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Program Development - May 22, 1998 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Twenty-one people made presentations to the plenary session in Kansas City. The majority were ARS customers, partners and stakeholders, and most spoke on needs and issues of greatest concern to them. These speakers were chosen as representatives of ARS customer groups. The remainder of the speakers were ARS scientists chosen to summarize ARS research in various component areas of the manure program. These speakers were meant to complement the customer representatives, helping workshop participants begin to identify gaps between research needs and ARS' current research agenda. Available summaries of all those presentations are reprinted here, in agenda order.
Allan Sutton, Purdue University The summary below is based upon a task force report created by the Council for Agricultural Science and Technology to determine the state of knowledge about the effects of animal waste management systems on the environment. The purpose of the report was to assess current livestock and poultry production, identify environmental and public health concerns, review components of integrate animal waste management, evaluate potential uses and principles of environmentally sound animal waste management, and discuss current and future research and education needs to improve animal waste management. Historically, there has been reduced numbers of production units with similar or increasing food and fiber product production and consumption. With the increased sizes of production units, however, much greater volumes of manure are produced per operation that must be collected, stored and utilized. One of the greatest challenges facing animal agriculture in the next 30 years is providing food supplies for a population that is anticipated to double, but with much less available farmland. Over 1 million acres of farmland is lost to urban development each year. In addition, many of the general public do not know where their food comes from and are not familiar with animal agriculture practices. Economic Perspectives The production sector has little incentive to implement best management practices when there is little or no return for their investments. In addition, the public sector is expecting high environmental standards but is reluctant to pay for it. However, the general public may need to share in the cost of some pollution prevention. If stricter regulations are promulgated, smaller operations may be forced out of business. In a survey, 62.5% of lenders rejected loan applications and 45% discontinued certain types of loans because of potential environmental liabilities from livestock operations. Obviously, the net system costs differ significantly by size of operation and larger operations can implement newer more costly technologies. Storage cost is not recovered by enhancement of manure nutrient concentrations. Currently, only incorporation may be cost effective with concentrated manure. Governmental Solutions Regulation of air and water quality standards offers one means of controlling pollution. Other means of pollution control are levying polluter taxes or paying subsidies and other incentives to encourage pollution reductions. The USDA Conservation Program from 1984-1990 spent nearly $1 billion to control erosion, conserve water and improve water quality, but only about $40 million went to manure management practices. However, the recent EQUIP program is a good start in encouraging BMP =s and facilities to correct manure pollution problems. Some times the restrictions of federal programs give conflicting responses, i.e., Federal Acreage Reduction program and Conservation program restricting manure application or injection on the land, respectively.Environmental Quality Issues (Water, Soil, and Air) Potential contaminants are listed below:
Use of current properly designed facilities and best management practices for manure systems, sanitation practices within facilities, and disease prevention techniques have resulted in very little risk towards water pollution and cases of human diseases. Current areas of concern are accumulations of phosphorous in the soil, odors and disease vectors from manure, nitrate and pathogen contamination of drinking water and surface water quality for esthetics, recreation, wildlife, etc, loss of property value and dust. Animal agriculture is blamed for contamination of water, however, animal manure is a Ano discharge@ system with nutrients applied to the soil in the root zone for plant utilization. In contrast, municipal treatment plants often discharge raw waste into streams and are permitted to do so and septic tanks discharge over 1 trillion gallons of partially treated waste water from 66 million Americans into the soil below the root zone.Manure System Components A vast number of collection, storage, transfer, treatment, and utilization systems have been developed and implemented. With the flexibility of the components available, specialized and efficient animal waste systems can be installed for site-specific situations that will protect the environment and serve the livestock producer. Relative costs will depend upon the components required to meet performance standards of the environment and specific objectives of the operation. Manure Nutrient Utilization/Plant Use Manure nutrient content varies considerably due to species and diets. Handling, storage and application systems also, greatly affects manure composition and fertilizer value. Manure nutrient availability depends upon soil, weather, cropping program and source. Manure improves the physical, biological and chemical properties of soils. Manure is at least equivalent to and often times superior to commercial fertilizers. Nitrogen is a mobile nutrient that can be lost from leaching, runoff or volatilization. In contrast, when phosphorus becomes the limiting nutrient for land application rates, the land base required for a livestock production unit will increase significantly. Development of a total nutrient management plan for each operation is an important management practice, which is site specific due to soil characteristics, topography, cropping program, etc. Injection or immediate incorporation of manure into soil saves nitrogen from volatilization, reduces odors and decreases nutrient runoff potential. Over the U.S., collectible manure produced can provide 15% of N, 42% of P and 59% of K commercial fertilizer purchased which is worth more than $3.4 billion. Recycling Nutrients for Feed This is not a new concept since animals have practiced coprophagy for centuries. Animal excreta must be processed (ensile, dry, deep stack, acidify) to insure safety and stabilization of the product. Any antibiotic drug use in feeds must be documented and legally approved. Withdrawal periods are recommended and required in many states. Value, as feed, is highest for poultry excreta, then swine, dairy and beef (on a nutrient basis, from 4 to 7 times higher than a fertilizer). Generally, this practice is found in niche areas to reduce the cost of feeds or when feed resources are limited, i.e., during drought. Producing Fuel and Energy Biogas production has not been economical due to low energy costs. There is a greater requirement for management, need for efficient and dependable fuel storage and less maintenance. Covered lagoon systems may be possible for biogas recovery in a warm climate. However, the biogas production gives the lowest dollar return compared with fertilizer use or recycling nutrients in feed. Other Processes Oil production (pyrolysis) for fuel, algae production for animal feeds, composting for mushroom production, and specialty soil amendments are examples of further processing of manure. The success and viability of these processes are dependent upon niche markets and relative ease of operation. Animal Mortality Management The declining rendering business, severe restrictions on burying and the cost of incineration to meet emission standards has been major concerns. Other methods used are composting, centralized collection, fermentation, and on-farm freezers/refrigerator which may have potential. Composting systems are safe, practical, and economical. Future Research Needs Listed below are areas of research with specific goals:
The new challenge is to encourage, educate and implement current technology, continue Acutting-edge@ research and develop new technology for on-the- farm use to achieve efficient, economical, environmentally friendly and socially acceptable animal agriculture.Regulatory Policy The voluntary approach is preferred versus mandatory regulations. Incentives to encourage adoption of best management practices would be helpful. AOne size fits all@ can not be accomplished due to diversity of regions, climates, etc. Site-specific solutions are needed and standards should be performance-based to be effective in improving and protecting the environment. Risk assessment is critical to determine the benefits (payoff) for high level environmental management for certain practices. Identification of Areal@ problems is necessary; determination of what caused the problem, establishment of base line data and implementation of corrective technology. A total nutrient management plan is highly recommended for the entire operation. Regulations should be based upon scientific evidence and the latest technologies. Regulations should be enforced on purposeful mismanagement.CAST. 1996. AIntegrated Animal Waste Management@ Report. 129. Authors: A.L. Sutton, J.F. Power, D.L. Day, J.P. Fontenot, D.L. Forster, D.M. Huber, D.D. Jones, K.A. Kelling, T.A. McCaskey, J.A. Moore, L.M. Safley, Jr. Council for Agricultural Science and Technology, 4420 Lincoln Way, Ames, IA 50014-3447. (515-292-2125) 87 pp.Return to Top
Ellen Hankes, National Pork
Producers Council 1998 will be an exciting year in the pork industry. This year, 140,000
pork producers will raise more than 100-million head of hogs, export more
than 1 billion dollars worth of pork, generate 11 billion dollars in farm
level sales, 64 billion dollars in total economic activity and employ
600,000 Americans. We will continue our development as the most efficient
producer of high quality pork in the world.
The U.S. pork industry will also continue refining the
information-driven, systems approach that has led to rapid advances in
production efficiency and has made pork farms look differently today than
they did 30 years ago. Information about consumer preferences for lean
products has led producers to make significant changes in swine genetics.
Information about the animal health and production efficiency gains which
are possible through multi-site housing and segregated early weaning has
led to specialized facilities for farrowing, nursery and finishing phases.
These changes have, in turn, led to a high degree of specialization and
consistency within individual management systems.
It's important to recognize these developments have not been limited to
only one category of producers. These management systems are being adopted
by producers in nearly all size categories. In fact, USDA inventory
reports for 1997 show the largest increase in producer numbers has not
been in the very largest category, five-thousand head and above, but in
the mid-sized category, two-thousand to five-thousand head. These, for
example, are the 200-sow operators who are expanding to 600-sows to bring
another generation back to the farm. These are the local producer networks
and cooperatives who combine their resources to take advantage of the
efficiencies possible through specialized facilities and management. The
trend in the pork industry is not simply toward a monolithic, completely
vertically integrated model, but toward coordinated models. In fact, there
are many different production models being adopted, which means producers
of many sizes will continue to have the opportunity to be part of the pork
industry, whether they use confinement facilities or hoop buildings.
The overall effect has been a dramatic increase in many production
efficiency parameters. For one example, consider that twenty-five years
ago, thirteen-hundred pounds of pork were produced each year, on average,
for every breeding animal in the herd. Today, the average is
twenty-five-hundred pounds per breeding animal. It's increased an average
of thirty pounds per year the last ten years. This is an example of how
pork production rewards attention to detail, specialization and an
information-driven systems approach to production challenges.
The environment is the production challenge to which we now need to
apply that information-driven, systems approach and the reason we need the
research capabilities of the Agricultural Research Service. Environmental
management is the key growth-limiting factor for our industry, for
producers of all sizes and in many different management systems. While we
are producing those 100 million hogs this year, we will also be producing
enough nitrogen fertilizer for 12 to 15 percent of the U.S. corn crop. By
the way, for perspective, for every pound of nitrogen we produce and apply
to cropland through swine manure, 2 pounds flow directly in rivers and
streams from industrial and municipal waste water treatment plants. That
fact does not relieve pork producers of our responsibility for appropriate
management of our manure. If we do not substantively address issues
related to water quality and odor, we will increasingly be unable to
operate existing facilities or to build the new, more efficient facilities
which will allow us to be the most competitive supplier of pork in the
global market or even in our own domestic market.
USDA's Agriculture Research Service has a critical role in providing
the research tools producers need to develop and refine environmentally
sustainable and community friendly production systems. Our key research
needs fall generally into five key areas.
In odor control and measurement, key research topics include:
Research is also needed in the area of atmospheric deposition of
nitrogen-based compounds and pathogens. Specifically:
In the area of manure storage and treatment facilities, additional
research is needed in:
Research is also needed to develop precision water quality monitoring
techniques. Specifically:
A crucial research area is the interaction of manure nutrients with
crops and soils as we refine our sustainable pork production system.
Additional research in the following areas will speed this process:
These suggestions reflect the pork industry's drive toward an
information-driven, systems approach to manure management that will result
in environmentally and economically sustainable pork production systems.
It is only through long-term sustainable systems that the U.S. pork
industry will be successful as the highest-quality provider of the most
popular meat in the world. USDA's Agricultural Research Service will have
a key role in achieving this goal. Return to Top
Larry Goff, Poultry Water Quality Consortium
Poultry production is a leading agricultural industry in the United
States. Poultry production ranks number one in total dollar value of
agricultural production in many states. Data provided by the National
Agricultural Statistics Service indicates a total of 21.8 billion dollars
was received from the sale of broilers, turkeys, eggs and chickens in the
U.S. in 1996. The value to the economy of states is many times greater
than 21.8 billion dollars considering industry and grower investments,
jobs, associated industry, grain sales, etc.
