Agriculture groups have joined – some of them reluctantly – with state air quality regulators to find ways to lower nitrous oxide emissions (N20) from nitrogen fertilizer as part of the mandated statewide reduction in greenhouse gases to 1990 levels. Over the next decade, California agriculture faces the task of eliminating millions of tons of N20, one of the five naturally occurring gases that contribute to global warming.
Emitted both by farming and industrial activity, and also when solid waste or fossil fuels are burned, N20 is considered by scientists as 100 times worse than carbon dioxide. In agriculture, N20 is released into the air mostly during the breakdown of nitrogen in the soil and is believed to be caused by widespread use of chemical fertilizers, although use of natural nutrients such as manure is also a factor.
Neither agriculture nor the California Air Resources Board (CARB), one of the agencies involved in the state’s climate change efforts, are certain about the best way to reduce agriculture-related N20. “At this point we haven’t identified anything specific to be done,” reported Cynthia Cory, environmental specialist with the California Farm Bureau Federation, one of two dozen or more groups participating from agriculture. “But one thing is certain; we don’t want to be sacrificing crop production for a little bit of nitrous oxide reduction.”
Dale Shimp, the CARB official who has been dealing with the agriculture community, agrees that “we don’t know exactly how to prevent it.” Shimp, who handles special agriculture and forestry projects, believes the answers may be in the composition of the fertilizer or the way it is applied or how deep it goes into the ground. Yet he insists that a solution will be a win-win for the state and agriculture, which could benefit from more efficient nitrogen usage.
Shimp said some groups agreeing to participate are concerned that the outcome could be additional regulations for the industry. “They like the concept,” he remarked, “but they’re still watching (how the study develops) with caution even though more regulation is not our intention.”
The Western Plant Health Association is one of the participants, along with others that include the Western United Dairymen, the Nisei Farmers League, and the California Cotton Assn.
WPHA President and CEO Renee Pinel still has a lot of questions about the study. First, she offered, CARB needs to make sure its figures are accurate on how much N20 agriculture contributes. She doubted that much can be done with reformulating the fertilizer, but suggested considering areas such as revising application methods or making changes in equipment. Pinel isn’t convinced the result will be merely voluntary guidelines for the industry, as CARB has suggested, rather than additional regulations. “Voluntary guidelines have a habit of turning into mandatory regulations,” she noted.
Others have suggested that emissions can be reduced by better targeting of fertilizer applications, both in space and time, and minimizing waste with better balance between fertilizer and crop yield. California became the first to act statewide on climate change in 2004 with passage of a regulation to reduce passenger car greenhouse gases by about 30 percent by 2016. Action by both the governor and the legislature in 2005 established that greenhouse gases be reduced to 1990 levels ?Çô or approximately 25 percent by 2020, and then 80 percent below that by 2050.
According to figures obtained by the California Farm Bureau, nitrous oxide levels from agriculture or otherwise are expected to reach 32 million metric tons, or 8 to 9 million higher than the 24 million tons in 1990. Even though there aren’t any obvious targets at present, the Farm Bureau’s Cynthia Cory concluded that “we have to be involved to figure out what are the best ways to achieve these goals and to stay in business.”