2015 is shaping up to be a big year for soil — in addition to being Global Soil Week’s third year running, the United Nations Food and Agriculture Organization has declared it the International Year of Soil. José Graziano da Silva, director of the FAO, has called soil a “nearly forgotten resource,” and has implemented more than 120 soil-related projects around the world to mark the International Year of Soil. Farming First, a global agriculture coalition with more than 150 support organizations, has also called for soil health to be a top priority in the UN’s new Sustainable Development Goals.
So why is soil so important?
“If you look at the global carbon created in nature under land-based systems, soil and trees are the two dominant reservoirs where carbon is,” Rattan Lal, director of the Carbon Management and Sequestration Center at Ohio State University, told ThinkProgress.
Soils — and the microbes that live within them — store three times as much carbon as is in the atmosphere, and four and a half times as much as in all plants and animals. “If the soil carbon reserve is not managed properly,” Lal said, “it can easily overwhelm the atmosphere.”
Climate change can stimulate the release of carbon from soil in a few different ways. Normally, carbon is bonded to minerals in the soil, which helps keep carbon locked in the soil and out of the atmosphere. A recent report by scientists at Oregon State University, however, found that when chemicals emitted by plant roots interact with minerals in soil, it can cause carbon to break free. This exposes the carbon to decomposition by microbes in the soil, which pass it into the atmosphere as carbon dioxide. As the climate warms, the scientists found, more carbon dioxide in the atmosphere will stimulate the growth of plants, which will in turn stimulate the production of the root compounds that breakdown carbon and soil minerals.
“We thought for many many years if you just increase plant productivity, soil carbon will just go up,” Kate Lajtha, professor of biogeochemistry at Oregon State University, told ThinkProgress. “What more and more models are seeing now is that the opposite is true.”
The full article by Natasha Geiling can be read at thinkprogress.org.