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Basic Composting Klickitat County Solid Waste in cooperation with The Washington State Department of Ecology Credits To: Northeast Regional Agricultural Engineering Service On-Farm Composting Handbook Composting to Reduce the Waste Stream Cornell University Tom Richard Prepared by John Longfellow under a grant from the Washington State Department of Ecology. ---PAGE BREAK--- Topics We Will Discuss Methods of Composting The Biology of Composting Building and Maintaining Environment Using Compost Health, Safety and … Resources ---PAGE BREAK--- Methods of Composting Grass-Cycling Mulch Heaps Soil Incorporation Holding units Turning units Worm Bins ---PAGE BREAK--- Mulching Benefits include: z control of weeds z reduced evaporation z soil temperature moderation z reduced erosion. Mulching works best around trees and perennials. ---PAGE BREAK--- Heap Approximately three feet high and five feet wide. Cover with layer of soil, yard waste or mulch to conserve moisture. ---PAGE BREAK--- Soil Incorporation Hole or trench must be deep enough so at least 8 inches of soil can be placed on top of compost material. Works for non-fatty wastes. Decompose in 1 month to 1 year. ---PAGE BREAK--- Holding Units Slow Method z Add waste as it is generated z 6 months to 2 years for finished compost. ---PAGE BREAK--- Turning Units Fast composting z best for batch composting ---PAGE BREAK--- Worm Bin Works best for food waste ---PAGE BREAK--- Biology of Composting ---PAGE BREAK--- Two Types of Decay Break down waste at the molecular level z Bacteria z Mold z Fungi z Actinomycetes z Protozoa Break up waste into smaller particles and transport microbes z Mites z Millipedes z Sowbug z Worms z Snails CHEMICAL DECAY PHYSICAL DECAY ---PAGE BREAK--- Food Web of Compost ---PAGE BREAK--- Anaerobic Decomposition Dominates when oxygen drops below 5% Process is slow and more nutrients lost By-products harmful to plants: z Acids z Alcohol Odors: z Hydrogen sulfide (rotten egg) z Cadaverine z Putrescine ---PAGE BREAK--- Aerobic Decomposition Dominates when oxygen above 15% Faster than anaerobic decomposition pH tends to self regulate in a safe zone Odor tends to be less offensive More nutrients are stabilized ---PAGE BREAK--- Factors Affecting the Process Surface area and particle size Aeration Moisture pH Carbon/Nitrogen ratio Time Composting Method Chosen ---PAGE BREAK--- Surface Area and Particle Size Smaller particles provide more surface area. Microbes do their work on the surface of the material. ---PAGE BREAK--- Surface Area and Particle Size ---PAGE BREAK--- Surface Area and Particle Size ---PAGE BREAK--- Aeration z Aerobic microbes consume available air. z Particle sizes need to be large enough to allow passage of air into center of the pile. z Excessive moisture can block air flow. z Compaction can block air flow. z Materials with good structure like straw, wood chips, corn stalks and leaves will enhance circulation of air. z Turning the pile will improve circulation. Factors affecting air flow ---PAGE BREAK--- Natural Air Flow ---PAGE BREAK--- Moisture Microbe activity occurs in a thin liquid film on the surface of particles. Optimum: 40-60% moisture Too dry will stop activity. Too wet will block air and leach nutrients. ---PAGE BREAK--- Temperature 90-140°F is optimum range for a heap or batch compost pile z over 140°F inhibits microbe activity The size or volume of the pile affects the ability of the pile to hold heat Ambient air temperature affects rate of heat dissipation ---PAGE BREAK--- pH Compost process is relatively insensitive to pH. z In normal compost cycle, early release of acids will temporarily lower the pH. z Later stages of compost cycle will raise pH z Addition of lime or ash is not recommended • can cause loss of nitrogen in the form of ammonia • may interrupt the natural cycle • compost should be tested after curing if pH effect on plants is a concern ---PAGE BREAK--- Time Time required for finished