Discovering Natural Processes--Nitrates, Silicon,
Compost and Ginger
By Hugh Lovel
“Why,” I am asked, “is the ginger on the left so robust?” In picture one below, the ginger on the
left received six tons/hectare (3 tons/acre) composted chicken manure plus six tons/hectare (3
tons/acre) of palagonite, a fine, foam-like volcanic glass powder. The ginger on the right received only six
tons/hectare (3 tons/acre) of composted chicken manure.
The thing is, growers usually apply more nitrogen to drive cell division and get large size. Cells
require amino acid nitrogen to duplicate their DNA. Here, we see silica combined with nitrogen to yield
large size. My experience is similar with diatomaceous earth, also a rich silica source.
Why Silicon?
Silicon is essential for the efficiency of photosynthesis. Ginger evolved as a rainforest understory
plant which implies efficient photosynthesis in a very shady environment where the forest litter is rich in
silica as well as nitrogen. Since photosynthesis is where the energy for biological activity begins, efficient
photosynthesis requires efficient transport, a function of silicon. Efficient photosynthesis results in high
brix, a measure of dissolved solids in plant sap, about 90% of which are sugary carbohydrates.
Nitrogen from synthetic fertilizers and raw manures usually enters plants as nitrates along with
water uptake. These salty nitrates flush the silicon out of capillary vessels, expanding cells, lengthening
transport vessels, weakening structures and in general making photosynthesis less efficient. Unlike salty
nitrates, amino acids and proteins are biological compounds that hold the patterns of activity we call life.
A rule of thumb is it takes ten units of sugar, along with a sprinkling of related minerals, to produce one
amino acid by direct fixation from the atmosphere – which is 78% nitrogen.
Ideally all plant nitrogen would be living amino acids and proteins. But, along with water, plants
also take up urea, ammonium or nitrate because these soluble salts are often found in water uptake. In
particular, nitrate is poisonous to plant chemistry. It flushes boron and silicon out of plant transport
systems. Thus a plant’s first priority is converting nitrates into living form – which takes ten units of sugar
for every unit of nitrate. When nitrates arrive in the foliage, a plant uses its sugars to make this
conversion, leaving no surplus for root exudation. Then the plant is low brix.
Unfortunately, the soil food web needs plants to feed it with sugary exudates, since this is where
most nitrogen fixation occurs. With high nitrates this fails to occur.
On the other hand, high brix plants give off abundant sugars as root exudates, feeding the soil
food web ample energy for its nitrogen fixing bacteria. This involves a complex system, of course.
Nitrogen fixing bacteria do not simply give their amino acids directly to plants. Single celled soil animals
called protozoa, and other more complex soil animals, must digest the nitrogen fixers to excrete a steady
stream of freshly digested amino acids where
roots take them up on an hourly and daily basis.
If this system of nitrogen fixation and soil animal
life is working, the limiting factor usually is the
large amount of sugar nitrogen fixing bacteria
need to produce amino acid nitrogen. Plenty of
available silicon gives ginger this advantage as
long as nitrate levels are low.
Nitrate Damage
Picture One: Happy ginger on the left received six
T/Ha silica fertilizer (Palagonite) along with six
T/Ha compost, while the ginger on the right
received only six T/Ha chicken manure compost.
Soil nitrate levels above 40 ppm can be
tragic since nitrate uptake flushes boron and
silicon out of the capillary structures in the
plant’s transport system, called the xylem. Then high nitrates use up sugars and starve nitrogen fixing
bacteria. This shuts down nitrogen fixation. Moreover, nitrates dilute plant protoplasm, including
chlorophyll. This further reduces the efficiency of photosynthesis, which depends on resonance.
Chloroplasts ring like lead bells instead of silver bells. In short nitrate, which oxidizes fertilizer boxes if
they aren’t made of stainless steel, is the antagonist of structural silica and its co-factors, boron and
manganese.
The remedy is providing available silica so the plant returns to efficient sugar production as
nitrates are used up. By using Palagonite or Diatomaceous Earth to supply ample available silica, nitrogen
fixation is assured.
