Composting

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Composting

• Methods and Uses
• Dr. Lynne Carpenter-Boggs
• BIOAg Specialist
• WSU CSANR

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BIOAg Organic and/or bio-intensive, if its
sustainable.

Organic agriculture A legally defined and
regulated practice that focuses on use of natural
materials non-use of synthetic pesticides,
fertilizers, etc. Biologically Intensive
using renewable biological materials
processes. Sustainable Producing high quantity
and quality food fiber with long-term economic,
environmental, social viability.
Organic
Biologically- Intensive
Sustainable
BIOAg
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What is composting?

• Decomposition en masse
• The transformation process is similar to that
  which occurs in every topsoil
• Transformation of raw materials
• biologically
• chemically
• physically
• Bacterial and fungal activity
• thermophilic heat-loving organisms
• Microaerobic not fully aerobic, not anaerobic

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Composting is a biological process wherein
organic raw materials or feedstocks are
transformed by organism activities into a
stabilized soil-like material called compost.
Heat
CO2

• Raw materials
• Organic matter
• Oxygen
• Water
• Microbes

Finished compost with humic matter
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Compost Temperature

• Tremendous microbial activity produces heat.

• At 130 F, most plant and animal pathogens and
  weed seeds die.

Thermophiles
130 F ?
active phase
Temperature
Time
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Growth response of organisms
Growth rate
Hyperthermophiles
Psychrophiles
Thermophiles
Mesophiles
Temperature (F ) 15 50 70 105
150 165 250
Temperature (C ) -10 10 20 40
65 75 120
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Compost Temperature

• Tremendous microbial activity produces heat.

• At 130 F, most plant and animal pathogens and
  weed seeds die.

Thermophiles
130 F ?

• Eventually some resource will become limiting
  simple foods, oxygen, or nitrogen will be used up
  and
• microbial activity (and
• temperature) will drop off.

active phase
Temperature
curing phase
Time
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• Bacteria single-celled prokaryotic organisms
  (1-10 µm).
• Dominate compost in thermophilic stages
• Feed on very easily degraded materials such as
  sugars proteins
• Grow insanely fast doubling time can be less
  than 1 hr. In one day 1 cell can become 20
  million cells.
• Some can grow without oxygen, so dominate
  internal volume of compost piles.

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• Actinomycetes also single-celled prokaryotic
  organisms, but grow as threads (1-5 um diameter).
• Grow much more slowly than bacteria
• Feed on complex materials
• Usually relegated to outer layer of compost piles
  unless very dry or porous.

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• Fungi grow as long threads (hyphae) 10-50 µm in
  diameter
• Different species feed on different foods very
  simple to very complex.
• Like actinos, found in aerobic areas.
• Wood other high CN material favor fungi
• Acidic pH favors fungi

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Create a Composting Environment

• Factor OK range Optimum
• CN 201 501 25-301
• Moisture 40 65 50 60
• Oxygen gt5 gtgt5
• pH 5.5 9.0 6.5 8
• Particle size 1/8 ½ varies

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Narrow or low CN
Animal carcass
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Energy materials
Soil humus
101
 
Young grasses
20 - 401
 
Balanced materials
Manure
20 - 501
 
 
Wheat straw
801
 
Bulking materials
Tree leaves
60 - 1001
 
 
 
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Types of Composting

• Passive
• Aerated
• Turned
• Specialized
• Certified Organic
• Animal Mortality
• Home Composting

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Passive composting pile

• Temperature will rise, stabilize, slowly drop.
• Minimal management
• Inconsistent results.

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Composting Bins
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4-bin composter - Iowa
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Aerated Windrow Composting
Blower
Perforated pipe
NRCS National Engineering Handbook Part 637
-Chapter 2 Composting
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Compost Temperature Passive or static system
130 F ?
active phase
curing phase
Temperature
Time
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Turned composting

• Heavy equipment used to mix compost every 1 - 14
  days

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Compost Temperature Turned System

• When compost no longer reheats after turning,
  curing begins.
• Decomposition continues to slow, but never really
  ends.

130 F ?
turn
turn
turn
Temperature
active
curing
Time
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Industrial Composting

• Turned windrows
• In-vessel

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WSU Composting Facility
4 acres Established 1994 up to 1,000,000
annual savings
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Special-use compost organic agriculture

• Moderate-to-high quality compost
• Must follow special NOP regs
• Feedstock mix CN must be 15 601
• Temperature must reach 131 F at least 3 days
• Turn or ensure that all parts of pile reach temp
• Test for E. coli, Salmonella
• Use a turned or aerated system, not passive
• No biosolids, no prohibited materials used
• If requirements not met, use as if its manure

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Specialized composting livestock carcass disposal

• Not rocket science, but must be done right
• Some high carbon feedstock necessary for
  collecting moisture, odor, balancing the high-N
  carcass
• Composting saves money and nutrients

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Mortality is a Waste Management Issue

• A carcass is a concentrated source of organic
  matter
• it is a source of odors
• it is a source of undesirable critters
• it is a potential source of pathogens
• it is a source of nutrients
• Thus, the mortality problems are similar to
  manure problems

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Planning for the Impossible...

