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Composting. Bill DeKramer. 1. 03/09/2012. What is Compost?. Nature recycles organic matter (OM) in place Composting is a man-made system to recycle OM more quickly and efficiently. 2. 03/09/2012. Topics for tonight. Compost and soil structure / value Elements of a compost pile
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Composting • Bill DeKramer 1 03/09/2012
What is Compost? • Nature recycles organic matter (OM) in place • Composting is a man-made system to recycle OM more quickly and efficiently 2 03/09/2012
Topics for tonight • Compost and soil structure / value • Elements of a compost pile • What makes compost work - the bugs involved • Types of composting • Building some models 3 03/09/2012
A Compost pile is not a garbage pile 4 03/09/2012
Compost and soil structure • Structural components of soil • Sand • Silt • Clay 5 03/09/2012
What ratios would you like in your garden? • Medium Loam: • 20% clay • 40% sand • 40% silt 6 03/09/2012
Benefits of compost to the soil • Organic Matter (OM) • Microbes 7 03/09/2012
What is Organic Matter? 8 03/09/2012
Organic Matter • Food for soil food web microbes • Humus (not hummus) • OM that has reached a point of stability, i.e. won’t break down any more • Humus is a colloidal substance, and increases the soil's cation exchange capacity, hence its ability to store nutrients by chelation. 9 03/09/2012
What Makes Compost Work? • Microbes
What Microbes are in Compost? 12 03/09/2012
Microbes • Bacteria • Fungi • Amoebas, slime molds, multi-celled algae • Nematodes • Bugs 13 03/09/2012
Essential Elements for Compost • Carbon • Nitrogen • Oxygen • Water 14 03/09/2012
Elements to Control in Compost • Food stock: Carbon and Nitrogen • Moisture • Air • Temperature • Particle Size • pH 15 03/09/2012
Food stock • Carbon sources: • Hay and Straw • Leaves • Black and white newspaper • Sawdust and Wood chips • Old Natural Fibre clothing • Nitrogen sources • Kitchen scraps • Weeds (without seed heads) • Animal manure (except dog, cat, pig or human) 16 03/09/2012
What not to add • Kitchen scraps like meats, oils, fish, bones and dairy products • Weeds that have gone to seed or spread by their roots (quack grass, etc.) • Herbicide treated grass clippings or weeds • Dog, cat, pig or human faeces 17 03/09/2012
Diseased Plants in Compost There are different opinions about whether to add diseased plants to compost or not. • In favor of: • By adding diseased plants, the microbes in the compost that feed on the disease multiply and in this way strengthen the soil food web • Against: • The disease may not be controlled by the composting process and spread into the soil
Carbon / Nitrogen ratio • Having the right carbon / nitrogen ration makes a difference in how quickly the food stock breaks down. • Ideal is 25 : 1 carbon to nitrogen 19 03/09/2012
Common Compost Materials • Kitchen / Table scraps 15:1 • Grass clippings 12:1 • Old manure 20:1 • Fruit waste 25:1 • Corn stalks 60:1 • Old leaves and straw 80:1 • Paper 170:1 • Sawdust and wood chips 500:1 20 03/09/2012
Prohibited for Organic Production • Prohibited • Sewage sludge • Glossy paper and coloured ink • Paraffin from waxed cardboard (not to exceed .75%) • Regulated • Slaughterhouse, hatchery, fish-farm waste • Yeast fermentation waste • Whey • Mushroom compost 21 03/09/2012
Moisture • Ideal is about 50% • Rule of thumb: like a wrung out sponge • The amount of moisture determines if the pile is aerobic or anaerobic 22 03/09/2012
Air • There are 2 types of compost piles • Aerobic • Anaerobic (Bokashi is fermentation) • If an aerobic bin gets too wet, it can become anaerobic and create toxins 23 03/09/2012
Temperature • Hot Compost • Cool Compost 25 03/09/2012
Hot Compost (50º-75º C) • Relies more on aerobic bacteria • Makes compost quickly • Can kills pathogens and weed seeds • Requires frequent turning • Requires attention to brown/green ratio • Very fertile, but not as fertile as cool compost 26 03/09/2012
Cool Compost (25º-50º C) • Low maintenance • Can be built (layered) over time • Takes longer to finish than hot compost • Doesn’t kill all pathogens or weed seeds 27 03/09/2012
Particle Size • The smaller the particle, the quicker it decomposes • For example, grated apples break down faster than whole apples 28 03/09/2012
