On Wed, 21 May 2003 14:47:56 GMT, "Stephen M. Henning"
wrote:

Unless your are fattening hogs or feeding starving people, the brix
level is meaningless. It measures calories (sugars and starches), not
the nutrients we eat fruit and vegetables for. The nutrients of
interest are the vitamins, minerals, antioxidants, etc., not the
calories. Fewer calories is good. However this sap reading is also
misleading, since many larger vegetables have a more dilute sap but
contain the same amount or more of sugars and starches.


Many of us ARE starving nutritionally. Much of the world IS starving!

in an interview in AU Dr. Arden Anderson wrote:

Arden: You must always take environmental factors into consideration
when using a refractometer. For a start, the 12-brix reading must come
from the weakest part of the plant. You also have to consider the
dehydration issue. Dehydrated plants have concentrated sugar in the
leaf, and you will always get a higher reading. You must always
correlate brix readings with field observation. If I have a brix
reading of 20 and I have pest problems, then that is obviously an
aberrant brix reading. When we have factored in all conditions, a true
12 does not have insect problems. Let’s take sweet corn as an example.
You may take a reading of the ear and you may have 24 brix, yet the
corn borers are running rampant. What you will find with that sweet
corn is that, if you take a reading of the stem or the main roots, you
will have a brix reading of 4 or 5. What’s happening is that nature is
moving all of the carbohydrate into the ear in an attempt to reproduce
the species, so it’s a fictitious level in the cob. The other
influence at work here can be genetic manipulation and breeding, where
free sugars are forced into the fruit without the plant having the
opportunity to utilise these sugars to keep the whole plant healthy.
So, again you look at the weakest point of the plant - you don’t
measure the fruit. Another source of false brix is what we call
vascular plugging, where there is no sugar transport out of the
leaves. It just sits there, but it’s not healthy. It’s just like
constipation in humans. You could say you’re full, but you haven’t had
a bowel movement in a week. If we take these things into
consideration, then the refractometer is a very valuable tool to
monitor plant health. Remember though that all tests should be used
within a context as to what you are going to do about it. You may need
to correct a deficit or you may need to catalyse availability with a
biological, but you make that decision based on a variety of
observations, and refractometer readings are one of those. Even
conventional analysis should be considered within a context like this.
It is common, for example, using conventional leaf analysis, that you
will be told that your nitrate is low. However, your crop may be doing
fine - It’s putting on fruit, the fruit is growing and you don’t have
an insect problem. One sure way to get insect problems in this system
is to add nitrate nitrogen when it is not needed, because then you
lower your brix reading, you get more water in the plant and the
insects move in. No test data should be used in isolation. If the
field evidence contradicts the test results, then more evaluation is
needed before taking action. For all deficiencies you must always
evaluate whether it is a quantitative or qualitative deficiency.




"Nature, left alone, is in perfect balance.
Harmful insects and plant diseases are always present,
but do not occur in nature to an extent which requires the use of poisonous chemicals.
The sensible approach to disease and insect control is to grow sturdy crops in a healthy environment."

Masanobu Fukuoka, One Straw Revolution--1978