Onfarm Composting of Organic Waste

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On-farm Composting of Organic Waste
Caitlin Price Project Coordinator, WSU On-farm
Mortality Compost Research and Education Project
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• Basic compost biology
• Compost management
• Examples of compost systems
• Mortality compost
• Plenty of time for questions

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SOIL COMPONENTS
Mineral Matter Pore Space Organic Matter
www.physicalgeography.net
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SOIL TEXTURE
Mineral Matter Pore Space Organic Matter
The percent of sand, silt and clay particles
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SOIL STRUCTURE
Mineral Matter Pore Space Organic Matter
The aggregation of the sand, silt, and clay
particles
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SOIL STRUCTURE

• Important for
• 1. Water Movement (macropores)
• - How quickly water moves through the soil
• 2. Water Holding Capacity (capillary pores)
• - How much plant available water the soil can
  hold
• 3. Air Movement
• - Oxygen availability

Mineral Matter Pore Space Organic Matter
Affected by 1. Soil texture and structure 2.
Compaction and disturbance 3. Organic matter
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SOIL ORGANIC MATTER
Mineral Matter Pore Space Organic Matter
Soil Organic Matter plant and animal materials
in various stages of decomposition

• Long-term storage of nutrients
• Soil structure increases porosity and root
  penetration
• Increases water holding capacity, drought
  resistance, water infiltration
• Excellent source of nutrients and energy for soil
  microbes, insects, worms, etc.

Sources compost, manure, cover crops, natural
breakdown of roots, crop residue
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SOIL ORGANIC MATTER
Ca
NO3-
NH4
H2O
- -
K
NO3-
- - - -
- - -
- -

- -
- -
- - - -
NH4
Clay
H2O
- - - -
S.O.M
- -

NH4
H2O
- - - -

K
- -
Mg
- - -
HPO3--
K
NO3-
Ca
H2O
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COMPOST AND S.O.M
On-farm composting is a great way to turn organic
waste from the farm into a valuable soil
amendment

• The same basic principles apply regardless of the
  materials or size
• Compost does not make nutrients more available
• Long-term nutrient storage
• Slow release (less leaching)
• Improve soil structure, biology

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WHAT IS COMPOST?

• Controlled aerobic decomposition of plant and
  animal remains into stable organic materials.
• Transformation of raw organic materials into
  biologically-stable, humus-rich substances
  suitable for growing plants.
• Microbe farming keep the microbes happy and let
  them do the work for you!

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COMPOST BIOLOGY
(Adapted from Sylvia et. al., 2005)
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COMPOST BIOLOGY
Nutrients Moisture Oxygen Management
Microorganisms require nutrients in specific
ratios for metabolism and organic matter
decomposition
Carbon and nitrogen are most important to manage
in compost determined by raw materials Excess
carbon slows metabolism, reduces rate of
decomposition Excess nitrogen volatilization
(gas) and leaching of nutrients, odors

• The optimum CN for active composting is
• 251 301

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COMPOST BIOLOGY
Nutrients Moisture Oxygen Management

• Water is essential for microbial metabolism and
  organic matter decomposition
• Excess moisture anaerobic conditions, leaching
• Insufficient moisture lowers microbial
  population and metabolism

The ideal moisture content of a compost pile is
50-60 Rule of thumb Squeeze a handful of
material in your fist. If it drips its too wet,
if it falls apart its too dry. A film of water
on your palm is just right!
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COMPOST BIOLOGY
Nutrients Moisture Oxygen Management

• Oxygen is essential for aerobic composting
• Aerobic microbes are the most efficient (consume
  O2, produce CO2)
• Anaerobic microbes produce compounds that smell
  bad (CH4, H2S)

Oxygen is managed by particle size (pore space),
moisture of raw materials, and turning/aerating
the pile
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COMPOST BIOLOGY
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COMPOST MANAGEMENT

• Other considerations
• Type of system management intensity, size
• Location neighbors, drainage
• Seasonal differences climate, materials
• End product use and storage

