Regardless of your personal opinions on the climate change issue, it’s a concept that all land managers will have to get informed about in the years to come. Just as you track and project your annual turfgrass nitrogen requirements and irrigation budgets, my guess is that we’ll eventually be projecting and tracking our operational carbon accounts.
Carbon dioxide (CO2) is a greenhouse gas implicated in a warming climate. Simply put, the turfgrasses on your ballfields and all the plants in your surrounding landscapes pull CO2 out of the atmosphere and bind or “sequester” the carbon into new tissues, releasing oxygen (O2) back into the atmosphere. Much of this carbon eventually ends up in the soil, stored for a period of time in dead roots and shoots – Soil Organic Carbon (SOC). It’s estimated that a healthy turfgrass/soil system can absorb as much as 800 pounds of carbon per acre every year using this solar-powered process. That’s the good news.
But unless your field is completely left alone in a natural state – not maintained and never used – you also have to account for what are known as Hidden Carbon Costs (HCC). So when you mow, fertilize or irrigate, you’re directly or indirectly introducing new CO2 into the atmosphere, canceling out some or all of your SOC gains.
Your operational carbon account is determined by subtracting your hidden carbon costs from your soil organic carbon accumulation (SOC-HCC). The goal is to determine to what extent turfgrass management programs are a net CO2 sink or a net CO2 source for our atmosphere, and to identify areas within the operation that can improve our carbon efficiencies.
Mostly focused on the much larger scales involved with lawns, this line of turfgrass management research is still in its infancy and your carbon accounting would depend greatly on which model you employ and how far you take it. For example, do we need to account all the way out to how much CO2 (and other greenhouse gases) was released in the manufacturing of our fertilizer products? Some early studies suggest that a well-maintained turfgrass is a net carbon sink. Another complexity is that your SOC may accumulate to a “saturation point” in the soil after 10 to 25 years.
What would all this mean for the sports field manager? First, we need to begin educating ourselves about turfgrass carbon cycle systems to understand what may be coming down the pike. It will make us all better sports field managers, no matter where the science and politics take us.
More immediately, we now have an initial idea of how we can start to track our carbon account, and in the process gain efficiencies in our field management operations that may translate to budget efficiencies.
We should support more research, because there’s so much to consider in the sports turf carbon accounting models. For example, how do we account for those operations where sodding part or all of a natural grass athletic field is a routine part of the yearly management plan? We’ll need to include the sod farm in our models. What about all the carbon sequestered by the mature turfgrass plants that provide all the seed we use in routinely overseeding our grass fields? How do we carbon account for synthetic fields? Where can we as turf managers get the most bang for our buck in reducing HCCs? Is it fuel type? Returning clippings? Product sourcing?
As with any new frontier in sports field management, carbon accounting is an opportunity for our industry to gain new insights into how to best manage our turfgrasses, soils and sports fields. And as with all new lines of research, we can count on some great new turfgrass science and technology discoveries coming out along the way.