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 C skeletons H2S degradation (slow) VOCsFecal N(20-40% of N) Microbial N NH4

+ SlowUrine N aerobic Anerobic

(60-80% of N) Microbial NH3 NO2 N2

O urease (rapid) pH (volatile)

H2N C NH2 + H+ + H2O 2NH4+

2HCO3-

• In poultry•Urinary N is secreted as uric acid with the feces

• 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

COMMON MANURE STORAGE• Solid

– 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 C:NOptimum >30:1Manures Dairy cow 10:1 Beef cow 10:1 Beef feedlot 13:1 Swine 7-8:1 Poultry 7-9:1 Horse 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

• 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

• Covers to limit NH3 and odor release

• 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

N loss, % N retention, %Daily scrape and haul from barn 20-35 65-80Open lot 40-70 30-60Pile (Cattle/Swine) 10-40 60-90Pile (Poultry) 5-15 85-95Compost 20- 50 50-80Deep pit (Poultry) 25-50 50-75Litter 25-50 50-75Pit under floor (Swine) 15-30 70-85Tank above ground top loaded 20-35 65-80Tank above ground bottom loaded 5-10 90-95Tank above ground with cover 2-30 70-98Holding basin 20-40 60-80Anerobic lagoon w/ no cover 70-80 15-30Constructed wetlands 15 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 .22 Growing .15 Finishing .15 Sows and litter .17 Sow gestation .07 Gilts .088 Boars .055Beef 450-750 lb .11 High energy finish .11 Cows .12Dairy 50 lb milk/d .18 70 lb milk/d .22 100 lb milk/d .27 Dry .11 Heifer .11Layers .30Broilers .40Turkeys .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 ratesSoil moisture % OM-N available< 18% 35> 18% 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 factorsApplication method % NH4-N availableInjected or side-dressed during growing 100seasonInjected 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 applicationScraped manure Livestock .6 .5 -Poultry litter .6 .5 -Liquid slurry Dairy or Beef .7 .5 .4 Swine .7 .4 .3 Layers .7 .5 .4Anerobic lagoon Dairy or Beef .8 .5 .5 Swine .9 .5 .5 Layer .9 .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 lb plant available N/acre/yearSoybeans 30-45Alfalfa 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 Efficiency of harvested crop, N use, N required Crop wet basis __%__ for cropCorn Grain .81 lb/bu 83 .97 lb/bu Stover (Baled) 17.80 lb/ton 100 17.80 lb/ton Soybeans Grain 3.54 lb/bu 166 2.13 lb/bu Stover (Baled) 13.60 lb/ton 100 13.60 lb/tonAlfalfa (Baled) 46.10 lb/ton 200 23.05 lb/tonBromegrass (Baled) 39.20 lb/ton 100 39.20 lb/tonReed canarygrass (Baled) 28.00 lb/ton 100 28.00 lb/tonSwitchgrass (Baled) 21.80 lb/ton 100 21.80 lb/tonAlfalfa haylage 25.90 lb/ton 200 12.95 lb/tonCorn silage 9.00 lb/ton 100 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 rateExample: 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 removedCrop RYE N removed/unit lb total N removed/acreCorn grain 180 bu .81 lb/bu 146Corn stover (Baled) 4 ton 17.80 lb/ton 71Soybeans 55 bu 3.54 lb/bu 195Alfalfa (Baled) 5 ton 46.10 lb/ton 230Bromegrass (Baled) 4 ton 39.20 lb/ton 156Reed canarygrass 5 ton 28.00 lb/ton 140(Baled)Corn silage 20 ton 9.00 lb/ton 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 Injection or incorporation Greater N volatilization Less N volatilization Greater potential for N loss in run-off Less run-off potential Nutrients further from crop roots 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