As for OM in soil, that depends on many different factors, including regional
climate, soil type, and incorporation or non-incorporation of residue. In coastal
plain loamy sands in North Carolina, we applied and incorporated composted cotton
gin trash at 37 wet tons/acre over two years (now into the third), and OM% was not
significantly different than soils with synthetic fertilizer applied (>0.5%).
Other things that must be considered are prevalent plant diseases, and the crops
that will be grown in the fields.
Floyd Johnson wrote:
> I don't think any thing could compete in this cover. maybe if rolling
> will kill it then we could Aer-Way it and No-till plant. But for the
> microbes is the residue better on top or incorporated in top 6" or
> deeper? We are trying to build our soil organic matter to 5% or more.
> The rolling stalk chopper requires rye to be at least 18" for it to
> work most people say to kill it sooner.Will chopper work on red clover
> and what would be the time frame?
> Elane Ingam spoke about microbes an said the best thing we could do for
> them is to keep living roots in soil all of the time. If we kill cover
> early to keep it from getting to big ,but cant plant for a while, what
> impact is this having on the microbes? Is there any reason to feed
> anaerobic microbes?
What happens in the rhizosphere (that soil surrounding the root zone) is very
important. Many rhizosphere bacteria (and fungi) are extremely important (think
legumes-rhizobium, and mycorrhizhae). Some anaerobic and aerobic bacteria are
nitrogen fixers (Clostridium is a strict anaerobe, being killed in the presence of
oxygen. Azobacteria are free-living N2 fixers, and may play as important a role in
nitrogen fixation as rhizobia.)
Further, some decomposers can serve to protect living roots from plant pathogens.
So leaving dead roots in soil is not always a bad idea. Again, it depends on
prevalent diseases in the soil. Things like root knot nematodes require living
roots to survive (except eggs, which are extremely resistant). Also, many plant
pathogens are not that good at competing in the soil without a host present (while
others are _very_ good at surviving in the soil).
Well, I've given you a lot of options, and what seem to be contradictions as well.
Most of what I've mentioned above are conditional statements, depending on
environmental conditions, pathogens present, etc., etc.
If anyone has any questions feel free to contact me. . . or the group.
Type to you later. . .Russ
-- L. Russell Bulluck, III Ph.D. Candidate Department of Plant Pathology North Carolina State University PO Box 7616 Raleigh, NC 27695-7616 (919) 515-6808 lrbulluc@unity.ncsu.edu ----------------------------------------------------------- The soil population is so complex that it manifestly cannot be dealt with as a whole with any detail by any one person, and at the same time it plays so important a part in the soil economy that it must be studied. Sir E. John Russell, The Microorganisms of the Soil, 1923 -----------------------------------------------------------
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