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How to guard against low-protein wheat
Because of last year’s good
growing conditions, North Dakota and other Upper Midwest wheat growers
harvested high yields. But poor protein levels came hand in hand with the
bumper crop, causing deep wheat-price losses.
“Normally, protein falls in
the range of 13% to 15%,” says Dave Franzen, North Dakota State University
(NDSU) Extension soil specialist. “This past year, protein levels were ranging
from 9% to 14%. There has been so much low-protein wheat in the market that
producers are being docked up to $1 a point.”
While some protein loss can
be credited to the high yields, last year’s unique planting and growing
conditions may have contributed.
Understanding the causes
can, in some cases, help wheat producers modify management practices to
safeguard crops against future losses in wheat protein and price.
Spring flooding of soils
from the snowmelt of the 2008-2009 winter played a role in contributing to the
conditions leading to low-protein wheat.
“Saturation of the soil,
particularly in the eastern third of the state, can lead to gaseous loss of
nitrous oxides,” says Franzen. “When soils are saturated, bacteria in the soil
activate and transform nitrates to nitrous oxides, leading to gaseous nitrogen
In the sandier soils of the
western part of the state, the record snowfall and subsequent snowmelt may have
led to leaching of N.
Prolonged wet soil
conditions late into the spring may have contributed, too, to poor N
assimilation into the soil from fertilizer applications. The wet soil
conditions challenged seedbed preparation and efficient incorporation of
“When the soil was worked,
there were clods and gaps in the surface, and these conditions lend themselves
to N loss from ammonia volatilization,” says Franzen. “Anhydrous ammonia was
applied to soil that was often wet a few inches below the soil surface, leading
to ammonia losses over the course of several days following application.”
When applying anhydrous to
wet soil, such losses of ammonia can be reduced by using equipment capable of sealing
the application trench with earth.
Last spring, soil fertility
would have been lost, too, in no-till fields where urea was applied to the
surface. Such applications require rain or mechanical intervention in order for
the urea to be incorporated into the soil.
“Last year it didn’t rain
after seeding for a few weeks in many areas, and some of the urea applied to
the soil surface likely volatilized,” says Franzen.
In many cases, reduced soil
fertility resulted also from reduced application rates. Growers tended to
reduce fertilization rates because they expected lower yields due to late
seeding dates and hot weather likely to accompany growing conditions associated
with late planting. Instead, growing conditions were ideally cool, yielding
bumper crops from soils low in N, thus producing low-protein grain.
fertilization recommendations (see Learn More below) can help prevent such an
outcome in the future. Rather than applying fertilizer according to a
prediction of the coming year’s yield, Franzen suggests basing application
rates on historic yields.
“Past yields provide a
better prediction of how much fertilizer to apply,” he says.
Consider Variety, Too
Consider wheat variety, too,
when determining fertilization rates.
“Put more nitrogen on fields
growing varieties of wheat with low-protein characteristics to make sure the
wheat gets close to a 14% protein level,” he says. “If you’re growing a
high-protein variety, you may be able to back off on the rate.”
Consider your tillage system
as well when determining fertilizer application rates. Franzen’s research shows
that fields that have been in continuous no-till for more than five years
require 50 pounds per acre less supplemental N than conventional-till fields in
order to maintain a protein level of 15% in the wheat.