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Sizing Up California’s On-Farm Carbon Footprint

Comet FarmHow can farmers know their farm’s carbon footprint?  Not just a qualitative idea, mind you, but the actual shoe size?

USDA’s COMET-Farm™ and its more recent and high-cut cousin, COMET-Planner™, can help. The free, online tools allow farmers and ranchers to quantify their atmospheric outputs (emissions) and carbon benefits (sequestration) based on their site-specific soils, crops, and management practices.

Farms have frequently been seen as a source of carbon emissions traced to operations such as tillage, fertilizing and methane from livestock. But farms also grow prodigious amounts of plant life—and that pulls carbon dioxide out of the atmosphere. 

Thus gauging agriculture’s total carbon ledger—with all of its emissions and sequestrations – has been a bit of a head scratcher. That’s where the COMET tools come in, says Adam Chambers, one of the team members who developed the online tools. Chambers is with the Energy and Environmental Markets Team of USDA’s Natural Resources Conservation Service.  NRCS joined forces with Colorado State University to build the tools and joined with other key partners to make sure the tools are user-friendly.

According to Chambers, you can improve a farm’s atmospheric benefit by implementing beneficial conservation practices such as reduced or no-tillage, cover crops, riparian buffers, hedgerows and many other climate-smart conservation practices. Chambers has identified more than 30 NRCS conservation practices that are “climate-smart”, the benefits of these practices can be calculated using the COMET tools. “The practices have long been recognized as good for soil, water and habitat,” says Chambers, “now they are getting credit for keeping carbon (a.k.a. soil organic matter) underground too. “

The COMET tools allow farmers to play with “what if” scenarios, says Chambers.  “What if you change from conventional tillage to reduced till? What if you add a quarter mile windbreak—or a strip of buffer along a field or stream? What if you change your form of fertilizer or the way you apply it? You can get a quantitative idea of how these or other actions will create atmospheric benefits on your farm or ranch,” he says.

“Some farmers may be merely curious about their carbon footprint while others may be interested in supplying the information to buyers who are increasingly eager to market such information to discerning consumers,” says Chambers.  Only the farmer who enters the information has access to the data and the calculated results, but he or she can choose to share the information with customers or buyers.

Someday carbon markets may be another incentive for conservation-oriented farmers.  Current prices for a ton of carbon are quite low but future conditions could change this, Chambers says.

Carbon sequestration not only helps the atmosphere, it helps the farmer too--enhancing fertility and water holding capacity.  Restoring carbon to the underground ecosystem feeds the busy microbial community that recycles old plant matter into nutrients and builds water-holding capacity. No where is such vital activity more important than in an arid state like California,” says Chambers.

Farmers who use the COMET tools will end up with a report that uses the same quantification methodologies as the US Greenhouse Gas Inventory—a national report that ultimately represents our nationwide greenhouse gas emission and carbon sequestration.  The National Greenhouse Gas Inventory is submitted to the United Nations on an annual basis and the report contains individual chapters on agriculture and land use, says Chambers. The most common greenhouse gases emitted by the agriculture and land use sectors are carbon dioxide, nitrous oxide, and methane, and we know that healthy soils and healthy biomass are very capable of removing large amounts carbon from the atmosphere and storing (or sequestering) that carbon.

For more information or to play with the online Comet tools see Comet-Farm for a complete greenhouse gas analysis, or go to Comet-Planner for a quicker, big-picture evaluation.