MANURE HANDLING AND STORAGE TO
MINIMIZE N LOADING OF THE ENVIRONMENT
• Reason to store manure
– Preserve and contain manure nutrients until it can be
spread onto the land at a time compatible with climate and
cropping system
• Goals
– Maintain excreted N in non-volatile organic forms
• Undigested protein
• Microbial N
• Urea
– Minimize volatilization of NH3
– If N is volatilized, it should be in the form of N2
– Prevent losses of N into surface and ground water sources
• Provide adequate storage until it can be safely spread
N TRANSFORMATIONS IN LIVESTOCK
PRODUCTION AND MANURE STORAGE
FACILITIES
Manure N
Anerobic microbial
degradation (slow)
C skeletons
H 2S
VOCs
Fecal N
(20-40% of N)
Microbial N
NH4+
Urine N
(60-80% of N)
Microbial
O
urease (rapid)
H2N C NH2 + H+ + H2O
2NH4+
Slow
aerobic Anerobic
NH3
pH (volatile)
2HCO3• In poultry
•Urinary N is secreted as uric acid with the feces
NO2
N2
• NH3 volatilization increased by:
– Increasing rumen pH
• Increased by increased HCO3 and NH3
– Increasing moisture
– Increasing temperature
• From outside of confinement buildings
– Greater ventilation
– Concentrations of NH3 greater inside confinement buildings in
cold weather
• From outside lots
– Greater surface area
METHODS TO LIMIT AMMONIA VOLATILIZATION
FROM MANURE
• Dietary approaches
– Reduce N excretion
– Feed acidic Ca and P sources to decrease manure pH
• Examples
– Calcium chloride
– Phosphoric acid
• Limitations
– Unpalatable
– May cause ulcers in mouth
– Feed Yucca extract
• May inhibit microbial urease
• Technological approaches
– Frequent removal of manure from facilities
• Ne feedlot
– One-time cleaning, 68% N loss by volatilization
– Monthly cleaning, 55.5% N loss by volatilization
– Increase carbon in manure
• Increases C:N ratio to increase microbial growth
• Approaches
– Feed more fiber
– Use more bedding
– Separate liquid and solids
• Separates urea in urine from urease in feces
• Methods
– Gravity (Inclined floors, sedimentation pits)
– Mechanical (Screens, centrifuges, presses)
• Separated solids
– Land applied
– Composted
• Liquids
– Need further processing
– Urease inhibitors
• N-(n-butyl) thiophosphoric triamide (NBPT)
• Must be applied weekly to feedlot surface
• Currently not cost effective
• Solid
COMMON MANURE STORAGE
– Systems
• Poultry
– Litter
• Swine and Dairy
– Separated solids
– Bedded manure
• Beef
– Scraped
– Facilities
• Concrete pad with sides
• Settling basins
– Advantages
• Low volume
• Low odor
• Moderate nutrient retention
– Disadvantages
• More labor
• Must prevent precipitation run-off
BEEF FEEDLOT WITH SETTLING BASIN
– Composting
• Treatment to stabilize N
• Requirements
– Appropriate C:N ratio
Optimum
Manures
Dairy cow
Beef cow
Beef feedlot
Swine
Poultry
Horse
C:N
>30:1
10:1
10:1
13:1
7-8:1
7-9:1
19:1
– Temperature
» 140o F
» Requires frequent turning
– Moisture level
» 40-60%
– Adequate porosity
» Particles should be > 1 inch
» Straw a better source than paper
– pH
» 5.5 – 7.5
• Slurry
– For livestock and poultry confinements
– Facilities
• Pit under slatted floor
– Needs access ports for pumping and agitation at 40 foot
intervals
– Ventilation is necessary
– Manure is either applied directly or after storage
• Fabricated storage tank
– Manure is either scraped or pumped into structure
– Easily covered
• Earthen basin
– Provides a large volume at low cost
– Soil materials must seal basin
– Vegetation must be maintained on berms
– Advantages
• Less volume than liquid storage
• Possible to cover to reduce volatilization
• High nutrient retention, if covered
– Disadvantages
• Higher odor than solids
• Toxic gases
– H2S
SLURRY SYSTEMS
• Covers to limit NH3 and odor release
• Floating covers
– Natural
» Crust floating on top of manure
– Artificial organic
» Straw, chopped corn stalks, wood shavings
– Artificial
» Polystyrene foam, air-filled clay balls, geotextile
– Effectiveness
» Provides a barrier between liquid manure and the atmosphere
» Provides aerobic media to all microbes to degrade odor
compounds
» Limitations
Straw will only last from 2 weeks to 6 months
