February 11, 2009

Blowing soil can fill seed furrows and partially bury small wheat plants in the spring, resulting in increased plant stress that weakens the plants and makes them more susceptible to further damage by disease and other environmental stresses. (File photo)

Percent of normal precipitation for period from Nov. 15, 2008 to February 12, 2009. (Map courtesy of the High Plains Regional Climate Center)

Moisture from recent snow was welcomed in the Panhandle, however, a combination of dry conditions, fluctuating air and soil temperatures, and numerous days of strong winds have already taken their toll on this year's winter wheat crop. The area has received just one-half to two-thirds of normal rainfall over the last 90 days.

In portions of Kimball, Banner, and Box Butte counties as much as 30% of the winter wheat has suffered serious damage from blowing and drifting soil. Growers throughout the Panhandle have started to conduct emergency tillage operations to try and reduce damage from moving soil (see G1537 Wind Erosion and Its Control). Irrigated wheat fields that were planted late last fall and produced little growth have been particularly hard hit.  The prospect of more damaging winds before active wheat growth looms high.

Countering Erosion from Wind

If you think you have lost your wheat stand in a significant portion of a field, one of your first priorities is to prevent further soil erosion from causing problems on adjacent ground. This may be done with tillage or by applying manure or straw to the area.

Timing. Wheat can be planted directly into thin or dead spots in existing stands or planted in new stands; however, it must be planted early enough to assure adequate vernalization of the seedlings. The process of vernalization is necessary for normal development and heading in winter wheat. Planting after March 1 in the Panhandle is risky because imbibed seeds or seedlings must experience four to six weeks of night temperatures below 40°F.

Variety Selection. To reduce the risk of inadequate vernalization, select wheat varieties with shorter vernalization requirements. Winter hardiness is a less important trait in spring-planted winter wheat and varieties from Kansas and Colorado have generally performed well in this environment.

Equipment. A disk drill may do less damage to existing wheat plants, but it does little to create surface roughness, which may be important in areas suffering from soil erosion. A hoe drill used perpendicular to prevailing winds will create surface roughness that may provide some protection from strong winds. It is probably best to avoid seeding wheat field areas where wheat stands are still viable. (See NebGuide G1429, Estimating Winter Wheat Grain Yields, for how to estimate yields and determine plant viability.) This late seeded wheat will mature after the fall-seeded wheat and could complicate harvest.

Planting. Plant at the normal depth (one to two inches deep), but use higher than normal seeding rates because less tillering will occur in the spring-planted wheat. Use a seeding rate of 1.5 to 2 times the normal rate; for example, use 90 lb/ac in dryland or 120-150 lb/ac in irrigated. Apply starter ferlizer with the drill to help aid early plant growth.

Stand Assessment. Growers should be able to tell if the wheat has vernalized by May 21. If it has, the wheat will begin to joint and the growing point will be elevated above the crown. If not, the wheat can be grazed or a summer crop can be planted.

Expected Yields. Yields of spring-planted winter wheat are generally 60% to 80% of fall-seeded wheat and are usually slightly better than spring wheat yields.

Spring Wheat

Interseeding spring wheat with winter wheat is not recommended. Most spring wheat varieties available were developed for cooler environments and are limited in their adaptation to this area. Also

• Spring wheat will mature about two or three weeks later than winter wheat, upsetting harvest plans and increasing loss due to shattering.
• Mixing the two wheat classes will often result in significantly discounted prices at the elevator because it is graded as mixed wheat.
• In Nebraska spring wheat is frequently damaged by hot summer weather, producing shriveled kernels, low test weight, and reduced yields.

Drew Lyon
Extension Dryland Cropping Systems Specialist
Bill Booker
Extension Educator, Box Butte County