Re: soil microbes

From: Steve Diver (steved@NCATARK.UARK.EDU)
Date: Wed Dec 18 2002 - 20:49:43 EST


Recently I found myself explaining enzymes and microbial
inoculants in the context of a process-oriented approach
and a product-oriented approach.

"In a process-oriented approach, microbes act upon organic
amendments, or substrates, common to agricultural production
-- such as crop residues, cover crops, and animal manures.
In essence, microbes occur wherever organic amendments are
present. Bacteria, fungi, and other microbes and soil biota are
essential in the decomposition of organic matter and subsequent
release of plant nutrients."

"Biological farming is a good example of a process-oriented
approach. Biological farming is heavily focused on organic
amendments and natural processes to regulate nutrient cycling,
humus formation, and suppression of pests. This includes crop
rotations, cover crops, green manures, animal manures,
composts, organic mulches, and the use of plant and animal
byproducts such as blood meal and cottonseed meal applied
as organic fertilizers. All of these organic amendments are,
essentially, substrates upon which microbes and enzymes act.
In addition, all of these practices and amendments will
enhance the activity of soil microbiota, and therefore,
soil enzymes."

"In its purest form, a process-oriented approach assumes that
native microflora are sufficient, especially when microbial food
sources (organic amendments) are added to the soil. Likewise,
the purest viewpoint would state that soil microbes occur naturally
and therefore amending the soil with microbe-containing
products would have no additional benefit. Evidence for the
validity of this approach is available, empirically, through
centuries of productive agriculture based on the biological
farming method, and secondly, through volumes of data
that show enhanced soil quality as a result of 'feeding the
soil' with organic amendments."

"In a product-oriented approach, products containing
microbial inoculants are viewed as a useful catalyst to
enhance or stimulate natural processes, usually in association
with organic substrates such as feedstock in a compost windrow,
crop residues, etc. Thus, in practice, a product-oriented
approach is an adjunct to biological farming practices and
organic amendments, rather than a substitute for these
practices and amendments. The biocatalyst is a tool for
manipulating the system, and will usually have an intended
function such biocontrol, decomposition, nitrogen fixation, etc."

"Eco-farming, which takes a sophisticated approach to the
adoption of soil- and foliar-applied amendments to enhance
soil quality and crop health, is the alternative farming system
that immediately comes to mind in terms of the use of
soil microbial products. To reflect their multi-purpose use,
some of the soil and foliar products used in organic production
are classified as biocatalysts, enzymes, and biostimulants."

"To become better acquainted with the broad range of alternative
soil products in the market place, see the ATTRA
publication 'Sources of Organic Fertilizers and Amendments'."
http://www.attra.org/attra-pub/orgfert.html

Steve Diver
ATTRA

"The test of any process for converting the waste products
of agriculture into humus is flexibility and adaptability to
every possible set of conditions."
        --Sir Albert Howard, An Agricultural Testamant.

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