[NAFEX] Organic and Micronutrients

Stephen Sadler Docshiva at Docshiva.org
Wed Mar 2 14:21:43 EST 2005

-----Original Message-----
From: nafex-bounces at lists.ibiblio.org
[mailto:nafex-bounces at lists.ibiblio.org] On Behalf Of Jim Fruth
Sent: Wednesday, March 02, 2005 4:26 AM
To: nafex at lists.ibiblio.org
Subject: [NAFEX] Organic and Micronutrients

   There is one HUGE problem with organic farming and needing
micronutrients.  If you are low on one but not others, adding any organic
supplement, ie. kelp, that supplies a host of micronutrients could be
disasterous.  You could rectify your problem while bringing others up to
toxic levels.

Jim Fruth
Pequot Lakes, MN  

Theoretically, yes.  Practically, I haven't seen it - although that doesn't
mean it doesn't happen.  In small-scale multiple-product farms (which are
more like large gardens), or backyard gardening, the broad-spectrum
micronutrient content of fish/seaweed emulsion usually finds a balance.  If
the amounts of nutrients are close to normal ranges, organisms don't always
take up excess or toxic amounts; and even when they do, the utilization
changes within the organism.  The mechanisms of bioavailability and
bioutility vary with the nutrient and the organism, and the processes are
fascinating.  There are also limiting reactions that occur in different soil
types.  Gardening in humus and using unrefined fertilizers with a broad
range of necessary micronutrients (and, of course, limited salinity) seems a
safe and useful approach.

One could, say, use a zinc-rich fertilizer in soil that is already
particularly high in zinc - that could cause a problem.  But the fertilizer
might also contain enough copper to provide a catalyst for limiting
bioavailability of the zinc, so it could work out, even improve.

Any garden or farm will benefit from soil testing and customizing amendments
accordingly.  Large single-type plantings can really be customized for the
plant -thus, extra Zn for the hickories.  And if you (the universal you, not
the specific) are using any sort of simple-shotgun approach to
micronutrients (fish and seaweed spray, for example) and you suspect it's
causing a problem, test your soil.  Conversely, if the sprays improve
conditions but not enough, try to determine which component is helping out,
and make more available to your plants.

Jim, it sounds like you really make sure your plants have a good nutrient
balance, and I know you're successful. 

My simpler (ok, lazier) approach is nice for the extremely varied gardens I
plant.  It also puts into real-world practice the very first research I did
in botany, comparing synthetic micronutrient mixes with organics which test
at the same levels.  There sure were some toxic effects with the synthetic
blends (depending on plant and soil), but not with the organic/unrefined.
Something in the product matrix is ameliorating.


Stephen Sadler, Ph.D.
USDA 9, AHS heat zone 8, 
Sacramento CA - Mediterranean climate

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