Threats to Soil Productivity Risks Food Supplies

It turns out that we need to save our soil if we want to save our food supply. Scientists have taken a closer look at the world's soil resources and the possible ramifications for human food security in a new study.

"Soil is our planet's epidermis," said Donald Sparks, one of the researchers, in a news release. "Historically, humans have been disturbing the soil since the advent of agriculture approximately 10,000 years ago. We have no reached the point where about 40 percent of Earth's terrestrial surface is used for agricultural purposes. Another large and rapidly expanding portion is urbanized. We're already using het most productive land, and the remainder is likely to be much less useful in feeding our growing population."

The population of the planet is projected to be about 11 billion people by 2100. However, the key to producing enough food will be to find better ways to manage the agricultural lands we already have, rather than expanding into new areas.

Currently, soil erosion greatly exceeds the rate of soil production in many agricultural areas. For example, in the central United States, soil is currently eroding at a rate at least 10 times greater than the natural background rate of soil production.

"The evidence for this is in the recent spike in the price of fertilizers," said Sparks. "The primary components of fertilizer are either very energy-intensive to produce or they are mined from limited supplies on Earth. It's a classic supply-and-demand situation leading to large price increases that must eventually be passed on in the price of food."

It's likely that fertilizer prices will only increase over time, as well. It will be crucial to design better ways to protect and recycle soil nutrients in the future, and make sure that they are used by crops efficiently rather than being washed away.

"Human civilizations have risen and fallen based on the state of their soils," said Sparks. "Our future security really dependso n our ability to take care of what's beneath our feet."

The findings are published in the journal Science.

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