The poultry industry has seen phenomenal growth in the past 15-20 years
and provided tremendous financial strength, jobs and income to farmers,
integrators, state and local governments. In an ever changing world there
are numerous issues that need to be addressed in the poultry industry as
is true with any industry.
Issues
Many states have or are considering the elimination of burial pits for
dead bird mortality. There is concern that rules and regulations may
affect incineration as an alternative due to air quality standards. The
public perceives these and other dead bird mortality disposal systems as
unsafe for ground/surface water and air quality.
Many fields have received heavy applications of poultry litter and are
now yielding high readings of nitrogen, phosphorus and in some instances
trace elements such as copper and zinc. There is concern these areas will
affect the soil in the long run for some agricultural production and
possibly provide nutrient runoff in to receiving streams. There is concern
that phosphorus will become the primary nutrient of concern which will
make nutrient management plans very difficult to achieve due to a lack of
adequate land for spreading litter.
Many areas where poultry operations exist are becoming urbanized.
Public perception of poultry is not always favorable due to a perceived
notion that the industry is not in the best interest of maintaining the
environment. There is concern that states and or local government are
taking legislative action that will impact negatively in the poultry
industry based on knee jerk reactions or perceived problems.
There is concern for additional costs of meeting government and
environmental requirements while many times accepting decreased
profitability.
These and other issues must be addressed and mutually agreed to by all
parties. The poultry industry provides tremendous financial support to
growers, vendors, farmers, communities, local, state and federal
governments. Poultry growers provide one of the best known records of
small farm sustainability. The industry provides excellent healthful food
to the U.S. and export countries at a competitive reasonable price.
Resolution to these issues, acceptable to all parties, must be a
priority for the continued good of the industry.
High Priority Research Needs
Return to Top
Art Darling, Sunshine State Milk Producers
The dairy farm industry’s problem is shared by all other animal
industries to greater or lesser degrees and by all of agriculture in
general. Historically, organic and inorganic fertilizer was cheap crop
insurance—if a little was good, a lot was better. It was cheaper than the
fuel one used to spread it, so put it on thick one time and be done with
it. Manure regardless of source was piled up and put out either after the
crops were harvested or just before they were planted depending more on
how big the pile was than on crop nutrient need. We often built our barns
and parlors next to ditches and streams to flush the manure into them.
These same streams were convenient watering spots for the livestock and a
good place for them to stand and cool off in the summer time. Then—thanks
to fast cars, good roads and the world’s best economy—we got neighbors who
knew little about profitable farming but had a strong perception about
what open country should look like, smell like and sound like. When their
experience did not measure up, we started to hear about it and read about
it.
Now we have dairy farmers being harassed, challenged in court,
arrested, fined and even jailed. We have regulations being placed on us
with little hard science to back them or to tell us how to comply with
them. We have middle-aged farmers who need training in a new regulatory
arena. NRCS is vital to our industry’s survival, but too slow to
accept--for cost-share purposes--the new technologies needed to comply
with these tough regulations. We need to get on the pro-active side of
this issue or we are going to witness a faster exodus of farmers out of
dairying than we currently are. Here in broad, general terms are the
problem areas: Nutrients, Odor, and Appearance.
Nutrients
What dairy farmers have is too much of a good thing and they are being
harassed for economic-social reasons as much as for true environmental
oversights. Nutrients—whether organic or inorganic—can cause ground water
and/or surface water problems. However, in their zeal to regulate,
activist regulators and environmentalists may gain animal agriculture
compliance only to discover that they have dealt with far less than half
of the ground and/or surface water problem. Often this hard-nose approach
causes the demise of long existing farms with less than major nutrient
problems only to replace them with a hundred two-acre ranchettes
containing a double wide, septic tank, four old automobiles and a Joe or
Suzy Homeowner who dumps their used motor oil around the power pole and
drowns anthills with insecticide.
Odor
In many cases smell is the real source of our public relations problem
whether dairy, beef, poultry, swine or sheep. We need to get a handle on
odor control now. Odor was not a problem (we fondly called it the smell of
money) until we got non-farm neighbors. Someone offended by the odor of a
farm operation can be unyielding in their quest to quell the offending
party.
Appearance
This is not a scientific research area, it is a social research area
and one which the dairy farmer can address himself. If odor is the
offense, appearance can confirm the suspicions. If nutrients are a
problem, appearance may be the first thing to draw complaints.
So you can see we have political, policy and public relations
challenges, but where can the scientific research come in to help us (you
should have started at least five years ago but it takes a crisis to breed
bucks).
Odor Research
Odor abatement is vital. What can we do to the feed? What can we do to
the dry lot? Are there natural plant barriers that will help? Can
engineering designs be developed that will make a difference? Are feed
additives out there that need to be researched? Has anyone looked into the
claims of all these odor abaters that show up being peddled wherever
animal producers have a problem? How about something we can do to the
lagoon before spraying sends fowl-spelling effluent thirty feet into the
air. Direct spraying has real possibilities but we need some analysis to
demonstrate that it is acceptable and reliable equipment to apply it. Odor
is not always from manure. What about doing research into silage and feed
commodity odors, which can be pretty rank?
Nutrient Research
Can we further minimize the "pass-through" of fed nutrients? What plant
material is the best in animal occupied pastures for holding and/or
recycling nutrients? How many nutrients are passing through to groundwater
under various soil, plant, and animal density conditions? What are the
mineralization rates of nutrients in dairy manure under various conditions
of soil type, moisture, temperature, tillage practices, etc. This
determines the availability of nutrients to plants as well as the
potential for nutrients to leach into groundwater. Research on overland
flow, especially related to phosphorus, on low concentration runoff would
be helpful. Can the productive and holding capacities of various soil
types be improved? How can we accurately determine how much nutrient is
passing through the soil to the ground water? Is animal density an exact
quantity in relation to nutrient contribution to the soil or is a method
of handling and recycling nutrients possible that allows for greater
animal density? What about utilizing methane generation as another key to
containment and nutrient control with a payback potential? Is any research
and development being conducted that could denitrify, volatilize or
immobilize nitrates from water? We also need some scientific evidence to
determine if we really need to contain storm events from spray fields and
other lower intensity areas, or if a vegetative buffer is sufficient. When
manure is sprayed or spread after one day, three days, seven days, 30 days
or 6 months, how much of the nutrients are left, what form are they in,
and how much is readily available to the plants, and at what rate is it
available? We need to know a lot more than we do about lagoon construction
and operation. Has anyone thought about trying to determine under what
conditions phosphorus will not be a problem? Can a cheaper method
of ground water monitoring than drilling wells be developed or can other
mathematical or computer models be worked up? The industry needs market
development ideas for moving excess nutrients inexpensively to other users
such as organic growers, horticulture operations or row croppers. Can
someone develop an inexpensive, on-farm manure-nutrient analysis kit? Has
anyone looked into adapting municipal wastewater treatment systems to the
farms? If a cost-effective design can be done, it might be the savior for
land-limited dairy farms. Has anyone considered rewarding farmers for
adapting BMPs rather than fining them for not making changes?
It should be obvious that dairy farmers need research help. They needed
it about a decade ago, but better late than never. The fixes to meet new
environmental regulations that one sees going onto farms currently are too
expensive for many existing smaller operations. Agriculture has always
done more with less and that mindset needs to be the cornerstone of manure
handling research. Return to Top
Lew Britt, National Cattlemen's Association The National Cattlemen's Beef Association is very concerned over the
sensationalized rhetoric related to the impact that Concentrated Animal
Feeding Operations have on the environment. The beef feeding industry has
been under a "zero discharge" requirement since the mid-seventies and has
had an exemplary record of compliance to the Clean Water Act. However,
opportunistic single-issue activists are exploiting the confusion about
CAFO regulations to achieve very narrow objectives and advance personal
agendas. Toxic imagery has contaminated the debate. Environmental issues
are being confused with social issues, using the language of
environmentalism to promote anti-corporate, class-struggle positions. The
livestock industry, no matter how sincere in its efforts to satisfy
legitimate environmental concerns, has been branded as one of the greatest
threats to a clean and safe world. Extremists' themes are all too familiar
"doom and gloom". They have everyone neurotic, worrying about "invisible
poisons" while the world's population explodes to an expected 12 billion
people by the middle of next century. They project a sense of being
beholden to no one and to no thing except their own vision. It concerns me
greatly that they want to be perceived as the only representatives of the
public.
Scientific analyses and solutions are the key to putting forth credible
arguments against extremist agendas. It isn't always heard however, as has
been the case in the recent debate over EPA's new ambient air quality
standards and in the Administrations position regarding the recent Kyoto
Climate Treaty. Still, the support of scientific research can never take a
back seat if we are to seriously tackle the environmental challenges that
face our nation and our planet. This is very apparent as it relates to the
management of natural, organic nutrients from CAFOs. Exactly what are the
threats?
We know that nutrient loadings can be harmful in certain situations. We
know that phosphorus loadings can quickly reach a saturation level,
however, it is still unclear the environmental impact, if any, when there
are no surface waters involved. NCBA feels like a greater emphasis should
be placed on accurate measurements of nutrient or pathogen movement from
land surfaces to water. The end product of the research then becomes what
practices producers can use to feasibly reduce quantifiable contributions
to water quality impairment. Where will the technology needed to address
this problem come from? How will the problem be identified correctly to
begin with? This is the reality that faces us. We are allowing
site-specific problems to be construed as representative of a greater
national crisis when the truth of the matter is it is the variances in the
causes of the site-specific problems that need to be verified and
highlighted. I can't imagine that the physical, chemical and biological
variables of the water quality equation for instance, are constant across
the board, yet our producers need to identify with some predictability
what management practices will yield what results given a particular set
of circumstances. Bottom line here is that beef producers whether it be at
the cow/calf level, the stocker operator level or the feedlot level need
help in defining economically feasible remediation strategies to address
environmental challenges that are site-, situation-, and species specific.
The greatest challenges to be faced with manure management have to do
with water quality. Nitrogen and phosphorus output from fed livestock has
generated a great deal of concern. It is important that value is added to
livestock manure so that these beneficial nutrients are utilized and not
lost. As mentioned above, ARS can define the extent and under what
conditions, land application of these nutrients becomes detrimental to
water quality. Further, if science can help industry better utilize these
nutrients during the animal's feed conversion, less nutrient output will
occur and substantially reduce some of the potential concerns associated
with land application. There is considerable private research being done
now on this issue as you well know. Alternative uses for manure will add
value and create incentives to move the land application of the organic
nutrients outside an area where land application has reached a threshold.
What these new value added alternatives will be is totally dependent on
the economics of the technology to be used that helps generate/create a
new demand for manure resources. The safety of lagoons and other earthen
storage structures and their ability to protect groundwater aquifers is
needed. Again, much research has been done, but definitive statements from
ARS and other government entities regarding their safety are essential to
ease the current backlash against their use. It has been an accepted
practice to use lagoons as a step in the treatment of human as well as
animal wastes yet that message is being undermined by isolated instances
where lagoons failed to prevent contamination of underground and surface
water due to improper design and materials used given the engineering
challenges at those site-specific locations.
Odor is obviously a driving force for greater public scrutiny of the
locating of livestock production facilities within an area. The problem I
think that producers face is the perceived threat to health that odor
presents. Where science continues to support the benign health
consequences of odor, we still need to determine those properties/
chemical constituents that can be altered or eliminated so as to reduce
the unpleasant effects that continue to propel this debate forward.
