mycorrhizae tolerance to fertilizer

Eric Grunden egrunden at prairienet.org
Sat Dec 28 18:15:49 EST 1996



>In a previous article, gdwill at earthlink.net (Garry Williams) says:

>>In my state (NC) in recent years there have been a number of fish
>>kills in the rivers directly attributable to a nasty little
>>microorganism that seems to multiply in large numbers when there is
>>excess nitrogen in the waters, which studies have shown to come from
>>agricultural runoff, be it "chemical" fertilizers, hog waste or
>>whatever. Since fishing is an important part of the economy in our
>>state, this provides a clear environmental impact that directly costs
>>us. I mention this only in passing until we get to the questions.

			*******

Without seeing the studies (or knowing who performed them) it is
difficult to comment. Assuming that the study is accurate, I would
venture to say that a relatively small number of farmers located
near the study site are from the "old" school (conventional til,
no wetland sinks, nitrate-only fertilizer) of farming and are thus
behaving irresponsibly, resulting in erosion and nitrate runoff. 

			*******

>>I have gathered, possibly incorrectly, that as a result of our farming
>>practices that the rich, loamy topsoil has virtually disappeared in
>>many farming areas and that this increases the need for fertilizing,
>>making it particularly tempting to use concentrated, low cost
>>fertilizers. Is this so, or have I been misled, or is this an
>>oversimplified view of the situation?

			*******

Not being familiar with N.Carolina, I can't say with accuracy which
is true. It's probably a little of each. Keep in mind that the
soils of the south are generally poor to begin with due to centuries
of natural weathering, increased/sustained microbial activity, no
glacial activity, etc. Couple this with traditional southern crop choices 
which are extremely demanding on soils (tobacco, cotton), and the 
combination has probably resulted in soil degradation for those regions.
Additionally, outdated agricultural practices many times resulted in
erosion of one form or another. The best solution to this problem entails
years of fallow crop land. In this scenario, the use of mycorrhizal
innoculation would do wonders. It has proven effective for reclamation
of marginal areas left fallow. However, it has been my experience that
the majority of agricultural soils are NOT marginal, and are not degrading.
Here in the upper midwest, upper soil horizons are extremely deep,
and very rich. The preservation of this condition is foremost in the
strategy of farmers, who incorporate no-til, grass waterways, wetland 
basins, crop residue, terracing, etc. into their regiment of practices.
Do they use synthetic fertilizers? Yes, of course, for to not do so
would result in economically non-viable yields and a steady reduction
of the nutrient pool in the soil. Sole use of mycorrhizae would most likely
hasten such a reduction, and it would get worse each year as mycorrhizae
work most effectively in nutrient-poor conditions snatching the few
nutrient cations left in a dying soil. The mycorrhizae-selling people
will say this can be offset by additions of organic material, but
from where? Crop residue alone can not be recycled indefinitely, for
a percentage of nutrients will always be lost to the harvested part.
Manures can lead to leaching, are many times unavailable, are
relatively nutrient poor/uneffective, and are increasingly falling
under regulatory jurisdictions drawn up by people who don't like the
smell or decreased property values. So where are the magic replenishing
materials to come from? I guess we could chop down the forests, mulch
it up and spread it,  right?   

			*******

>>Apparently the farmers in my state don't know about Enserv, or it's
>>not readily available, or it's too expensive, or it's not as effective
>>as you say, or the farmers have no economic incentive for using it or
>>some other explanation, but the fact remains, as I mentioned above,
>>that the excess nitrogen from large scale agriculture in my state is
>>causing serious fish kills and closing recreational areas (another
>>serious economic concern for my state). I would be interested in
>>hearing your thoughts about this situation?

			*******

My thought is that if there is "excess" nitrogen, then someone is
doing their job poorly and should be shut down, period. They will
go out of business eventually from throwing their money away,
but why wait when it causes environmental concerns.

			*******


>>As I understand it, organic farmers add the nutrients back in the form
>>of compost, manure and such, and that this works with the natural soil
>>processes much better than adding chemical salts. Correct or
>>incorrect? Explanations appreciated.

			*******

Compost from where? Manure from where? What kind of manure? What
is "and such" , where do you buy it and how much does it cost?
Agriculture today is (for good or bad) a business like any other,
which requires input parameters as highly defined as possible.
"It might work under these conditions....." or "If the temperature, 
rainfall and microbial populations stay within these limits....." 
are of little reassurance to someone trying to stay in business.
Organic farmers are presently able to stay in business because
the "organic" label enables them to sell their trendy products at a 
higher price due to less competition. If supply goes up, competition
ensues, and yields must be increased to account for falling prices.

Everything in existence is built/comprised of atoms of 
elements. Those elements are absolutely unchangeable by the very 
definition of the word "element". If compost worked with the natural 
soil and plant processes much better, then plant growth and yield 
would reflect such, and it does not. What you are calling "chemical
salts" are manufactured molecules that contain these elements bonded
to inert carriers. Manure is no less apt to leach than urea, and
since urea can be purchased encapsulated or pelletized, it is
actually the safer choice. 

			*******


>>I'm not sure I understand your argument here. Our bodies need Na, H, O
>>and Cl, yet I wouldn't recommend that one try to get those nutrients
>>by drinking  a solution of sodium hypochlorite. Are you saying that it
>>doesn't matter to plants what forms the nutrients come in, that their
>>natural evolution has enabled them to take up nutrients in any old
>>form that comes along? I am asking seriously. I honestly don't know
>>the answer to that and would like for you to tell me, if you would be
>>so kind. And if you could provide a layman's view of the mechanisms
>>involved in the transfer of the elements that plants need, so much the
>>better.
			*******

Many many factors play a part in how well plants are able to obtain
their nutrition. Your analogy of our bodies would have been more
accurate if you would have portrayed the nutrient decision as 
whether to take human-produced vitamins, or swallow the spores of
some fungus that we hope is able to fight off microbial competition
and parastization, form a highly fragile symbiosis, and in the end
won't become pathogenic on us if the conditions change, or our
defenses let down.







 
--
			*******************
The Spirit of Nature, a powerful force,
	belongs and returns to its creative source.
- Excerpted from The Collective Works of Johnny Pokerface -



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