Keeping track of carbon

In the March 2020 issue of the NODPA (Northeast Organic Dairy Producers Alliance) News, Ed Maltby (NODPA’s executive director) answered the question: “How will organic production’s positive contribution to (abating) climate change be recognized?” Early in his answer, Maltby stated that organic production is “the gold standard for creating healthy soil and a healthy environment, and is the best example of a holistic, climate-friendly system of farming.” He further states that organic regulations spell out soil health requirements that mandate the reduction of greenhouse gas emissions… as well as the sequestration of carbon in the soil.

To add heft to these regulations, Maine organic farmer and U.S. Congresswoman Chellie Pingree (D-ME) introduced the Agriculture Resilience Act (ARA) which would “address the most pressing farm issue of our day: climate change.” Her bill, once ratified, will establish a set of aggressive but realistic goals for farmers committed to helping mitigate climate change — while, at the same time, increasing agricultural resilience. There are six key objectives in Pingree’s proposed bill: agricultural research, soil health, farmland preservation and viability, pasture-based livestock, on-farm renewable energy and food waste. Under the category of soil health, Pingree lists the following primary targets: “retaining year-round cover on at least 75% of cropland acres, eliminating farmland and grassland conversion (to non-agricultural uses), (and) increasing crop-livestock integration by at least 100 percent.”

Once made into law, the ARA would expand funding for working lands’ conservation, including the Environmental Quality Incentives Program, and the Conservation Stewardship Program (CSP). CSP’s mission is fortified with its Innovation Grants program. The bill is intended to “increase and assure steady future funding for technical assistance to producers in mitigating, and adapting to, climate change”. Running parallel to the soil health mission is the goal of pasture-based livestock.

According to Maltby, within the framework of the “pasture-based livestock” line item, “The ARA would revive the dormant Grazing Lands Conservation Initiative and create four new authorities: animal-raising claim labeling (e.g., grass-fed, pasture-raised, no added hormones, etc.), with auditing and verification procedures; a grant program to assist very small meat processors serving the growing niche meat sector; an alternative manure management program to support non-digester dairy and livestock methane management strategies to reduce emissions; and a new pilot Conservation Reserve Program (designed) to create long-term protection for five million acres of grassland at risk of conversion to cropping or development.”

Sadly, Maltby cautions in view of the present political climate (called “Beltway Mentality” by some), ARA is not likely to become law any time soon — certainly not before election 2020 becomes history. He expresses optimism by saying, “These bills (like ARA) are a sign of a debate that has long been relegated to Washington’s back burner — (and now) re-emerging.” While waiting for the political landscape ship to assume a pro-ecology tack, conscientious land stewards can make soil health improvements on the land that they own — or at least control. Towards that end, understanding a few fundamentals of soil health is very beneficial.

Soil organic matter (OM) readings give a report card on the eco-friendly skills of the land manager in question. This is the case, whether the involved farmer is certified organic — or not. It’s safe to say that soils with higher OM are healthier than soils with lower OM. During my Cooperative Extension agronomist days (1973-1978) I learned from Cornell Professor W. Shaw Reid (PhD), that OM is approximately 58% carbon. The other 42% consists of oxygen, hydrogen, and proteinaceous nitrogen — plus negatively charged anions (like nitrates, phosphates, and sulfates). Thus, with a 6-inch deep topsoil layer, conveniently presumed to contain 1,000 tons of earth (2,000,000 pounds) per acre, for one percent of lost soil OM, the soil in question has released 11,600 pounds of carbon into the atmosphere (2,000,000 x 0.01 x 0.58); that lost carbon is mostly in the form of carbon dioxide (CO2), a greenhouse gas (GHG). Some of that dissipated carbon is in the form of methane (a much worse GHG). Soils with healthy microbes give off minute amounts of CO2 as part of their respiratory function (without degrading OM).

Soil biological activity can be assessed at certain laboratories. One such lab is Woods End Lab in Maine. From their website we learn about Woods End Lab’s Solvita 24-hour CO2 Burst test: “Many micro-organisms give off CO2 as a result of aerobic respiration. The Solvita 24-hour CO2 Burst test quantifies the amount of respired CO2 after rewetting a dried soil sample, employing a pre-calibrated CO2-absorbant gel. The amount of CO2 measured over a 24-hour period represents ‘active carbon’ or ‘respirable carbon’ that was acted upon by the microbes and may also be used to estimate potential mineralizable nitrogen and phosphorus from the soil organic matter.” [Dairy One Lab (www.dairyone.com) in Ithaca NY has offered the Solvita test since 2015.]

I leave with you five concise carbon concepts to take-home: first, when beneficial soil microbial activity increases, so does pollinator activity. Second, improved soil OM increases the carbon-based energy needed to support diverse bio-activity — and this indirectly extends the grazing season. Third, as cropping practices become more mono-cultural, biodiversity decreases. Fourth, deteriorated soil OM can be rebuilt at a rate of 0.5% per year (up to a certain point); in other words, forgiveness for soil mismanagement is possible (but only if accompanied by repentance). And fifth, if soil OM is high enough, the cropland becomes drought-proof.

Let’s make the above quintet into an even half-dozen. If that lost one percent of soil OM had avoided destruction, the resulting retention of 11,600 pounds of carbon would have increased that soil’s water reservoir benefit by 16,000 gallons. Photo proof of this last statement appeared in a picture taken after October 2015’s Hurricane Joaquin subsided from coastal South Carolina: a flooded sod-covered meadow appeared unfazed, very much intact. Adjoining that meadow was a field of continuous corn, which showed more gullying than standing stubble. Referring back to the report card mentioned earlier, one southern corn grower clearly earned failing grades.

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