Agricultural
Engineering News, Issues, and Research: Animal
Agriculture and the Environment
DANA O. PORTER
Agricultural Engineering Specialist
WVU Extension Service
The following summaries are compiled from recent
publications, research articles, and presented papers.
They are intended to inform readers of agricultural
engineering developments and related issues of interest
to West Virginians. These brief summaries are not
comprehensive; they do not represent all data, results,
and conclusions of the articles. Readers are encouraged
to obtain the complete publications for more information.
While it is believed that the sources are reliable,
caution is urged in application of this information.
Animal Agriculture and the Environment:
Nutrients, Pathogens, and Community Relations
The Animal Agriculture and the Environment Conference,
held Dec.11-13, 1996 in Rochester, New York, addressed
many issues faced by dairy, poultry, swine, and beef
producers in the northeastern United States and Canada.
The proceedings are available from Northest Regional
Agricultural Engineering Service (NRAES) (NRAES-96) for
$30. Included are 33 papers divided into six categories:
environmental concerns, protecting the environment, land
application, animal management, considerations in public
policy, and cost to the farmer. The proceedings will be
of interest to producers and their advisers, community
officials and their consultants, state/province
regulatory agencies and legislatures, cooperative
extension and university educators, crop consultants,
rural land owners, soil and water conservation district
staff, federal government staff, and watershed managers.
Three of the papers presented at the conference are
highlighted below.
Environmental Protection Can Save the Farm
Money
Best Management Practices (BMPs) commonly associated
with nutrient management can save money for many farmers.
Some sources of savings include "legume
credits," "manure credits," and soil
testing. "Legume credits" represent nitrogen
carry-over from legumes in rotational cropping. By taking
a nitrogen credit for the carry-over in a nutrient
management program, a producer can reduce fertilizer
costs. Similarly, nutrients contained in applied manure
can be substituted for commercial fertilizers. Fractions
of these nutrients are carried over from year to year, so
previous years' applications contribute to this credit.
Manure testing services have facilitated more accurate
accounting of nutrient availability from manure.
Field-specific soil testing is recommended to optimize
use of fertilizers and manures. Dr. Steinhilber,
coordinator of the Nutrient Management Program at the
University of Maryland Cooperative Extension Service,
cautions nutrient management advisers that nutrient
management BMPs are not guaranteed to save money for all
producers. Apparently, however, the greatest cost savings
are likely to be incurred by below-average nutrient
managers.
Patricia M. Steinhilber. 1996. "Environmental
Protection Can Save the Farm Money." In: Proceedings
from the Animal Agriculture and the Environment North
American Conference. NRAES-96. Northeast Regional
Agricultural Engineering Service, Cornell, NY.
Improving Nutrient Cycling in Animal
Agriculture Systems
According to Meisinger and Thompson (1996) at the
USDA-Agricultural Research Service (ARS) Natural
Resources Institute in Beltsville, Maryland,
"Constructing nutrient balances that characterize
nutrient inputs, exports, and changes in nutrients stored
within the soil-crop-animal system (is) a fundamental
approach for effective nutrient management. A whole-farm
nutrient balance provides the basis for a well-designed
nutrient management plan which assures an adequate and
sustained supply of high-quality feed, supports high
nutrient recycling, and minimizes environmental
impacts."
Meisinger and Thompson discuss the main steps in
constructing a nutrient budget, including: defining the
system and subsystems; documenting nutrient inputs and
outputs; evaluating potential changes (such as nutrient
losses) in storage within the system; and identifying
surplus and/or deficit areas and potential sites of
accumulation and/or depletion. The authors recommend
manure testing, on-farm quick nutrient tests, soil
sampling to monitor nutrient status, timely application
of manure to coincide with crop demand, immediate
incorporation of applied manure into the soil, and more
efficient ration formulation which maximizes use of
farm-grown feeds.
J.J. Meisinger and R.B. Thompson. 1996.
"Improving Nutrient Cycling in Animal Agriculture
Systems." In: Proceedings from the Animal
Agriculture and the Environment North American
Conference. NRAES-96. Northeast Regional Agricultural
Engineering Service, Cornell, NY.
Potential Pathogens in Manure
Manure (including feces, urine, and possibly bedding,
waste feed, and water) contains microbial organisms,
including potential pathogens (viruses, bacteria, and
parasites capable of causing infection or disease in
animals or humans). In order for pathogenic organisms to
be spread in manure, they must be present in sufficient
number to be infectious, multiply in the environment, or
survive manure processing and storage conditions long
enough to accumulate to infectious population levels.
High temperatures achieved during ensiling, aerobic
composting, and mesophilic anaerobic digestion will kill
most pathogens within days. For example, bovine
parvovirus survives 20 to 43 days in manure stored in
anaerobic pits at 61 oF. Survival of the virus
is decreased to four to eight days at 95 oF
(mesophilic anaerobic digestion conditions), and to less
than one day at 131 oF (thermophilic anaerobic
digestion or aerobic composting conditions). Escherichia
coli populations held in mesophilic anaerobic
digestion conditions at 95 oF are decreased by
90% in 0.8 to 1.5 days.
Other environmental factors that limit activity or
survival of some pathogenic organisms are sunlight,
moisture, freezing, high or low pH, oxygen levels, and
chemical compounds. Salmonella survival is
decreased by aerobic (oxygen available) storage, low pH,
and higher temperatures. Listeria monocytogenes
survival is decreased by exposure to sunlight, low pH
(<4.0), and higher temperatures.
This article addresses viruses, bacteria, and
parasites that may be present in manure. It also
addresses consequences of infection by these pathogens in
animals and humans. The authors are on faculty at the
College of Veterinary Medicine at Cornell University.
Susan M. Stehman, Christine Rossiter, Patrick
McDonough, and Susan Wade. 1996. "Potential
Pathogens in Manure." In: Proceedings from the
Animal Agriculture and the Environment North American
Conference. NRAES-96. Northeast Regional Agricultural
Engineering Service, Cornell, NY.
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