What’s carbon got to do with it?

Carbon credits and potential markets for farmers and agriculture are all the rage and are intended to compensate producers for sustainable practices that store rather than release carbon into the atmosphere. In this way, farmers and ranchers that sequester carbon, and reduce the amount of greenhouse gases released, will benefit financially for reducing overall emissions. Some of the farm and ranch best practices to decrease emissions or increase carbon capture and storage might include, for example:

Mark Boggess

Director / U.S. Meat Animal Research Center

Email Mark Boggess

Decrease fertilization – Nitrous oxide is a greenhouse gas that is 300 times more potent than CO2
Alter manure management and feeding practices
Reduce fuel consumption
Switch to alternative fuels
Produce biofuels feedstock
Implement rotational grazing programs
Changes in tillage practices and crop rotations
Conversion of farmed acres to grasslands
Reforestation – planting trees or seeds to change open land into forest or woodland
Reduce stocking rates (both reduces emissions and sequesters carbon)

That list is probably not news to many of you, but what you may not know is that, recently, these ideas have been transferred into real markets for farmers and ranchers, with payments ranging from $7 to $40 per acre, per The Wall Street Journal. That is real money.

Unfortunately, there is much more to the story. Notice in the previous section I used the phrase “might include.” Carbon is a real thing, and carbon is definitely stored in soil. After that, things are less clear. For example, soil types and long-term soil moisture levels greatly influence the capacity of the soil to secure and store carbon. Carbons stores are also easily reversed, meaning years of carbon sequestration can be reversed with a single tillage event or surface disruption.

Additionally, verification of increased carbon sequestration is also very difficult. Most agricultural soils already have some to a lot of carbon stored, and changes (due to land management practices) are difficult to measure accurately even over a five- to 10-year period. Practices like minimum tillage are considered to promote carbon storage but, in some cases, may simply be redistributing it via increases in the surface layer and decreases deeper in the soil profile. In rangeland settings, factors such as extended drought or periods of excess precipitation can potentially influence the amount of carbon stored in spite of the management practices provided.

Another factor that is difficult to quantify is the level of inorganic carbon in a soil profile. When we talk about soil carbon storage, we are really talking about organic carbon. But many soils also contain inorganic carbon (calcium carbonate, caliche) which varies widely by soil chemistry and soil moisture, further confusing the accurate measure of soil carbon capture efforts.

To date, USDA’s Agricultural Research Service (ARS) research has demonstrated many of these challenges. For example, we have shown that soil profiles vary according to tillage practice, from shallow to deep and with respect to inorganic versus organic soil carbon storage. Further, we have shown that corn silage production, even with extensive manure application, does not store net amounts of carbon. In fact, the carbon losses with corn silage are significant. Corn grain production with minimum tillage also does not store net carbon, although less is lost when compared to corn silage production and further gains may be possible with manure application or cover crops. These are places where we are continuing research to provide solutions for producers.

But like a lot of complex challenges we face in agriculture, clarity is pending. (Thanks to Dr. John Baker, a really smart person, at USDA ARS in St. Paul, Minnesota for contributing his expertise to this carbon discussion.)

So what does this mean for us – forage and livestock producers and managers and researchers in ARS? Like a lot of you, we have more questions than answers. The difference is: At ARS, it is our job to help answer your questions, and there are more questions all the time.

Our response is now even more focused on better understanding and optimizing complex agricultural systems – easy to say, but hard to do. For example, I am proposing development of a national beef systems research consortium to bring thought leaders and resources together to best address these complex challenges. This effort will include our land-grant university partners, producers and stakeholders. Using the beef systems research consortium work as an example, these are some of the questions we are now asking and hopefully answering through research.

For example:

How does carbon (and nitrogen) move in an integrated beef production system?
How do we determine the net carbon footprint for an individual operation or production system?
Are there opportunities to improve net carbon storage?
How do these systems vary across environments and management systems for carbon storage, and what are the trade-offs?
What role do annual and perennial forage systems play in regard to soil carbon?
What are the long-term economic opportunities that could be realized for producers?

In addition to these questions, many other questions must be addressed to optimize the long-term economic and environmental sustainability of a production system and to ultimately provide maximum benefit to society.

For example: What are the societal and long- and short-term economic benefits to beef and forage production systems via ecosystem services such as minimum tillage, perennial production, managed grazing intensity, use of cover crops, fire abatement or management, co-grazing, management of silvopastures, erosion control, water quality, combating invasive weeds, etc.? We know how to influence many of these in a production environment, but we do not know how to value these services or properly value and qualify their benefits on the farm or ranch. More specifically, how do our grazing and forage production practices best promote economic and environmental sustainability while providing maximum benefit to society?

Yes, lots of questions, and we need better answers and understanding.

The good news is: We are now asking these questions and building research programs to begin to answer them. At ARS, we are constantly striving to address industry priorities and find solutions to these complex challenges. Consequently, we greatly appreciate the support of our stakeholders and are always searching for ways to serve you even better. Let us know what you think.