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Re: [compost_tea] Vegetable quality



Regarding BRIX and Compost tea applications - time of day and weather conditions when the reading is taken are very important  to interpreting the numbers. These comments Hugh Lovel made about a year ago on the BD Now site may help:
 
"Brix can be very revealing. But it is a bit more complex than just high brix
equals high sugar and good taste with insect and disease resistance."
 
"Brix is a measure of dissolved solids, not all of which are sugars by any
means. Salts and amino acids enter the picture for starters.
 
"High brix in the morning generally indicates the plant has not translocated
its sugars to its roots and shed them to the soil overnight, feeding the soil
food web.
 
"This feeding of (mostly micro) organisms in the rhizosphere believe it or not,
is highly desirable. If the plant does this it gets the soil food web stoked up
and cranking out highly elaborated nutrients. Probably the most important of
these are complex amino acids. If the plant gets its nitrogen as amino acids
instead of nitrogen salts, the assembly into proteins in the cells becomes rich
and full blown as there are no nitrogen salts to interfere. Then one gets
plenty of long chain aminos. That's mostly where the great flavour comes in for
people. But for insects with their more rudimentary digestion they greatly
prefer short chain aminos and can't digest the long chain stuff. So they leave
such plants alone.
 
"If you have (relatively) high brix in the morning, then this is undesirable.
Almost surely it means boron deficiency, as the plant would otherwise respond,
with adequate boron, by translocating its carbon fixings (mostly sugars) to the
roots at night--what Elaine Ingam calls carbon shedding.
 
"When a plant sheds carbon compounds abundantly, at its roots, it really grows
like gangbusters. If you can get this going well enough you can grow corn as a
soil improvement crop without fertilizer while getting superior (in every way)
yields. With a BD program this is nearly a cinch. Horn clay is a must though,
as it optimizes the ebb and flow of sap between the root and the growing tip.
 
"High brix in the afternoon means your plant has been building an abundant
inventory of sugars during its daytime photosynthesis. That's great stuff, of
course. But take care to consider what time of day you take your reading.
 
"Also, sometimes plants will send their sugars to the roots in the afternoon if
the barometer drops enough, anticipating a severe thunderstorm. If you take
your reading just before such an event and get low brix, you have a healthy,
with-the-program plant that has adequate boron despite the low reading in the
afternoon.
 
"So use your refractometers intelligently. They are great tools, and probably
the quickest way to evaluate low boron (which may be occurring in more than 70%
of crops in the US)."
 
In response to the question, "Does this rhythm, release of dissolve solids
(sugars & amino acids) apply to all families of plants? i.e. do broccoli  or
potatoes, say, shed carbon from their roots?"
 
Hugh replied, "In general I would say yes. Definitely broccoli and potatoes
shed carbon. Different plants shed a different mix. Corn, for example, sheds a
clear, jelly-like mix rich in polysaccarides, which are polymer (chain) sugars.
Lettuce, which can be a vigorous carbon shedder, gives off a milky latex.
Buckwheat sheds a mix that really stimulates the microorganisms that make
phosphorous available, while hemp gives off a mix that stimulates those
microbes that make potash available. Potatoes, need plenty of available potash
but don't give off the rights stuff to make it available in a soil that is low
in accessible potash. So potatoes give a much better yield following hemp--if
we could only grow it in the US! But from this I guess you'll see some of the
major reasons for crop rotations, cover cropping and the like.
 
"In general where sugars are being concentrated in fruit the plant is NOT
sending these to the roots. That's only at the end of the growth cycle, and by
then they aren't needed in the root zone anymore anyway."
-----Original Message-----
From: soilfoodweb@aol.com <soilfoodweb@aol.com>
To: compost_tea@yahoogroups.com <compost_tea@yahoogroups.com>
Date: Wednesday, November 27, 2002 7:22 PM
Subject: Re: [compost_tea] Vegetable quality

OK, I have to do a better job of remembering to take the refractometer with me. 

Now for a way to test protein levels, or as precursors to protein production, free amino acids as easily. 

But as has been pointed out, if free amino acids get stuck in that form, and don't get moved into protein synthesis, you'll attract pests.  So, both Kapular and Jose can be correct, you have to understand plant physiology. 

The question becomes, why are your amino acids getting stuck in that form and not moving on to protein?  You need to be able to tell when too many are not a good thing.  Too much protein sitting around doing nothing will kill plants too.  Protein has to get moved into structure and function. 

In fact, quite soon, as in tomorrow, we'll be doing one of those annual rituals where all the people in the house will be happily vegetating, sitting watching a movie or something, too many free amino acids running amok in the digestive system, getting turned into... well, preferably protein and not flab. 

I hope all of your loved ones make it to your Thanksgiving Feasts, in thought, in memory, in person, or by phone.   Enjoy!

Elaine
President, Soil Foodweb Inc.
www.soilfoodweb.com


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