[USCC] technical definitions of finished compost

[frank]

Cathy,
I look at it this way: But there are many ways to look at it.

"Finished" is when compost is 'stable' and has 'cured'.

Stability  is when the available carbon  under ideal conditions (pH, 
nutrients, porosity, temperature etc)  are degrading (producing CO2 and 
using up O2 from the environment) at a rate low enough so the loss in 
oxygen during decomposition can be easily replenished in the environment 
(not go anaerobic) and the rate is slow enough so the changes in 
chemistry (available N, uptake of N etc) can be easily handled by the 
farmer.

Curing; Once a compost has stabilized there can be pockets of toxins 
remaining due to the speed the stabilization has occurred. Now that the 
oxygen demand has slowed there is more available to let the microbes 
convert ammonia to nitrates (example) etc.

Frank




Cathy Gill wrote:

>Hi all! 
>
>You've been so helpful in the past so I was wondering if you wouldn't mind answering a couple of more questions for me.
>
>What is the technical definition of when compost is "finished"? does it have to reach a certain temperature and then cool? Or is it based on levels of microorganisms that are active? I am very interested in knowing the science behind this.
>
>Also, I have read somewhere that, at least in a home setting, compost that is finished may still need to be cured. How does one know when it is cured? What happens during the curing process? 
>
>Thanks in advance!
>
>Cathy Gill
>
>AthenaES
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-- 
Frank Shields
Soil Control Lab
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