The extent to which ARS can help in broadening the database on
particulate matter generated from livestock feeding operations will be
helpful in the continuing process of updating and correcting erroneous
data that is currently being used in the consideration of State
Implementation Plans designed to meet the obligations of the Clean Air Act
for PM 10. The situation becomes even more complex when PM 2.5 is
considered. At this time we can't even accurately measure the quantities
of PM 2.5 much less the sources. More importantly, we don't have the
technology to reduce 2.5 economically. Livestock producers must meet the
high expectations of the consumer for safe, wholesome and affordable food.
At the same time, we must address the public's concerns regarding the
impact of agriculture production systems on the environment while
simultaneously maintaining profitability and competitiveness in a global
economy. NCBA will continue to support federal government investments in
agriculture research, extension and education to meet these challenges.
NCBA strongly recommends utilizing production demonstrations conducted in
partnership with real world commercially viable farms and ranches. We
encourage establishing partnerships with private commercial operations,
with the federal and state governments contributing matching funds
necessary to establish and operate these demonstrations to validate the
applicability of new technologies, methods and practices in real world
settings. These projects would demonstrate that research and education can
be integrated at the producer level to assure producer profitability,
stimulate rural economies, and expand U.S. exports while continuing to
protect the environment. Return to Top
Ken Olson, American Farm Bureau Federation As a representative of Farm Bureau I really represent all species. Our
membership is nationwide and includes producers of virtually all species
of livestock and crops. As such, our members face all challenges possible
in dealing with questions of animal waste utilization and management.
Farmers and ranchers are by nature, stewards of the soil. They live in
the same environment where they work, raise their families there and
depend on it for their livelihood. Most have a sincere desire to pass on
to the next generation, farms and ranches that are in better condition and
more productive than they were when they began operating them.
I am a dairy scientist by training, so most of my experience is with
dairy cattle. However, the environmental challenges faced by animal
agriculture are not really species related. While the composition and
nutrient content of manure and other related products may vary somewhat by
species, the basic challenges are the same. How do we utilize this
valuable resource in a manner that minimizes any potential negative
impacts on the environment and the public, while maximizing its value for
producers?
The American Farm Bureau Federation (AFBF) is concerned about the
impact agriculture has on the environment and the ramifications for
producers. AFBF is directing significant resources to develop effective
manure solutions at the local, state and national levels. We have formed a
national Water Quality Task Force that works to address issues from
research needs to seeking to assure that any regulations put in place are
based on sound science, reasonable and likely to result in some benefit.
In addition, AFBF works as a partner on many species specific initiatives.
Farm Bureau has also directly invested in research on these issues.
Through the American Farm Bureau Fund for Agriculture, we are currently
providing funding for two projects in the area under discussion in this
conference. The first is "Development of an Accurate Manure Spreading
System to Protect Water Quality, Improve Waste Management and Farm
Profitability" at the University of Wisconsin-Madison. The second is a
project to "Improve Nitrogen Management from Manure in a Corn-Soybean
Rotation" at the University of Minnesota-Waseca.
To enhance and expand manure product utilization, there are several
areas where additional research and development would be useful in
addressing societal and agricultural concerns. Many are really
multi-disciplinary, and as such, will require coordination of efforts
within ARS along with other interested parties.
Facility and management technology choices, rather than animal numbers,
tend to define the method of utilization that is chosen. Manure products
that are completely utilized contribute no negative liabilities to the
environment. Processing by composting or capturing methane gas even
enhance the environment. These factors should be considered when designing
new facilities.
Recognizing that many existing facilities need to address these issues
also, manure product treatment, storage and handling systems from the
animal to the ultimate use deserve additional study. This appears to be
primarily an engineering problem, but may also involve production
management specialists to evaluate any impact of facilities modification
on animal care. From this starting point, we may look at various means of
utilization of the waste. Land based application is the most common
method, but what opportunities exist for development of other value added
products? Where access to adequate acreage is limited, are there other
innovative uses for animal waste that can be implemented by producers in a
cost effective manner?
Odor is a major concern. This is particularly true in hog operations at
the present time, but there are also concerns in handling liquid manure
from other species. Scientists have broken swine odor down into its
chemical components, but how do we minimize any negative impacts on the
surrounding community? This is likely to require a multi-disciplinary
approach to be effective.
As noted, the primary means of manure product utilization is currently
land based application. To do this most effectively we need to know the
interaction between differing soil types and landscapes, with the various
nutrients in animal manure products. What are the nutrient carrying
capacities of different soil types? What consideration needs to be given
to seasonal variation? How does the addition of a treated manure product,
such as compost or digester effluent influence nutrient uptake, water
holding capacity and soil biology? We also need to look at the ability of
various plants to take up nutrients. Which species will work best in
filter strips to remove nutrients and sediment from water? Can we develop
plants that will do a better job?
From an animal nutrition or genetic standpoint, can we minimize the
nutrients excreted in manure? If animals can better utilize the nutrients
in the feed, it means less that passes through. This should be a win-win
situation. Producers would gain in feed efficiency, while at the same time
they have fewer nutrients to find a home for from the animal manure
products.
Technology transfer to producers, regulators and interested members of
the public is a vital need. They need to know what can be done and how can
it be done most effectively. Right now, producers are trying to deal with
the issues on a personal basis as it impacts their operations. At the same
time they face actual or potential regulation at the national, regional,
state and local level. In addition, regulations frequently fall under more
than one agency in whatever jurisdiction is involved. This can often lead
to conflicting advise to producers ,and, in some cases conflicting
regulation and enforcement.
ARS priorities and program statements look appropriate. The challenge,
as with all similar endeavors, is to see that they result in appropriate
action. I see our responsibility as providing input to you, and then also
working to assure that Congress provides the resources needed to get the
job done.
Many challenges lie ahead. We need to work together to assure that
producers have the information that they need to do the best job possible
of protecting the environment for future generations. We look forward to
working with you to assure that this happens. Return to Top
John Crabtree, Center for Rural Affairs
Agricultural research over the last few decades has focused on
improving "agricultural efficiency" by utilizing capital intensive methods
of production that enable fewer people to produce the Nation's food and
fiber. Nowhere has this research focus been more intense than in livestock
production and waste management systems. Most recent applications of
technology in livestock operations require increased scale of operation to
offer an acceptable rate of return on the substantial capital investment.
Gains in productivity per unit of land or labor have been heralded as a
great success of agricultural research and technological innovation.
During this time very little research has focused on improving the
profitability of owner-operated farms. The search for knowledge needed to
help these farmers use their labor and management skills to reduce capital
expenditures, add value to their farm products, and capture more of the
dollars spent on food has been passed over in favor of research focused on
a vertically integrated, industrial model of livestock production. The
Agricultural Research Service (ARS) has devoted a lion's share of time and
research resources to serving the interests of the nation's largest
producers and left a majority of farmers to their own devices.
One explanation for the focus on industrial production in agricultural
research is that agriculture is being rapidly industrialized and many have
made the claim that this "trend" in inevitable. Aside from the fact the
ARS should not blindly follow short-term trends, the inevitability of the
industrialization of agriculture requires the assumption that there are no
viable alternatives. If real, practical alternatives are available then
any trend toward one agricultural model or another must be driven by
choices made by people. It is not only reasonable, but necessary that
publicly funded research examine and evaluate those choices.
Sustainable agriculture presents real and viable alternatives. Those
alternatives are exemplified by the hoop house, developed by Canadian
researchers. Hoop houses are ideally suited to small scale, dispersed
production. They can be constructed for about one third the cost of total
confinement buildings, making them economically accessible to small
sustainable farmers.
Hoop houses require more intensive management in the barn than total
confinement, making them appropriate for small sustainable farmers. These
management requirements tap the principle competitive advantage that
sustainable farmers have over corporate farms - the presence of an
experienced and highly motivated owner-operator in the barn.
The net cost of production in hoop houses is comparable to large total
confinement systems in spite of the fact that public sector research
institutions have invested hundreds of millions of dollars in research to
perfect total confinement production, and a pittance to perfect
sustainable hog production systems such as hoop houses.
These systems are ecologically far superior to industrial systems. They
rely on deep bedding with straw or corn stalks, resulting in natural
composting of manure in the barn. Because of their smaller scale, their
compost is easily applied to surrounding crop land at levels it can absorb
in a stable form that minimizes runoff and infiltration in ground water.
The compost builds soil organic matter and quality, and diminishes
reliance on chemical fertilizers.
Manure so handled does not produce significant amounts of methane. It
does not leak into ground water, spill into streams or produce odors at
levels that the atmosphere cannot absorb. If manure is widely dispersed
and managed well, it will stay on crop land to enhance it rather than
moving into air or water to pollute it.
Odor research has become a USDA focus (4 of the 25 current ARS national
program plans include odor research as a key research topic). Odor
research is another example of how the Agricultural Research Service
continues to serve the needs of industrial livestock producers over the
needs of sustainable agriculture. Odor has become a problem, not for all
livestock producers, not even for all pork producers but for a number of
industrial producers that have chosen to concentrate a large number of
animals into a small number of confinements and are now seeking a way to
reduce the social impact of those operations using public monies.
The effect of these and other research priorities that favor
large-scale, industrial producers is that small farmers and potential
beginning farmers who could be the basis of the transformation of the
livestock production to a sustainable system, are walking away and leaving
hogs to the corporate giants. Industrial agriculture will win by default,
and the public and the environment will lose, unless we define an
alternative, sustainable approach, reach out to small farmers and enable
and inspire them to challenge the vertically integrated, industrial model.
ARS should develop and implement a small farm research initiative. This
initiative should focus on the assets available to smaller farms, namely
the ability to use less capital intensive, sustainable methods of
production that utilize skilled labor and management. Research in this
area should include biological, economic and social research in an
interdisciplinary approach. Obstacles faced by smaller, more sustainable
operations as well as future opportunities that have not as yet been
explored should be addressed. Return to Top
George Halberg, The Cadmus Group, Inc.
The environmental impacts of livestock production have long been
recognized as an important and challenging issue. Resolving the problems
of animal waste has been one of the more troublesome issues facing
agriculture – a problem we never quite seem to face up to. Attention has
waxed and waned over the years, but it has clearly come to the forefront
once again. These issues have been on our agenda for enough years that
some in attendance will find few new or revolutionary ideas in what is
said. Hopefully, though, this gathering marks an added commitment to
action and innovation, beyond just a research agenda, to march toward
implementation and solutions of these important problems. My charge today
is primarily to frame the issues you must consider Many of the "hot-button" topics reaching the headlines that touch on
agricultural environmental problems are at least in part related to animal
agriculture and manure. From freshwater fish-kills to estuarine shellfish
problems, from the continuing saga of Tilamook Bay on the west coast, to
Pfisteria on the Atlantic seaboard, to hypoxia in the Gulf of
Mexico and other estuaries, manure and nutrient loading are part of the
picture. From Crytosporidium to "mad-cow" disease and the use of
manure as a feed, to various food safety concerns, the issues mount up.
These are some of the factors that bring us together.
Recognition of the need to address these issues has been emphasized in
the provisions of the 1996 Farm Bill – the Federal Agricultural
Improvement and Reform Act – particularly in the EQUIP program where half
the funding each year is directed to address problems associated with
livestock production. This and other policy directives (e.g., the new
Clean Water Action Plan) are, of course, another reason we are
here. Besides the issues noted above, contributing to the policy
recognition has been the recent increase in intensive management of
livestock, particularly very large-scale confinement operations. The
concentration of livestock operations has brought out a spectrum of
concerns from the farm community itself, as well as the general public –
concerns ranging from environmental issues to socioeconomic and property
rights issues.
