Volume
3 Issue
12
August
8, 2006
Feasibility of Winter Wheat Following
Soybeans in Northwest Minnesota
The number of Hard Red Winter Wheat (HRWW) acres
in Minnesota is historically low when compared to hard red spring
wheat (HRSW) acreage. Lack of a suitable previous crop and the risk
of winterkill are two main reasons why winter wheat acreage is
small. Winter wheat offers a number of advantages over HRSW. First,
inclusion of winter wheat in the crop rotation allows for more
efficient use of labor and equipment by spreading out the labor.
Thus inclusion of HRWW in a crop rotation has the potential to
reduce fixed cost per acre in both winter wheat as well as the other
cereals, improving the profitability of those enterprises
indirectly. Second, HRWW offers the potential to reduce the need for
crop protection inputs. The canopy of HRWW establishes much earlier
than HRSW. HRWW may be able to out-compete annual broadleaf and
grassy weeds. This eliminates the need for a selective herbicide,
and lowers the variable inputs per acre. Finally, HRWW may have a
higher grain yield potential than HRSW because the crop is already
established in the spring and growing when HRSW still needs to be
planted. This may also mean that the period of grain fill occurs
earlier in HRWW (partially) escaping the summer heat, thus
increasing the grain yield potential.
The risk of winterkill can be greatly reduced if and when a snow
cover protects the dormant wheat seedling. Even a few inches of snow
greatly reduces the risk of winterkill. No-till cropping systems
that maintain as much standing stubble as possible enhance snow
trapping and provide the needed protection for HRWW. In addition,
no-till systems offer the advantage of preserving soil moisture at
planting which increases the odds that germination and emergence
will be faster and more even. Finally, no-till systems can reduce
wind and water erosion in the fall and spring. No-till production
systems have steadily allowed HRWW acreage to increase in the
Canadian provinces in the past decade. Implementation of no-till
practices in Minnesota in general and northwest Minnesota in
particular has been limited because of the short growing season and
the delays that no-till systems generally cause with seedbed
preparation in the spring.
A suitable previous crop to HRWW would preferably be something
other than HRSW. Soybeans are an excellent previous crop to HRSW.
Soybean acres have dramatically increased across northwest
Minnesota. HRWW is traditionally planted in the last week of August
and the first week of September. At that time, the soybean crop has
not yet matured. When soybeans serve as a previous crop to HRWW in
northwest Minnesota, planting of HRWW is delayed by a month to the
last week of September or first week of October.
Previous research demonstrated that winter wheat could be
established successfully following soybean in our region. To
evaluate the performance of additional HRWW varieties following
soybeans in northwest Minnesota, two yield trials were established
in the fall of 2004 at two on-farm locations in northwest Minnesota.
The trials were located with Vig Farms in Fosston and AWG Farms in
Crookston and were planted on September 30, 2004, and October 1,
2004 in Fosston and Crookston, respectively. Site preparation
included a single pass with a harrow to spread the soybean residue
evenly across the field. Care was taken not to disturb the standing
soybean stubble. No tillage operations were performed to prepare a
seedbed. Plots were directly seeded with an Almaco plot drill. The
seeding rate for each variety was adjusted for percent germination
and kernel weight to a goal of 25 plants/ft2 for all varieties.
Fertilizer was applied for a 60 bu per acre yield goal. Weeds were
controlled with a tank mix of Puma and Bronate Advanced at label
rates applied at the 5-leaf stage of wheat.
Results
The amount of winterkill averaged 17 to 18% across varieties.
Varieties differed for the amount of winterkill in Crookston.
‘Infinity CL’ and ‘Nekota’ showed significantly less winterkill than
any other variety while ‘CDC Raptor’ showed significantly more
winterkill (Table
1). No significant differences for winterkill were
observed among varieties in Fosston (Table
2). Grain yield is expressed as percentage of the trial mean.
‘Arapahoe’, ‘Infinity CL’, ‘Jerry’, and ‘Millennium’ were among the
top yielding varieties in both Crookston and Fosston.
Test weight averaged 60.5 lb/bu and 59.7 lb/bu in Crookston and
Fosston, respectively. ‘Jagalene’ and ‘CDC Falcon’ had significantly
lower test weight than any other variety in both Crookston and
Fosston.
Grain protein averaged 11.1% and 12.2% in Crookston and Fosston
respectively. Significant differences were detected among varieties.
‘Roughrider’ and ‘Jerry’ were among the varieties with the highest
grain protein content.
 Table
1. 2005 Grain Yield, Quality, and Winterhardiness of Hard Red
Winter Wheat Varieties in Crookston, MN.
Table 2. 2005 Grain Yield, Quality,
and Winterhardiness of Hard Red Winter Wheat Varieties in
Fosston, MN.
Management Tips
- Winter wheat can be established successfully following
soybeans in northwest Minnesota.
- Percentage of winterkill will likely decrease with use of a
no-till drill or air seeder with narrow shanks to plant the
winter wheat.
- Weed control may not be needed in the winter wheat following
soybeans.
- Control of leaf rust with a fungicide may be warranted in
years when leaf rust is able to infect susceptible cultivars
prior to flag leaf emergence. Active scouting for leaf rust (and
potentially stripe rust) is needed as many of the tested winter
wheat varieties are, at a minimum, moderately susceptible to
leaf rust.
- Apply a starter fertilizer at planting of hard red winter
wheat. Apply the balance of the recommended fertilizer in early
spring as the crop breaks dormancy.
Jochum Wiersma
Small Grain Specialist
U of Minnesota, NWROC-Crookston
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