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?