Agriculture Reference
In-Depth Information
ent imbalances? If your fruit trees only produce fruit every other year, that's an energy or
fertility problem. The same goes if your lettuce and other greens bolt to seed early or if
your fruits and vegetable don't develop fully.
Soil tests are one tool for figuring out what kinds of problems you might need to ad-
dress. Cation exchange capacity gives us an indication of the soil's capacity to hold
cations. The CEC number should confirm the ribbon and/or sedimentation test you did. A
low CEC means sandy soil with little organic matter. It will need to be watered and fertil-
ized more often, but the good news is it's easier to balance the nutrients. Soils with a high-
er CEC need less irrigation and fertilizer, but are harder to balance because you need a lot
more fertilizer to make a change.
Look at your base saturation test and see if you have 60-75% calcium 7-20% magnesi-
um, 2-5% potassium, and 0.5-3% sodium. If anything is low, you need to find materials
from the fertilizer chapters that will contribute more of the lacking minerals.
The Reams test gives a better indication as to what was available in your soil right
when the test was taken. Comparing it to the base saturation test, look for discrepancies. If
any of the cations are plentiful on the base saturation test, but not on the Reams test,
adding raw materials may not be as important as doing something to activate the nutrients
you already have.
You're aiming for somewhere between a 7:1 and 10:1 calcium to magnesium ratio, with
Reams test values of 2,000-8,000 pounds per acre of calcium. You're aiming for some-
where between a 2:1 and 4:1 phosphate to potash ratio, with Reams test values of 400 and
200 pounds per acre, respectively. You're aiming for a potash to sulfate ratio of 1:1. I tend
to pay little attention to anion values from the more conventional part of a soil test, but I
definitely look at them on a Reams test — particularly the phosphate mentioned above, as
well as nitrate nitrogen and the cation ammonia nitrogen.
Liquid calcium often helps to activate calcium in the soil and can give you a huge jump
on your Reams test. I'll often try this before investing in calcitic lime. Sugar and vitamin
B12 can do this, too. Molasses often helps to activate phosphorus. All of these can be
mixed together. Organic matter and microbes help to release everything. Simply adding
some compost may bring potassium up on a Reams test. Gypsum supplies calcium and
sulfur.
If you're a serious food grower, get a soil biology test done and consult with the lab on
how to improve your soil food web with specific composts, compost teas and microbial
inoculants. Regardless, consider using any or all of these things anyway. Molasses and
other sugars and biostimulants help stimulate existing biology.
Consider getting a refractometer and start measuring brix, not only of the food you
grow, but of the food you buy. Measure your plants regularly during the height of the
growing season and see which biostimulants have the most positive effect. Same goes for
a conductivity meter to measure ERGS.
