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Ohio State University Extension


C.O.R.N. Newsletter 2004-06

Dates Covered: 
March 17, 2004 - March 31, 2004
Greg La Barge

Late Winter Wheat Condition

Authors: Patrick Lipps

Most of the winter wheat crop was planted about a week to ten days later than normal mostly due to the delay in soybean harvest. By October 12 only 43% of the wheat crop had been planted and only 3% was emerged. Colder than normal temperatures in late October limited rapid development of the crop such that by the time of winter dormancy in mid December the plants in most fields were small consisting of only 2 to 3 tillers each. The crop reporting service has indicated that about 900,000 acres of wheat have been planted for harvest in 2004, down by about 15% from last years crop.

Flooding rains during the first week of January followed by colder temperatures left many fields covered with ice. Continued cold temperatures throughout January and into mid February permitted snow to cover bare ground and ice. The lack of freezing and thawing during this period probably helped protect the plants from injury even though the tops were encased in ice.

By the end of February warmer weather and limited precipitation permitted the ice and snow to melt leaving plants in reasonable shape. During the last days of February and the first week of March the temperatures rose to highs at least above 50oF causing the wheat to regain some green color, especially in the southern part of the state. Freezing and thawing of the soil in late February and the first two weeks of March contributed to heaving of plants in areas with wet, high-clay soils.

Regardless, by mid March the wheat appears to be in reasonable shape except for a few areas in west central and northwest Ohio that were late planted and hurt by freezing injury early in the year. Assuming we will not have additional heaving from cycles of freezing and thawing over the next two weeks, the vast majority of wheat in the state is in good shape to achieve high yields.

Assessing Wheat Stands In Late Winter

Authors: Patrick Lipps

Assessment of wheat stands can only be made after late winter green up when the risk of excessive freezing and thawing is low. This usually occurs by mid March, but in some years with extended winter weather this may not be before the first week of April. The first inspection of wheat fields should be to look for heaving.

Heaving is recognized when the crowns of the plants are pushed up out of the soil as the soil freezes and thaws during late winter. Close examination of the plants indicate that the crowns and upper roots are exposed with only a few roots remaining in the soil. These plants will green up and look normal for a while, but within a few weeks heaved plants will turn brown and die. Growers generally describe this as fields 'going backwards'. Heaving is generally worse in fields with wet, high clay content soils. Generally, heaving is more important in conventional tilled fields with little surface residue than in no-till fields with residue that protects against wide changes in temperature of the upper inches of the soil. Wheat that is too shallow planted is also more prone to heaving problems than wheat that has been planted at the recommended one and a half inches deep.

Adequate tiller development is essential for high yields, but excessive tillering is unnecessary and may lead to lodging. Fields planted within 10 to 14 days of the Hessian Fly Safe Date using 1.3 to 1.6 million seed per acre (18 to 24 seed per ft of row) with about 20 to 25 lb of N/A applied at planting rarely have any problems with low tiller numbers in the spring. In fact they generally have many more tillers than are needed for maximum yield. Our experience from counting heads of wheat in fields prior to harvest indicate that most Ohio fields have from 40 to 60 heads per foot of row. If 20 seed were planted per foot of row then each plant will end up with 2 to 3 head bearing tillers. These are the main tillers that were developed during fall growth.

Yield potential is reduced if tiller numbers fall below 25 per square foot after green up. Fifteen tillers per square foot is considered minimum for an economic crop. The number of tillers per square foot is equal to the number of tillers in 20.5 inches of 7 inch wide rows or 14.5 inches of 10 inch wide rows. Obviously, late planted fields should be visited to determine if adequate numbers of tillers are present.

Wheat plants will continue to develop tillers until the stems begin to elongate at Feekes' growth stage 6. This growth stage generally occurs in early April in southern Ohio and by mid-April in northern Ohio. If nitrogen was applied in the fall at planting then there is no need to hurry an early spring application of nitrogen to stimulate tiller formation. They are going to develop anyway, as long as the moisture, temperature and day length (less than 14 hours per day) are favorable. Nitrogen applications can be applied anytime between green up and growth stage 6 to achieve maximum yield.

