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What grass farmers have known all along—research shows grass sequesters carbon

By Martha Holdridge, West Wind Farm

Editor's note: This article is reproduced with permission from the Summer 2008 Grassfed Gazette, published by the American Grassfed Association.

American Grassfed Association member Martha Holdridge, owner of West Wind Farm, used soil samples to determine that her West Virginia farm sequestered 15 tons of CO2 per acre over the past four years (photo by Kenny Kemp, Charleston WV Gazette).

From 1987 to 2007, at West Wind Farm, we regularly sent soil samples from our pastures to the West Virginia University (WVU) testing lab--in some years requesting organic matter tests. In those same years, there has been increasing public alarm about greenhouse gasses and global warming. In the fall of 2007, Dr. Ed Rayburn, extension forage agronomist at WVU, reminded me that an increase of organic matter in the soil means that carbon dioxide (CO2) is being drawn from the air into the soil. He kindly agreed to calculate the rate of carbon sequestration in the pastures of West Wind Farm.

Our average organic matter in 2002 was 4.1 percent, in 2004 it was 7.0 percent, and in 2007 it was 8.3 percent. According to Rayburn’s calculations based on a 2-inch deep sample, over five years (2002-2007) we had sequestered 15 tons of CO2 per acre or four tons of carbon per acre.

Measuring or estimating soil carbon

How do you measure or estimate soil carbon?

Here are some handbooks

1. Peter Donovan. Measuring soil carbon change: a flexible, practical, local method. 2010. A basic guide for do-it-yourselfers and the method for the Soil Carbon Challenge. Includes planning worksheet and plot data sheets.

2. Pearson, Timothy, Sarah Walker, and Sandra Brown. 2006. Sourcebook for Land Use, Land-Use Change and Forestry Projects. Winrock International.
http://www.winrock.org/ecosystems/files/Winrock-BioCarbon_Fund_Sourceboo... (661 K pdf file; right click and "save link as" to download)

Winrock also has a sampling cost calculator available from
http://www.winrock.org/ecosystems/tools.asp

3. Stolbovoy, V., Montanarella, L., Filippi, N., Jones, A., Gallego, J., and Grassi, G. 2007. Soil sampling protocol to certify the changes of organic carbon stock in mineral soil of the European Union. Version 2. European Commission, Joint Research Centre. ISBN 978-92-79-05379-5
http://eusoils.jrc.ec.europa.eu/esdb_archive/eusoils_docs/other/EUR21576...

summary poster:
http://eusoils.jrc.it/ESDB_Archive/eusoils_docs/Poster/Soil_Sampling.pdf

4. McKenzie, N., Ryan, P., Fogarty, P., and Wood, J. 2000. Sampling, measurement, and analytical protocols for carbon estimation in soil, litter, and coarse woody debris. Australian Greenhouse Office, Technical Report 14.
http://www.greenhouse.gov.au/ncas/reports/tr14final.html

5. Harnessing Farms and Forests in the Low Carbon Economy: How to create, measure, and verify greenhouse gas offsets edited by Zach Willey and Bill Chameides, Duke University Press, 2007.

Carbon farming in Marin County, California

An article from ODE magazine about soil carbon research and trials in Marin County, California.

". . . John Wick--who owns this ranch in the hills of Marin County north of San Francisco with Peggy Rathmann, author of the classic picture book Goodnight Gorilla--goes on to outline the climate crisis in terms all-too-familiar to anyone paying attention to the issue. But he then offers a solution that would astonish most people, especially green activists: 'Eat a local grass-fed burger.'"

Liquid, mycorrhizal carbon not often recognized

Christine Jones published an article in the Australian Farm Journal that may help to explain why the assumption is widespread among agricultural scientists that soil carbon cannot be increased quickly. The Roth C model, for example, ignores the role of mycorrhizal soluble carbon, focusing entirely on biomass input for humification:

The quiet carbon revolution in Australia

A short article from Australia on the work of Christine Jones:

"Thousands of farmers are joining a voluntary soil carbon movement adopting specialised cropping and pasture practices to improve yields and income, while measuring loads of carbon storage on their farms."

"But the Senate inquiry, looking into the impacts of climate change on agriculture, also heard the results have been largely shunned by the science fraternity because the carbon storage data does not fit into existing carbon models."

The soil organic carbon story

A good introduction to agricultural soil carbon -- what it is, what it does, how it forms -- from Saskatchewan, Canada.

Tool testing

For the really big problem(s) that we face such as biodiversity loss, scarcity of food and water, land degradation, and climate change, the available tools might be crudely lumped into these four columns. The three rows are a crude simplification of Holistic Management testing guidelines. The last row is similar to the social weak link guideline. For example, if we want to provide incentives or payments for ecosystem services, it must first become conventional wisdom for the organization to disburse the money.

Canadian prairie soils: historical perspective by Henry Janzen

A fascinating and detailed paper by Henry Janzen of the Lethbridge research station in Alberta. Early researchers noted a loss of organic matter and nitrogen availability upon cultivation.

Biosphere processes

Over the last decade the concept of ecosystem services such as filtration, regulation, pollination, and food production have gained currency. But these ecosystem services in turn depend on even more basic biosphere processes:

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