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: https://www.iowalearningfarms.org/page/webinars.

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

March 25 Webinar: Carbonate, the Other Soil Carbon

Iowa Learning Farms will host a webinar on Wednesday, March 25th at 12:00 pm, which will focus on carbonate research and the potential for carbon storage in Iowa soils.

Wind-blown loess soils of western Iowa contain a significant amount of calcium carbonate in the form of the mineral calcite. These soils are naturally calcareous due to the calcium carbonate that formed from minerals originally deposited in glacial parent material. Some carbonate is present in the form of carbonate nodules, which can readily be seen in the soil profile. How much carbon is stored as carbonate in Iowa’s soils? Are there land management practices that degrade or stimulate carbonate deposition? Mark Rasmussen, Director of the Leopold Center for Sustainable Agriculture, will discuss these questions, as well as other aspects of the research being done on carbonate, during this webinar.  

“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,” said Rasmussen. “A major focus of our study is to understand the biological and chemical processes that result in carbonate formation including the carbon source used in its formation.”

A Certified Crop Adviser board-approved continuing education unit (1 CEU) is available for those who are able to participate in the live webinar. Information about how to apply to receive the credit will be provided at the end of the live webinar.

Don’t miss this webinar!

DATE: Wednesday, March 25, 2020

TIME: 12:00 pm

HOW TO PARTICIPATE: shortly before 12:00 pm on March 25th:

Click this URL, or type this web address into your internet browser: https://iastate.zoom.us/j/364284172

Or, go to https://iastate.zoom.us/join and enter meeting ID: 364 284 172 

Or, join from a dial-in phone line:

Dial: +1 312 626 6799 or +1 646 876 9923

Meeting ID: 364 284 172

The webinar will also be recorded and archived on the ILF website, so that it can be watched at any time. Archived webinars are available at https://www.iowalearningfarms.org/page/webinars.

Hilary Pierce

Another month of growth…

Over the last two weeks, Iowa Learning Farms team members (with help from our friends at Practical Farmers of Iowa) have been visiting ISU Research and Demonstration Farms statewide, checking up on our cover crop mixture plots planted as part of the National Conservation Innovation Grant.   Our visits to the six sites include collecting fall above-ground biomass from each of the cover crop plots, the final water sampling of the season, and winterizing the suction lysimeters until sampling resumes in spring.

In a previous blog post, I shared photos from the Armstrong Research and Demonstrations Farm in Southwest Iowa from our trip there at the end of September.   After another month-plus of growth, the cover crops are flourishing!  So for comparison purposes, let’s take a look post-harvest:

Treatment #1: Single Species Cover Crop (rye pictured here in corn plots)

Treatment #1: Single Species Cover Crop (Rye in corn plots, 9/26/2014)

Treatment #1: Single Species Cover Crop (Rye in corn plots, 11/5/2014)

And how about those mixtures?

Treatment #2: Cover Crop Mixture (Blend of rye, radish, and rapeseed shown here in corn plots)

Treatment #2: Cover Crop Mixture (Blend of rye, radish, and rapeseed in corn plots, 9/26/2014)

Treatment #2: Cover Crop Mixture (Blend of rye, radish, and rapeseed in corn plots, 11/5/2014)

And a few views from the soybean plots:

Cover Crop Mixture used in Soybeans (Blend of oats, radish, and hairy vetch)

Cover Crop Mixture used in Soybeans (Blend of oats, radish, and hairy vetch, 9/26/2014)

Cover Crop Mixture used in Soybeans (Blend of oats, radish, and hairy vetch, 9/26/2014)

Collecting water samples from suction lysimeter in Cover Crop Mixture plots (Blend of oats, radish, and hairy vetch, 11/5/2014 – All species present, but definite frost damage observed here)

Two sets of biomass samples are collected in each plot:

DSCN8439

Biomass Sampling in Progress: All cover crops within the quadrant are cut at ground level, collected in bags, and brought back to ISU for analysis to determine the amount of cover crop growth (# biomass/acre) and well as total carbon/total nitrogen content of the cover crop biomass collected. Biomass is collected in the fall (as close to hard freeze as possible) and in the spring (as close to termination as possible).

 

Want to learn more?   Join us for one of our upcoming November field days!   Detailed information for each is available on the Iowa Learning Farms website.

Nov. 12, 10:30 am-12:30 pm
Wallace Learning Center at Armstrong Research Farm
Lewis

Nov. 18, 10:30 am-12:30 pm
Borlaug Center at Northeastern Research Farm
Nashua

Nov. 19, 10:30 am-12:30 pm
Fire Department building
Kanawha

Nov. 20, 10:30 am-12:30 pm
Rob Stout farm, Washington Co.

Nov. 25, 11 am-1 pm
Truro Lions Club, Madison Co.

Ann Staudt