ARB Research Seminar

This page updated June 19, 2013

Non-Enteric ROG Emissions from Dairies in San Joaquin Valley, California

Charles F. Krauter, Ph.D., Plant Science Department, Jordan College of Agricultural Science and Technology, California State University, Fresno

March 11, 2010
Cal EPA Headquarters, 1001 "I" Street, Sacramento, CA

Research Project


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 California 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 g/m²/minute from the vertical silage pile face and 19,170 g/m²/minute for loose, disturbed silage used for mixing feed. Fluxes from feed were 15,022 g/m2/minute when first placed in the feed bunker, though the rate decreased to 2,929 g/m²/minute as it was consumed. Flux rates for the flush lanes were considerably lower with a rate of 353 g/m²/minute prior to the flushing operation that decreased further to 21 g/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 g/m²/minute, while the shallow manure pack in the open lots averaged 102 g/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.

Speaker Biography

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.

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