Samples of winter wheat plants pulled up over the past month at Ducks Unlimited (DU) locations in North and South Dakota are showing good development, although some of the southern winter wheat varieties did show plant stress.
“We have the potential for a good winter wheat crop,” said Blake Vander Vorst, DU senior agronomist. Even with plant stress, if the plants are alive, producers can often manage the crop to produce decent yields.
Winter wheat plantings increased last fall in North Dakota and Minnesota and decreased slightly in Montana, a major winter wheat producing state. In North Dakota, plantings went from 400,000 acres to 700,000 acres; in Minnesota, plantings increased from 30,000 acres to 50,000 acres and in Montana, acres decreased slightly from 2.25 million acres to 2.2 million acres.
With the mild winter, except for a couple of cold snaps in January, agronomists are watching how the spring breaks over the next month.
The worst case scenario for the winter wheat would be if temperatures warmed up to 35 or 40 degrees during the night and warmer during the days, the plants would break dormancy and take off.
Then, if that is followed by a late cold snap and the ground froze to 10 to 20 degrees, the plants might not be able to handle the cold again, Vander Vorst said.
However, as long as the producer has at least eight plants per square foot across the field, they should be able to manage the crop to produce a profitable yield, he added.
Research conducted by ARS-Mandan’s Northern Plains Research Center showed when there are eight plants per square foot, the yield is 40 bushels per acre or 88 percent of maximum. At 14 plants or more per square foot, the yield is 45-46 bushels/acre or 100 percent. At 10 plants per square foot, the yield is 43 bushels/acre or 95 percent of maximum, and at five plants per square foot, the yield is 31 bushels or 68 percent of maximum.
If producers are concerned about their winter wheat stand, they can perform a bag test, Vander Vorst said.
Ducks Unlimited agronomists pull up the whole plant and clip the roots below the crown and the stem about an inch above the crown, wet the plant with some moisture. put it in a zip-lock bag, blow air into the bag to produce carbon dioxide, seal it and wait a couple of days.
Vander Vorst said if little shoots start sprouting beyond the main stem and tillers, it is alive and if it looks like mold may be starting to grow in the crown or if it discolors in a few days, it could be a dead plant.
“However, you can mess up a bag test,” he added. Taking another test a few days later will verify the results.
How do producers manage winter wheat to produce a good yield and a profitable crop?
Vander Vorst said the importance of planting into stubble plays a dual role.
“You want to keep the plant from breaking dormancy in late February or early March and that is why planting into taller stubble that holds the snow later into March is so important, so the ground doesn’t become exposed in the sun and warm up as quickly as plants seeded into low or no stubble,” he said.
The stubble also protects the soil and plant from the cold in the winter, Vander Vorst said.
Research at NDSU’s Dickinson Research Center showed winter wheat planted into the tallest stubble had the warmest ground temperature during the cold weather in January.
The effect of crop residue on winter wheat survival was demonstrated in a North Dakota trial (2003/2004) that showed that even the least winter hardy varieties had yields in the high 90s and low 100s when planted into wheat stubble.
The less winter hardy varieties planted into soybean residue had yields in the 60s, while Jerry, a good winter hardy variety, planted into wheat stubble had yields of more than 100 bushels/acre.
Plant survival depends upon three main factors, Vander Vorst said. Those factors include if the producer chose a more winter hardy winter wheat variety; if they planted into good stubble versus bare ground; and the stage of growth in the fall.
A low stubble such as soybean can work in South Dakota and portions of southern North Dakota if the producer can take his crop off early enough in the harvest season (mid-September) to allow a winter hardy winter wheat to grow enough before the ground freezes and there is enough moisture for timely germination, he said.
Winter wheat varieties were compared with data from 44 trials in North and South Dakota and eastern Montana from 2001 to 2011. Jerry from NDSU is the most common winter hardy variety that other varieties are compared to.
The most winter hardy variety was Accipiter, followed by Peregrine, CDC Buteo, Jerry, Radiant, and Decade, in that order.
The least winter hardy varieties were AP503CL2, Settler CL, Art, and SY Wolf, while Overland, Yellowstone, and Ideal were in the middle of the pack.
Winter hardiness can be decreased if soil temperatures at the winter wheat crown reach critical levels, Vander Vorst said.
“An occasional cold period of one to three days with low nightime temperatures will not cause any significant loss of winter hardiness,” he said. “But if nightime temperatures consistently stay above freezing for several days and the plant breaks dormancy, there will be some loss of winter hardiness.”
According to Ducks Unlimited, the peak level of winter hardiness (late December through January) in wheat occurs when temperatures get cold and stay cold all winter.
If the producer thinks his plant stands are thinner than he would like, Vander Vorst recommends adding nitrogen in the spring at the onset of tillering so the plants can really take off and increase tiller and head numbers to compensate for the lost plants.
“Producers should assess their fields and if there is stand loss, add 25-50 pounds per acre of nitrogen,” he said. However, if some N was applied in the fall, producers may only need 15-25 pounds per acre of N in the spring to encourage growth of tillers.
However, be careful with nitrogen. Too much can increase lodging and increases disease potential.
Vander Vorst said DU agronomists usually go out in late March or April and apply N. Later, to help preserve tillers, they add a half-rate of fungicide in the tank mix when they apply herbicide at the four to five leaf stage.
He recommends producers try this to have good profitable winter wheat yields this summer.