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Non-Enteric ROG Emissions from Dairies in San Joaquin Valley, California
This page updated January 27, 2010
Chair’s Air Pollution Seminar |
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Thursday, March 11,
2010
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Non-Enteric ROG Emissions
from Dairies
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Charles F. Krauter,
Ph.D.
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Dairy
operations in California were assumed in 2004 to be major sources of
reactive organic gas (ROG) and therefore, ozone formation in the
Central Valley. In 2005 this project was proposed to
determine the specific sources and components of ROG in emissions from
dairies. An advisory group of public agency, industry and
academic members was formed to develop the initial plan and supervise
revisions in accordance with initial results. Six dairies
were selected to be sampled three times each year to evaluate facility
and seasonal differences. Ambient air samples were collected
initially to identify specific ROG components and develop analytical
methods for dairy air samples. The initial data indicated the
predominance of alcohols in feed components of dairy ROG emissions and
a sampling program was designed to focus on those while also monitoring
other dairy ROG sources. The sampling program was conducted by Dr. Charles Krauter at Califnornia State University, Fresno and the corresponding analytical program was administered by Dr. Donald Blake at University of California, Irvine. After review of the initial data, in 2006, the advisory group revised the sampling program to reflect the discovery that alcohols from the feeding operations, rather than manure management appeared to be the most significant ROG source. The six dairies were sampled three times from June, 2007 through July, 2008. The highest flux rates were for silage and feed with an average flux rate of 4,229 µg/m2/minute from the vertical silage pile face and 19,170 µg/m2/minute for loose, disturbed silage used for mixing feed. Fluxes from feed were 15,022 µg/m2/minute when first placed in the feed bunker, though the rate decreased to 2,929 µg/m2/minute as it was consumed. Flux rates for the flush lanes were considerably lower with a rate of 353 µg/m2/minute prior to the flushing operation that decreased further to 21 µg/m2/minute after the flush. Open lots and exercise corrals were similar to the flush lanes. Areas of the corrals where the manure pack was relatively deep had flux rates of 243 µg/m2/minute, while the shallow manure pack in the open lots averaged 102 µg/m2/minute. The anticipated seasonal effects appear to be less significant than expected. Only emissions from the open lots correlate with surface temperatures, increasing in the summer and declining in winter. When the areas represented by each of these operations were applied to the flux values, it became apparent that feed was the dominant (60%) ROG source, followed by the open lots (25%), flush lanes (8%) and silage piles (7%). These proportions were calculated as an example of a fictitious dairy that was a composite of the six sampled facilities. These percentages would vary when calculated from actual fluxes and facility dimensions but feed would probably remain the dominant source of ROG. After the sampling program was established at the six dairies, additional funding from other state and federal sources became available to include monitoring of ammonia, other N fluxes, other methodologies for alcohols and analysis of the feed and manure from the surfaces sampled by the flux chambers. Most of these projects are still in progress but the ammonia flux project is complete and some data will be reported here. Ammonia fluxes were generally similar in magnitude to the ROG from open lots and flush lanes. The ammonia flux from feed sources was higher than that from manure but averaged less than 1000 mg/m2/minute, much less than the ROG fluxes from feed and silage. When the flux rates were used to calculate estimated emissions as was done for ROG, the largest source was the open lots at 56%, followed by flush lanes at 38% of the estimated total.
Charles F. Krauter, Ph.D., is professor emeritus at
California State University – Fresno. Dr. Krauter was an
Associate Professor (1979-83) and then Professor (1983-2009) of soil
and water science in the Plant Science Department of the Jordan College
of Agricultural Science and Technology at CSU Fresno. In that
capacity, Professor Krauter taught undergraduate and graduate courses
in soils and irrigation full time until 2003 when his appointment was
split and became half teaching/department chair and half
research. He remains the coordinator of air quality research
in the Center for Irrigation Technology at CSU Fresno. His
research from 1971 to 1999 was related to water management and water
quality problems in irrigated agriculture. In 2000, he began
a study with Dr. Chris Potter of NASA-Ames to determine ammonia
emissions related to fertilizer applications. That study has
evolved into further research related to Reactive Organic Gases from
agricultural production and dairy operations. Dr. Krauter
received a B.S. in Soil and Water Science (1969) and a Ph.D. in Soils
(1974) from the University of California, Davis. Dr.
Krauter has published and presented numerous papers on water quality,
water management techniques, plant nutrition and air quality problems
related to agricultural production and dairy operations. for her
research.
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