University of Illinois

No. 14/June 27, 1997

Wheat Season Nearing the End

The two big spring threats to the Illinois wheat crop--wet May weather and high temperatures--stayed away for the most part in 1997. As a result, harvest is just beginning on what should be one of the best crops in recent years. Head size and numbers are good, and the crop is relatively free of disease and weeds. The high temperatures of the past week have brought on maturity very quickly: The substantial amount of green leaf area observed on many entries in the Brownstown variety trial on June 18 had all but disappeared by June 24. A field of Clark (identifiable by the bronze color of the heads at maturity) was being harvested near Belleville on June 24, but most fields still need several days of drying before they reach combine ripeness.

The June estimate of wheat yield for the Illinois crop was 55 bushels per acre, which would rank this crop among the top three of the last ten. I would not be surprised if yields come in a few bushels above this. There is little mystery about why: The cool, dry weather during much of the spring was ideal for tillering and growth, and the dry weather in Southern Illinois during flowering helped to hold down diseases. For reasons that are not clear, the nitrogen-spread patterns in many fields are still visible, and seem to indicate that much of the crop received less N than it needed for top yields. Late spring N application in many fields, lack of adequate rainfall to move N into the soil, and deep root systems may have resulted in some of the N not reaching the root system.

Emerson Nafziger, Department of Crop Sciences, (217)333-4424