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By Hugh Lovel
In February of 1994 at the Austin, Texas Eco Fair
I lunched with Neal Kinsey, one of America's top soil consultants.
Neal was lecturing about the key importance of calcium in the early stages of
fruit development where cell division occurs, and his metaphor was an apple not
much bigger than a prune had virtually all the calcium it would get by harvest.
He tested soils for calcium and applied it as needed, but unfortunately this
did not guarantee that sufficient
calcium got into the apple.
When I asked him what he did in regard to boron, which was
responsible for sap pressure, he responded, "Of course, boron is necessary for
calcium uptake, and we test for boron. If it is needed we put it there, but we
still can't guarantee that calcium gets in the apple."
Humm. So I asked what he did about silicon. My biodynamic experience
showed silicon was the basis of transport in both plants and animals. Neal's
response was classic, "We don't test for silicon. It's in all soils, whether
sand or clay."
Until then it hadn't sunk home with me that I was used to looking
for the visual signs of silicon in plants and I hadn't actually seen any soil
or leaf tests that included it. This got me wondering, and as I investigated I
found, almost uniformly, soil and leaf testing labs did not test for silicon
unless it was specifically requested.
As a biodynamic grower, I was annoyed. Biodynamic fore-runner,
Rudolf Steiner, with his doctorate in math, chemistry and biology, identified
the oxides of calcium and silicon (lime and silica) as the opposite poles of
life chemistry. I'd used this concept for years and years, along with Jochen
Bockemühl's leaf studies from his book, In
Partnership with Nature and Johann W. von Goethe's treatise, The Metamorphosis of Plants as guides.
Neal's comment that he didn't test for silicon caught me by surprise. But on
the other hand, my university curriculum was biochemistry rather than
agricultural chemistry, so I hadn't realized how 19th Century
agricultural chemistry was. Looking further, I found that in the early days of
agricultural chemistry Justus von Liebig tested both soils and plants for
silicon, found it in all cases, was unable to prove it was an essential
nutrient by excluding it from plant media, and thereafter dropped it from his
tests. This became the norm for agricultural testing.
Neal Kinsey, with his riddle of getting calcium into early fruit
development, got me thinking. Gradually I realized there was an obvious
hierarchy of how elements worked in living organisms. One thing had to occur
before the next thing could happen, and on down the line in a sequence. In 2004
I put together a PowerPoint slide show for Graeme Sait's agronomy team at
Nutri-Tech in Yandina, QLD, and in it I summarized this hierarchy of elements,
calling it the Biochemical Sequence.
I told the Nutri-Tech agronomists that boron kicks off this sequence by activating silicon, making it an
amorphous fluid and providing sap pressure. I knew that boron was used in
making glass, which is amorphous fluid silica; and I'd found this relationship
also held true for plant chemistry.
Of course, sap pressure would be no use without a transport system
to contain it, and silicon provides
the actual transport of nutrients. Interestingly, applying too much boron too
early in a crop cycle is notable for burning seedlings and young
transplants-such as sprouting squash, beans or tomatoes-because too much sap
pressure in such a tiny plant drives sodium out the leaf margins. Nevertheless,
in plants where leaf veins are highly branched, like flowering beans, squash
and tomatoes, boron is important in later growth to maintain strong enough sap
pressure to make such a complex system work.
On the other hand, highly siliceous plants, such as grasses, need less
boron to give them sap pressure since their transport vessels all run parallel
without branching. That's like irrigation lines that only feed one sprinkler
head-it doesn't take much pressure. An exception is bananas, which have a huge
transport system with lots of fluid flow. They need plenty of boron to send
calcium and amino acids all the way to the top of the bell stalk for cell
division to occur in the bunch.
Obviously without robust transport, nowhere near as much nutrient
reaches the leaves or is stored in the fruits. Chemical agriculture gets around
this to some extent, since-even with a weak transport system-anything that is
highly soluble, such as potassium nitrate, is simply taken up along with water.
Though this dilutes the sap, it flows quite easily due to low sap density. This
is why chemically grown foods commonly have coarse, watery cell structure, as
well as lower nutrition and poorer keeping quality. However, without a robust
transport system, heavier nutrients such as calcium, magnesium, complex
carbohydrates and amino acids can easily be left behind.
Third in the biochemical sequence is
calcium. This is the last thing you
want to leave behind because of its role in nitrogen fixation and amino acid
chemistry. Calcium balances charge in proteins and is particularly important in
cell division, which is the first thing that happens in fruit or seed formation
after pollination. Without it there would be no fruit or seed.