Background In Brief – Problems to Address
Livestock and poultry production represent a significant segment of the
agricultural industry of the US. They directly contributed an estimated
$96 billion to the economy in 1996. Since the late 1980s, animal numbers
have increased in all but dairy. Poultry numbers have increased about 60%.
The most pronounced changes have taken place in the concentration of swine
and poultry production. Growth, accompanied by a movement from small farm
production to large integrated containment facilities, is changing the
complexion of the swine and poultry industries. While the total production
of swine has not changed greatly (within the range of cyclical market
swings) the total number of hog farms has declined substantively, an
estimated 70% over the past 15 years.
Livestock systems and manure pose particularly difficult environmental
problems. Direct discharge of manure reaching surface water disrupts
aquatic ecosystems While water quality problems have long been recognized, there are many
other issues being raised ranging from local and global air quality
concerns, odor control and quality of life issues, animal welfare and dead
animal disposal, the continued evolution of antibiotic resistance as a
public health and animal health concern, and worker health and safety
issues for those working in confinement operations. Partly because of the
concentration of livestock, odor and air-quality concerns have reached the
public agenda – often pitting farmers and rural families against other
agricultural producers who operate large CAFOs.
Odor can be a general public nuisance but the constituents of the
"odor" problem raise further concerns for public health and the
environment. Airborne irritants associated with livestock feeding
operations include dust, ammonia (NH3), methane, and other
gases, and concerns have been raised about airborne transmission of
pathogens. Feedlots and confinement buildings present health risks to
those that work in them. Airborne dust, enteric bacteria, endotoxins, and
various gaseous emissions cause health problems in confinement workers.
Animals in these units may also be affected, causing disease and decreased
performance.
With growing concerns about greenhouse gases, long-term air quality and
climatic effects, simply letting the emissions of NH3, methane
and nitrous oxides go unchallenged is no longer acceptable. Ruminant
livestock constitute the second largest source of US methane emissions
(~30-35 MMTCE). Manure from all livestock is estimated as the fifth
largest source (~17MMTCE). While we may be limited in ability to reduce
natural ruminant emissions, methane and other emissions from manure
storage could be markedly improved.
In Europe, emissions have been looked at in more detail and animal
agriculture is estimated to be responsible for 5.2 million tons
NH3/yr being released to the atmosphere. Atmospheric
NH3 comprises up to 10% of total N entering the aquatic
environment with 85% being deposited within 100 km of its origin.
In 1993, the National Research Council’s Board on Agriculture, issued
the report Soil and Water Quality: An Agenda for Agriculture. The
Report clearly pointed out that improving livestock and manure management
is a key element to improving the economic performance as well as the
environmental performance of farming systems. In its recommendations the
report noted that improvements in manure management must be a high
priority in the nation’s programs to improve water quality. Better
management of manure, as pointed out in the Soil and Water Quality
report, may also improve soil quality. But as noted in the report, there
is no simple, single "BMP" Livestock and poultry in the US excrete approximately 900 million tons
of manure annually (depending on how it is estimated). This represents
significant nutrient value that we must find ways to realize instead of
treating it like waste. In Soil and Water Quality we developed an
approximation of regional and national nutrient budgets for perspective.
In most crop-producing regions, the recoverable phosphorus from manure was
estimated as more than a third of crop removal, and in some regions 80% to
more than 100%. For manure recoverable-N the estimates are lower – but
recovery can be substantially improved, as well. Adding legume-N/rotation
effects (common in many cattle areas at least) with manure-N we often
account for 50-60% of crop needs. While imperfect, as any such estimates
are, they help emphasize the need for improved nutrient management.
In areas, such as Iowa or the Chesapeake Bay states, where significant
improvements have been made in fertilizer management to reduce nutrient
loading to the environment, it is clearly recognized that to make further
substantive progress we must improve manure utilization and management. We
must recognize the resource value of manure instead of focusing on waste
disposal.
But there are important obstacles that make improvements in manure
management difficult and costly, or that require difficult policy
deliberations. There are uncertainties and risks in managing manure
nutrients; there are equipment, farm infrastructure, and labor costs and
concerns. In some areas, the local or regional concentration of livestock
production result in more manure being produced than can be effectively
used on available cropland.
While these problems provide a "laundry list" of research topics they
all need to be incorporated in a systems approach to livestock and manure
management.
Systems Approaches – From Front to Back, We Need Solutions
I won’t pretend to give you a research agenda. But I will take the
liberty to touch on some topics that should not be overlooked. In a
systems approach, we can start at the very front end of the problem.
Feed and nutrition are often overlooked as part of the manure
management solution. Work on this end can provide source reduction.
Nutrient composition of manure can partly be altered by changing diet
composition to provide a better balance in nutrient output. Greater feed
efficiency is generally economically desirable and can reduce the quantity
of manure, can reduce methane generation, and can reduce the total
quantity of nutrients voided. Research on phytase, for example, has shown
significant improvements in phosphorus retention. But in a complete
systems approach, we also need to look at the effects of phytase on other
dietary components and endocrine-metabolic system function.
Feed efficiency can also be addressed through genetics and biotech
approaches both in the animals themselves and their feedstock. On the
"low-tech" end, there is still the need to continue to improve pasture,
grazing, and forage management. Rotational grazing and appropriate use of
manure on grazing lands still need attention.
But no matter how much we improve conditions on the front end, we will
always have manure to deal with. So, at the other end of the system, there
are a myriad of management issues. These range from better, low-cost
containment facilities, to improved storage and application methods,
improved nutrient retention, to odor control options. Further research is
still needed for optimizing crop production with manure without excessive
nutrient build-up in the soil or the loss of nutrients, trace elements and
pathogens to water supplies. Some studies have suggested that manure may
provide some long-term pest management benefits. Does this need to be
looked at? An animal waste management system should be part of a total
soil and water conservation plan for farms producing livestock and
poultry. How do we best integrate these? How do we integrate these at the
watershed scale, as well? Can we further calibrate needed BMPs, such as
the placement and use of filter and buffer strips for delivery reduction
of runoff? And what about complete environmental and production
assessments of innovative management systems, such as hoop structures for
hog production?
Many studies have shown that the areas with the greatest excess of
nutrients usually have a combination of manure application and
fertilization because farmers don’t take adequate credit for their manure.
This is partly because of the variability in nutrient value of the manure,
lack of confidence in the nutrient value, and problems in uniform
application and control. At the 1997, National Research Council, Board on
Agriculture’s Symposium on The Environmental Implications of Livestock
Feeding, participants identified various needs, ranging from better
characterization of nutrient values, to more rapid manure and soil tests
to facilitate better utilization. Improved injection equipment that can
provide better calibration and uniformity of application is also needed,
as well as application methods that reduce soil damage. Many of these
needs can also be addressed by finding ways to improve the uniformity of
the product.
We proved 20 years ago, with the "oil/energy crisis" of the ‘70s that
we can economically recover methane from manure and generate energy, and
at the same time reduce or eliminate many of our odor and air-quality
problems, and improve the consistency and manageability of the remaining
manure. With the large manure storage systems in development today, there
would seem to be a great opportunity to put these techniques into use.
What do we need to do to further improve the efficiency of these
approaches to get them in to use? On many fronts agriculture has an
opportunity to find support for developing sustainable energy.
In too many areas we are now generating more manure and manure
nutrients than we can use sustainably for local crop production. Can we
add value and find other products and markets for manure? What other
options are there for manure use besides agricultural nutrients or compost
for non-agricultural use? The market for compost is considered saturated
and we must look beyond. Are there centralized options for energy
generation? Other uses? With an improved and more consistent product can
we overcome the impediment of transport costs enough to enhance use? Can
we affect brokering of manure among farmers, among watersheds?
Beyond the scientific and engineering questions there are sociological
and economic research needs, as well. While we need economic evaluation of
many of the benefits of improved manure use, we need to assess how we
promote and accelerate adoption of improved manure management. In that
regard, it is good to see that you have many of your partners and
customers here (in the jargon of the day). Having producers, NRCS and EPA
involved in the design of research can certainly help to make it more
relevant to their needs and enhance potential adoption and program
coordination. But I am disappointed not to see a greater presence of
Extension. It is imperative that results get delivered and put into
practice. Hence, I would urge that you coordinate your efforts with
Extension and support their efforts to affect implementation. The best
research agenda will not resolve the problems of animal agriculture and
manure management. If the knowledge and management tools we have today
were being applied we wouldn’t be facing the problems you have gathered to
discuss!
And that would be my final, parting shot. I encourage a spirited
dialogue over the next two days to develop and refine your research
framework. But I also implore you to think beyond research issues to the
critical component of implementation. We must get the research into
practice, into the hands of producers, and onto the ground. For my one
slide, I leave you with a battle cry on the theme of more productive and
efficient use – from an Iowa bumper sticker – Manure Happens…Take
Credit. Return to Top
Barry Kintzer, United States Department of Agriculture, Natural
Resources Conservation Service Animal Diet/Nutrition
Animal Housing - Waste Storage/Treatment Facilities
Waste Handling/Application
Water Quality/Runoff--Nutrient/Phosphorus Issues
Buffers/Vegetative Filters
Return to Top
Susan Heathcote, Iowa Environmental Council
Livestock production is an important element in our nation's economy
and in sustainable farming systems. Livestock producers, of every size,
must operate in a way that enhances the environmental and social well
being of the larger community. Just as we all have certain individual
rights, we also have responsibilities. Federal, state, and local
governments each have a role to play in reconciling these rights and
responsibilities.
One of the fundamental issues related to manure management is the
initial choice a producer makes about whether to consider manure as a
resource, a waste product, or a combination of the two. This choice will
influence every subsequent choice about his or her entire livestock
operation. And it will be a significant factor in environmental impact.
For example, the choice of whether to use manure as a resource or as a
waste will influence whether to use a covered manure storage system or an
open anaerobic lagoon, what crop to plant, how much land is needed for
manure application, whether to test the soil and manure before
application, and whether to spray irrigate manure or inject it into the
soil.
If the choice is to use it as a resource, there will be fewer negative
environmental impacts and, in fact, there can be positive environmental
impacts. Negative environmental impacts are more likely when manure is
disposed of as a waste. We also know that weather, accidents, and human
error can result in negative impacts with even the best systems. We need
more research on ways to maximize the benefits of manure as a nutrient
resource. In addition, we need technical assistance, incentives, and sound
regulations that will protect humans and the environment from the negative
impacts of manure when it is disposed of as a waste.
Environmental issues related to livestock management systems include
water quality, atmospheric deposition, manure management, lagoon siting
and performance, agricultural drainage wells, air quality, soil quality,
and regional impacts. The following is a brief summary of these issues
from the perspective of the Iowa Environmental Council.
Water Quality
We know that livestock waste can have a significant impact on water
quality, but we have barely begun to understand the full range of water
quality, ecosystem, and related human health issues. From experience in
Iowa and other states, we know some of the immediate effects of
catastrophic spills such as fish kills but we know little about the full
ecosystem impacts -- and know almost nothing about long-term effects.
Nutrients, primarily nitrogen and phosphorus, in excess of what crops
can use (or in the wrong place or at the wrong time) can contaminate both
surface and groundwater. Drinking water supplies from surface water
commonly have problems with nitrate contamination. Nitrogen contamination
of groundwater is also significant and is common in areas with shallow,
unprotected aquifers.
