13 March 2009
Status of Indiana Winter Wheat Crop
Ellsworth Chrismas and Charles Mansfield
Agronomy Dept., Purdue Univ.
West Lafayette, IN 47907-2054
Email address: echristmas
At this point in time, the 2009 Indiana wheat crop looks quite good with no obvious signs of winter injury. Zero and sub-zero temperatures occurred several times across Indiana this winter. During these events, a large portion of Indiana had 2 or more inches of snow cover which provided a good insulating blanket for the wheat. Since the snow melted, temperatures have dipped to single digits on two or three occasions. These low temperatures do not seem to have injured the wheat, in fact, wheat is exhibiting much less leaf burn than normally occurs.
Wheat in the Lafayette area has not yet had enough warm days to show signs that it has broken dormancy. However, in the southern one-third of Indiana temperatures have warmed sufficiently that wheat has broken dormancy and is beginning to grow very slowly. As we approach mid to late March, temperatures in central and northern Indiana will begin to rise more rapidly. With this rise in temperatures, wheat will begin to break dormancy in these areas of the state.
If you are curious as to whether your wheat has broken dormancy, there are two ways of making this determination when examining wheat plants. First, carefully wash the roots of a wheat plant and look for new root growth from the crown area of the plant. These roots should be snow white and may be very short (1/4 to 1/2 inch) if the plant has just broken dormancy. Secondly, look closely at the top two leaves of the plant. You should be able to see a line across the leaf at the point where the leaf was covered by the leaf sheath. The area below the line is the new growth and can be characterized by a brighter or shiny appearance when compared with the area above the line.
For those of you that have not yet done so, as the wheat begins to break dormancy, it is time to top-dress with nitrogen as soon as soil conditions permit. Assuming that 30 pounds of nitrogen was applied at seeding time, the rate of top-dress nitrogen is directly related to yield potential. With a yield potential of 50 bushels per acre, we recommend 40 lbs. of N as a top-dress, at 70 bu/ac we recommend 60 lbs. of N and at 90 bu/ac, 90 to 100 lbs. of N. On soils with a cation exchange capacity less than 10, the N rate may need to be increased by 10-15 lbs./acre to compensate for leaching losses. When top dressing wheat, we recommend the use of dry materials or the use of streamer bars when using liquid materials. Every effort should be made to keep as much of the nitrogen fertilizer off the wheat leaves as possible. Nitrogen fertilizer applied to a plant with lowered vigor and dead leaf tissue could cause a significant Rhizoctonia problem.
For those of you in southern Indiana, keep an eye on the growth of the garlic. Many of the product labels recommend that for best control, herbicide application should be made before garlic reaches 12 inches in height and with 2 to 4 inches of new growth. The herbicide application for garlic control only should be made before the flag leaf appears on the wheat. Any growth regulators that are being applied for the control of other weeds should be applied before jointing, unless used as a harvest aid. Be sure to read and follow the label directions for the product that you are using.