds at less than half the cost.

Before the program started, one-third of Malawi was on food aid and the country wasn't growing enough food for itself, Sanchez said. It was producing 1.2 million tons of maize in 2005. In 2006, Malawi had more than doubled its production. By 2007 and 2008, the crop was up to 3.4 and 3.3 million tons. Now Malawi is exporting corn.

"In two years, the country has changed from a food aid recipient to a food aid donor and is self-sufficient,'' Sanchez said. "if Malawi can do it, richer countries like Nigeria, Kenya can do it.''