• Liquid systems
– Anerobic lagoons
•
•
•
•
Most common liquid system
Usually treats liquid fraction separated from solids
Requires warm temperatures for microbial activity
Advantages
– Large storage volume
– Can use conventional pumping equipment
• Disadvantages
–
–
–
–
–
Very high NH3 volatilization
Requires appropriate soil materials to seal lagoon
Requires solids separation
Manure additions must be slow and uniform
High odor in spring when microbial activity increases
under Midwest conditions
– Requires periodic sludge removal
– Alternate treatments to limit NH3 loss from liquid systems
• Aeration
– Converts NH3 to NO3
– Requirements
» Second lagoon with aerator
Surface pump
Compressed air
Aerobic biofilters
» One lagoon with 2 compartments
Aerobic top and Anerobic bottom
– Disadvantages
» Expense
» Limited effectiveness
» Production of NOx gases
• Methane production
–
–
–
–
–
Enclosed anerobic fermentation
Can supply energy for farm or for sale
Requires additional structure for storage of effluent
Good N retention if additional storage is covered
Expense
• Constructed wetlands
– For processing liquid fraction after solids separation
» N trapped in plants growing in or on wetland
– Types
» Surface
Most common
» Subsurface
Water treatment in a gravel bed
Works better in winter than surface wetland
May plug
» Reciprocating
Recurrently fill and empty
Causes aerobic and anerobic zones
N LOSSES FROM DIFFERENT MANURE
HANDLING AND STORAGE SYSTEMS
Daily scrape and haul from barn
Open lot
Pile (Cattle/Swine)
Pile (Poultry)
Compost
Deep pit (Poultry)
Litter
Pit under floor (Swine)
Tank above ground top loaded
Tank above ground bottom loaded
Tank above ground with cover
Holding basin
Anerobic lagoon w/ no cover
Constructed wetlands
N loss, %
20-35
40-70
10-40
5-15
20- 50
25-50
25-50
15-30
20-35
5-10
2-30
20-40
70-80
15
N retention, %
65-80
30-60
60-90
85-95
50-80
50-75
50-75
70-85
65-80
90-95
70-98
60-80
15-30
85
FACTORS AFFECTING SIZE OF MANURE
STORAGE
• Volume of manure and wastewater produced
– Include wash water, run-off from open lots and feed storage,
and water for flushing
• Limitations for spreading
– Amounts of land available for spreading
– Crop nutrient requirements
• Length of storage period
– Climatic limitations
– Length of application windows
– Needs
• A minimum of 6 months storage
• Equipment capabilities
• Discharge regulations
– All beef and dairy CAFOs
• No discharge except for a 25-year, 24-hour storm
– All new or renewed swine, poultry, and veal CAFOs
• No discharge except for a 100-year, 24-hour storm
MANURE APPLICATION TO MINIMIZE N LOADING
• Considerations
– Manure N concentration
• Needs laboratory analysis to adjust for factors like diet, volatilization,
water dilution, and bedding
• If developing a CNMP, need to consider total N production
Manure N (lb N/lb animal wt/yr)
Swine
Nursery
Growing
Finishing
Sows and litter
Sow gestation
Gilts
Boars
Beef
450-750 lb
High energy finish
Cows
Dairy
50 lb milk/d
70 lb milk/d
100 lb milk/d
Dry
Heifer
Layers
Broilers
Turkeys
.22
.15
.15
.17
.07
.088
.055
.11
.11
.12
.18
.22
.27
.11
.11
.30
.40
.27
– Availability of N to plants (PAN)
• PAN = Organic N x mineralization rate + NH4-N x volatilization factor
+ NO3-N
• Mineralization rate of organic N
– Generally slow
– Increases with:
» Lower soil moisture
» Increased soil temperature
» Increased soil pH
» Nutrients for soil microbes
– Average rates
Soil moisture
< 18%
> 18%
% OM-N available
35
25
• Volatilization of NH3
– Very rapid with surface application
– Rate dependent on:
» Application method
Lower with injection or incorporation
» Temperature
Greater from surface applied at higher temperature
» Plant uptake
Losses lower when plants actively growing
– Average factors
Application method
% NH4-N available
Injected or side-dressed during growing
100
season
Injected or incorporated in spring
65
(Reduce by 12% for each day delay in incorporation)
All other conditions
0
• Plant Available Nitrogen (PAN)
– After storage loss
Storage type
Proportion of manure N available after storage
Feedlot
.60
