Components of a Complete Manure Management Plan
Prepared by:
James C. Barker, Professor and Extension Specialist
Biological and Agricultural Engineering
Joseph P. Zublena, Professor and Extension Specialist
Soil Science
North Carolina State University
Raleigh, NC
Published by: North Carolina Cooperative Extension
Service
Publication Number: EBAE 185-93
Last Electronic Revision: March 1996 (JWM)
Existing regulations for animal waste management are generally invoked by the
North Carolina Department of Environment, Health and Natural Resources,
Division of Environmental Management ( DEM ), in response to citizen
complaints about water quality problems after degradation has occurred. DEM
believes a more proactive mechanism is needed to help farmers plan and
operate animal waste management systems to protect surface and ground water
before problems occur. Therefore, DEM is proposing to amend existing
nondischarge regulations by establishing minimum criteria to be met before
waste management systems serving animal operations are deemed permitted.
While the wording of the above statements is still in the draft stage and
subject to be amended, the implication is clear. Within the next few years,
every livestock and poultry farmer who has more than 100 animal units will be
required to have a complete farm manure management plan utilizing available
technology. For many producers this will simply mean documenting those
practices already being employed. For others, it will mean proper management
or upgrading existing components into a complete and environmentally safe
system for managing manure, residuals such as lagoon liquid and sludge, field
runoff, and animal mortality. Some components of this plan are briefly
outlined as follows.
SITE SELECTION
For new producers or those anticipating significant expansion, site selection
is probably the most important single consideration associated with the
entire operation. Adjacent land use should remove from consideration those
sites near residential developments, commercial enterprises, recreational
areas, or other prime areas for non-agricultural uses. Wind direction
probability diagrams will help to locate facilities downwind of warm season
prevailing winds. The strategic planting of hedge rows or tree barriers at
property boundaries serves to shield the production and manure management
facilities from direct sight and to reduce wind speed across the facilities
allowing any emitted gases more opportunity to rise vertically and dissipate
into the atmosphere. A site may seem ideal with respect to transportation,
feed supply, accessibility or land ownership, but may be inappropriate
because of existing or proposed development.
Soil properties and limitations should be investigated. Soil types with
limited permeability which will rapidly seal are desirable for lagoon
construction. Coarse sands will probably need to be amended to speed up the
sealing process. An erosion control plan to stabilize and maintain a site
during construction should be considered. When possible, locate production
facilities near the center of a tract of land large enough to allow manure to
be applied at agronomic rates. Pollution control and manure management
facilities should be located as remotely as possible from areas of high
environmental sensitivity such as drainage canals, streams, or natural
wetlands. Buildings in flat, high water table areas should be built on pads
of earth excavated from the lagoon. Elevating these buildings several feet
above ground routes surface drainage away from them and allows flushed manure
to flow by gravity to a lagoon built above the water table. Upland
facilities should be built on high ground and as far away fr om water sources
as possible to allow wastewater management options.
TYPE OF OPERATION AND ANIMAL INVENTORY
The type of operation ( dairy - lactating cow, dry cow, heifer, calf ;
swine - farrow-to-weanling, farrow-to-feeder, nursery, finishing, farrow-
to-finish ; turkey - brooder flock, grower, breeder ; etc. ) affects
most manure management practices. The maximum number of animals and
corresponding total live weight expected on the farm on any given day is also
necessary for most manure management calculations.
TYPE OF PRODUCTION FACILITIES
Different environmental management practices are required for different
production facilities and systems. Stock trails and improved stream
crossings may be required in vulnerable pasture areas. Fencing of animals
from streams in intensively used areas where animals tend to congregate or
along highly erodible reaches may be required. Animals maintained on unpaved
lounging areas or drylots not supporting vegetation will in some instances
require conservation practices to minimize the effects of lot runoff. These
animals will most likely be denied direct access to surface waters or
wetlands. Partially enclosed facilities with animals on open slabs will also
be subject to runoff control. Totally enclosed facilities can affect the
production performance as well as potential odors emitted depending on floor
surface, ventilation, and manure management. In-house manure collection
methods and frequency affect gas and odor levels. Modern manure removal
methods such as flushing, pit recharge, and mechanical scr aping have
drastically reduced the gas and odor levels inside production facilities.
