Wednesday, March 28, 2012

Interseeding Red Clover with No Frost and Advancing Wheat Growth Stage

The unusually warm weather of the past few weeks prevented traditional conditions for frost seeding from developing and also accelerated winter wheat development. Successful interseeding is still possible if the soil surface is dry and cracked, but the wheat grow stage should be should be checked to determine the potential for creating wheel tracks. Most wheat in extreme Southeast Wisconsin is at the Zadoks 30 or “Pseudostem erection” stage, meaning the growing point is above the soil surface and a small hollow cavity has formed at the base of the stem. From this point on, wheel traffic has the potential to break the stem, creating permanent tracks and reduced yield. If this is the case, plans for broadcasting seed alone with an ATV mounted seeder should be abandoned in favor of applying seed with N fertilizer using commercial scale air-flow equipment to minimize the number of wheel tracks and associated yield loss. Please visit “Verify Wheat Growth Stage Before Applying Growth Regulator Herbicides” which contains an image of wheat at the Zadoks 30 stage.

For more information please see Frost Seeding Red Clover in Winter Wheat

Tuesday, March 27, 2012

Verify Wheat Growth Stage Before Applying Growth Regulator Herbicides

Unconfirmed reports of wheat that is approaching jointing near the WI/IL border prompted an unexpected field trip to the Arlington Research Station today to confirm crop growth stage. Our inspection of the wheat crop found that the wheat head is right at the soil surface and nearly at the Pseudostem erection crop growth stage (Zadoks 30; Feekes 4-5; Image 1). As a point of reference we normally do not reach this crop growth stage until May 1st. As we move forward over the next few weeks it is imperative that retailers and growers properly identify the wheat crop growth stage before applying dicamba or 2,4-D. When wheat has a visible joint (Feekes 6), wheat can be very sensitive to dicamba and 2,4-D herbicides. If we remember back to 2009 we had several reports of 80 bushel wheat dropping to 20 bushel wheat when dicamba was applied at Feekes 6. After jointing there are several other herbicides that can be safely used. Please refer to Pest Management in WI Field Crops Bulletin A3646 for these options.

Please click to view a YouTube video on Identifying the Hollow Stem and Jointing Growth Stages in Wheat

Image 1. Feekes 4-5 or Zadoks 30 growth stage in wheat

Tuesday, March 13, 2012

Be Cautious With Your Wheat Nitrogen Timing this Spring

With record high temperatures predicted this week if your winter wheat crop had not broken dormancy it soon will. I would like to caution growers and retailers to not get too anxious to apply N yet this spring. It is important to remember that the functional purpose of spring N is to 1. stimulate tillering and 2. provide crop nutrition. If ample tillering (> 70 tillers per square foot) has occurred growers can delay N applications up to pre-joint (Feekes 4-5; Zadoks 30). This practice will aid in minimizing early spring N loss. Applications of N made after this growth stage may lead to wheel track damage. If growers have < 70 tillers per square foot it is important to get across those fields as soon as possible to minimize yield loss due to low tiller/head counts. My concern related to an early application of N to a well tillered wheat crop is that we will stimulate crop growth and development which may increase the risk of yield damage if we get a sudden cold snap. I do not have a crystal ball but I would bet we have another heavy frost in our future. For more information related to freeze damage to winter wheat and to assess your risk for yield loss please read Know Your Wheat Growth Stage to Predict Wheat Freeze Injury.

For more information on assessing winter wheat stands please view Wheat Stand Assessment and Nitrogen Timing