product depends upon the intended end use. z Potting soil needs to be completely cured. z Mulch compost can be relatively unstable. Factors that lengthen required time: z low moisture z high C:N ratio z low ambient temperature z compaction of material z large particle size z woody materials ---PAGE BREAK--- Composting Time Method Material Time Curing Passive Bedded Manure 6-24 months - Pile infrequent turning Manure + amendments 4-8 months 1-2 months Pile frequent turning Manure + amendments 1-4 months 1-2 months Worm Bin Food Waste 4-6 weeks - Rotating drum Solid Waste 3-8 days 2 months Effect of compost method on length of composting time ---PAGE BREAK--- Carbon/Nitrogen Ratio Microbes need both in a ratio of about 30 parts carbon to one part nitrogen. z Carbon is a source of energy for the microbes • About 2/3 of available carbon is used for energy z Carbon and Nitrogen become part of the microbe cell structure • This is how nitrogen is stabilized in compost ---PAGE BREAK--- Making and Maintaining a Compost Pile Materials Location Construction Maintenance Troubleshooting ---PAGE BREAK--- Common Compost Materials High Nitrogen High Carbon Bread Coffee grounds Egg shells Evergreen needles Fruit Fruit peels and rinds Garden waste Grass clippings Manure: Cow- Horse-Sheep Leaves Paper Sawdust Straw Sod Tea leaves Vegetables Wood ash Wood chips ---PAGE BREAK--- Don’t Try to Compost These... Butter Bones Cat manure Cheese Chicken Dog manure Fish scraps Lard Mayonnaise Meat Milk Oils Peanut butter Salad dressing Sour cream Vegetable oil General Rule: avoid meat, fat, oil, dairy products, or manure from carnivorous animals. ---PAGE BREAK--- Important Characteristics of Materials C:N Ratio: optimized for organism’s needs Moisture: 40-60% by weight – squeeze test Porosity/bulk density: air flow and particle size Degradability: banana vs wood chip Odor potential: 2 week old bagged grass clippings Cleanliness: inorganic matter ---PAGE BREAK--- Choosing Amendments Most Important Characteristics z Total C:N ratio of mix z Total percent moisture of mix Amendments: z Bulking agents: for structural qualities, include wood chips, corn stalks, straw or tire chips. z Carbon sources: to balance C:N ratio z Nitrogen sources: to lower C:N ratio z Compost: to inoculate pile with microbes ---PAGE BREAK--- The Math and the Mix Data required for each material: z moisture content z percentage of nitrogen (dry weight) z percentage of carbon (dry weight) or C:N ratio z bulk density ---PAGE BREAK--- Math for Individual Materials ---PAGE BREAK--- Math for Availability of Carbon z additional data required • cell wall as a percentage of total solids • lignin as a percent of total solids ---PAGE BREAK--- A Recipe without the Math Www.KlickitatCounty.org/SolidWaste/ z click on Compost in the right hand column z Look for “Compost Mix Calculator” z Click on the link “…Click for Details” z Read the instructions z Click the “Compost Mix Calculator” link to create your recipe z Click the “Detailed Information” link to read more about Carbon Availability ---PAGE BREAK--- The Compost Mix Calculator ---PAGE BREAK--- Location Shade: conserve moisture Wind: conserve moisture Water: near water hose Storage: room for accumulated material Convenience: close to kitchen and garden Well and Surface Water: contamination Rain: avoid low spots and runoff channels Vehicle Access: hauling raw material ---PAGE BREAK--- Step 1 Collect enough material to create a 1 cubic yard pile. Start the pile with a 4-6 inch layer of high-carbon material. Chop or shred coarse material to increase surface area. How to Construct a Batch Compost Pile ---PAGE BREAK--- Step 2 Add a 4-6 inch layer of high nitrogen material Vegetative kitchen waste should be added in this layer. If food wastes are added, an additional thin layer of soil, sawdust, leaves, straw or compost should be added to absorb odors. How to Construct a Compost Pile ---PAGE BREAK--- Step 3 Mix the layers. How to Construct a Compost Pile ---PAGE