AgWatch


Wheat Going Into Winter

DR. ANTHONY OHMES

JACKSON, MO.
   I have had several talks regarding concerns about winter wheat emergence and yellow to browning wheat color. Wheat planting was delayed in some areas this season with a slightly prolonged corn and soybean crop. In addition there was heavy rainfall in areas during emergence and cold temperatures that hit early this month. In total, some wheat fields are showing signs of this stress.
   Wheat stand counts can be taken this winter to determine condition of plants and how tillering has progressed. Ideal final stand counts should be 30 to 35 primary plants per square foot with an ideal tiller number of two by winter vernalization. Now, working from that stand point yield can be maintained with stand counts as low as 25 plants per square foot. If tillering has not begun then in late January to early February re-evaluate stands and consider a spring green-up application of nitrogen to help improve chances of spring tiller development.
   Wheat has a low tolerance to wet soils. Some of the yellowing this year was due to wet soil and oxygen depletion around the developing roots. Also in some wheat fields following corn, the higher yields and residue compete for nitrogen. In general, when planting behind a high residue crop consider applying 10 to 30 units of nitrogen. This is usually achieved if a phosphorus product such as DAP is applied. Wheat can handle this stress to some level. Cold temperatures and wind can cause freeze burn of older leaves. This is generally cosmetic and wheat will continue to develop leaf material once spring green-up begins. One concern with freezing and thawing soils and poor root development is plants heaving out of the soil exposing crown and roots. This can reduce stands, therefore stand counts in spring are helpful when determining whether you are producing a grain crop or cover crop.
   This time of year the only action is to scout once before vernalization requirements are reached then again prior to spring green-up. For more information on management of wheat contact University of Missouri Extension to obtain IPM Guide 1022, “Management of Soft Red Winter Wheat.” ∆
   DR. ANTHONY OHMES: Agronomy Specialist, University of Missouri
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