We know little about risks to human health from pathogens, hormones,
antibiotics, and antibiotic-resistant organisms in livestock
waste--whether related to contamination of groundwater and surface water
supplies used for drinking water or to recreational contact.
Atmospheric Deposition
All manure management systems lose some nitrogen to the atmosphere, but
the extent of this loss depends on the type of manure management system.
Some of the nitrogen escapes into the atmosphere as nitrous oxide, a
greenhouse gas. Most nitrogen lost to the atmosphere comes back to the
earth in rainfall. This may be a benefit when it falls on cropland, but it
also falls directly on lakes, streams, wetlands, and prairies where excess
nutrients can be harmful.
The potential for damage to natural habitats has been extensively
documented in the Netherlands. In the U.S., added nitrogen in rainfall has
resulted in shifts in plant populations toward species that use high
amounts of nitrogen causing the loss of native species adapted for low
amounts of nitrogen. Current research indicates that atmospheric nitrogen
deposition may harm survival of the Midwest's remaining tall grass
prairie.
Manure Management
Land application of manure has potential for negative impact on both
surface and groundwater quality. Manure management plans are needed for
all sized operations and conservation plans are needed for all land. There
is little data documenting the performance of current land use and manure
management practices. What we do know is that theory and practice often do
not completely overlap. We need to find out what is really happening on
the land and what works.
If manure is being used as a resource then the producer has a financial
incentive to use that resource wisely to minimize costs and maximize
benefits. Education and technical assistance can enhance this type of
farming system. However, if manure is treated as a waste, more careful
oversight and regulation will be necessary to minimize environmental
impacts and external costs that society pays -- in atmospheric nitrogen,
ground and surface water pollution, and air pollution.
Lagoon Siting, Construction, and Performance
The sites chosen (and permitted) for confinement operations must avoid
vulnerable areas. Important factors such as groundwater vulnerability,
local drinking water sources, unique habitats, and recreation areas must
be considered when sites are chosen and permits issued. We also need to
deal with many poorly sited older facilities and make sure protections are
in place to cope with their potential impacts.
We have little information on the actual performance of earthen
livestock waste lagoons. There is more information about the performance
of earthen lagoons used for municipal sewage. This research indicates a
high percentage leak in greater amounts than the allowable design standard
and, in some instances, groundwater contamination has been documented.
There is every reason to believe animal waste lagoons may, in general,
have a worse record because there are often less rigid design standards
and less oversight of construction, operation, and maintenance.
In considering appropriate design and construction standards, we tend
to focus on engineering possibilities, design options, and technological
fixes. Often left out of these discussions are the realities of how
animals, lagoons, and manure are managed in the real world and the
impossibility of managing "Mother Nature". Experience indicates the need
for much better protections, including backup systems. This is
particularly true for very large lagoons where catastrophic failure could
result in ecological disaster.
Agricultural Drainage Wells (ADWS)
Iowa has 290 agricultural drainage wells (ADWs), which are wells
drilled mostly in the early 1900s to drain vast wetlands in north central
Iowa. Many ADWs discharge surface drainage water directly into aquifers
that provide high quality drinking water for public and private water
supplies. Iowans belatedly realized that over 20 ADWs are within 1/4 to
1/2 mile of multi-million gallon earthen manure lagoons. In 1997
legislation was passed in Iowa that requires these ADWs to be closed by
the end of 1999.
Significant issues remain concerning management of the remaining 270
ADWs in Iowa, including many drainage wells located in areas experiencing
rapid growth in the number and size of livestock operations. Livestock
management concerns related to ADWs may also need to be addressed in other
states. EPA inventory records show ADWs in at least 19 other states,
although the number and locations are not well documented.
Air Quality
Solving air quality issues related to swine confinement is more
complicated than just "solving the odor problem". Air quality concerns
include odors, of course, but also gases and airborne particles. Over 160
compounds have been identified in the air around swine production
facilities. We believe that a broad range of research is needed to address
all aspects of air quality: the odors, the gases, and particulates.
Air quality issues include worker health related to indoor air
exposure, including respiratory problems from exposure to gases and
particulates as well as confined space hazards associated with exposure to
hydrogen sulfide. While the level of gases and odors for neighbors are
considerably lower than inside production facilities, reports indicate
that odors and gases cause nausea, vomiting and headache; shallow
breathing and coughing; upset sleep and appetite; cause eye, nose and
throat irritation; and can lead to depression. Hydrogen sulfide and
ammonia are particularly serious if present in high concentrations.
Microbial contaminants and organic dusts have been measured in air down
wind from confinement facilities and may produce inflammation and allergic
reactions, especially in sensitive individuals.
Control of odor through the use of various techniques including the use
of biofilters, covers, and pit additives are being studied as a means to
"solve" the odor problem. Even if this research is successful, we must
remember that odor control is not the only objective.
Soil Quality
If land application rates for manure are based solely on nitrogen needs
of the soil, we know that phosphorus and potassium will accumulate, as
well as heavy metals. The build-up of phosphorus can result in run-off
causing algal blooms in surface water and phosphorus movement into
groundwater. The impact of heavy metal accumulation (primarily copper and
zinc) on soil health and productivity require additional research.
Regional Impacts
Typically, management and regulation of farms has been addressed on the
scale of the individual operation, not at a regional or watershed level.
At the regional level, environmental effects depend not only on the manure
management of individual operations but also on the nutrient balance for
the region. When excess nutrients are present, pollution is a given.
Excess nutrients go into groundwater, surface water, soil, or the
atmosphere. We must work regionally, nationally and worldwide to balance
the capacity of the environment to assimilate pollutants. We must balance
not just one producer's need to dispose of large quantities of manure with
the amount of available land, but also consider the burden that disposal
places on the regional ecosystem.
Whether we talk about large or small livestock operations, a critical
element in our discussions, research, incentives, and regulations must be
balance for long-term sustainability. Return to Top
Michelle Smith, Food and Drug Administration It's a pleasure to be here this afternoon and to have an opportunity to
be a part of this workshop. I recently found out that there are 17 Federal
agencies in the US concerned with food safety research. This workshop is a
great example of the agencies working together, along with other
stakeholders, to address common concerns.
As many of you may be aware, FDA recently released a proposed guidance
document geared towards minimizing microbial food safety hazards for fresh
fruits and vegetables. Our concerns relative to animal waste issues are
not limited to fresh fruits and vegetables. However, I think the proposed
guide is a good jumping-off point for this discussion.
I'd like to very briefly outline relevant aspects of the Produce Safety
Initiative and how it fits into the larger Food Safety Initiative. I'd
then like to give a very quick overview of the proposed guide, including
how it was developed and next steps. I'll hit some of the high points in
the proposed guide dealing with manure management and use and identify
some of the areas where additional research is needed.
The Produce Safety Initiative, announced October 2, 1997, directed the
Secretary of Health and Human Services, and the Secretary of Agriculture,
in cooperation with the agricultural community, to develop voluntary
guidance on good agricultural and good manufacturing practices (GAPs/GMPs)
for the growing and packing of fresh fruits and vegetables. This
initiative also includes important education and outreach, technical
assistance, and research components.
On April 13, 1998, FDA published a FEDERAL REGISTER notice of
availability for the proposed voluntary guidance document, Guidance to
Industry -- A Guide to Minimize Microbial Food Safety Hazards for Fresh
Fruits and Vegetables" (the proposed guide). The proposed guide
incorporates comments from 7 public meetings and over 50 letters
containing comments on a November 25, 1997 working draft of the document.
The guide can be seen on the WWW at http://www.fda.gov. We're providing
75 days for comment on the proposed guide (until June 29, 1998) and expect
to have a final guide available by October, 1998.
On of the first things that became clear to us in drafting the guide,
and in other phases of this initiative, is how much we do NOT know.
Consequently, as additional information becomes available, we plan to
update the guide. In essence, it will be a "living document."
On the other hand, current, sound science and knowledge of the pathways
by which produce may become contaminated enable us to set out broad scope
recommendations, which, if followed, can help reduce the risk of microbial
contamination of fresh produce.
The proposed guide sets out basic principles for food safety (such as
"prevention of contamination is preferred over corrective actions") and
addresses potential microbial food safety hazards common to the
agricultural and packing house environments. These potential hazards
include: agricultural and processing water, manure and biosolids, worker
and facility sanitation and hygiene, and transportation. For this
workshop, I'll focus on manure.
Manure - Microbial Hazard
Animal manure can be a beneficial fertilizer and soil amendment. It
also represents a significant potential source of human pathogens. A
particularly dangerous pathogen, Escherichia coli O157:H7,
originates primarily from ruminants such as cattle, sheep and deer, which
shed it through their feces. In addition, animal and human fecal matter
are known to harbor Salmonella, Cryptosporidium, and other
pathogens. Therefore, the use of manure in the production of fresh produce
must be closely managed to limit the potential for pathogen contamination.
Growers (and animal producers) must also be alert to the presence of
fecal matter that may be unwittingly introduced into the produce growing
and handling environments. Potential sources of contamination include use
of untreated or improperly treated manure, nearby manure storage or
treatment areas, and livestock or poultry operations. (Microbial
contamination of aquaculture and fishing waters is also a concern, along
with the effects of eutrophication of waters from non-point-source
pollution on pathogens.)
Good agricultural practices (GAPs) for handling manure to reduce the
potential for introducing microbial hazards include treatments to reduce
pathogen levels and maximizing the time between manure application to crop
fields and harvest of crops.
Passive treatments
Passive treatments rely primarily on the passage of time, in
conjunction with environmental factors, such as natural temperature and
moisture fluctuations and UV irradiation, to reduce pathogens. To minimize
microbial hazards, growers relying on passive treatments should ensure
manure is well aged and decomposed before applying to fields.
Additional research is needed to better define "well aged and
decomposed" in terms of pathogen reduction.
Active treatments
Active treatments include pasteurization, heat drying, anaerobic
digestion, alkali stabilization, aerobic digestion, or combinations of
these.
Composting
Composting is a controlled and monitored process, commonly used to
reduce the microbial hazards of raw manure. The high temperature generated
during composting can kill most pathogens in a number of days. Thus, the
risk of microbial contamination from composted manure is reduced compared
to untreated manure. However, some pathogens, such as the hepatitis A
virus, have a higher thermal threshold than others. In addition, the time
and temperature required to eliminate or reduce microbial hazards in
manure or other organic materials may vary depending on regional climate
and the specific management practices of an individual operation.
Much of the research on the composting of manure and application of
manure to field crops has focused on the effects of different practices on
soil fertility and crop quality. Research on pathogen survival in
untreated manure, treatments to reduce pathogen levels in manure, and
assessing the risk of cross-contamination of food crops from manure under
varying conditions is largely just beginning. Additional research is also
needed on improved methodologies for pathogen detection at low levels in
manure, and on simple process control methods operators may use to ensure
that treatment conditions that are adequate to reduce pathogen populations
have been achieved (e.g., time/temperature "confetti").
Handling and Application
Growers should review existing practices and conditions to identify
potential sources of contamination. Growers should follow GAPs (e.g.,
securing manure in storage areas or establishing run-off controls) to
minimize contamination of produce from manure in open fields, compost
piles, or storage areas onto nearby maturing crops. Untreated Manure Use of untreated (raw) manure on food crops carries a greater risk of contamination compared to the use of manure that has been treated to reduce pathogens. Competition with soil microorganisms may reduce pathogens.
Incorporating manure into the soil (e.g., prior to planting) may reduce
microbial hazards. Conversely, incorporation may protect pathogens from
temperature and moisture fluctuations and UV irradiation that are also
known to reduce pathogen. Additional research is needed to
determine most appropriate manure handling practices for different crops
and regions.
