Monday, June 24, 2024

Carbon soil baselines needed before entering the carbon market

• By Larry Oldham •

soil sampling in the fall for carbon soil analysis
Pull soil samples in the fall and have the soils lab run a carbon analysis. This establishes a soil carbon baseline against which improvements can be gauged — photo courtesy Mississippi State University

Participating in the soil carbon (C) market requires baseline information about the producer’s inventory to offer potential buyers. This fall is the time for the soil carbon-curious growers to begin establishing their benchmarks. Surveys show the number of farmers participating in soil C markets has tripled over the past six months — it has gone from 1% to over 3%!

Over half of the producers survey anticipate offering their soil C within the next three years as things sort out in the marketplace. (Data from

Before delving into the details of inventorying current soil C, we must acknowledge that many whole-farm management level issues are still solidifying. Some questions were discussed here: a few weeks ago.

Issues to consider

They include:

• Assignment of credits to landlords or lessees, including any future changes in relationship.

• Data ownership.

“Additionality” or the adoption of new conservation practices versus legacy conservation-based management.

• The ongoing role of U.S. Department of Agriculture programs: ongoing or new implementation, role of incentive programs.

• Verification of carbon presence in the soil: who does it, when, and how.

• Consistency and certification of soil laboratory procedures.

• Whether current market makers will be stable in the longer term.

These are beyond the purview of ground-level soil science practice. While the intellectual product is data ownership and use, the physical end-product is C at the field and farm levels.

This C originated from anything formerly living, such as stalks, roots or other organisms, that has been transformed into soil organic matter via biologically mediated decomposition. Depending on the species, 20% to 70% of the C fixed by plants (removed from the atmosphere via photosynthesis) ends up in roots that are recycled in the soil.

Benefits of fall sampling

You don’t know how far you have traveled if you don’t know the starting line. Fall soil sampling is common on many Mid-South farms and can provide a baseline assessment of the soil carbon inventory.

The Mississippi State University Extension Soil Testing Laboratory offers routine soil nutrient and pH analysis for $8 per sample; carbon analysis is an additional $2 per sample.

The cost for organic matter, nitrogen and carbon testing is $4 per sample if routine analysis is not requested. These initial (pre-contract) C soil test results will establish the baseline that future verification data will be judged against. Contact the laboratory for more information about C testing services.

Remember that beyond this baseline C documentation, growers will need to track the “what and when” of conservation practice implementation and tillage operations. Specific information about other farm management operations that C brokers request from the growers vary by company and need to be specified in any contract.

Dr. Larry Oldham is an Extension soils specialist with Mississippi State University. He may be reached at

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