September 25, 2007  

 

Iowa State University Extension Information for Southeast Iowa
By Jim Fawcett, ISU Extension Field Agronomist
4265 Oak Crest Hill Rd. SE
Iowa City, IA 52246
319-337-2145

 

WINTER WHEAT

 

The high wheat prices are causing some to consider trying winter wheat for the first time. I’ve found that most growers who make winter wheat a profitable crop are good at marketing the straw. Maybe this isn’t as critical with today’s prices.  For maximum yields the wheat should be seeded by October 1, although mid-October seedings can be successful. Make sure you can market the wheat. Soft red winter wheat is more suitable for eastern Iowa and easier to market. Select a variety with good winter hardiness and disease resistance. The wheat variety trial results for 2007 for Crawfordsville, Nashua, and Ames is at http://www.croptesting.iastate.edu/smallgrains/data/data.html. Yields averaged 60 bu/A this past year in the trials, but averaged 95 bu/A in 2006, one of the best ever for wheat. Wheat seed is in short supply this fall because of the increase in interest. Phosphorus is important for a good wheat crop and applications of 50 pounds/acre of nitrogen in March are typical. Fungicides are occasionally needed for maximum yields. Check herbicide labels for crop rotation restrictions, especially if seeding on corn ground. For more information, see Lance Gibson’s article at http://www.agron.iastate.edu/faculty/lgibson/Wheat.htm.

FALL STALK NITRATE TEST FOR CORN

A useful tool to help fine tune nitrogen management in corn is to use the fall stalk nitrate test. The ideal time to take the stalk samples is 1-3 weeks after black layer. Many corn fields may be beyond this window now, but later work done by Fred Blackmer indicated that sample can be taken later as well with similar results. An easy way to take the samples is right after harvest. An 8-inch segment of stalk with the leaf sheaths removed needs to be taken 6 inches above the soil. If the head is set to cut the stalks about 14 inches above the ground, the upper 8 inches of what’s left in the field can be cut off to be sent to the lab. It is recommended to send 15 stalk samples for each area being sampled. I’ve found the test to be especially useful on manured fields to identify where excess nitrogen was used or to make sure there was sufficient N. In areas where there were excess rain and nitrogen losses, the test can confirm the lack of N. Instructions for the test can be found at http://www.extension.iastate.edu/Publications/PM1584.pdf. If you choose to use the ISU lab, the form can be found at http://www.agron.iastate.edu/soiltesting/CSN.pdf.