Applying raw manure to produce fields during the growing season (e.g.,
broadcasting or sidedressing crops) is Growers may reduce the risk of contamination from manure by maximizing
the time between application of manure to a field and harvest. The
National Organic Standards Board, formed under the Organic Food Production
Act of 1990, following the guidance of the act, recommended that raw
(untreated) manure should Treated Manure
Composting and other treatments may reduce but might not eliminate
pathogens in manure. A few points not directly covered in the guide:
Prevention Not all animals are shedding pathogens of human health significance at
all times. Additional research is needed on animal health and production
practices to minimize the prevalence of pathogens in animal populations
which may be shed in feces and cycle or recycle into the food chain.
Risk Assessment
A number of comments on the working draft suggested that we use risk
assessment to rank the hazards and the GAPs/GMPs in the guide. Gaps in the
science and the broadscope nature of the guidance document make this
difficult. However, with additional data and more specific guidance (such
as guidance targeted to specific regions, practices, or crops), this may
be possible in the future.
For example, DNA fingerprinting of pathogens found on produce might
help determine where there is a link with manure use. Data on the
probabilities of (1) crop contamination from manure use, (2) pathogen
survival until harvest, (3) pathogen survival of post-harvest handling,
and (4) resulting foodborne illness (dose/response) is needed.
Brad Barham, Program on Agricultural Technology Studies, University
of Wisconsin at Madison We are preparing to enter the fourth decade in which a significant
amount of state and federal money will be spent attempting to mitigate the
impacts of farming activities, especially livestock agriculture, on water
quality. Manure and nutrient management practices are widely identified as
critical variables affecting the environmental performance of most farms
in Wisconsin and, indeed, throughout much of the nation. To protect
surface and groundwater resources, a number of technical and managerial
solutions have been designed to minimize nutrient leaching and runoff from
barnyards and farm fields. An impressive array of educational programs,
financial subsidies (e.g. cost sharing of manure storage and retention
facilities), and regulatory incentives has been employed to encourage
livestock producers to manage their manure in environmentally responsive
ways. Additionally, researchers in land-grant universities, USDA, and
other agencies and institutions are working hard to develop new
technologies (e.g. remote-sensing guided manure spreading) that might
provide both improved returns to farmers by more effectively utilizing the
nutrients present in manure and diminished negative environmental impacts
by spreading manure in less risky places. These efforts appear likely to
grow in importance, especially if regulatory bodies around the country
come under pressure to improve the environmental performance of livestock
agriculture.
Yet, a basic question needs to be asked of the participants
(individuals – agencies) involved in research, extension, and programmatic
efforts in the manure management arena – Technical solutions that build on advances in instrumentation,
information-processing, and structural design to achieve, on paper,
improved returns and lower environmental costs are not necessarily ones
that farmers will adopt for a whole variety of reasons. Policy
recommendations or programs that look good on the drawing board may be
non-starters on the farm or in rural areas for a whole variety of reasons.
While the message of needing a better understanding of client groups is
certainly not new, and is indeed largely the rationale for this forum, it
is quite apparent that it remains unheeded in many publicly funded
institutions where ongoing efforts at improved manure management are being
designed or promoted. Worse yet, there seems to be a prevalent mindset
among many of those participants that the more technically complex
solutions of today (which are admittedly well beyond the reach of most
farmers now) will be the wave of tomorrow’s future on livestock farms,
because they will all be big and more likely to adopt such technologies or
practices. That approach is particularly unsettling, because it provides
both a weak excuse for not answering today’s problems and ignores the
historical evidence that the structural transformation of agriculture is
slower and involves considerable diversity.
This point is perhaps best illustrated by sharing some data we have
gathered in Wisconsin from random-sample surveys regarding the manure
management practices of livestock farmers, especially dairy farmers. The
presentation will share some basic points that hopefully will stimulate
discussion. First, livestock farmers do not follow commonly recommended
practices despite considerable public investment designed to encourage or
finance necessary investments for such behavior. Second, the reasons they
do not do so are infrequently ones of ignorance, and are much more likely
to be based on the objectives and constraints of their operations (in
terms of size, labor availability, profitability, and so forth). Third, in
fact, little attention has been put into efforts to fit manure management
solutions into the variety of biophysical, social, and economic situations
of livestock farmers. Fourth, the changes in the structure of livestock
activity in Wisconsin, at least if we look at the dairy sector, are not
occurring fast enough to obviate the fact that moderate-scale,
family-labor dairy farms are likely to remain a major portion of the dairy
industry for the foreseeable future. In other words, we have to find ways
to think creatively about tailoring solutions to the problems of livestock
farmers today, and not the ideal or "representative" farms of tomorrow,
because we are still a long way from addressing ongoing needs of the
customer base.
The bad news is that the effort to bring social science issues into
research design do not stop at the farm gate but reach well beyond into
other clientele groups in society, again a point that is probably broadly
perceived but not too well understood. Thus, in addition to the
applicability or appropriateness of a given technology to different types
of farmers, there is a need for researchers to consider the other
stakeholders involved and how these new initiatives might affect them. In
other words, the social impacts also need to be brought explicitly on the
table for discussion. A handout offered at the talk will raise some of the
relevant questions and point participants toward some means for doing so.
Suffice it to say, that especially when it comes to ex ante
research design, there is considerable uncertainty involved in this type
of effort, but inclusive public discussions throughout the research
process (original research ideas through testing through implementation)
can help to ensure that the broader social and environmental impacts are
not merely left for future participants to try and "manage" as waste
rather than nutrients. Return to Top
ARS Presentations
Barbara Glenn and Vince Varel, Animal Feeding and Management
Introduction The environmental impact of animal manure is a high priority to livestock producers, the animal industries, and the consumer. Animal nutrition directly impacts the volume of manure, the excretion of nutrients and gaseous and odorous losses. Cattle feedlots and swine facilities lose up to 75% of the nitrogen excreted by the animals under current waste management systems. Phosphorus in manure is a rapidly growing problem for poultry, swine, and cattle producers. Animal nutrition (feeds and feeding) is the single most costly expense in animal production, often as much as 70% of the total cost of production. Therefore, research to study the effects of animal nutrition on manure production and nutrient excretion will be required in the future for economical and environmentally friendly production of meat and milk. National Research Programs Linking Animal Nutrition to Manure Utilization The effect of animal nutrition on manure production and nutrient excretion is a research program in ARS that resides in the linkage of two National Programs: Animal Production Systems and Animal Manure, Waste Utilization and Management. The National Program on Animal Production Systems includes emphasis on three areas: Animal Nutrition, Integrated Animal Systems Research and Integrated Information for Animal Production Systems. Strategies to improve nutrient use and reduce losses in manure including odor are being developed by ARS researchers. These strategies must be included in decision aids to integrate components of animal production with whole farming systems programs. Manure management on the farm in the future must include all components within the animal-manure-soil-crop cycle. Current ARS Research Manure production and nutrient excretion. There is a significant level of ARS research being conducted on the effect of diet on manure production and nutrient excretion. For swine and poultry, effects of level of dietary phosphorus supplementation, dietary phytase, and low phytate corn on phosphorus excretion are being studied. For dairy cattle, there is considerable emphasis in research on optimizing or minimizing dietary nitrogen for ruminal fermentation and milk protein recovery. Different forage sources (grasses vs. legumes), different starch sources (altering starch degradability), and level of degradable protein for milk production are currently being studied for their impact on manure production and nitrogen excretion. Level of dietary phosphorus in diets for lactating cows has been studied to determine the requirement for phosphorus. There is a database compiled from research in the energy metabolism program at Beltsville that predicts manure production and whole farm nitrogen excretion from diet composition and other variables. Two locations are incorporating data on effect of diet into decision support modules for manure composition and whole farm manure use. One model is DAFOSYM, developed by ARS researchers; the other modules are being developed in conjunction with Northeastern land grant university personnel who already have rumen or whole farm models. For beef cattle, there is a significant program on optimizing or minimizing nitrogen and phosphorus use for feedlot systems. One scientist has found that alternating dietary protein concentrations from day to day will reduce nitrogen excretion without affecting overall production. In order to reduce manure volume, there is a significant level of research to study different dietary ingredients or microbial systems that can improve digestibility. Mass balances for nitrogen and phosphorus in the feedlot have been conducted. Manure Odors and Gaseous Losses. Diet also affects odors and gaseous losses. Urease inhibitors that can be supplemented to the diet have been successfully used to reduce ammonia losses from both swine and beef cattle manures at Clay Center, Nebraska. Intestinal odor precursors in swine digesta are being studied. The effects of microbial substrate inhibitors that could reduce fermentative activity and odors are being studied in beef cattle manures. Ammonia, methane and odors will be measured accurately and precisely from dairy cattle fed different diets and housed in an environmental chamber in Beltsville. There is a database compiled from research in the energy metabolism program at Beltsville that predicts methane production by dairy cows from diet composition and other variables. In addition, the composition of feed yard dust was studied in Bushland, TX and found to contain numerous microorganisms, many that could have originated from manures. Effect of Diet in the Future. In the future, diets fed to swine, poultry, dairy cattle and beef cattle will include new feedstuffs that will help in reducing manure production and nutrient excretion. The development of low phytate corn was recently announced by ARS in collaboration with Pioneer, and has the potential to reduce phosphorus excretion by swine and poultry. Since natural phytase cannot tolerate temperatures of feed processing, including pelleting, an ARS scientist has discovered that a heat tolerant phytase may be synthesized inexpensively by a desert fungus species. The research group is exploring the possibility of inclusion of the genes coding for heat tolerant phytase into soybean plants. Also it was recently announced that the gene for heat tolerant phytase has been inserted in a transgenic alfalfa. These new feedstuffs could be used to include phytase in the diet. Improvements in diet digestibility could reduce the volume of manure significantly. Researchers are studying new plant genetics to improve digestibility of the cell wall in alfalfa and corn lines. One scientist is studying ruminal microbes to determine if there is a fibrolytic microbial species that could improve digestibility of fiber. Finally, there are several locations studying improvement in disease resistance in forages, which would ultimately improve digestibility of a forage. Conclusions Animal nutrition is a primary factor controlling the volume of manure and quantity of nutrients excreted. Diet also affects gaseous and odorous losses from the animal. Strategies to improve nutrient use and reduce losses in manure and approaches to control odor are being developed by ARS researchers. These strategies must be included in decision aids to integrate components of animal production with whole farming systems programs. Effects of diet must be included in modules of decision support tools for manure management. The diet of the animal is a central component of whole farm manure and nutrient management. Return to Top