MANURE STORAGE / TREATMENT FACILITIES
Producers must decide whether their objective is manure nutrient conservation
for maximum fertilization or nutrient reduction for ease of management. If
nutrient conservation is desired, then scrapers moving manure to outdoor
holding tanks or basins, or settling basins prior to lagoons for flushed
waste will be needed. Liquid manure spreaders or slurry irrigation systems
will move the manure nutrients to large field crop acreages for spreading.
If, on the other hand, nutrient reduction prior to land application is
desired, then solids separation and/or anaerobic lagoons become very
important parts of the overall treatment system. Lagoons, storage basins and
holding ponds must be properly sized according to USDA-Soil Conservation
Service specifications using correct construction, start-up, and management
procedures. When properly planned and managed, lagoons can reduce overall
odor levels around a production facility, reduce nutrients to be land applied
by up to 85%, provide flexibility for land applica tion scheduling, and have
minimal impact on shallow groundwater.
AGRONOMIC PLAN
Manure Characterization
Summaries and estimates of manure quantities
and nutrient content are available from the N.C. Cooperative Extension
Service, USDA-Soil Conservation Service, N.C. Dept of Agriculture, N.C.
Agricultural Chemicals Manual, as well as other sources. When no other
information is available, such as when planning a new operation, these
averages provide "ball park" figures and should be utilized. Existing
operations are encouraged to develop individual estimates of the volume of
manure, litter, feedlot runoff or lagoon liquid to be land applied, e.g.,
using water meters to measure the amount of water used in a production
facility or by recording the lagoon levels periodically and determining the
accumulated volume. Representative samples of the material to be land
applied should be analyzed twice annually for nutrient and mineral content.
The N.C. Department of Agriculture provides this service with interpretations
of results for a nominal fee.
Crop / Soil Selection
Soil types should be mapped for each field on the
farm to receive manure. Soil infiltration rates will often determine maximum
irrigation rates or how much lagoon liquid can be applied before runoff
occurs. Soil types also determine the fate of unused nutrients. Well-
drained sandy soils provide more potential for unused nitrogen to convert to
nitrates and leach downward. Heavy soils or poorly-drained soils reduce
infiltration rates and water-holding capacity but provide more potential for
unused nitrogen to denitrify harmlessly. Clay soils have more capacity to
tie-up and hold phosphorus in place than do coarse soils.
Soil types also influence the yield potential of selected crops. If a corn
crop, e.g., only has a yield potential of 100 bu/A on a given soil type, then
it should only be fertilized for 100 bu/A, since any more nutrients would be
wasted and become potential pollutants. Crop types should be selected for
their nutrient requirements. A range of fertilization rates from 50 lbs of
available nitrogen per acre on stands of pine trees to 400 lbs of available N
on bermudagrass hayland allow flexibility depending on land availability and
farm objectives.
Application Rates
Application rates of manure, litter or wastewater
should only supply the fertilizer needs of the crops. Since the manure
nutrients are not a balanced blend for most crops, some nutrients will either
be under- or over-applied. Some overapplication of phosphorus and potassium
may be tolerated, however significant and prolonged overapplication of P and
K should be avoided. Supplemental fertilizer will be needed if rates supply
only the P and K requirements of the crop. Under no circumstances should
available nitrogen be overapplied. Plant available nitrogen is currently
estimated to be half of the total nitrogen in irrigated lagoon liquid and 70%
of the total N in manure slurries that are soil incorporated. Worksheets are
available from the Cooperative Extension Service to help calculate available
nutrients and application rates.
Scheduling of Manure Application
Manure nutrients should be applied as
near to the period of plant uptake as possible. Nutrients that are readily
available, such as in lagoon liquid, are more efficiently utilized by the
crop in several small applications throughout the growing season. Nutrients
should only be applied to crops during their normal growing season. For
example, bermudagrass normally thrives from May to September and should not
receive manure at other times of year except when overseeded with a cool
season grass such as rye. Cool season crops are necessary to allow
application to proceed during the cool season, or enough storage is necessary
to avoid having to spread. Land application of manure nutrients on fallow
soil or onto dormant crops will only lead to nitrate leaching downward toward
ground water.
Manure Application Equipment
Most manures will either be hauled with farm
liquid manure spreaders, spread with irrigation systems, or applied by a
custom applicator. Costs and time required for hauling, additional acreages
required for concentrated slurries, soil compaction, odor considerations, and
availability of custom applicators need to be considered for slurry
management. It is not cost effective to haul wastewater. Most farms with
lagoons will use simple farm irrigation systems, use portable company
irrigation equipment, or hire custom irrigators. Those farms with field
crops or tree stands will probably find portable systems such as travellers
or center pivots most advantageous. Also, if portability to several
different fields or large acreages are to be irrigated, travellers will be
selected. On the other hand, if small acreages of grass are to be irrigated
and equipment portability is not necessary, small-nozzle, moderate-pressure,
permanent irrigation systems provide low-labor and mo re uniform distribution
of lagoon liquids. All manure equipment should be calibrated periodically
for application rate and uniformity. Appropriate equipment or contractual
arrangements must be available whenever manure or lagoon liquid needs to be
land applied.
