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INTRO TO MANURE
MICROBIOLOGY
Dan Miller, USDA-ARS, Lincoln, NE
Manure Considerations
Different animal sources
Operations differ
Management options
Storage, Application
RESOURCE OR WASTE?
Manure Issues
Nutrient Loss (runoff & volatilization)
Greenhouse gas emissions
Odor
Pathogens
Pharmaceuticals
Insects
MICROBES
INVOLVED IN
ALL ASPECTS
What Is Manure?
Water
Organic matter
Undigested feed
Feathers/hair
Bedding
Insects
Microbes
Simple organics
Inorganic nutrients
Manure as an Ecosystem
Oxygen availability is key
Plenty of substrates (organic matter, urea, NH4)
O2 = aerobic
NO O2 = anaerobic
Organic Matter
OM CO2 + nutrients + H2O
OM CO2 + nutrients + CH4 +
H2O + VOC (odor compounds)
Undigested feed, animal slough (hair, feathers, etc)
OM composition affects the decomposition products
Linking Diet & Manure
Wet Distiller’s Grains are nutrients, crude protein
Manure NH3 and H2S
Dry-rolled versus Steam-flaked corn
DRC higher residual starch, manure yields more VFA
Anaerobic Pathways for Odors
Decarboxylation
Diamines
(putrescine)
(cadaverine)
Initial
Hydrolysis
Proteins Carbohydrates
(Starches, Cellulose)
Initial
Hydrolysis
Amino Acids Mono & Disaccharides
Fermentation
Straight Chain VFA
Deamination
Straight Chain VFA,
Branch Chain VFA,
Phenols, Indoles,
Benzoates, Sulfides, NH3
Odors
Substrates
VOC is Odor
Volatile Organic Compounds = fatty acids, aromatic
ring compounds, alcohols, ketones, sulfides
VOC
• Acetic acid = vinegar
• VFA = fecal smell
• Skatole = fecal smell
• Sulfides = rotten eggs
With O2, bacteria can
consume all of these!
Nutrients--Phosphorus
Similar fate in both environments
Usually bound to particulates, runoff losses
Organic P PO4
Organic P PO4
Nutrients--Nitrogen
Organic N, NH4, NO3
Many changes, many losses
Org N NH4
NH4 NO3
NH4 NH3 (gas)
Org N NH4 (leach, runoff)
NO3 N2 (gas) + N2O
N2O
Other Roles for Microbes
Affect manure nutrients and organic matter in
ground water
Up-gradient = 60 ppm NO3; 0 ppm NH4
Other Roles for Microbes
Potential pathogens & antibiotic resistance What is the natural ‘background’ level?
Other Roles for Microbes
Do pharmaceutical compounds (antibiotics & hormones) build up or affect ‘natural’ bacteria?
Some bacteria break down pharmaceuticals!
Manure—Resource or Waste?
Many benefits to soil health and sustainable
crop production
Soil carbon
Nutrients (N, P, K, and micronutrients)
Beneficial microorganisms
Manage environmental issues in order to reap
the benefits
Questions & Discussion?