Pat Hunt,
Handling/Storage/Treatment Handling and Storage--Odor, Ammonia, and Particulate Emissions One of the most passionate and politically charged aspects of animal waste management is the area of odor control. The problem is being addressed from many directions that include diet alterations, odor retardants, odor barriers, aeration treatment, composting, and anaerobic digestion. Odor is often associated with particulate emissions, and their reductions can lower odor as well as meet air quality standards. Ammonia emissions from solid waste, particularly poultry, are being addressed by alum additions. Alum has the added benefit of binding phosphorus in an unavailable form. Ammonia losses from liquid waste can be controlled by nitrification; this is best accomplished after the organic load has been reduced by separation of liquids and solids. Separation of solids also greatly reduces the cost of transporting a liquid material. This separation allows the use of much smaller lagoons and the associated reduction in spill hazards. Separation of waste and rain water also allows for both reduced spill hazards and treatment requirements for runoff water during extended periods of high rainfall. Treatment Many different methods of treatment are being used, but no one treatment has emerged as the best alternative to the traditional lagoon and land application combination. Some of the proposed treatments are rather passive, e.g.. media filtration and constructed wetlands. Others are more intense and use treatment enhancers such as fixed cultures of specialized bacteria. It may well be that the optimal system for waste management will be a natural treatment sequence with enhanced microbial components, gas exchange, and pH/Eh control. Examples of some specific systems under investigations by USDA-ARS at Florence, SC follow. Solids/liquid separation: Animal manures are generally stored and applied to land in liquid form. Problems associated with concentrated land applications near the confinement houses can be solved by separation of solids from the untreated manure liquid, and transport to nutrient deficient areas. However, most of the organic nutrients are contained in fine suspended particles that are not separated by screens and presses. One solution is to use chemicals to bind together the fine particles and increase capture and removal of N and P nutrients. Our research has shown that polyacrylamide (PAM) polymers are very effective for separation of nutrients from effluents in animal operations. Removal efficiencies of about 80% for suspended solids, organic N and P were obtained with PAM rates of 25 to 100 mg/L applied to swine wastewater before screening. In contrast, only 5 to 20% were separated without PAM treatment. Studies were also conducted during a growing cycle in feeder-to- finish operations to determine optimum polymer rates with varying wastewater strength. A Fund for Rural America project Advanced Waste Treatment Systems for Environmentally Sound and Sustainable Swine Production has been initiated to develop and evaluate new total waste management systems as an alternative to traditional anaerobic lagoons. It includes state-of-the-art separation technologies such as in-line flocculators for efficient mixing of PAM and quick-drying filter beds for fast dewatering. Efficient separation not only enhances capture of nutrients but also reduces BOD sufficiently to allow wastewater treatment without the anaerobic lagoon. The system is completed with variable sequencing of aeration, nitrification, denitrification, and phosphorus recovery technologies to reduce odor and ammonia emissions along with on-farm nutrient loads. Nitrification treatment: The purpose of this project is to examine options for nitrification treatment of swine wastewater. Technologies include overland flow, media filter, and encapsulated nitrifiers. Overland flow is a low-intensity system that can remove large amounts of N per unit area through nitrification and partial denitrification. Performance data of a 4x20-m plot showed N removal rates of 22 to 42 kg N/ha/day. Media filter is a medium-intensity system popular among small waste generators that was adapted for animal waste using marl gravel media and enhanced aeration by intermittent application. The rate of nitrification obtained was 142 g N/m3/day. Encapsulated nitrifiers is a high-intensity system designed for fast and efficient removal of ammonia. The application for municipal wastewater treatment has been recently developed in Japan; our research showed that it has the potential for development of highly-efficient and low-cost treatment technology for animal waste. It uses fluidized bioreactors containing acclimated nitrifying cells in 3- to 5-mm polymer pellets. The rate of nitrification of swine wastewater obtained with a 4 h retention time was 604 g N/m3/day. A state-of-the-art pilot unit has been constructed and installed in Duplin Co., NC. A USDA-FAS Scientific Cooperation Program project with Japan is being initiated to investigate treatment of animal wastewater using biotechnology. Objectives are to develop nitrifying pellets using bacteria strains adapted to high free ammonia levels and application of biological deodorizing systems to treat animal lagoon odors. Constructed Wetlands: A demonstration project is being conducted on constructed wetlands to manage liquid animal waste in a swine operation in Duplin Co., NC. Three wetland systems have been evaluated during the last 4 years; they contained either wetland plants or water-tolerant agronomic crops. Each system consisted of two cells (3.6-m x 33.5-m) connected in series. Two of the systems contained wetland plants: a mixture of rush and bulrushes, or a mixture of bur-reed and cattails. The third set contained soybean grown in saturated-soil culture in one cell connected to a second cell with flooded rice. Average N reduction rates were similar between wetland plants and agronomic crops. During the first year of the evaluation, we applied an N loading of 3 kg/ha/day and obtained an average mass N reduction of 94%. During the second year, the N loading rate was increased to 8 kg/ha/day and mass N reduction was 87%. In the third year, the loading rate was doubled to 15 kg N/ha/day and removal efficiency was 83%. During 1997, the removal rates did not decrease even though the application rate was 25 kg N/ha/day. At this rate, wetlands removed about 8 Mg N/ha/yr. We also found that wetlands are very effective for denitrification. When nitrified wastewater was added to a wetland microcosms, the N removal rate was four to five times higher than when non-nitrified wastewater was added. Results to date indicate that constructed wetlands can remove large amounts of N in small areas. Current research efforts at the study site focus on the development of integrated systems sequencing nitrification and denitrification processes. Return to Top
Jim Schepers, Land Application Application of manure to agricultural land can provide valuable
nutrients to crops and improve soil physical and chemical properties, but
when done improperly can lead to environmental and human health problems.
Environmental concerns arise when runoff carries nutrient-rich sediments,
soluble compounds, and possibly pathogens into rivers, lakes, and oceans.
Variability in climate, soils, topography, crops, and type of animal
waste makes it difficult to develop effective manure management systems
without a practical appreciation for land application practices and a
comprehensive understanding of the factors that can affect losses
resulting from manure application. ARS addresses these needs through a
series of specific research projects intended to effectively utilize
nutrients in manure and protect the environment.
An example of manure utilization research conducted by Agency
scientists involves land application to cropland with emphasis on carbon,
nitrogen, and phosphorus cycling within the food chain (Pennsylvania,
Wisconsin, Maryland, Nebraska, Texas, Iowa, and Arkansas). These
activities involve dairy, beef, swine, and poultry manure. Opportunities
for incorporation of manure into soil vary with the type of manure,
climate, crop, and tillage system. Some production systems involve
applying manure to established perennial crops such as alfalfa or
pastureland where it is not possible to incorporate the manure. In the
later situation (Georgia), environmental risks associated with runoff
occur both from the applied poultry manure and the actively grazing
livestock.
One of the common problems facing livestock producers is that climatic
and physical limitations do not readily permit land application of manure
when it is generated. For these reasons, manure frequently must be stored
until it is convenient for land application. ARS scientists in Wisconsin
are addressing this problem by developing ways to separate the liquid from
the fiber portion of the manure to simplify storage and land application.
Composting of beef and dairy manure is also being developed as a manure
management tool in Nebraska, Maryland, and Texas where land application is
limited to a short time when crops are not growing. An accelerated version
of anaerobic composting is represented by the treatment of municipal
sewage. Sludge produced by these systems can be used as manure, but may
require special considerations in terms of heavy metals and other
synthetic compounds (Minnesota).
Because runoff from agricultural land is inevitable, ARS scientists are
working to develop technologies to both reduce nutrient losses in runoff
and to prevent nutrients from reaching streams and rivers. For example,
research in Arkansas is targeting the addition of alum to poultry manure
to reduce ammonia volatilization and to stabilize phosphorus in manure so
that it is less likely to be lost in runoff. Other studies involve various
kinds of grass and woodland filter strips (Georgia, South Carolina,
Arkansas, Iowa and Nebraska) between cropland and streams to minimize any
environmental consequences of runoff. At several locations (Texas,
Georgia, Arkansas, and South Carolina), wetlands are being evaluated for
removal of nitrate from runoff water through denitrification. Several
locations are specifically addressing the issue of pathogens in runoff
water (Maryland and Georgia).
Even though cultural practices (tillage, crop residue management, and
manure application times and amounts) minimize the potential for surface
water contamination from manure application, leaching of nitrate to
shallow groundwater is a concern. ARS has research underway to address
nitrate leaching from the application of poultry manure to wheat in
Maryland, beef manure to corn in Nebraska, and swine manure in North
Carolina. A unique aspect of nitrate leaching is studied in Iowa where
tile lines (subsurface drainage) intercept the percolating water and
discharge the water-borne nitrate into streams and rivers. Here the
concern is over how, when, and in what amount to apply manure to meet crop
nutrient needs while minimizing the potential for nitrate leaching.
Nitrate leaching is also a concern where liquid manure and runoff from
confinement operations (swine, dairy, and beef) is applied to cropland.
Even though the liquid materials in lagoons are usually low in nitrate and
not normally subject to leaching, soil micro-organisms quickly convert the
immobile forms of nitrogen (ammonium and organic) to the highly mobile
form (nitrate). Examples of these studies are underway in Texas, Iowa,
Wisconsin, and Georgia.
Sometimes it is difficult to evaluate the fate of nutrients (runoff,
infiltration, crop uptake, entrapped in riparian areas) in land applied
manure under natural rainfall conditions. To work around these climatic
uncertainties, several ARS locations (Nebraska, Texas, Georgia, and
Wisconsin) use large sprinkler devices that simulate rainfall conditions
and thereby permit evaluations over a range of field situations.
Volatile losses from manure can be a problem when in storage or applied
to the land. Sometimes these gaseous losses go undetected because they are
not associated with an odor. Nonetheless, enhanced gaseous nitrogen oxides
and carbon (carbon dioxide and methane) losses contribute to the
greenhouse effect. The extent to which manure contributes to methane
losses from fields receiving swine manure is under investigation in Iowa.
Nebraska studies involve both enhanced gaseous nitrogen and carbon losses
in fields where beef feedlot manure is applied.
Sometimes it may be possible to modify what goes into livestock and
poultry (feed stuffs) so that what comes out (manure) will be easier to
manage and have fewer environmental consequences. Examples include lower
protein rations for beef to reduce nitrogen losses in urine and feces
(Texas); modified poultry rations to increase energy utilization
(Maryland); reduced phosphorus in dairy rations to improve manure
properties as a fertilizer (Wisconsin); and feeding of high available
phosphorus (HAP) corn to poultry (Arkansas) and swine (Nebraska) to
increase phosphorus recovery from corn and reduce phosphorus content in
manure.
Efforts to increase nutrient use efficiency by crops and develop more
environmentally sound and profitable cropping systems are a goal of
"precision agriculture". Technologies from several disciplines make
site-specific management a reality. ARS efforts are underway to better
utilize nutrients in manure and capitalize on the known soil building
attributes by using remote sensing, yield maps, soil survey maps, etc. to
apply manure where it will have the greatest influence on crop yield and
the least impact on the environment (Nebraska, Georgia).