BREAK--- Step 4 Conduct a squeeze test. Add water until squeezing a handful will yield a couple of drops of water. How to Construct a Compost Pile ---PAGE BREAK--- Step 5 Continue adding layers, mixing them as you go, until pile is 3 or 4 feet high. How to Construct a Compost Pile ---PAGE BREAK--- Pile Maintenance: 7th Day Temperature should be around 110°F Reconstruct pile placing top and side material into center Check moisture ---PAGE BREAK--- Maintenance: 14th Day Temperature 120-140°F Original material coffee brown color Reconstruct pile placing top and side material in center Break up compacted material Check moisture ---PAGE BREAK--- Maintenance: 21st Day Temperature 120-140°F Original material not recognizable Reconstruct pile placing top and side material in center Check moisture ---PAGE BREAK--- Maintenance: Final Cure Temperature within 10°F of air temperature Dark crumbly texture Earthy odor Notice how the thick fabric in the sweatshirt of the person in the photo makes it appear he has a weight problem. ---PAGE BREAK--- Using Compost Mulch Top dressing Soil incorporation Potting soil ---PAGE BREAK--- Benefits of Compost Use Improved soil structure z holds moisture in sandy soil z improves aeration and porosity in clay soil • improved water absorption • resistance to compaction z attracts worms that add humus to soil Slow release of nutrients over long period of time ---PAGE BREAK--- When is it ready to use? Microbes in compost with a high C:N ratio will compete with plants for available nitrogen. z Can be used on top of the soil around shrubs to keep weeds from sprouting. Just after active composting most available nitrogen is in the form of ammonium. z It takes three months for ammonium-nitrogen to be converted to nitrate-nitrogen. ---PAGE BREAK--- Usage by Plant Species Fresh Compost: ammonium-nitrogen z young plants absorb ammonium better than mature plants z Ericaceous species: blue berries, azaleas, rhododendrons, mountain laurel, andromeda and leucothoe absorb most nitrogen in form of ammonium-nitrogen. Aged Composts: nitrate-nitrogen z Grasses, flowering annuals, herbaceous perennials and vegetable plants absorb most nitrogen in form of nitrate-nitrogen. Note: Most woody perennials not mentioned above absorb both. ---PAGE BREAK--- Crop Gardens Use only fully cured compost. Use only well screened compost. Work into soil before seeding or planting. z If only small amounts of compost are available work compost directly into planting row. ---PAGE BREAK--- Safety, Health and Pesticide and Herbicide Pathogens Pernicious weeds Diseased plants Insect infestations Pests: ---PAGE BREAK--- Pathogens Active or unfinished compost worked into soil may provide nourishment to plant pathogens. Placing manure from cats, dogs and swine into compost pile may allow pathogens to be transmitted to root crops. Horse manure can carry encephalitis. Breathing dust from dry compost can cause reaction in some people. ---PAGE BREAK--- Pernicious Weeds Weeds with rhizomatous root systems may survive compost process. z morning glory z buttercups z grasses (quack grass) ---PAGE BREAK--- Diseased or Infested Plants Plants with diseases and harmful insect infestations should not be composted. z Landfill z Incinerate ---PAGE BREAK--- Pests Addition of fatty foods, meat and bones will attract rodents, raccoons, dogs, cats, flies and other pests. ---PAGE BREAK--- Environment Odors z raw materials in storage and poorly maintained compost can create obnoxious odors. Leaching z runoff from compost is high in nitrogen • negative impact on surface water plant and animal species • can contribute to high nitrate levels in well water ---PAGE BREAK--- Internet Resources Information z www.KlickitatCounty/SolidWaste/ z www.cfe.cornell.edu/compost/Composting_homepage.html z www.mastercomposter.com/ z gardening.wsu.edu/text/libr.htm Worms z www.wormdigest.org/ Tools z www.composters.com/ ---PAGE BREAK--- Local Resources Neighbors Klickitat County Solid Waste The End