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Jan 02, 2016
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*Compost is a mixture of decayed organic materials decomposed by microorganisms in a warm, moist, and aerobic environment, releasing nutrients into readily available forms for plant use.
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DecomposersDecomposers
These are the microbes (mainly bacteria and fungi) that do all the work for you.
Food for the decomposersFood for the decomposers
The organic materials to be The organic materials to be compostedcomposted..
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Anaerobic composting
Aerobic composting
oxygen absent or in limited supply
presence
toxicity
odor
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1 .Chemical makeup of raw ingredients or feedstocks.
2 .Physical size and shape of feedstocks and porosity of the pile.
3 .Population of organisms involved in composting process.
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Turning the pile mixes fresh air into the pile
Turning the pile mixes fresh air into the pile
Turning tools can make the job easier
Turning tools can make the job easier
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*Optimal range 45-60% by weight.
*Low moisture impededs composting process because
1 .microbes need water
2 .dry pile will become cool, slow down composting.
2 .Moisture level
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*Particle size regulate microbial access to food.
*Small particles have more surface area than large particles ; easy access.
4 .Particle size
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*Carbon (C) and nitrogen (N) are the primary nutrients required by the microorganisms
involved in composting .
*Microorganisms use carbon for both energy and growth, while nitrogen is essential for protein production and reproduction.
6 .Carbon/nitrogen ratio
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*If amount of C relative to N is too high, slows composting process.
*If C:N ratio is too low, more likely to lose N as ammonia gas (bad odor).
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Browns
High carbon materials such as
Leaves (30-80:1)
Straw (40-100:1)
Paper (150-200:1)
Sawdust (100-500:1)
Animal bedding mixed with manure (30-80:1)
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High nitrogen materials such as
Greens
Vegetable scraps (12-20:1)
Coffee grounds (20:1)
Grass clippings (12-25:1)
Manure
– Cow (20:1)
– Horse (25:1)
– Poultry (10:1), with litter (13-18:1)
– Hog (5-7:1)
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Feedstock C:N Ratios
Materials High in Carbon
C:N Ratio
Fall leaves30-80
Straw40-100
Wood chips or sawdust100-500
Bark100-130
Mixed paper150-200
Newspaper or cardboard560
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*Provides humus or organic matter, vitamins, hormones, and plant enzymes which are not supplied by chemical fertilizers.
*Kills pathogenic organisms, weeds and other unwanted seeds when temperatures of over 60oC is reached.
*Acts as buffer to changes in soil pH.
*Improves soil .
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1 .Biological Contributions:
*Inoculation or increased microbial diversity.
*Increases microbial activity in soil, primarily by providing carbon as a food source for the microorganisms
*Can reduce soil borne plant diseases
Improvement of soil by
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2 .Physical Contributions
*Increased water absorption
*Increased water retention
*Improved drought tolerance
*Reduced soil erosion
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3 .Chemical Contributions
*Increase cation exchange (more negative charges) which increases soil ability capacity to hold
nutrients .
*Good source of micro nutrients .
*May buffer pH ( greater stability or resistance to change pH).
Have many nutrients that not exist in chemical fertilizer .
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Garden trimmings
Kitchen scraps
Grass clippings
Leaves
Also• Used potting soil• Manure• Sawdust• Hair
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Cat or dog waste
(attracts pests, could spread disease)
Diseased or insect ridden plants
(could infect or attack garden plants when compost is used)