Jerry Hatfield, Environmental Issues Scope of the Problem Environmental issues surrounding livestock production encompass all aspects of nonpoint source pollution. There are reports of impacts of livestock production on surface water, subsurface drainage, and ground water quality; air quality; and contamination of soil with excessive salts, pathogens, mobile phosphorus, and antibiotics by the application of manure to soil. These problems have been continually discussed in many different forums and often center on the issue of scale and species. Livestock production is a valuable agricultural enterprise, and problems with potential nonpoint source pollution must be addressed. There are several categories of problems that must be successfully addressed at the national scale in order to develop more sustainable agricultural systems. These can be broken into soil, water, and air issues, however, in reality they deal with the offsite movement of nutrients, gases, or particulates. For this discussion we will use parameters rather than the transport medium. Nutrients Nitrates and phosphorus are applied as nutrients from manure. Two issues have begun to emerge in the current debate about livestock production and these deal with the application rates of nutrients and the potential overloading of the soil that would lead to movement offsite. Nitrate-nitrogen is highly mobile with water and can leach through the soil profile. In the Midwest with the extensive subsurface drainage systems in fields, nitrate concentrations often exceed the 10 mg/L drinking water standard. The potential effect of manure on these concentrations has not been extensively studied; however, some evidence would suggest that the source of nitrate-N is a result of mineralization in the soil rather than leaching of applied nutrients. This is and will continue to be of concern. Phosphorus has emerged as a problem with surface water and movement through the soil profile. Phosphorus loss from the surface is carried by sediment eroded from the field. More mobile forms of phosphorus have been shown to leach through the soil profile and often enter into surface water via subsurface drainage or ground water-surface water interactions. These preliminary studies would suggest that there is a need to understand the phosphorus dynamics in different soils and develop tests that can be used to assess the proper P application rates for soils that would reduce the offsite movement. Nutrient management guidelines for fields can provide guidance on the proper use of nutrients from all sources; however, producers have been reluctant to use these tools because of perception about the value and quality of manure. To achieve this goal will require better decision tools for producers to use, the development and evaluation of Best Management Practices (BMP’s) that reduce offsite movement, and placement of buffer strips or riparian zones to help further reduce any movement to streams, rivers, or lakes. These evaluations will need to be made at the field scale to enhance their transferability to producers and land managers. Pathogens There are different forms of coliform bacteria present in manure. It is assumed these move quickly in the soil and potentially into ground water. Seepage from manure storage systems is thought to be the primary path of movement. There is little scientific evidence to provide guidance on the potential extent of this problem and the distribution of the problem with age and size of production facility. Movement of pathogens that carry diseases among production facilities is a critical aspect of sanitation and food safety. These efforts must be addressed from a watershed scale approach. Gases and Particulates Gases and particulates generated, emitted, and dispersed from buildings, manure storage, and manure application areas is one of the most critical environmental problems relative to livestock and manure issues. There have been many attempts to characterize the types of gases, however, very little is known about the emission rates of the different gases among production systems, throughout a year, and across locations. There are several groups addressing this problem with a variety of techniques. Research will have to focus on the anaerobic digestion processes and the classes of volatile organic compounds (VOC’s) generated and released. This can be extended to include methane and nitrous oxide because of the implications on global climate change. Particulates may be the transport mechanism from buildings while release of gaseous forms will occur from manure storage and application methods. Air sampling techniques for gases and particulates will have to be developed to measure these analytes across a range of production systems. Dispersion of gases and particulates across a landscape is not a simple process, and understanding dispersion will require improvement of currently existing atmospheric models. The nonhomogeneous terrain that surrounds most livestock production units adds complications to understanding of air movement patterns. Air quality from a standpoint of the dilution factors in air or the elimination of odors will require a coordinated effort among a number of disciplines. Challenges Environmental issues relative to livestock production are multi-disciplinary and multi-dimensional. To address these issues will require an integration of understanding the processes and application of that information to different systems and scales. The challenge is to link producers and users of the information into the research program in a way to promote effective transfer of information as quickly as possible. Much of the problem will have to be addressed from a watershed or airshed scale across a number of locations and production units to have the maximum benefit to the American public. Agricultural Research Service scientists will have to develop integrated teams in partnerships with different groups to effectively define, address, and deliver solutions to these problems. Return to Top
Philip Moore, Alternative Approaches One of the primary problems with using animal manures as fertilizer is
the fact that there is normally a nutrient imbalance (not enough nitrogen
and too much phosphorus). This imbalance, referred to as a low N/P ratio,
results in an accumulation of P on land fertilized with manure at rates
high enough to meet the crop N requirements. As a result, P runoff and
leaching of P in sandy soils, is becoming one of the biggest problems
facing the animal industry in the U.S.
Currently there are several different approaches to this problem that
are being investigated at the ARS unit located in Fayetteville, Arkansas.
These include; (1) adding aluminum sulfate to manure to precipitate P, (2)
reducing P inputs into diets using low phytic acid corn and/or phytase
enzymes, (3) developing threshold P levels for soils above which manure
cannot be applied, (4) using vegetated filter strips at the edge of fields
to intercept nutrient runoff, (5) using constructed wetlands for
wastewater remediation on swine farms, (6) utilizing crops that reduce
phosphorus runoff by increasing water infiltration or by having a high
nutrient uptake capacity, (7) adding aluminum, calcium and/or iron
amendments to soils to increase the P sorption capacity, (8) identifying
hydrologically active areas (hotspots) in watersheds to avoid during
manure application, (9) adding chemical and/or microbial amendments to
composting animal manure to reduce N losses via ammonia volatilization and
to precipitate P, (10) determine the long-term effects of normal manure,
alum-treated manure and ammonium nitrate on soil and water quality, (11)
determine the relative effects of beef manure and poultry litter on
phosphorus runoff, and (12) determine the effects of land use on water
quality.
One of the most promising technologies to combat this problem is the
addition of aluminum sulfate (alum) to manure to precipitate soluble P.
Most (80-90%) of the P in runoff water from pastures fertilized with
animal manures is in the dissolved form. This soluble P can be
precipitated by adding many different compounds that contain aluminum,
calcium and iron. Research conducted on small plots using rainfall
simulators has shown that P runoff can be reduced by as much as 87% when
alum is added to poultry litter. These studies have also shown that tall
fescue yields are significantly higher when fertilized with alum-treated
litter as compared to normal litter, due to increased N availability. This
increase in N availability is due to higher N contents in alum-treated
litter, which was believed to be due to a lower ammonia volatilization
rate. This was confirmed in laboratory and small chamber studies on
ammonia volatilization, which showed that alum is one of the most
effective compounds in reducing ammonia losses.
As a result of this preliminary research, an EPA 319 demonstration
project was initiated to determine the effects of alum addition to poultry
litter on broiler production and P runoff from small watersheds. Two
broiler farms were chosen for this study in NW Arkansas; one had four
houses, the other had six houses. Half of the houses at each farm were
treated with alum at a rate of two tons per growout. The alum was spread
and incorporated using a litter decaker. Alum applications lowered litter
pH for several weeks, resulting in lower ammonia volatilization rates.
This resulted in lower atmospheric ammonia in alum-treated houses, even
though the growers were using less ventilation in these houses than the
untreated control houses. Broilers grown in alum-treated houses were
significantly heavier than controls (3.80 versus 3.65 pounds). Birds grown
in alum-treated houses also had better feed conversion and tended to have
lower mortality. Energy use was lower in the alum-treated houses, due to
lower ventilation requirements in winter months. An economic evaluation of
this data indicated that this BMP has a benefit/cost ratio of 1.96;
indicating that the alum treatment is very cost effective.
Two one-acre watersheds were constructed side-by-side at both farms to
measure phosphorus runoff from alum-treated and normal litter. These
watersheds were equipped with flumes that were outfitted with automatic
water samplers. Litter application to the watersheds was initiated in
1995. Runoff never occurred at one of the farms, so sampling was
discontinued at that site after one year. However, runoff frequently
occurs at the other farm and monitoring has continued at this site for
three years. The data shows that alum reduced P concentrations in runoff
water by 75% over the three year period. Other parameters, such as pH and
aluminum content of runoff water, were unaffected.
Long-term (20 year) studies were also initiated in 1995 to determine
the impact of normal poultry litter, alum-treated litter and ammonium
nitrate applications on soil and water quality. There are 13 treatments in
this study; one control, four rates of normal litter, four rates of
alum-treated litter and four rates of ammonium nitrate. The litter
application rates are 1, 2, 3, and 4 tons/acre. The ammonium nitrate rates
are based on the amount of nitrogen available with alum-treated litter
(65, 130, 195 and 260 kg N/ha). Research to date has shown that heavy
metal (arsenic, copper, and zinc) and hormone (estrogen) runoff is
significantly lower from alum-treated litter, compared to normal litter.
Soils data indicates that water soluble P levels are increasing
dramatically in plots fertilized with normal litter, particularly at the
higher rates, whereas water soluble P levels in plots fertilized with
alum-treated litter are not significantly different from unfertilized
control plots. Ammonium nitrate applications have been shown to reduce
soluble P levels the most, but are resulting in a reduction in soil pH,
compared to unfertilized controls. This is not the case for alum-treated
or normal litter, which result in increases in soil pH.
Scientists at this location have also cooperated with personnel from
universities, private industry, and local, state, and federal agencies to
conduct research on using alum to improve poultry production and reduce P
runoff. Studies conducted on 30 million birds indicate that alum does have
a very positive effect on poultry health and productivity.
Since P chemistry is basically the same in different kinds of manure,
lab studies have been conducted to determine the effect of alum additions
to swine manure on P solubility and ammonia loss. These studies indicate
that alum may work better in swine manure than in poultry litter. Hence,
larger scale studies are now being initiated to determine the rates of
alum needed to reduce ammonia emissions and precipitate P in swine manure.
This research includes developing a liquid alum delivery system for animal
rearing facilities that have flush systems. Return to Top
Eric Line,
Public Health While Americans enjoy the safest food supply in the world, recent food
and waterborne illness outbreaks suggest that even more could be done to
protect our food supply. Several recent food and waterborne illness
outbreaks have been traced to contamination of fresh fruits and vegetables
by microorganisms or viruses. Agronomic practices such as the utilization
of irrigation water and manures containing pathogenic or parasitic agents,
are considered to be an important factor in the occurrence and
epidemiology of foodborne disease. As agronomic areas are more compressed
and the proximity of animal production units comes closer to areas used to
cultivate crops receiving little further processing such as fresh produce,
the potential for contamination of irrigation water or soils and
subsequent cross-contamination of food crops increases. Contamination by
foodborne pathogens and their increased survivability or multiplication
during storage is a concern because most fresh-cut produce in consumed
without any effective decontamination process such as heat treatment.
In spite of all we know about potential vectors of foodborne pathogen
contamination, many critical research questions must be answered if we are
to further our understanding of pathogen transmission and increase the
safety of our food supply. For example, survival of pathogens in manure
and compost is not well understood. How long can Salmonella or
E. coli survive in manure spread on to forage land? What methods of
decontaminating manure work best? How can we work to reduce pathogen
carriage by food animals? How can runoff and transmission of pathogens
best be prevented? What is the importance of wild animal vectors (deer,
birds, etc.) in spread of pathogens? What irrigation practices are least
likely to contaminate produce? Where on various fruits and vegetables
(surface/inside) are we most likely to find the pathogens? How are the
pathogens attached and how can they best be removed? Scientists within ARS
are working to address all of these questions.
Some selected on-going and proposed ARS projects investigating food
safety and/or manure issues are listed in Tables 1 and 2. Scientists are
currently working to understand the epidemiology of pathogens in livestock
and are developing interventions to control and reduce pathogen carriage
by farm animals (Table 1). ARS scientists are also working to improve the
safety of manure utilization by determining the survival of pathogens in
manure/compost, monitoring the transport of pathogens and other materials
in soil/water and developing pathogen reduction processes (Table 2). Other
projects are designed to increase food safety by describing the attachment
of pathogens to food, developing interventions to improve food safety and
quality of produce, developing technologies for reducing pathogens in food
processing environments and by developing rapid detection methods for
pathogens (Table 2). There are a number of ARS programs looking at the
environmental impact of manure management strategies and subsequent water
quality issues (Table 3). Many of these projects are involved with
monitoring chemical runoff but potentially could be expanded to allow
incorporation of microbiological analysis so that more information could
be gained from ongoing studies. Table One: Current ARS Projects Investigating Epidemiology
and Control of Human Foodborne Pathogens in Livestock and Poultry
Table Two: Selected Ongoing and Proposed ARS Projects Investigating Food Safety and/or Manure Issues
Table Three: Selected ARS Projects Investigating Manure Management and Water Quality Issues with Potential for Increased Food Safety Emphasis
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