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Composting

Vaughn Hammond

Extension Technologist

University of Nebraska –Lincoln

Kimmel Education & Research Center

vhammond2@unl.edu

402-873-3166

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What is Composting?

Composting is the transformation of organic material

(plant matter) through decomposition into a soil-like

material called compost. Invertebrates (insects and

earthworms), and microorganisms (bacteria and

fungi) help in transforming the material into

compost. Composting is a natural form of recycling,

which continually occurs in nature.

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Composting Historically

Ancient practice trace to Marcus Cato-Scientist and

Roman farmer 2,000 years ago

He maintained that composting was a fundamental

soil enhancer and essential in maintaining fertile,

productive agricultural soils.

By the 19th century most farmers and agriculture

writers were familiar with the practice in the U.S.

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Why Compost

Many environmental benefits beyond the soil

Reduce waste stream into our landfills

Reduces methane production in landfills

Reduces acidic leachates

Removes poor combustible materials from

incinerating facilities increasing the efficiency of

power generation

Reduces amount of pollution generated

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Why Compost

Benefits to the soil

Soil structure –organic matter

Aeration

Texture

Water holding capacity

Increase soil fertility

Contributes to erosion control

Helps balance pH

Lightens clay soils

Increases water holding capacity of sandy soils

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Composting--Decomposition

Naturally occurring process

Micro-organisms and invertebrates do the job

Success depends on the organic matter used and

the decomposer organisms

Best decomposing organisms require oxygen

The more diverse the group of composting is the

more efficient the process is

It is a ecosystem

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Decomposing Organisms

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Factors Affecting the Process

C:N ratio

Surface area

Aeration

Moisture

Temperature both inside and out

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C:N

The 2 fundamental elements of composting

Micro-organisms digest carbon as a energy source

and nitrogen for protein synthesis. The food and

digestive enzyme

Bulk should be carbon—30:1

3-4 pounds of N per 100 pounds of C

To little N and the process slows to much and it

stinks

Carbon—leaves N—grass, manure, blood meal

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Surface Area

Particles must have surface area that contacts air

Increase surface area by grinding, chopping ,

mowing—general reduction of size

More surface area the more area foe MO to feed

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Aeration

Decomposition will eliminate all air and stop the

process

Aeration replenishes the air supply

Aerobic decomposition

Can occur naturally through wind or as heat builds

leaving the pile drawing new air in – generally

inadequate for fast decomposition

Active turning

Too little oxygen results in anaerobic decomposition

and odor

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Moisture

40-60% moisture level for microbes to flurish

Below 40% and the organisms will go dormant

Over 60% and oxygen is forced out, nutrients are

leached and anaerobic decomposition and odor

results

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Temperature

Micro organisms generate heat as they decompose

organic matter

Healthy pile temp ranges from 90-140 degrees F.

Over 140 F is too hot for the MO

Under 90 is too cool for most

Some MO are active at colder temps

Higher temperatures kill weed seed

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Types of Composting

Cold composting

Very easy

slow

Hot composting

Labor intensive

Fast

Vermicomposting

Takes up little room

Great way to use kitchen scraps

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Compost Tea

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Vermicomposting

Great for disposing of kitchen waste

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Red Wigglers

Consume and produce their weight in castings a day

3 weeks for eggs to hatch—20 young

3 months sexually mature

Finished product in 2-3 months

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Extension is a Division of the Institute of Agriculture

and Natural Resources at the University of Nebraska–

Lincoln cooperating with the Counties and the United

States Department of Agriculture.

University of Nebraska–Lincoln Extension educational

programs abide with the nondiscrimination policies of

the University of Nebraska–Lincoln and the United

States Department of Agriculture.