Nutrients Moisture Oxygen Management
Challenges Pests hard to get rid of! Odors
anaerobic, leachate, raw materials Weeds,
pathogens temperature
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COMPOST MANAGEMENT
Nutrients Moisture Oxygen Management
Management is essential! Start with a simple
system and make changes as you go Record
temperature weekly best measurement of
success Observe for disturbance, odors, pests
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EXAMPLES OF COMPOST SYSTEMS
Three-bin garden compost system
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Aerated bin for horse manure Courtesy of O2
Compost Systems
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Two-bin system for composting fish mortalities in
Idaho
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Covered bins for composting poultry mortalities
in Maryland
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Windrows of grape pomace compost in California
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Turned windrows at WSU compost yard
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Windrows with passive aeration
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Tractor pulled windrow turners
Virginia cooperative extension and www.sru.edu
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Static on-farm compost piles
courtesy of www. bridgeandtunnelclub.com
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Turning (and compacting) a static compost pile
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On-Farm Mortality Composting
Caitlin Price WSU On-farm Mortality Composting
Research and Education Project
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The Problem

• Even with the best management, animals sometimes
  die and producers have limited disposal options

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The Solution
With proper management and materials, on-farm
composting can be an economically viable and
environmentally sound method of mortality
disposal.
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Composting a controlled decomposition process in
which aerobic microorganisms convert the carcass
and co-composting materials into stable, nutrient
rich organic matter

• Advantages
• Reduced cost of disposal
• Useable end-product, keep nutrients on the farm
• Reduce pathogens, pests
• Immediate disposal year around

• Challenges
• Requires careful management
• Dedicated area
• Time

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Materials
Carbon Source straw, wood chips, sawdust, old
feed, silage, etc. Nitrogen Source manure,
carcass
Objective create a mix of materials with the
right CN ratio, moisture, and porosity
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Pathogens

• Pathogen reduction in compost is largely due to
  the high temperatures caused by microbial
  metabolism.
• Minimum internal temperature for pathogen
  reduction in a static pile is 131oF for at least
  three days. (PFRP)
• Temperature can easily reach 150-160oF w/in 1
  week
• - Best measurement of success
• Turning the compost exposes all materials to
  heat
• and pathogen reduction

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Find a good location away from any ground water,
neighbors, or other animals. Make sure there is
adequate drainage.
ON-FARM MORTALITY COMPOSTING RESEARCH AND
EDUCATION PROJECT www.mortcompost.info
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Windrow Layout for Large Animal Mortality
Composting
25-35 ft

• Windrows should run up and down the slope to
  allow for best drainage.
• Do not drive over the materials. Compaction will
  restrict oxygen availability in the pile.
• Add each mortality to the pile as they occur and
  note the date and location.
• Calves can be stacked together, or placed with a
  cow.

20 ft to the next set (or enough space to
maneuver loader)
Leave 2 ft for airflow and equipment
ON-FARM MORTALITY COMPOSTING RESEARCH AND
EDUCATION PROJECT www.mortcompost.info
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Monitoring the process

• Temperature 1 x week
• Moisture
• Settling or Disturbance
• Scavengers and Pests

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WSU Trial 1
Building the Pile November 1
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WSU Trial
10 weeks later
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Yakima County Dairy
Primary composting phase lasts 90 120
days Temperatures peak between 135 and 145oF
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Skagit County Dairy
Primary composting materials sawdust with
manure, spoiled silage and hay Minimal management
system
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WSU Trial 2 at 7 weeks
Pile started with 1 cow Offal and processing
waste from 10 pigs and 5 cows was added at 3
wks Peak temperatures of 145 to 160oF
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WSU Trial 2 at 7 weeks
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WSU On-farm Mortality Composting Research and
Education Project

• Funded by WA Dept of Ecology and Dept of Ag, WSU
  BIOAg Program, and the Center for Sustaining
  Agriculture and Natural Resources
• Demonstrate large carcass composting at sites
  around Washington state.
• Sunnyside, Moses Lake, Othello, Pullman, Mount
  Vernon
• Evaluate new Dept of Ecology regulations
• Develop simplified guidelines, informational
  website
• Host field days and demonstrations at trial sites
• Publish WSU Extension bulletin

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Composting the remains of a 30-ton Northern Right
Whale!
Paleontological Research Institution, Ithaca NY