WASHINGTON — In a December letter to the Environmental Protection Agency, a coalition of agriculture producers and processors encouraged the agency to acknowledge the science of carbon cycles in agriculture and limit regulation to emissions that add excess greenhouse gases to earth’s atmosphere.

The Biogenic CO2 Coalition urged the E.P.A. to maintain its March 2020 timeline for the issuance of proposed rulemaking to clarify that there currently is no basis for the agency to regulate biogenic emissions from processing or use of agricultural crops under any Clean Air Act program, rule or permit.

“Currently, E.P.A. is the only government agency in the world that regulates biogenic emissions without recognizing the applicable lifecycle science,” the letter said.

In a 26-page attachment to the letter, the coalition presented “well-documented and not controversial” scientific findings supporting the deregulation of agricultural biogenic emissions. The lengthy attachment details the short cycle of agricultural growth that includes both capture and release of carbon from the atmosphere during the processing of the biomass feedstock.

“In other words, agricultural feedstocks used at a processing facility come into the facility with a low-carbon balance, which is netted out when the feedstock is processed and the carbon is released back into the atmosphere,” the letter said.

The coalition is composed of nine organizations, including the American Bakers Association, the American Farm Bureau Federation, the Corn Refiners Association, Enginuity Worldwide, the National Corn Growers Association, the National Cotton Council of America, the National Cottonseed Products Association, the National Oilseed Processors Association and the North American Millers’ Association.

The coalition’s communiqué to the E.P.A. followed a similar letter sent to the agency in mid-November by 18 U.S. senators urging deregulation of biogenic CO2 and a clear ruling on biogenic carbon emissions they called de minimis. That letter cited the economic benefits of an unencumbered path forward for a U.S. bioeconomy valued at $459 billion in 2016 and at risk of being further outpaced by a European Union bioeconomy valued at $688 billion a year earlier.

The December letter from the coalition said the bioeconomy by 2016 “provided 4.65 million American jobs, and each job in the bioeconomy created 1.78 jobs in other sectors across rural America.”

“While providing food, fuel and fiber to American families, the bioeconomy also reduces greenhouse gases from the atmosphere, thus playing a role in achieving climate policy goals,” the letter said.

The letter asserted the United States is well-positioned to capture the lion’s share of global bio-based economic growth and employment opportunities. But it said bioeconomic investment is in jeopardy from E.P.A. policy statements that refuse to ”recognize that American farmers capture carbon while growing feedstocks and that the same biogenic carbon is organically released as part of the natural carbon lifecycle when crops are subsequently processed or used to produce bioproducts, food, fiber, biofuels and bioenergy.”

The proposed rulemaking will cover, among other processes, fermentation for production of food, industrial or consumer products, and/or biofuels; biogas associated with biological decomposition of biomass; and energy use, combustion or gasification of biomass feedstocks, including all types of agricultural feedstocks, crop residues and agricultural material.

The letter’s attachment, “Scientific support for Agriculture-derived biogenic De Minimis Rulemaking,” cited other areas of existing policy in which biogenic emissions are accounted for or credited, including Title II of the Clean Air Act, the Energy Policy Act of 2005 and the Energy Independence and Security Act of 2007.

“Biogenic greenhouse gas emissions have little, if any, adverse effect on the accumulation of concentrations of CO2 in the global atmosphere,” the attachment stated. “Because of their participation in the natural carbon cycle, U.S. farmlands remove hundreds of millions of tons of CO2 from the atmosphere each year as biomass grows through photosynthesis. In fact, other than uptake of CO2 by the oceans, the only meaningful global removal of CO2 from the atmosphere comes from capture of CO2 by plants.”