• Natural disasters can and do happen
• Flooding (IA, 1993 NC, 2000)
• Heat Waves (CA, 2005)
• Snow (Blizzard of 1993)
• millions of broilers and chicks lost to building
  collapse and loss of power for heating
• Whole herds may be destroyed

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Responding to tragedy
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Passive Piles or Windrows
Place the carcass on gt24 high-carbon base to
absorb moisture allow airflow
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Cover the Carcass, Build the Pile
Minimum 24 co-composting material around the
carcass to help decompose, discourage critters,
and allow airflow
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WAIT -- Composting takes time

• An active pile stays hot. This pile was 135-152
  F through December.

• With carcasses, wait 2-6 months before
  disturbing the pile

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Typically only large bones are left identifiable
after 2-6 months. Re-compost these quickly.
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Allow 1-2 more composting periods

• Temperature will rise again, but not as hot.

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Home composting

• For materials with known CN ratios, mix them to
  achieve an overall CN of 201 501 (251
  301 is ideal).
• For materials with unknown CN ratios, use 1
  volume of browns to 1 volume of greens.

Green yard waste grass clippings and weeds.
Energy Brown yard waste leaves, small brush
and twigs. Bulking
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Ingredients NOT for the home composter

• Carcasses
• Pet poo
• Meat, dairy
• Raw manure
• Herbicide-treated trimmings

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• For composting you can use traditional
  free-standing compost heaps or homemade or
  manufactured bins.
• There are a variety of manufactured composting
  bins
• A bin or some type of enclosure may save space
  and be more attractive, and may provide
• Insulation
• Aeration
• Pest protection

Heap gt 1yd3 5 ft at base x 3 ft high
Bins
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• Or make a home-made compost bin from a number of
  materials including wire fencing, lumber, used
  pallets, and cement blocks.
• Whatever materials you use, it's important to
  design the bin to allow for good air movement and
  easy accessibility to turn the pile and remove
  the finished compost.

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Slow composting

• Ingredients green and brown yard waste, water as
  needed.
• Directions
• In a heap, layer your yard waste as it
  accumulates. For faster composting, chip it up
  first.
• Water so compost is kept as moist as a wrung-out
  sponge.
• In a year to 18 months, the material at the
  bottom and center of the pile will be dark,
  crumbly compost. Sift, and use the uncomposted
  material to start a new batch.

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Slow composting is cool

• And involves more mesofauna

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Fast composting
Water as needed

• Ingredients green and brown yard waste
• Directions
• Mix one part green yard waste with two parts
  brown to form a pile (an average size is 4 x 4
  x 4). For fast composting, chop it up first with
  a hoe, chipper, or lawn mower.
• Mix in one inch of soil or finished compost.
• Keep the pile as moist as a wrung-out sponge (not
  soggy).
• Turn the pile every week to let air in.
• Finished compost will take between 4 weeks and 1
  year, depending on how often you turn it and how
  well you maintain the moisture of the pile.

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Fast composting is also HOT

• The main reason to be concerned about pile
  temperature is that maintaining a minimum pile
  temperature of 131F for 3 days is desirable to
  destroy weed seeds or plant pathogens.
• If your pile does not heat up, don't worry
  Compost Happens! at all temperature levels. 

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Vermicomposting

• To start vermicomposting, you'll need
• a bin for your worms
• a supply of biodegradable bedding
• a supply of food waste
• and worms, of course.

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Trench or Garden Composting

• Dig trench or hole 1 ft deep
• Add wastes garden soil
• Cover with soil
• Easy
• Protects from pests
• Improves garden soil

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What is proper composting NOT ?

• Rotting
• Fermenting
• Stinky
• On Fire
• Dangerous

Most of these problems are caused by too much
high energy materials.
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Now you have compost

• Compost quality determines its best use.
• 5 uses for best to worst compost potting soil,
  soil amendment, turf topdressing,
  agricultural/garden amendment, mulch (esp. for
  compost with CNgt25)
• The closer the plant contact (in space and time),
  the greater the quality and maturity must be.
  Lower quality composts may still be used as
  mulch, or less mature compost may be incorporated
  in soil several months prior to planting.

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Good compost builds rich topsoil

• Complex humic acids (humus) form.
• Composted material is darker, particles are
  smaller and softer, texture is fine like good
  topsoil.
• Good compost is often unrecognizably different
  from its feedstocks.
• No unpleasant odor, no undecomposed material, and
  stable in long-term storage.
• Approx. ½ of C, volume, and mass have been lost
  but most nutrients were retained.

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Sources of SOM amendments

• Manure, sludge, biosolids
• Variable longevity in soil
• Watch out for salts, metals, N burning
• Biosolids not allowed in organic agriculture
• Peat, humic acids
• very low nutritive value
• may/may not be stable
• less chemical or biological benefit
• Compost
• slow-release fertilizer, partially humified
• more likely to BUILD OM
• may decrease diseases

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Benefits of compost to soil

• Slow-release source of plant nutrients
• N, P, K, S, micronutrients
• Neutralizes soil pH
• Increases soil moisture-holding
• Improves soil tilth structure
• Provides biotic food and habitat
• Many others

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Compost as fertilizer

• Concentrates nutrients in initial organic
  materials
• Add mineral fertilizers to increase their
  bioavailability
• Greensand (K)
• Rock Phosphate (P)
• Azomite (micronutrients)
• Other rock powders
• Lime
• Compost teas
• Supply soluble nutrients, humic acids, and
  microbial inoculant

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Allow time for nutrient release from compost
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Composting Its hot!