Crop Management Utilization
It is important to remember that regardless
of what crops are grown on land application sites, they all must be regularly
harvested and removed from the site. Otherwise, nutrients will simply
recycle back into the soil system and eventually become pollutants. For most
field crops, readily established markets are available for the products. For
grass crops, markets for hay may not be readily available and may need to be
developed. Consideration should be given to marketing a particular crop
before selecting that crop for land application.
Labor Availability / Accessibility
The availability of labor and the
ability to use that labor in the most efficient manner for manure management
and farming chores outside of the production facilities should be considered.
An irrigation system, e.g., that requires sprinklers to be moved or changed
every two hours might require a laborer to shower out/in of the production
complex for biosecurity reasons each time attention is given to the system.
Would different irrigation equipment or management plans allow the labor to
be used more efficiently? The same applies to crop establishment,
maintenance, and harvest.
ANIMAL MORTALITY MANAGEMENT
Dead animals are required to be properly disposed of within 24 hours. On-
farm mortality management options have consisted of below ground disposal or
incineration. Below ground burial or pit disposal of animal and bird
mortality may contribute nutrients to ground water in areas with coarse
textured soils or high water tables. Mortality management alternatives
currently being explored are collection for rendering or on-site composting.
These alternatives would reduce below-ground point-sources of nutrients and
produce a safe and marketable end product.
CONSERVATION PLAN
Erosion Control Soil as well as manure nutrients should be kept on the field
where they are applied. Some nutrients such as phosphorus adhere to soil
particles and only move when the soil particles move. Fields where manure is
to be applied should have sound conservation practices where appropriate such
as terraces, strip cropping, and conservation tillage.
Runoff and Drainage Management
It is difficult to avoid occasional
applications of manure that are immediately followed by a rainfall event.
When this happens, conservation practices such as field borders, grassed
waterways, sediment basins, and vegetative filters help to minimize the
transport of nutrients and organics off-site. Fields receiving manure that
have artificial drainage systems should have a water management plan in
action. Some nitrates that have formed in the upper soil layers will be
collected in the tile drainage and will be delivered to the drainage ditches
or canals. Management of the water levels in these ditches and canals by
water control structures can accelerate the denitrification of these nitrates
harmlessly.
Cover Crops
Double cropping or cover crops after harvest can help hold
soil in place and remove some of the unused nutrients left in the upper soil
layers. Crop rotation also tends to use certain nutrients or elements that
otherwise would remain in the soil or be lost.
PUBLIC RELATIONS
Planning a group of buildings and their surroundings to present a wholesome
image is as important as planning for productive efficiency. When the public
sees a livestock or poultry farm, they see much more than buildings and
grounds. They see an attitude -- an attitude of pride in the business or an
attitude of indifference. They see an environmental protector or an
environmental polluter. Farm operators who take pride in maintaining the
farmstead are generally better managers than those who practice poor
housekeeping. Employees take more pride in their jobs and work output
improves (Morris et al., 1973).
After weighing the important points of alternative manure management systems,
a producer must decide which system appears best, then commit to providing
the attention and management necessary to make the system function. No
production or manure management system will take care of itself. An ounce of
prevention is worth a pound of cure. The appearance of buildings and grounds
on farms constantly generates images of the product, good or bad. A good
farm image helps sell the product. Portraying an attitude of success is
contagious -- to employees, to neighbors, to consumers and to the general
public (Morris et al., 1973).
REFERENCE
Morris, T.B., W.C. Mills,Jr. and D.G. Harwood. 1973. Profit From Improving
Your Image. PS&T Guide #17, N.C. Agricultural Extension Service, Raleigh,
NC. 2 pp.
Distributed in furtherance of the Acts of Congress of May 8 and June 30,
1914. Employment and program opportunities are offered to all people
regardless of race, color, national origin, sex, age, or disability. North
Carolina State University, North Carolina A&T State University, U.S.
Department of Agriculture, and local governments cooperating.
EBAE 185-93
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