Planting Date

• October 1–November 1
• October 10–November 10
• October 15–November 20

Late-planted wheat yield potential depends on several factors, including date of emergence, seeding rate, variety, fertility management, and of course the weather during the rest of the fall and winter. Planting dates in research plots and production fields in previous years has shown that in northeast Arkansas, acceptable wheat yields can be realized with November plantings as late as Thanksgiving, with little or no yield loss compared to optimum planting dates. Last year in our Wheat Research Verification Program, the highest yielding field (93 bu/acre) was planted at 120 lbs of seed/acre on November 11th in Greene County with an emergence date of approximately November 25th. Granted, the warm dry fall and winter provided ideal conditions last year for late- planted wheat, but this does show we do still have potential for good yields if Mother Nature will cooperate with us. To help realize good yields in late-planted wheat, the following management practices can help increase yields.  

Seeding Rates:  Increase seeding rates 10 to 20 lbs/acre above normal seeding rates. Since wheat will likely have less of an opportunity to tiller, increasing seeding rates will help overcome the reduction in tillering. Optimum planting date recommendations of 26 seeds/ft2 would equal approximately 90 lbs of seed/acre based on an average seed size. Keep in mind seed size will vary between varieties and seed lots. Increasing the seeding rate 20 lbs/acre or more will be justified. 

Fall Nitrogen:  The addition of 30 to 40 units of nitrogen applied preplant will help increase tillering and growth of small plants. If phosphorus is required, the use of DAP (18-46-0) would be an economical source of phosphorus and would likely provide enough fall nitrogen to stimulate growth and tillering.

Variety Considerations: Avoid planting late-maturing varieties if possible when planting late. Granted, many producers already have their seed and an alternative variety may not be available, but in general early maturing varieties will perform better in a late planting scenario than late maturing varieties.

New Ryegrass Control Option
Bob Scott, Extension Weed Specialist

Axial herbicide from Syngenta recently received a section 3 label. Axial, which contains the active ingredient penoxaden, is from the same family of chemistry as Hoelon, but it has a slightly different chemical structure. While it is in the same family or group of chemicals as Hoelon, Select, Poast Plus and others (the Accase enzyme inhibitors), it is a "den," while the others mentioned above are sometimes called "fops" or "dims." This refers to the last part of the chemical name, for example Clincher herbicide is Cyhalofop, a "fop." All these chemicals are sometimes referred to as "the graminicides."

Because penoxaden or Axial has a slightly different structure than Hoelon, it has performed fairly well on Hoelon-resistant ryegrass in our trials over the last few years. One would suspect that cross resistance might not take long to develop, since these chemicals are very close in structure. However, for now it does appear to be a viable option for Hoelon-resistant ryegrass. On non-resistant ryegrass, Axial has provided excellent control, very similar to Hoelon or Osprey.

In Arkansas, Axial will basically be a ryegrass only material. It does provide some suppression of cheat; however it has no broadleaf activity and does not control annual bluegrass (poa). Unlike Hoelon, you can tank-mix Axial with most broadleaf herbicides, with the exception of 2,4-D.

The labeled rate of Axial is 8.2 oz/acre, and it comes in 40-acre packages with an adjuvant included (Adigor at 9.6 oz/acre). I have been told that the price will be comparable to Osprey, possibly slightly less expensive. However, Osprey does have a wider spectrum of activity.

Axial should be applied to actively growing ryegrass from 1 leaf to 3 tillers in size. It can be safely applied to wheat from the 2-leaf to pre-boot growth stages. Like Hoelon and Osprey, Axial does not provide any residual ryegrass control, so timing can be critical for season long control. In severe ryegrass infestations, it may be necessary to make both an Axial and Osprey application for season long control. Another option might be to use Finesse PRE and then follow that application with either Axial or Osprey later in the season. Keep in mind that only STS soybean can be grown following Finesse applications. Most crops, including soybean, have a 4 month rotational interval to Axial.

Wheat Research Verification Program
Matt Cordell and Trey Reaper, Coordinators

Thus far, seven of ten WRVP fields in south Arkansas have been planted. Currently Monroe, Phillips, and Pulaski county fields remained unplanted. Hopefully, we’ll catch a break in the wet weather and plant these fields within the next week. In Arkansas Co., soybeans were harvested, and Croplan 8302 was broadcast at 160 lb/A and incorporated earlier this week. Croplan 8302 was also planted in Desha Co. at 120 lb/A behind soybean. Agripro Beretta was the variety planted in Crittenden and Chicot Counties, and these fields have already reached the 2-leaf stage.  A small amount of ryegrass has emerged in Chicot Co. We’ll keep an eye on this in the upcoming weeks, but there’s not enough pressure to justify a treatment at present. Progeny 166 was drilled in Jefferson Co. at 110 lb/A behind soybean. All emerged fields have obtained adequate stands and numbers range from 18-40 plants/ft2. In general, fields look adequately drained and in good shape. 

So far only two northeast Arkansas WRVP fields have been planted and emerged. The Woodruff Co. field is in the 3-leaf stage at this time and has had significant rainfall over the last 10 days. The Mississippi Co. field looks good as many plants across the field are tillering. Weed pressure in both fields is very light at this time. Fields in Jackson, Cross, and Poinsett Counties are waiting for dry weather to allow planting. Soybeans still remain in the field in Lawrence and Greene Counties. So overall, we will be looking at later planting dates for this region in 2007.

Contact Information

Please contact your local county extension agent in Arkansas or the authors by email at jkelley@uaex.edu, bscott@uaex.edu, mcordell@uaex.edu, or treaper@uaex.edu, if you have questions or comments regarding this newsletter.

Acknowledgments

We appreciate the Arkansas Wheat Promotion Board and the Arkansas wheat producers for their support. The authors appreciate all feedback and contributions.

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