One would suspect that the soils that form on Earth's surface thousands of years ago would have little in the way of carbon. However, the findings of a recent report have been found to be the exact opposite. The ancient soils were discovered to have a very high carbon count, adding another dimension to our planet's carbon cycle.
These findings, which were reported in the journal Nature Geoscience, suggests that deep soils have long-buried stock of organic carbon which through erosion, agriculture, deforestation, mining and other human activities could contribute to global climate change.
Erika Marin-Spiotta, a University of Wisconsin-Madison assistant professor of geography and the lead author of the new study states, "There is a lot of carbon at depths where nobody is measuring. It was assumed that there was little carbon in deeper soils. Most studies are done in only the top 30 centimeters. Our study is showing that we are potentially grossly underestimating carbon in soils."
The soil studied by Marin-Spiotta and her colleagues is known as Brady soil. It was formed between 15,000 and 13,500 years ago in what is now the Nebraska and Kansas area. While most of the Great Plains area was covered by loess after the glaciers retreated, this area was not glaciated but underwent radical change as the retreating glaciers sparked an abrupt shift in climate. However, as displayed on an eroding bluffing in the area, when exposed, this fossil soil could contribute to climate change. When disturbed and uncovered, the carbon is released to the atmosphere and causes it to retain more greenhouse gases.
Carbon in the soil is great news for farmers as it helps crop production, but cropping also causes the carbon to release into the atmosphere. The more that farmers tap into high carbon areas, the more carbon is released into the atmosphere.