Manure pack under roof
.70
Bedded swine
.50
Liquid/slurry, covered
.90
Liquid/slurry, uncovered
.75
Storage pit under slats
.85
Poultry manure on shavings
.70
Compost
.70
Anerobic lagoon
.20
• After application
___________Application method______________
Soil incorporation
Broadcast
Irrigation
Proportion of manure N available after application
Scraped manure
Livestock
Poultry litter
Liquid slurry
Dairy or Beef
Swine
Layers
Anerobic lagoon
Dairy or Beef
Swine
Layer
.6
.6
.5
.5
-
.7
.7
.7
.5
.4
.5
.4
.3
.4
.8
.9
.9
.5
.5
.5
.5
.5
.5
• Total PAN = Total N x ( PAN after storage x PAN after application)
– Examples
• PAN of Feedlot manure applied with incorporation
– PAN = Total N produced x (.6 x .6) = Total N produced x .36
• PAN of Swine pit manure applied with incorporation
– PAN = Total N produced x (.85 x .7) = Total N produced x .595
• PAN of Anerobic lagoon manure applied with irrigation
– PAN = Total N produced x (.2 x .5) = Total N produced x .10
– Other N sources
• N-fixation by legume plants
– Supplies enough N to meet legume plant needs for growing year
– N-fixed by legume plants for following year
Soybeans
Alfalfa
lb plant available N/acre/year
30-45
50-125
• N fertilizer
– Rates should be calculated as the difference between plant N needs and
PAN from manure and legumes
– Crop N needs
• Nutrients should be applied to achieve Realistic Yield Expectations of the
crop
– The ‘Agronomic rate’
• Realistic yield expectations
– Factors
» Soil fertility
» Soil management
» Climate
» Plant populations
» Pest control
» Variety
» Grazing (60-75% of PAN reqt. for hay)
– Estimates
» Average of 3 highest years of last 5
» Can use county soil survey
– Plant N requirement for yield
N removal in
harvested crop,
wet basis
Crop
Corn
Grain
Stover (Baled)
Soybeans
Grain
Stover (Baled)
Alfalfa (Baled)
Bromegrass (Baled)
Reed canarygrass (Baled)
Switchgrass (Baled)
Alfalfa haylage
Corn silage
Efficiency of
N use,
__%__
N required
for crop
.81 lb/bu
17.80 lb/ton
83
100
.97 lb/bu
17.80 lb/ton
3.54 lb/bu
13.60 lb/ton
46.10 lb/ton
39.20 lb/ton
28.00 lb/ton
21.80 lb/ton
25.90 lb/ton
9.00 lb/ton
166
100
200
100
100
100
200
100
2.13 lb/bu
13.60 lb/ton
23.05 lb/ton
39.20 lb/ton
28.00 lb/ton
21.80 lb/ton
12.95 lb/ton
9.00 lb/ton
– Calculating manure application rate based on N
• Plant available N = Realistic yield expectation x Crop N reqt.
needs
• Manure application = Plant available N reqt / PAN conc in manure
rate
Example:
Say: Corn yield = 180 bu/acre
PAN needed, lb/acre = 180 bu/acre x .97 lb N/bu = 174.6 lb PAN/acre
Say: Swine lagoon manure containing 50 lb PAN/1000 gal which
will be injected
Manure applied, gal/ac = 174.6 lb PAN/ac / 50 lb N/1000 gal
= 3,492 gal/ac
USING CROPS TO ‘MINE’ MANURE N
• Some CAFOs look at harvested crop as method to
remove manure N from operation
• Potential amounts of N removed
Crop
RYE
Corn grain
180 bu
Corn stover (Baled) 4 ton
Soybeans
55 bu
Alfalfa (Baled)
5 ton
Bromegrass (Baled) 4 ton
Reed canarygrass
5 ton
(Baled)
Corn silage
20 ton
N removed/unit
.81 lb/bu
17.80 lb/ton
3.54 lb/bu
46.10 lb/ton
39.20 lb/ton
28.00 lb/ton
9.00 lb/ton
lb total N removed/acre
146
71
195
230
156
140
180
• Considerations
– To mine N, crop must either be sold or used in the diet to
reduce purchase of protein supplements on farm
– Grazing is effective at recycling N
• Therefore, grazing is ineffective for mining nutrients
– If N is applied at the agronomic rate, Phosphorus will
accumulate
• N rate is 2 to 3 times greater than the P rate
CONSIDERATIONS IN MANURE APPLICATION
• Application rate
• Method
Surface application
Greater N volatilization
Greater potential for N loss in run-off
Nutrients further from crop roots
Injection or incorporation
Less N volatilization
Less run-off potential
Nutrients near roots
• Site
– In Iowa, manure application can not occur within 200 feet of
a surface water source if no vegetative buffer
– In Iowa, manure application may occur up to 50 ft if
vegetative buffer and manure is incorporated
• Timing
– Manure should be applied shortly before nutrients will be
used for growth
• 30 days