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 NH 3 –If N is volatilized, it should be in the form of N 2 –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 H 2 S degradation (slow) VOCs Fecal N (20-40% of N) Microbial N NH 4 + Slow Urine N aerobic Anerobic (60-80% of N) Microbial NH 3 NO 2 N 2 O urease (rapid) pH (volatile) H 2 N C NH 2 + H + + H 2 O 2NH 4 + 2HCO 3 - In p oultry Urinary N is secreted as uric acid with the feces

NH 3 volatilization increased by: –Increasing rumen pH Increased by increased HCO 3 and NH 3 –Increasing moisture –Increasing temperature From outside of confinement buildings –Greater ventilation –Concentrations of NH 3 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:N Optimum >30:1 Manures Dairy cow 10:1 Beef cow 10:1 Beef feedlot 13:1 Swine 7-8:1 Poultry 7-9:1 Horse 19:1 –Temperature »140 o 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 –H 2 S

SLURRY SYSTEMS

Covers to limit NH 3 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 NH 3 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 NH 3 loss from liquid systems Aeration –Converts NH 3 to NO 3 –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 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 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.055 Beef lb.11 High energy finish.11 Cows.12 Dairy 50 lb milk/d lb milk/d lb milk/d.27 Dry.11 Heifer.11 Layers.30 Broilers.40 Turkeys.27

–Availability of N to plants (PAN) PAN = Organic N x mineralization rate + NH 4 -N x volatilization factor + NO 3 -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 % OM-N available < 18% 35 > 18% 25

Volatilization of NH 3 –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 % NH 4 -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 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/year Soybeans Alfalfa 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 crop Corn Grain.81 lb/bu lb/bu Stover (Baled) lb/ton lb/ton Soybeans Grain 3.54 lb/bu lb/bu Stover (Baled) lb/ton lb/ton Alfalfa (Baled) lb/ton lb/ton Bromegrass (Baled) lb/ton lb/ton Reed canarygrass (Baled) lb/ton lb/ton Switchgrass (Baled) lb/ton lb/ton Alfalfa haylage lb/ton lb/ton Corn silage 9.00 lb/ton 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 = lb PAN/acre Say: Swine lagoon manure containing 50 lb PAN/1000 gal which will be injected Manure applied, gal/ac = 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 N removed/unit lb total N removed/acre Corn grain 180 bu.81 lb/bu 146 Corn stover (Baled) 4 ton lb/ton 71 Soybeans 55 bu 3.54 lb/bu 195 Alfalfa (Baled) 5 ton lb/ton 230 Bromegrass (Baled) 4 ton lb/ton 156 Reed canarygrass 5 ton 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