Planting Winter Wheat (09/01/16)
Planting Winter Wheat
Winter wheat can be a profitable component of the farming system in North Dakota. Establishing a good stand of winter wheat in the fall is the first step in reducing the risk of crop losses due to winter injury and will be the basic foundation for a high yielding crop after green-up next spring. The following suggestions are recommended to aid in establishing a successful winter wheat crop:
1- When possible plant winter wheat into standing stubble. Survival of winter wheat during the winter is enhanced when it is covered with snow during the coldest months of the year. Standing crop residues can effectively retain snow that may fall. Tall, erect flax and canola stubble works best, but any erect stubble that will retain snow is recommended. Planting winter wheat into wheat stubble is not ideal for disease reasons, but as long as disease management is planned, wheat stubble can be an acceptable residue.
2- Plant winter-hardy adapted varieties. Weather is the main determinant of the amount of injury that will occur to the crop during the winter. Using a winter hardy variety, especially if you are not planting into standing residue, is a good way to reduce the risk of severe injury if the winter turns out to be open or colder than average. Refer to the winter hardiness ratings in the winter wheat variety selection publication https://www.ag.ndsu.edu/pubs/plantsci/smgrains/a1196_15.pdf to guide in you in selecting a variety with the best winter hardiness.
3- Plant early enough for good fall development: The optimum planting date for the northern half of the state is September 1-15 and for the southern half, September 15-30. In recent years, plantings during the first ten days of October have largely been successful. The last practical date that winter wheat can be planted will depend on the weather since there must be enough moisture and growing degree days so that the seed can germinate and the seedling vernalize by spring. Larger seedlings will over winter better than a small seedling. Target the earlier portion of the recommended planting date range if planting into bare, fallow ground. If the long term forecast suggests warmer than usual temperatures for late September and October, planting later than recommended may be successful, especially if soil moisture is ideal for rapid germination.
4- Plant 1 to 1.5 inches deep: Adequate moisture for establishing winter wheat is often a concern as the soil profile is usually depleted of moisture in the fall. If there is little or no moisture in the soil’s surface, planting shallow (1 to 1.5 inches deep) and waiting for rain is recommended. Furthermore, these relatively shallow planting depths allow for faster emergence when temperatures are rapidly declining.
5- Seed about a million seeds per acre: Generally a seeding rate of 900,000 to 1.2 million viable seed per acre is adequate. The higher seeding rate may be appropriate if planting late or when planting into poor seedbeds. Since winter wheat tends to tiller more profusely than spring wheat, 1.2 million seeds per acre is the upper end of the recommended seeding rate. Excessively high seeding rates can result in more lodging by harvest time, particularly if you are using a taller variety (like Jerry).
6- Break the green bridge. Breaking the green bridge is critical to reducing the risk of infection of the Wheat Streak Mosaic Virus. This disease is vectored by a tiny mite that moves from green tissue to green tissue largely by wind. Breaking the green bridge is particularly important when winter wheat is planted early, or into fields that were previously planted to small grains that have established volunteer plants.
The green bridge is broken by controlling volunteer cereal crops and grassy weeds in a field two weeks prior to planting. A two-week window of not having a host present assures that the mite has gone through its lifecycle without finding a subsequent host to feed on and transmit the virus.
7- Avoid varieties that are highly susceptible to scab. Scab is not always a problem in winter wheat but can be. Yield losses to scab and high DON levels were reported in recent seasons in some areas of the state each of the past few years. Since fungicides are only partially effective in controlling scab even when properly applied, using genetic resistance is an important way to help reduce losses. Although there are not many winter wheat varieties with a good level of FHB resistance as in spring wheat, avoiding those that are the most susceptible is highly recommended. Furthermore, there are a few varieties now available that show relatively good tolerance. Check the winter wheat variety selection guide for current ratings.
Extension Agronomist for Cereal Crops