Feekes' growth stage 6 or beginning stem elongation is determined when the first node is detected at the base of the larger tillers in the field. You can assess growth stage by pulling tillers from the field and stripping the lower leaves and leaf sheaths down to expose the lower stem. The first node will be visible as a hard swelling on the stem about one half inch to an inch and a half above the roots. Determining this growth stage is important for completing nitrogen applications and the timing of application of certain herbicides with restrictions after this growth stage.

Dr Robert Mullen Joins The Team

Dr Robert Mullen will be joining the Ohio State University’s, Department of Natural Resources as State Soil Fertility Specialist on April 1 with a research/extension appointment. Dr Mullen is an Oklahoma native with an academic and industry background. In his most recent position he served as Agronomist for NTech Industries involved in development and educational activities for GreenSeeker variable rate application systems. His research program at Oklahoma State University included a variety of soil fertility areas with different crops. We look forward to working with Dr Mullen on soil fertility issues facing Ohio’s agronomic crop industry.

Ohio Forage and Grassland Council Annual Meeting

The 2004 Annual Meeting of the Ohio Forage and Grassland Council has been set for Friday, March 26th at the OARDC Fisher Auditorium at Wooster, Ohio. The event begins with registration at 9:00 a.m. and concludes at 3:15 p.m. Two keynote speakers addressing the entire group are Dr. Dan Undersander, Forage Specialist at University of Wisconsin, speaking on “Relative Forage Quality,” a new forage quality measurement. Also Dr. Don Myers, Professor Emeritus for OSU will speak on Grass in Alfalfa.

Several Concurrent sessions will also be held which include:
“Grazing Topics” by Dr. David Zartman, Professor, Animal Science, The Ohio State University,
“Highlights of their Grazing Dairy in indiana” by Bob and Debbie Eash, Hudson, Indiana,
“Forage Research Update” by Dr. Bill Weiss, Professor, Animal Science, The Ohio State University,
“Traffic Tolerance in Alfalfa” by Dr. Dan Undersander, Forage Specialist, University of Wisconsin,
“Grass Research Update” by Dr. David Barker, Assistant Professor, Hort & Crop Science, The Ohio State University,
“Soil Health” by Dr. Ben Stinner, Professor, Entomology, Ohio Agricultural Research and Development Center.

The program will also feature a popular forage producer panel and an excellent Forage Industry Trade Show. Registration fees are $20 per person for OFGC members and $30 per person for non-OFGC members. Early registration deadline is March 19, 2004. For further information call Susan Mykrantz at 330-264-2488 or Gary Wilson at 419-422-3851.

Archive Issue Contributors: 

State Specialists: Pat Lipps & Anne Dorrance, Dennis Mills (Plant Pathology), Peter Thomison (Corn Production), Jeff Stachler (Weed Science), Bruce Eisley (IPM) and Ron Hammond (Entomology); District Specialists: Ed Lentz (Agronomy);Extension Agents: Roger Bender (Shelby), Steve Foster (Darke),Todd Mangen (Mercer), Bruce Clevenger (Defiance), Greg La Barge (Fulton), Howard Siegrist (Licking), Mark Keonig (Sandusky), and Dusty Sonneberg (Henry)

Crop Observation and Recommendation Network

C.O.R.N. Newsletter is a summary of crop observations, related information, and appropriate recommendations for Ohio crop producers and industry. C.O.R.N. Newsletter is produced by the Ohio State University Extension Agronomy Team, state specialists at The Ohio State University and the Ohio Agricultural Research and Development Center (OARDC). C.O.R.N. Newsletter questions are directed to Extension and OARDC state specialists and associates at Ohio State.