Carbonate, the Other Soil Carbon

On Wednesday, Iowa Learning Farms hosted a webinar about research on calcium carbonate and the potential for carbon storage in Iowa’s soils.

Mark Rasmussen, Director of the Leopold Center for Sustainable Agriculture, described how calcium carbonate is formed and shared information about its distribution. Regarding the research into carbonate nodules in soil, Rasmussen explained, “We are interested in these nodules because carbonate minerals form one of the largest reservoirs of carbon on the planet and these minerals play a significant role in the long-term balance between atmospheric carbon and climate.”

A slide from the webinar, detailing estimates of carbon amounts from Monger et al., Geology, 2015

Some of the research questions being posed are:

  • How are carbonate nodules formed?
  • How much carbon in a given soil profile exists as carbonate nodules?
  • How old are these carbonate nodules?
Carbonate nodules

Rasmussen said that the group hopes to carry out research this summer at the Iowa State University Western Research Farm, where they will collect soil samples in different areas and at different depths, and then measure the carbonate. They plan to study the effect of intensive row cropping on carbonate reserves, hypothesizing that, because intense row cropping and fertilizer use slowly acidifies soil, there will be less carbonate reserve in these intensely row cropped areas compared to others.

Watch the full webinar here! We also have many other great archived webinars available here:

Join us next week, at noon on April 1, when I will be presenting on my MS thesis research: “The Effect of Stream Channel Incision on Groundwater Depth in Riparian Corridors”.

Hilary Pierce