Examining the Connection between Soil Health and Your Carbon Footprint
What is an Agricultural Carbon Footprint?
“A carbon footprint identifies the quantity and source of GHG emissions (carbon dioxide, methane and nitrous oxide) associated with an activity or a product through its life cycle and, when benchmarked, highlights areas where improvements can be made that will reduce emissions and save money.
At the farm level emissions arise from the use of fossil fuels, manufactured inputs, manure, as a natural by-product of animal digestion, cultivation of soils and changes in land use and vegetation. Beyond the farm gate agri-food chains also emit emissions through activities such as processing, packaging, waste management and haulage.”
Agrecalc© Agricultural Resource Efficiency Calculator
Creating an integrated Soil Health Roadmap (SHR) requires that you examine all aspects of your farm management practices - from crop rotation to where and how you use machinery. This approach allows you to be in tune with how your farm “system” functions in real life, rather than just a narrow, singular perspective.
Learning more about your carbon footprint is perhaps a surprising but important perspective to consider when analyzing the overall health of your soil.
But the more vantage points you have- including the carbon cycling on and through your farm-, the better your perspective and the more informed your decision will be.
Developing a carbon footprint for your operation is another point of reference that can help you further clarify your goals and inform your management decisions and their impact on soil health.
Before you dive into creating a carbon footprint, it's helpful to step back and understand the bigger picture of how organic agriculture (and your work) fit into the broader issue of climate change.
“Greenhouse Gases and Agriculture: Where does Organic Farming Fit?” presents an excellent overview of the role organic agriculture plays in climate change that can help provide you a new ‘rooftop’ perspective.
Just as there are different types of nutrient budgets, there are also different ways of calculating your carbon footprint using a carbon footprint assessment calculator.
Find a list of calculators at the end of this post.
Learn all you can about the specific footprint calculation tool you decide to use, as well as understand the meaning and limitations of the resulting numbers.
Do you want to include only the greenhouse gas emissions associated with your current management practices or are you interested in a more holistic picture that includes things like the emissions associated with the infrastructure of your farm?
For example, the manufacturing process required to make your steel fence posts, high tunnel frames and plastic, tractors, barns, and other equipment all have a GHG emissions footprint.
How inclusive or limiting your scope is will define how complete your carbon footprint is.
The more comprehensive you strive to make your carbon footprint, the more complex recordkeeping and data you’ll need to calculate your footprint.
There is no one right answer.
My recommendation is to start simply, even if it’s just by modeling one portion of your operation.
Once you’re comfortable with how the process works, over time you can further develop and refine your model.
Generally speaking, you’ll need at least one year of records, including:
Crops and Pasture
Cropping sequence/rotation
Approximate planting and harvest dates
Type of grazing system (for pasture or range areas)
Type of tillage system
Rate, timing, type and application method for fertilizer and manure applications
Irrigation method and application rate
Residue management practices
Livestock
Herd size and composition (i.e., species, sex and age ratios)
Type of manure management system
More advanced methods to estimate livestock-related emissions are available if you have information on feed characteristics and feed supplements
Energy
Capital equipment purchases
Energy and fuel usage
On-farm renewable energy production
Think through your purpose for calculating the carbon footprint in the first place.
Obviously, as I mentioned, a footprint can provide another point of reference as you make management decisions to improve soil health.
Specifically though, there are a few different ways of utilizing your carbon footprint. How much time you spend entering your records can depend on what you hope to learn.
Do you seek to:
Have a general understanding/scope of the impacts your farm practices have on the environment?
Want to focus on running multiple scenarios to see the net effect certain management changes may have on your footprint?
Drill down to the major sources / drivers of your GHG emissions so you can brainstorm alternatives to reduce your footprint?
Use the carbon footprint metrics as a justification to pursue funding to implement management changes or prove your sustainability credentials?
From the SHR perspective, the importance of a carbon footprint assessment is to inform your management strategies as they relate to soil health.
If, for instance, your recommendations list includes items that also prove to be a significant source of GHG emissions, it can provide further justification and incentivize you to pursue an alternative.
Maybe you’re already considering replacing a certain piece of tillage equipment because it’s at the end of its useful life or it's not the right fit for your production practices.
For example, I’m interested in trading in my rototiller for a more appropriate primary tillage tool.
From a soil health perspective, a spader or chisel plow may be less damaging options.
Evaluating the impact of these two different implements from a GHG emissions standpoint could factor heavily into my decision.
A carbon footprint analysis can also highlight inputs or elements of your system that you may not have previously considered as significant factors.
For instance, when I completed my carbon footprint analysis, I learned that using peat moss was a major contributor to my farm’s emissions. The extraction of peat from peat bogs releases an excess of carbon into the atmosphere, not to mention the bagging and transportation emissions.
How does that relate to soil health?
Well, it makes me consider the purpose and benefits peat moss provides to my soil. I use it in my potting soil mix to increase water holding capacity, structure, and as a source of organic material (food) for soil microbes.
But are there other replacement materials I could source from my farm or nearby that would have a less damaging environmental effect, reduce my off farm inputs and improve soil health? I’m in the process of trialling a few alternatives, including adding shredded leaves and increasing the amount of compost to reduce the amount of peat in my potting soil mix.
These are the types of questions that a carbon footprint analysis can help highlight for you.
There are a number of free carbon footprint calculators available to farmers.
Ideally, stick with one tool, so that when you update your SHR, you’ll save time by simply updating the data for your carbon footprint.
Because this is an emerging field of science and because diverse farms are not easily “modeled,” I’ll be honest - analyzing your carbon footprint isn't the easiest step to undertake.
The tools currently available for growers to use most likely will not completely account for the complexity of.your operation.
When entering information into the carbon footprint model, you might need to generalize the basics of your production practices because you may not have the necessary records to account accurately for the intricacies of your diversified stewardship practices.
You won’t be alone - this is a common issues.
Given these limitations, is it worth calculating a carbon footprint for your farm?
I feel strongly that the answer is yes.
Even a rudimentary understanding of how a carbon footprint is assessed and what elements of your operation impact your carbon footprint can be important to helping you see your work in a new way.
If you decide to complete a carbon footprint for your farm, do your diligence and gather the necessary records, so the results are something you’ll have confidence in and find useful.
Set your sights on an achievable goal -- I recommend working on this step during the winter months or in your off season.
In the next step in this process of developing your SHR, you'll be putting all the pieces of your roadmap together.
As you evaluate the potential implications of some of your recommendations, you may want to input those scenarios into your carbon footprint model to see what the estimated effect of the change might be.
Just like creating your SHR, this is an iterative process.
Resources List | Carbon Footprint Assessments for Agricultural Operations
Depending on your farm’s location, size, and major enterprises, choose the best fit calculator or resource from the list below. I use Washington State University’s Organic Farming Footprint (OFoot) tool.