pH • Ideal pH is around 7 (neutral) • Usually don’t need to worry about pH if including a wide variety of food stocks, but some things like an excess of coffee grounds can make the pile acidic. 29 03/09/2012
Types of Composting • Layered • Worm (vermiculture) • Bokashi • Sheet composting (permaculture technique) 30 03/09/2012
Building a layer • When starting a new pile, lay some small twigs in the bottom to help keep air in • Alternate layers of brown and green • Sprinkle a handful or shovel full of soil or compost in with the layers as an inoculant • Finish with a layer of brown material that acts like a “scab” • Up to half the carbon and nitrogen can be lost to the atmosphere if exposed to the sun and air. • When starting a future set of layers, pull the scab back to allow the materials to be in contact 31 03/09/2012
Layered Compost • This is the most common form of composting • Layered composting is an evolution of the Indore method that focused on the carbon/nitrogen ratios and moisture. • Layers of brown and green material are alternated • Batch method is when the layers of the whole pile are built in one go. This is usually for the hot method • Continuous method is when layers of the pile are built periodically as the materials come available. This is usually for the cool method. 32 03/09/2012
Demonstration pile 33 03/09/2012
Composting in Winter 34 03/09/2012
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Screens for Finished Compost 36 03/09/2012
Worm Composting (vermiculture) • Composts food waste rapidly • Bin needs to stay between 12º - 25º C • Needs a moist environment (worms breathe through their skin) • Worms need oxygen and produce CO2 • pH around 7 but can tolerate 4.2 - 8.0 • Bedding can be cardboard, shredded paper, decaying leaves or peat moss 37 03/09/2012
Worm Castings • Worm castings are very rich • Produce plant-available nutrients • Wide variety of microbes inoculating the rest of the compost pile • Worms can produce their weight in castings every 24 hours 38 03/09/2012
Storing the Worm Bin 39 03/09/2012
The Worms 40 03/09/2012
Feeding the Worms 41 03/09/2012
Demonstration • Building a Worm Bin 42 03/09/2012
Bokashi • Bokashi is a Japanese term meaning 'fermented organic matter' • Bokashi is anaerobic composting utilizing a starter to inoculate the pile with specific organisms (facultative anaerobes) • Quick way to compost food scraps • Carbon / Nitrogen ratio is much less important • Microbes that grow in bokashi are very different from aerobic compost so it adds diversity to the soil food web • Food stock can include meat and dairy 43 03/09/2012
Facultative Anaerobes • Facultative anaerobes are organisms that can be simultaneously aerobic and anaerobic • They adapt to the oxygen level of their environment • When low oxygen they switch to their fermenting metabolism, which utilizes enzymes to break down food. • Fermentation only partially breaks down the food so it needs to be finished by other microbes 44 03/09/2012
Colette’s Potatoes (2012) Colette added Bokashi bran straight to the soil of one potato plant.
Colette’s Potatoes (2012) The plant on the right got the Bokashi bran. It did grow larger, but she mentioned it did not have a greater amount of spuds.
Sheet Composting • Sheet composting is a method of building a garden bed by creating a compost “pile” as the bed itself • Sheet composting is designed to mimic the natural processes that occur in forests. You build it right on top of grass or weeds so all the natural organic matter that's already there and the microbial populations don't get hauled away with stripping off the sod or weeds. 47 03/09/2012
Layers in a Sheet Compost • Cover the area with cardboard or newspaper and water it in well • To accelerate the decomposition of the grass and cardboard, you can put a thin layer of manure down under the cardboard • Cover the cardboard or newspaper with organic matter like compost, peat moss, straw, or leaves and water this well so it's like a damp sponge. • Plant it. Wherever you want to put a plant, push the straw and leaves away a bit, add a little soil and compost and put the plant in it. • This is covered more in Building a Garden Bed 48 03/09/2012
Quiz 49 03/09/2012
Summary • What are the most important points about composting? • Why would you want to compost? • How will you apply this information? 50 03/09/2012