[Prev][Next][Index][Thread]

Re: compost vs. raw organic matter



In article <Pine.SOL.3.95.960905212807.10577H-100000@rac9.wam.umd.edu>,
jgruv@wam.umd.edu (joel b gruver) wrote:

> Hello to all,
> I am investigating compost as
> a soil ammendment, specifically the unique
> characteristics of compost as a soil ammendment vs. land application of
> the raw compost ingredients.
> 
> If anyone has any unique insights on the following post them my way:
> 
> 1) What aspects of the composting process bring about the
> neutralization of pH ?
> 
> 2) Does compost have a unique/different capacity to modify soil
> physical properties as compared to additions of raw organic materials ?
> 
> 3) Does soil ammendment with mature compost have a significantly
> different effect on soil microbial ecology then the application of raw
> organics ?
> 
> I look forward to hearing your reponses and reference suggestions...
> Joel Gruver
> U of MD, Agronomy 
> jgruv@wam.umd.edu

Some answers:

1) The 'neutralization' of pH occurs because large chain C compounds,
often acids (tannic, acetic,etc.) which are common in OM break down into
their ultimate product CO2. This is the carbon cycle rapidly occuring.
Actually it is complicated, but has to do with the production of carbonic
acid (which all OM does as it breaks down. The Rx -HCO3 <> CO3= is the
equilibrium point between acidity & alkalinity - this is the true
'neutral' point in all soils, waters, and compost systems. the turning
point between acid/alkaline is actually a pH of 8.3! Compost will trend up
towards this (7.5-8.0) as it matures.
2) All OM added to soils must DIGEST before usuable by plants; losses from
leaching, volatilization, or poor digestion limit raw OM breakdown;
compost has been pre-digested & is full of bio-life at the tail end of a
succession of decomposers & is thus more efficient.
3) Yes - lots of research on this. Basically 1 ton/ac compost performs as
well as 5 t/c raw manurre, pommace, other amendments.

I can send more info by snail, post address..
Gregg Young, CPAg



Follow-Ups: References: