Concerned About Winter Wheat Stand

For farmers who have concerns over a poor plant stand, this article will cover some management options farmers can consider.

What is an Optimum Plant Stand?
An optimum winter wheat plant stand consists of 20-30 plants per square foot. It is well-known that winter wheat has the amazing ability to compensate for thin plant stands by increasing tillering. The impact of poor stands on yield is not black and white however. Research has shown that a plant stand of 7-8 plants per square foot yields about 70-80% of a normal stand. However, the key point to remember is a thin stand won’t likely compensate fully to produce full yields.
 
Fields with Small Patches of Poor Stands
For fields with small patches of poor stands, the best option is to leave the field and focus on management strategies such as controlling broadleaf and grassy weeds in a weed control program, early application of nitrogen to encourage tillering, and increase disease scouting since weakened plants may be delayed in growth leading to increased risk of rust and fusarium head blight infection. Please refer to the Guide to Field Crop Protection for herbicide and fungicide control options in winter wheat.
 
Fields with Large Patches of Poor Stands
If you have fields with larger patches with few or no plants, decisions become more difficult. The first option is to manage the field the same way you would for a field with small patches of poor stands. Another possible option may be to plant winter wheat into the larger gaps. Winter wheat planted in the spring will not vernalize so it will not produce a head. However, it will provide ground cover and compete with weeds until harvest.
 
Another option I have heard people mention is to seed spring wheat into the large gaps. However, it is important to remember that in August 2008 the Canadian grain industry introduced the new declaration system for western Canadian wheat. Producers will be required to sign a declaration annually for each company and delivery point to which they deliver wheat, and to verbally declare the class of wheat for each load they deliver. By declaring their wheat, producers are attesting that it only contains varieties that are eligible for a specific class of western Canadian wheat. If you do not declare that it is eligible for a specific class for which you are requesting payment, or if you grow a variety that is not listed on the variety designation lists, when you deliver it will only be eligible for the Canada feed class. Seeding spring wheat into the large gaps will increase the possibility of mixing the spring and winter wheat crop. The result could be downgrading to the feed wheat class. For more information on eligible varieties and the classes of wheat in Canada, please refer to the  Orders of the Canadian Grain Commission.
 
For winter wheat fields whose stand is extremely variable with large patches of dead or weakened plants, replanting may become a more realistic option. If you are considering reseeding and before destroying any wheat fields, you will need to contact your local MASC insurance agent. For more information on winter wheat insurance information, please visit MASC’s website.
 
If plant stands are determined to be unacceptable and you do decide to replant, a couple of management strategies should be noted. Winter wheat is hard to kill. Tillage and/or burn-down herbicides will not likely control all plants, especially if some are suffering injury and slow spring regrowth. Delay applications until the plants have greened-up and are actively growing. In-crop volunteer cereal herbicides may also be required.
 
Wheat streak mosaic may carry over from infected winter wheat fields into spring seeded cereals. Try to avoid replanting to cereals, especially wheat. If you do decide to replant to a spring cereal, it is recommended that there be 2 weeks with no living green material to try and mitigate the risk of infection to the reseeded crop. Also keep in mind that any winter wheat volunteers that produce grain may increase the possibility of downgrading of your reseeded crop.
 
Final Notes
Trying to make the decision on whether to keep that wheat stand or replant is never easy. Stands are rarely uniform and the variability within the field makes the decision more difficult. What is important to keep in mind is timely management in the spring increases the success of a winter wheat crop. A thin winter wheat stand with timely weed control and optimal spring nitrogen applied early will almost always be worth saving.
 
Sources
  • Managing Poor Wheat Stands in the Nebraska Panhandle. Drew Lyon & Bill Booker, University of Nebraska-Lincoln Extension, Institute of Agriculture and Natural Resources. Crop Watch News Service – April 2008.
  • Winter Survival and spring assessment of winter wheat. John Heard and Daryl Domitruk. Zero Tillage Facts – 2006.
  • Lafond G.P. and Y.Gan. 1999. Row spacing and seeding rate studies for no-till winter wheat for the Northern Great Plains. J. Prod. Agric., Vol. 12, no. 4.
     
For further information, contact your GO representative.