Sep 13, 2010 by Lee Hart

This isn’t a year to skip soil testing

Soil scientists and crop advisors have for years preached
from the agronomy pulpit about the value of soil testing, but for farmers in
those parts of Western Canada where it was really, really wet this year, it appears
to be really, Really, REALLY important to consider soil testing this fall.

After all this rain, in most areas except for the Peace
River region, the fact is you just don’t know what’s down there this fall, or
where it is, for that matter.

soil depth photo .jpeg

Nitrogen is always the big one, but there are other
important nutrients too. How much has leached down through the soil and where
is it sitting  – at 6”, 15”, 24” or
deeper?  Find out.

Soil scientist, Cynthia Grant with Agriculture Canada in
Brandon, Manitoba says there’s even a big question mark about soil nutrient
levels on fields that weren’t seeded this year. Usually on fallow fields
producers assume in a year of rest soil nutrient reserves improve. But, Grant
says with saturated soils and standing water on fields, even that is unknown
unless a soil sample is taken.

“With such abnormal conditions, we have to expect at lot of
variability,” she says. “Many producers, under more average conditions, go
along sort of on auto-pilot and assume there are certain nutrient levels in the
soil. Last year was unusual too, but in many respects it was still more normal.
This year conditions were very different, so there will be much more
variability.”

She says with most farmers knowing the high, medium and
lower yielding areas of their fields, soil testing needs to be done in those
various production zones.

In Alberta, soil specialist Ross McKenzie with Alberta
Agriculture has similar advice. He says once the crop is off and the soil cools
heading into fall, it will be important to make a soil analysis through that
top 24” to learn what nutrients are sitting where.

With wet conditions this year soil nutrients can leach down
into the soil profile and in the case of nitrogen, under wet conditions it can
also be lost to the atmosphere through volatilization and denitrification. So
under these extreme conditions it is impossible to guess at nutrient reserves.

Elston Solberg, a soil specialist with Agri-Trend Agrology
says even as nitrogen (and other nutrients) leach down into the soil profile,
they are not lost to next years crop.

“Even if nitrogen is sitting 2’ down, crop roots can easily
grow 3’ to 4’ deep in the soil,” he says. With soil sampling through that 0” to
24’ soil profile producers can manage their fall or seed applied nutrients to
support the crop until it reaches those deeper reserves.

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Lee Hart

Lee Hart


Lee Hart is a long-time farm writer, and honorary member of the Alberta Institute of Agrologists, with many observations on the agriculture industry, who never hesitates to admit he is wrong (should that ever happen.)


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