In Picture One the distance between nodes in the ginger corms shows the balance of activity
between silica and sugar on the one hand with lime and amino acids on the other. For maximum growth
silica and lime must work in tandem for sugars and amino acids to increase in volume and complexity.
Nitrate poisons this relationship. On the left the distance between nodes expands as growth progresses,
indicating increasing nitrogen fixation, more functional amino acid N and accelerating growth. On the
right the distance between nodes stays the same or shrinks, indicating a dependency on nitrate uptake
for amino acid production at the cost of a large percentage of the sugar produced via photosynthesis.
Growth decelerates with the loss of biological nitrogen fixation.
A Mentor and a Learning Experience
I learned the hard way about growing ginger on my farm in North Georgia. At first I mixed a
modest amount of (immature) compost into the soil, planted in April, harvested at the end of Summer
and grew ginger corms almost as big as my thumb—not too impressive. The next year I mixed in double
the amount of similar compost and grew ginger corms as big as my little finger. This was going in the
wrong direction.
In the back of my mind I kept hearing the advice of Luc Chaltin, a former Belgian market
gardener who set up Newton Homeopathics, a world class company in Stone Mountain, Georgia. I was
visiting Luc in the mid 80’s as he spread compost on the surface of his new market garden in Georgia.
His heavy, red clay was growing cabbages, broccoli, leeks, beets, carrots and daikons. I asked him how
was he going to mix the compost in? The plants were already growing and he was scattering his compost
on the surface.
"No, no” he said. “You never mix compost in—at least never more than just scratching it into the
surface to keep it from washing away. It works down into the soil from above to get where it belongs."
He continued scattering his compost lightly on the surface. "It doesn't take much compost, just enough
to provide cover and food for your little soil animals.
Mulch helps. Soil animals carry the compost in and
feed it directly to your plants."
Hmmm. I had to think. Was I disregarding
nature by mixing my compost in? Nature doesn't do
this. I was mixing lots of amino acid nitrogen into
the top six inches of soil, but it didn’t stay in the
amino acid form indefinitely. Gradually it oxidized
What good compost looks like.
into nitrates unless fully bound as clay/humus
complexes. To be honest most of my compost
wasn't well humified. Often it was a bit raw. Was I
guaranteeing a steady nitrate supply that my crops
would spend their energy converting into amino
acids?
The Right Stuff
I started spreading my compost on the
What good ginger production looks like.
surface, first with lettuce (grown from seed) and then with just about everything including potatoes,
pumpkins, garlic and ginger. Sure enough, careful observation showed when I left my compost on the
surface or under a little mulch, soil animals came up, had a chew and went back to the microbe rich
zone around plant roots. There they excreted the freshly digested goodies derived from snacking on
compost. This precision delivered amino acids and a mix of minerals right to crop roots with a minimum
of nitrification. The result was more efficient plants, better growth and greater complexity.
With such precise compost delivery, a lot less compost was required, even when spread after
planting. This also raised the bar on what I called good compost, resulting in a big improvement in crop
quality as well as root health.
On the practical side, I had to do something about the nitrate residues from my old low quality
compost already mixed into my soil. I came across research showing manures and composts mixed into
the soil released nitrates for several years. Of course, biodynamic preparations helped, especially the
nettle, oak bark, horsetail and horn clay preparations. But ginger seemed especially allergic to nitrates,
and maybe it didn’t need compost at all.
With this in mind I planted my next ginger patch with no compost in my lowest nitrate soil. This
time my ginger thrived and made robust clusters of corms that weighed more than a pound each. Even
better, turmeric and lemon grass liked this too. Of course, a few other factors, such as optimum spacing,
root exudate overlap and adequate molybdenum also influence nitrogen fixation and nitrate reduction.
But in sum, I found I could grow respectable yields of these tropical crops in summer in the mountains of
North Georgia where winter temperatures often plunged well below zero Fahrenheit. My experience in
Australia has been everywhere there is water you can grow fine ginger.