For example, in maize calcium leaf test targets are between 0.3 and
1.0 %, increasing as the maize approaches tasselling with the higher target
range more desirable during kernel formation. If calcium does not reach the ear
in sufficient quantities, the kernels near the end of the ear simply do not
fill out. With a crop like soybeans, double or even triple the calcium values
of maize are needed for full pod set without shedding pods-a common problem in
soybeans. Wouldn't you like to see every kernel on your maize fill out to the
end of the ear and every soybean blossom produce a pod of beans? This only
happens when boron, silicon and calcium work together optimally.
As just mentioned, wherever calcium
goes, there also goes nitrogen, which
is the basis of amino acid formation, protein chemistry and DNA replication.
Once nitrogen enters the picture all sorts of proteins, enzymes and hormones
are produced, and very complex things are set in motion involving trace
elements such as iron, zinc, copper, manganese, cobalt, molybdenum and so on.
Above all there must be energy harvest or plants would never grow.
Though all parts of a plant's protein chemistry require amino acid nitrogen,
large amounts of amino acids go into the formation of chlorophyll where energy
is gathered. Since photosynthesis requires magnesium,
it is fifth in the biochemical sequence, ahead of all the more minor trace
elements. Of course, photosynthesis is not simply a matter of chlorophyll
catching energy. The energy has to be transferred into producing sugars out of
carbon dioxide and water, which requires phosphorous
for energy transfer. Otherwise the chlorophyll burns up, and the leaves turn a
wine red colour.
However, as long as there is enough phosphorous, carbon is pried loose from carbon
dioxide so it can combine with water to make sugar and release oxygen. Then the
sugars pass into the plant's sap where potassium,
the electrolyte, conducts them to wherever they most need to go.
Understandably, this sequence is oversimplified. For example,
sulphur is the classic catalyst in carbon (organic) chemistry. Without it,
nothing-not even the boron-would work. Also, potassium has a very close
relationship with silicon, so when silicon carries calcium and amino acids to
the cell division sites in the plant, potassium plays the role of an electronic
doorway that lets the calcium and amino acids enter the cells that are
preparing to divide. If cold weather slows potassium down, or if it is in short
supply, then calcium and amino acids cannot reach the cell nuclei, the DNA
cannot divide, cell division fails and the fruit falls off the plant. Sometimes entire fruit crops are lost to a
couple degrees of frost when a light spray of kelp with potassium silicate
would save the day.
However, the most important thing to understand is the role of
boron, silicon and calcium in the hierarchy of plant chemistry. Growers who
simply feed plants nitrogen, phosphorous and potassium (NPK) tend to short
circuit the biological processes where strong sap pressure (boron) leads to
good nutrient transport (silicon), following which optimal cell division and
photosynthesis occur (calcium, nitrogen, magnesium and phosphorous). Then with
high plant energy (carbon, potassium) plants are able to shed enough of their
sap as root exudates to feed abundant microbial mineral release, nitrogen
fixation and protozoal digestion around crop roots so crops enjoy rich
nutrition and are truly healthy. This only works where boron, silicon, calcium
and amino acid nitrogen (from steady microbial fixation and digestion) are all
high. If calcium and amino acids are watered down with nitrate and potassium
salts, sap pressure is impaired, cell division is hampered, photosynthesis is
weakened, magnesium and phosphorous are diluted, and we're where NPK growers
are today.
Comprehensive testing (the subject of another article) reveals that
without taking the biochemical sequence into account it is common for
plants-even in organic situations where soluble nitrogen and potassium are
high-to luxury feed on nitrogen and potassium to the exclusion of calcium,
magnesium, phosphorous and trace elements, particularly zinc and molybdenum. In
sum, if we fail to solve Neal Kinsey's riddle, we can be caught in this situation
and suffer from the conventional NPK growers' problems of pests, diseases, poor
flavour and poor keeping quality.
*****
About the Author: Hugh Lovel-formally educated in maths,
physics, chemistry, biology and psychology-was a biodynamic farmer for more
than 30 years in the mountains of North Georgia (USA) before becoming an Australian.
He lives in Tolga on the Atherton tablelands and lectures, writes and consults.
His AgPhysics advisory service covers all aspects of agriculture including
livestock and environmental repair, with special emphasis on the underlying
patterns of energy that determine such things as weather, crop vigour, flavour
and keeping quality.
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