Re: CULT: trace elements
- To: Multiple recipients of list <email@example.com>
- Subject: Re: CULT: trace elements
- From: Linda Mann <firstname.lastname@example.org>
- Date: Wed, 11 Feb 1998 18:33:29 -0700 (MST)
N. C. Brady, The Nature and Properties of Soils, 8th ed. 1974 has a
chapter on trace elements. This is really out of date stuff - a lot of
work has been done on micro elements since then, but it has the basics.
I was particularly interested in boron since I had a soil analysis done
that recommended adding boron (helps fill out ears on corn).
normal range in soils 5 to 150 ppm
soil situations in which all/some micronutrients are most likely to be a
problem 1) highly leached (acid) sandy soils, 2) organic (muck) soils,
3) very alkaline soils. They also mention soils that have been heavily
fertilized with macronutrients can be depleted in micronutrients through
There is a table of various crops and the number of states reporting
deficiencies of micronutrients for their production. Boron: reported in
36 states for legumes, 3 for corn, 26 for leafy greens, 18 for root and
bulb crops, 22 for tree fruits, 2 for nut crops, 6 for cotton, 2 for
tobacco, and 0 for ornamentals.
Even naturally occurring micronutrients can be present at toxic levels
in some soils.
Another table shows functions of several micronutrients in higher
plants: zinc -"formulation of growth hormones, promotion of protein
synthesis, seed and grain maturation and production"
copper - " catalyst for respiration, enzyme constituent, chlorophyll
synthesis, carbohydrate and protein metabolism"
boron - "protein synthesis, nitrogen and carbohydrate metabolism, root
system development [implicated in drought sensitivity in forest trees, I
think I recall], fruit and seed formation and water relations"
manganese - "nitrogen and inorganic acid metabolism, photosynthesis,
carbohydrate breakdown, formation of carotene, riboflavin, and ascorbic
Boron deficiency decreases translocation of sugars [this could be
important in injury response?]
Boron is more available to plants in acid conditions, but is also more
readily leached. Organic matter helps keep it around for plant use.
And finally, the line between toxicity and deficiency varies from crop
to crop. "If the boron fertilization is adequate for a vegetable crop
such as red beets or even for alfalfa [both require a lot of boron], the
small grain crop grown in the [subsequent] rotation is apt to show
toxicity damage. Such a situation occurs commonly in western New
So, with no information on boron (or other trace element) requirements
in irises, who knows what to do. I think I will contact my local
agricultural extension and find out what levels of boron are in the soil
type here. If it's in the low range, I may experiment with a couple of
starts of APRIL IN PARIS if it hasn't died - see if it makes any
difference in leaf spot. And maybe other injury - like drought
Sulfur - not exactly a trace element. "Deficiencies are most common in
the southeast [coastal plain], the northwest, California, and the Great
Plains". Looks like the same crops that have high boron requirements
also have high sulfur requirements (alfalfa, clovers, soybeans, sugar
beets, cotton, ....). When this book was written, sulfur deficiencies
(or rather growth responses to sulfur additions) were being reported in
more and more areas as deposition of air pollutant sources of sulfur
Linda Mann east Tennessee USA
if that's not enough, I will see if I can find some more recent info.