Composting and Compost Utilization

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Composting andCompost Utilization

• Andy Bary
• WSU Puyallup
• Oct 3, 2002

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Composting Decomposition of organic materials by
aerobic microorganisms under controlled conditions
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Why compost

1. Compost good soil conditioner
2. Improved manure handling
3. Improved land application
4. Lower risk of pollution
5. Pathogen destruction
6. Nutrient management
7. Disease suppression
8. Saleable product???
9. Tipping fees

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Compost Draw backs

1. Time and money
2. Lack of equipment
3. Land
4. Odor
5. Weather
6. Materials
7. N loss
8. Farm operation

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Composting Process Flow Chart
Acquire Feedstocks
Analyze Markets
Amendments
Determine Recipe
Bulking Agents
Prepare Material sort, grind, chip, mix, shred
Active Composting Low Tech
High Tech
Curing Time
Screening
overs
Compost Quality Assessment
Product Refinement Marketing
Blending
Bagging
Adapted with permission from the On-Farm
Composting Handbook.
Additives
Storage
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Factors that affect composting Oxygen CN
ratio Moisture Porosity, structure, particle
size pH Temperature Time
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Preferred ranges
Reasonable ranges
CN ratio 20-401 25-301 H2O content
40-65 50-60 O2 gt5 gt5 Particle
size 1/8-1/2in. varies pH 5.5-6.5
6.5-8.0 Temperature 110-150F 130-140
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CarbonNitrogen Ratio
Compost 15-251 Grass clippings 151 Biosolid
s 51 Food wastes 151 Dairy
manure 201 Leaves and foliage 601 Straw 80
1 Bark 1151 Paper 1701 Wood or
sawdust 5001
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Composting methods
In vessel Aerated static pile Passively aerated
systems windrow bunker
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Composting methods
In vessel Aerated static pile Passively aerated
systems windrow bunker
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Composting methods
In vessel Aerated static pile Passively aerated
systems windrow bunker
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What can I compost?
Animal manures Straw, hay Vegetable matter Yard
debris Wood shaving/chips Newspaper Fruit and
vegetable wastes Fish processing wastes
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Organic Production Manures

• Raw manure OK if crop is not for human
  consumption
• Incorporated gt120 days before harvest if edible
  is in direct contact with soil or soil particles
• Incorporated gt90 days before harvest if edible is
  not direct contact with soil or soil particles

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Organic Production Compost non animal materials
Plant residues, etc No specific composting
regulations
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Organic Production Compost animal materials

• Initial CN 251 401
• Meet PFRP
• In vessel or covered 131-170oF, 3 days, All
  portion of pile meets this temperature.
• Turned windrow 131-170oF, minimum 15 days with 5
  turns.

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Soil fertility and nutrient management
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Nutrient Management

• Meet crop nutrient needs
• Maintain soil quality
• Conserve resources
• Protect water quality -- reduce leaching and
  runoff risk

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Plant Nutrients

• Major Nutrients
• Nitrogen
• Phosphorus
• Potassium
• Calcium
• Magnesium
• Sulfur

• Micronutrients
• Boron
• Iron
• Manganese
• Zinc
• Copper
• Chloride
• Molybdenum

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How nutrients become available
Mineral Matter
Organic Matter
N
K
P
Not available
Mg
Ca
S
-
-
K NH4 Ca SO4--
soluble, available
Mg
Ca
K
-
-
-
-
-
-
-
-
K
-
-
-
-
-
-
-
clay
OM
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Nutrient Anion Availability

• Anion Binding Solubility
• PO4-3 strong low
• BO3-3 medium medium
• SO4-2 v. weak high
• NO3- v. weak v. high

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Nitrogen Cycle
Plant residues, Manure
Organic N
NH4
Plants, Microbes
NO3 -
Leaching
Gases
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Organic Materials

• Little or no processing
• Low nutrient content
• Slow release of nutrients
• Plant, animal, or mineral sources

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Processed Manures Heated gt150oF for 1 hour and
less than 12 moisture
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Organic MaterialsSlow release nutrients

• Plants can only take up nutrients that are in
  available form (simple, soluble ions).
• Most nutrients in organic materials are in
  complex organic molecules or minerals, and are
  not immediately available to plants.

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Slow release nutrients

• Biological processes slowly release the nutrients
  in organic amendment into available forms.
• Rate of nutrient release depends on the nature of
  the amendment and environmental conditions.

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Nutrient uptake

• The forms of nutrients taken up by plants are the
  same for all types of fertilizer -- manufactured
  or organic.

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Organic materialsFertilizers vs. Soil amendments

• Fertilizer 1. High nutrient content and
  availability. 2. Main benefit is nutrients.
  3. Relatively small amounts applied.
• Soil amendment 1. Low nutrient content and
  availability. 2. Main benefit is organic
  matter. 3. Large amounts applied.

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CarbonNitrogen ratio

• Low CN supplies N to plants
• High CN ties up N by biological immobilization

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CN ratio and N availability

• CN
• lt101
• 101 to 201
• 201 to 301
• gt301

• N availability
• High
• Med - Low
• Very Low
• Negative

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High N ContentCN lt 101

• Rapid N availability
• Use as a fertilizer
• Over application leads to excess nutrient levels
  in soil -- potentially harming crop and water
  quality.

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High N ContentExamples

• Poultry manure
• Packaged organic fertilizers
• Fresh dairy or goat manure

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Moderate N ContentCN 121 to 251

• Slow N availability
• Can add large amounts without risk of
  over-fertilization
• Use as a soil amendment
• Expect some N immobilization (tie-up) shortly
  after application.

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Moderate N ContentExamples

• Compost
• Yard debris
• Cover crop residues
• Dairy solids

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Low N contentCN gt 301

• N immobilization
• Need to add N along with organic amendment
• Use as mulch or bulking agent for compost

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Low N contentExamples

• Straw
• Sawdust
• Paper waste

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Happy Composting
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Clopyralid in Compost
Cl
Cl
COOH
N

• Whats the story?

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Clopyralid

• What is it?
• A herbicide that kills many broad-leaved weeds.
• It is used on lawns, hay crops, wheat, and some
  other crops
• Legumes, nightshades, and composites are the most
  susceptible families.

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Clopyralid

• How does it get into compost?
• Applied to lawns by lawn care companies
• Clippings recycled as yard debris become
  feedstock for compost.
• Breakdown of clopyralid in compost is slow.

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Clopyralid

• Other sources of contamination
• Manure from horses fed grass hay treated with
  clopyralid
• Straw from grain crops treated with clopyralid

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Clopyralid

• Will contaminated compost kill my plants?
• No. But, there may be symptoms of damage on
  some susceptible garden plants, such as peas,
  beans, potatoes, and tomatoes. Most plants are
  unaffected by clopyralid.

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Peas, beans and marigolds grown in 31
v/v compostperlite mix Peas and beans show
symptoms, marigolds show no symptoms.
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Leaf from tomato plant grown in unamended soil.
Leaf from tomato plant grown in soil amended
with 50 compost.