Agriculture Reference
In-Depth Information
there is a good chance we'll make the wrong choices. It is much better to have data from
multiple sources in order to make more a informed decision. While the numbers you get
from the tests in this chapter are useful, it's important to also remember to look at your
soil, weeds and plants to see what they're telling you, and to bring all of this data together.
A soil test alone doesn't always give accurate enough information to make big fertility de-
cisions. Looking at your garden is just as important.
Most home soil test kits that you can buy are pretty much useless. In fact, even profes-
sional soil labs give widely different results from each other based on the methods they
use, even though they have good equipment. Still, these are many times better than the av-
erage home kit, although a decent home kit is manufactured by LaMotte and sells for
$600-$700.
Soil tests measure a moment in time, but the soil changes throughout the year, even
over the course of a few days. Temperature, moisture, and biological activity each have an
effect. To be honest, the results coming back aren't even close to 100% accurate. There
are too many factors to take into account. In fact, some people argue that professional soil
tests are a waste of time. It's true that they are rough estimates, but their usefulness has
been proven by thousands of soil consultants who have successfully used them to improve
soils and crops. It's important to always use the same lab, because at least it will be using
the same methods from year to year if it's a good lab that has been around for a while.
That way you can more accurately compare numbers between tests you do over the years.
Still, you will come across some well-known organic gardening adherents who don't
like soil tests. In
The Organic Method Primer
, a wonderful topic by the way, Dr. Bargyla
Rateaver says they're basically useless because they're based on the incorrect idea that
plants take up most of their nutrients in ionic form. The main test I recommend partially
overcomes this. Still, while the results we get back aren't 100% accurate, we know they're
helpful because soil management decisions based on them have been used for decades
with great success.
There are also some things we can do to improve accuracy. We can take a good soil
sample, choose a good soil lab and get the right tests done.
