Strength of Wheat Crop Being Questioned

March 20, 2002

WOOSTER, Ohio - Ohio's wheat crop has broken winter dormancy over a month early, raising concerns that the crop may be weakened prior to establishing re-growth come spring.

Ohio State University plant pathologist Pat Lipps said fluctuating winter temperatures have aided in the early "greening" and the crop is using carbohydrate reserves each time a warm spell occurs.

"The wheat crop shouldn't break dormancy until sometime in March. But because of the mild temperatures, we suspect the crop broke dormancy during the last two weeks of January," said Lipps, who works at the Ohio Agricultural Research and Development Center (OARDC) in Wooster, Ohio. "The plants utilize carbohydrate reserves in the crown tissues when they start to re-grow and if the plants do that several times during the winter, the food reserves are depleted so much that they have a difficult time re-growing in the spring." Lipps said that growers should be assessing their fields to determine the overall condition of their wheat crop, to decide whether the crop should be saved or discarded for a different commodity.

"They need to get out into their fields and see if the crop is starting to green up. Dig up a few plants and look at the tillers. See if the crowns are nice and white and not a brown or yellow color," he said.

One thing growers need to look for is damage to the plants from heaving, a situation where the crowns become exposed as a result of repeated freezing and thawing of the soil. "Heaving can occur on hillsides, hilltops or in poorly drained soils. The only part of the plant in the soil is the roots and, as a result, the plant is very susceptible to desiccation and has a difficult time re-rooting and growing in the spring," said Lipps.

The best way for growers to evaluate the overall condition of a wheat field is to count the number of plants standing per row and how many tillers are present on each plant. Researchers estimate that 10-13 plants per row in 7.5 inch rows provide a good economic indicator on whether to stick with wheat or switch to a different crop.

To estimate potential yield, multiply the number of tillers per foot of row by 2.5. For example, if nine plants per foot of row each have the capacity to produce three tillers, for a total of 27 tillers per foot of row, the yield potential would be in the 65 bushels per acre range. However, if these same plants only produce two tillers, the yield potential would be about 45 bushels per acre.

"It depends on how much of the field has been affected. If a grower has lost large areas, probably the best scenario would be to plant a different crop," said Lipps. "If a grower has only lost a section of rows, he can assess how much stand he should have and determine whether that's sufficient for a reasonable crop." Overall, the wheat crop is showing signs of improvement, despite the stand establishment problems the crop was experiencing earlier in the growing season.

"The wheat in the southern and north central parts of the state is in pretty good shape. The extended warm temperatures probably aided in a couple of more weeks of growth and helped with tiller development," said Lipps. "Right now the area we are most concerned about is the northwest corner of the state. This is a poorly drained area that got significant amounts of rainfall in October right after the crop was planted. A lot of those fields were replanted, but we are concerned with plant survivability and whether those growers should keep the stands or tear them up and go to a different crop." Lipps estimates it won't be until the first part of April, when new roots and tillers begin to develop, before the crop's overall condition and performance can be assessed. "This is a pretty unusual situation," he said. "This is probably the first year in almost a half a century that we've had such problems and people have had to replant on such a wide-scale basis."

Author(s): 
Candace Pollock
Source(s): 
Pat Lipps