Better Farming - October 2016

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Better Farming October 2016 Farm News First > 51
CROPS: THELYNCH FILE
I hope this explanation will help you
to understand. For instance, if your P
levels change from 18 to 21, that is
not a real change. Or, at the high end,
if your P levels change from 120 to 90
that also is not a big difference. But if
they change from 18 to 90, something
is not right.
If your pH changes from 7.8 to 7.2,
again no big deal. But if your pH
drops from 6.0 to 5.6 that is a big
drop. As a matter of fact, this June
and July I noticed a consistent drop in
soil pH. This is in part due to dry
weather and part due to a decline in
organic matter.
A real solution is to soil sample
and record over years. Two samples
over three years is good. But it is
better to have a 20- to 25-year history
of your soil. There are growers who
do have that type of history. You
should also develop a history of your
soil nutrient levels. And work with
someone who knows and under-
stands soil analysis. BF
Consulting agronomist Pat Lynch, CCA (ON),
formerly worked with the Ontario agriculture
ministry and with Cargill.
This sample is ready to send to
the lab.