Advanced Master Gardener Training: Composting and Compost Use for Land Care Stewards

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Advanced Master Gardener TrainingComposting and
Compost Use forLand Care Stewards

• Greg Evanylo
• Virginia Tech
• Phone [phone]
• Email gevanylo_at_vt.edu

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What is Composting?

• Microbial decomposition
• Aerobic
• Thermophilic
• Controlled
• Accelerated

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Recommended Composting Conditions
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Raw Materials

• Characteristics that determine recipes
• CN ratio
• Particle size distribution
• Moisture content

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Feedstock C and N Composition
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Feedstock Characteristics
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Composting Methods

• Windrow

• Aerated Static Pile

• In-vessel

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Windrow Composting

• Long, narrow piles turned/agitated
• Passive aeration
• Suited to high volumes (4-7,000 CY/Ac)
• Composting time 3-6 months

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Composting drum
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Tractor-pulled Watering tank
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Aerated Static Piles
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Isothermal Variation in a Sawdust Windrow(40
Fresh Sludge, 60 Sawdust)
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Oxygen depletion in an aerated static compost
pile using raw sludge
Blower off at Time 0 Blower on at Time 38
minutes 2 340 ft3/hr/dry ton
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Box/Tunnel Composting Systems
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Box/Tunnel Composting Systems
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Auburn (NY) Correctional Facility

• Wright Environmental Model 750

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Rotary Drum Composters

• Rotation mixes and aerates compost
• Preliminary grinding and mixing with bulking
  agent may be required
• Additional composting or curing needed

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Comparing Composting Systems
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Choices in Home Compost Bins
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Composting Operations, Management and Site and
Environmental Considerations
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Concentration of Aspergillus fumigatus
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Composting Regulations

• Regulated by VDEQ
• On-farm exemption
• Permit-by-rule
• lt 3000 CY/year
• Full permit

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O2/CO2
Process monitoring and troubleshooting
Moisture
Temperature
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Typical Compost Pile Temperature Profile
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Property Changes at Completion

• Volume 25-60 ?
• Mass 40-80 ?
• CN ratio ?
• pH neutralized
• Humus formation
• Recolonization by soil organisms

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Assessing Compost Quality

• Maturity
• Stability
• Phytotoxicity
• Soluble salts/EC
• pH and nutrients
• Bulk density
• Water holding capacity
• Pollutants

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Important Compost Properties
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Important Compost Properties
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Herbicide Residues in Compost

• Herbicide-like injuries (2000-2002)
• Tomatoes (Spokane)
• Vegetables (WSU)
• Vegetables (PSU)
• Traced to compost produced from yard trimmings,
  livestock manure bedding

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Properties of Clopyralid and Picloram

• Pyridine carboxilic acids
• Mimic plant growth regulators (auxins)
• Very water soluble
• Effective at low concs (lt10 ppb soil)

Picloram
Clopyralid
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Symptoms
Leaves cupped or curled
Leaves should be compound
Loss of apical dominance
Side shoots develop
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Herbicides that Present Risk
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Plant Tolerance to Clopyralid(Greenhouse
bioassay Dow AgroSciences, 2001)
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Tolerant Plants

• Grasses
• Bermudagrass
• Kentucky bluegrass
• ryegrass
• Tree and ornamentals
• Oak, maple, pine
• Azalea, juniper, yew
• Field crops
• Corn, wheat

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Compost Effects on Soil Properties (Shiralipour
et al.)
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Compost combats environmental stress

• PGR and anti-oxidant production
• Salinity and drought tolerance
• Disease suppression

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Acid sulfate soil near I-295 in Mechanicsville, VA
Soil amended with fertilizer and seeded.
Marginal Land Reclamation
Site after 3 years.
Soil amended with compost and lime and seeded.
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Potting Media
Compost used in container mixes at 20 to 50 as
peat or pine bark substitute.
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Turf Topdressing
Compost can replace topsoil, peat, and wood
fines mix in conjunction with aeration and
reseeding.
Apply ½ inch and rake.
Inexpensive source of nutrients and organic
matter.
Promotes seed germination and improves soil
properties.
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Orchard and Vineyard Mulch

• Application rate 2-3 inches thick
• Benefits
• Moisture
• Nutrients
• Disease suppression
• Plant growth regulator

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Erosion Control
Apply compost at rate of 270-540 cu yds/acre (2-4
inch layer).
Apply compost 3 ft over the top of slope to
prevent rill formation.
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Compost Filter Berms
Silt fence replacement
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Compost vs. Other Media
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Compost Use Estimator
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SE U.S. Bulk Compost Prices
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Benefits of Composting

• Reduces volume
• Improves handling
• Produces Class A material
• Creates beneficial product
• Potential tipping fees

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• Space, time and
• Weather
• Odor and bioaerosols
• Diversion of manure
• Reduced N availability
• Lower NP ratio
• Marketing

Drawbacks
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Composting References

• Natural Resource, Agriculture, and Engineering
  Service. 1998. Composting for Municipalities.
  NRAES-94. http//nraes.org.
• Evanylo et al. 2003. The Virginia Yard-Waste
  Management Manual. 2nd Ed. VCE 452-055.
  http//www.ext.vt.edu/pubs/compost/452-055/452-055
  .pdf
• Field Guide to Compost Use. 1996. U.S. Composting
  Council. http//www.compostingcouncil.org