Thread: Old Sawdust
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Old 28-04-2004, 07:06 AM
nswong
 
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Default Old Sawdust

Hi Fito,

let me ask a question as I am not sure
of the answer.


I'm also not sure of the answer. g

Does the sawdust lose it "Nitrogen stealing" ability as time
goes by (meaning, is the C:N ration no longer 500:1)? Even after a

year, if
it did get weaker, wouldnt it still be high in carbon? Still too

high to be
placed in soil?


From what I read, it give me an impression:

All life need carbon as energy, and need nitrogen to grow and
reproduce. Life in the soil normally will be in maximum constrain by
the available carbon. When we mix sawdust to soil, the available
carbon will increase, those life in soil will start to use available
carbon from sawdust as energy to reproduce. When life in soil
reproduce, they get nitrogen they need from soil, so available
nitrogen in soil will reduce. These nitrogen will release to soil when
life in soil die and decompose.

Carbon in available form(sugar, starch...) are plenty in fresh
sawdust, it will lost when time passby. Carbon still remain in old
sawdust are those(cellulose, lignin...) that are not directly usable
by most of the life in the soil, so this will not cause the suddent
increase of soil life.

Adding sawdust to soil will temporary reduce available nitrogen(change
to organic form), but not reduce nitrogen from soil.

So for organic matter add to soil to improve soil structure, I will
prefer lignin than other form, since lignin last longer. And I
believe that clay humus created from clay plus lignin, are the best
humus.

Regards,
Wong