About two weeks after the series of hard freezes in early April, it is apparent that the primary tillers of the wheat in much of central and eastern Kansas have been badly damaged, says Jim Shroyer, K-State Research and Extension wheat specialist.
"There is significant damage to the stems and heads of the primary tillers in many cases. Lodging from stem damage is a serious problem in the middle of the state, especially in about a 60-mile radius around McPherson County," Shroyer says. "In general, freeze injury tends to be most severe in early-planted fields, and least severe in late-planted wheat. Western Kansas appears to have little freeze damage overall, and far south central Kansas has less damage than areas north and east of Wichita."
Recovery from secondary and basal tillers is underway in most areas of Kansas now, since the weather has been warm for the past week to 10 days, the agronomist says.
"In some cases, secondary tillers were small at the time of the freeze and were not seriously damaged. If both primary and secondary tillers were damaged, the new re-growth will have to come from the base of the plants. In either case, re-growth from secondary or basal tillers will need good growing conditions in April and May to make a viable head."
Expected yield reductions vary considerably from one field to the next.
"There are some cases where it appears almost all the tillers were killed down to the crown and the crop is growing back very slowly, if at all. In those cases, the yield loss will be nearly complete and if possible, producers should consider re-cropping or harvesting the crop for forage. It would probably not be cost-effective to harvest a crop of 10 bushels per acre or less," he says.
Shroyer says some fields are showing good re-growth from the secondary and basal tillers. But even where re-growth is occurring rapidly, yields will likely be reduced by at least half or more. Yields depend greatly on weather conditions from now until harvest - which will probably be about two weeks or so later than normal if the primary tillers were killed.
"On the positive side, soil moisture and nitrogen levels are good, and could help the recovery. If surviving tillers are already more than a foot tall and growing rapidly, the yield losses will probably not be a severe as where the re-growth is just now getting started. Weeds and leaf diseases could threaten the ability of the crop to recover, however, and may limit yields," Shroyer says.
If the crop does re-grow from secondary and basal tillers, producers will probably notice that the crop has a very ragged appearance at harvest time, he added.