SWIFT CURRENT, Sask. – Brian McConkey pulls a chrome soil moisture
probe from a piece of ground at a federal research plot south of Swift
Current, Sask.
A strong, drying, south wind hums a deep, mournful tune from the open
pipe of the probe’s handle.
The dirt inside is wet from one end of the core to the other – wet down
to 90 centimetres.
Only 50 metres away, the probe couldn’t be forced more than 45 cm into
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the soil and one third of its sample was dry.
It was the same silty soil, the same lack of moisture, the same crops
and the same rotation – crop, fallow, crop, fallow.
Managing the fallow has been the secret.
For 22 years the moist plot has been fallowed between crops using
herbicides to control weeds, while the other has been tilled.
Another plot that has had a combination of limited tillage and chemical
fallow has slightly more soil moisture than the one relying solely on
cultivation, but the dramatic difference is seen where no tillage was
used.
In years with average moisture, grain yields on the three fallow
treatments vary only marginally. But in back-to-back drought years, the
chemically managed plots stand out, with 50 percent higher yields than
tilled fallow.
Similar tests on clay have provided similar results.
In sandy plots, even when precipitation is normal, zero till provides a
10 percent yield advantage.
McConkey studies these plots for Agriculture Canada’s Semi-arid
Research Centre in Swift Current.
“When drought occurs back-to-back, such as (1984 and 1985), we can
expect to see dramatic yield increases from the chem-fallow. In years
when we get timely growing season rains, there is only a marginal yield
advantage. This year is shaping up to be one of those where it could
pay off big …. We don’t know about next year yet.”
McConkey said this season more producers have been asking about fallow
strategies than in recent years.
Statistics Canada said in last month’s planting intentions commentary
that while summerfallow acres will drop to record lows nationally,
Saskatchewan and southern Alberta farmers may increase fallow acreage
if spring moisture doesn’t arrive.
Many growers haven’t considered a fallow rotation for several years
because in average conditions minimum till continuous cropping
increases yields.
Peter Gamache of Alberta Agriculture said the poor moisture conditions
of the last four years are causing some Alberta producers to rethink
summerfallow, but not tillage.
“Typically, the cost of ownership (of equipment) and operating for a
tillage operation is about $5 per acre. The option of chem-fallow has
more up-front costs for herbicides. The spraying operation usually
costs less, takes less time and involves fewer passes than tillage. At
three tillage operations, chem-fallow suddenly becomes very attractive.”
Ken Rosaasen, an agricultural economist at the University of
Saskatchewan, admitted it may make financial sense this season to plant
a crop that appears doomed to fail and plan to collect the crop
insurance. However, he said this undermines farmers’ long-term
insurance programs because it brings down their yield history.
“Long-term, summerfallow may be the answer in extreme droughts, but
each farm is different.”
McConkey said the answer may be found at the bottom line of a balance
sheet.
“Farmers are considering fallow because of the lack of moisture that is
out there this spring. You can’t blame them when input costs can easily
force them to look at a plan that has a best-option scenario that is in
the red,” he said.
“In the lighter land, the erosion control is one of the big factors.
There the chem-fallow really shines.”
McConkey said farmers can expect similar moisture and erosion
protection from canola stubble and wheat.
“Some producers are worried about canola not providing enough cover for
a chem-fallow rotation, but we have shown that it does very well.”
McConkey said snow appears to pack more tightly into canola than in
wheat and tends to melt later in the spring than it does in a cereal
stubble.
Rosaasen said the decision whether to plant or fallow is a tough one.
“Ask yourself the question, if I didn’t have crop insurance, would I
(summerfallow) this year? If the answer is yes, then it might the right
thing to do.”
