CFAES Give Today
Agronomic Crops Network

Ohio State University Extension


C.O.R.N. Newsletter 2008-38

Dates Covered: 
November 4, 2008 - November 18, 2008
Greg LaBarge

Varying Grain Moisture And Harvest Delays In Corn

Authors: Rich Minyo, Allen Geyer, Peter Thomison

This year I’ve received a number of reports, mostly from northern Ohio, concerning higher than expected grain moisture in corn at harvest. To some extent, the wetter than normal corn grain is not surprising since many affected fields were not planted until the last week of May or later (according to the NASS about a third of Ohio’s corn crop was planted after May 25). Dr. Bob Nielsen, the corn extension specialist at Purdue University, noted in a recent newsletter article ( that a “relatively cool June further delayed the crop's development to the extent that silking of the corn crop statewide occurred about two weeks behind the 5-year average…” and that “A relatively cool August certainly did not help the crop progress "catch up".” Although Dr. Nielsen’s observations are specific to Indiana in 2008, they are also applicable to many areas in Ohio.

Some of variability in harvest grain moisture this year may also be attributed to differences in hybrid maturities planted and differences in the drydown rates among hybrids which have been magnified by less than optimal dry down conditions. In some of my research plots, I’ve noted major differences in grain moisture (five percentage points or more) in fields planted within 1 to 2 calendar days in close proximity which only differed in hybrid maturity (three day relative maturity) and crop rotation. Slower than normal crop development may be related to drought induced N deficiencies and no-tillage, which are sometimes associated with higher grain moisture at harvest. Other factors influencing grain moisture may be premature plant death, stalk rots, and severe stalk lodging (caused by “Ike’s” winds in mid September)

Varying grain moisture at harvest across the state was evident in the 2008 Ohio Performance Trial. At several sites especially those in SW Ohio, Washington CH, Greenville, and S. Charleston, grain moisture at harvest was relatively low (ranging from about 14 to 20%), whereas at test sites in the north central/northeast region, grain moistures were higher. Grain moisture of hybrid entries ranged from about 15 to 35% at Beloit, about 17 to 35% at Bucyrus and about 15 to 25% at Apple Creek. However at Hoytville and Van Wert, in NW Ohio hybrid grain moistures were about 15 to 20% at harvest. Much of the variation in harvest grain moisture among entries at each test site, especially the north central/northeast sites, can be related to differences in hybrid maturity.

With the wetter than normal corn present in many northern Ohio fields, should growers delay harvest and rely on some more natural field drying or should they proceed with harvest, incur high drying costs but minimize field losses?

An article from the Purdue University Top Farmer Crop Workshop, Sept. 2008, “Evaluating Corn Harvest Timing”, by Bruce Erickson and Luc Valentin, addresses the economics of corn harvest timing and discusses a downloadable Excel spreadsheet to test various on-farm scenarios, including best-case and worst-case situations (considering harvesting capacity, corn prices and potential field losses). It’s available online at

By early November, field dry down rates usually drop to 1/4 to 1/2% per day and by mid November, probably 0 1/4% per day. By late November, drying rates will be negligible. Allowing corn to field dry below 20% at this late calendar date risks yield losses from stalk lodging, ear rots, and insect feeding damage. The loss of one "normal" sized ear per 100 feet of row translates into a loss of more than one bushel/acre and an average harvest loss of 2 kernels per square foot is about 1 bu/acre. This year growers must be prepared for severe lodging problems in many fields that will slow harvest and contribute to yield losses. Within fields, significant variation in grain moisture may exist among plants that died prematurely and stalk and root lodged severely.

Several years ago we conducted a study that evaluated effects of plant population (24,000, 30,000, 36,000, and 42,000 plants/A) and three harvest dates (early-mid Oct., Nov. and Dec.) on the agronomic performance of four hybrids differing in maturity and stalk quality. The following are some findings from this research.

• Delaying harvest until early-mid November decreased grain moisture content by 5.8% (from 23.8 to 18.0%). Further harvest delays achieved almost no additional grain drying.

• Nearly 90% of the yield loss associated with delayed corn harvest occurred when delays extended beyond early-mid November.

• The greatest increase in stalk rot incidence came between harvest dates in October and November. In contrast, stalk lodging increased most after early-mid November.

For more details concerning this study, including table summaries, check out
“Effects of Harvest Delays on Yield, Grain Moisture and Stalk Lodging in Corn”. C.O.R.N Newsletter 2005-34 (October 10, 2005 - October 18, 2005); available online at

Weather Trends for the Rest of 2008 and Early 2009

Authors: Jim Noel

The pattern continues with temperatures overall near average and below average precipitation through November.

This week will be marked by much warmer than average with no significant rainfall. There will be a cold front Friday with 0.10 to 0.50 inches of rain, but most places will see 0.35 inches or less. Much colder weather with light rain and snow showers will occur this upcoming weekend. Next week will see the cold moderate to near normal temperatures with a weak weather system about midweek. However, I do not see any major storms on the horizon the next few weeks.

Longer term, as we head into winter, we are currently in a sunspot minimum year with El Nino/La nina conditions neutral. With those conditions, I found historic years similar since the 1940s. Graphics which show a comparison of temperature and precipitation based on this historically period were generated for the December to February time frame. These indicate we will likely see temperatures will be close to normal. Precipitation trends will be near normal for northern areas and near or below normal precipitation in the south area of the state. Snowfall would likely be near or slightly above average. This fits well into current outlooks.

OSU Extension Sun Hats Available For Purchase

Authors: Mark Loux

The OSUE Ag. Safety and Health group is selling a Columbia sun safe hat with the OSU Extension logo. OSU weed scientists field tested this hat extensively last summer, and we have given it our stamp of approval (you can judge for yourself what this is worth). We really appreciated its functionality, and it’s also not goofy looking, which is usually the case with sun hats. We can state confidently that this is the most wind-proof hat of its type, and it also effectively reduces sun exposure. We received a number of comments from people interested in purchasing one. Now is your chance. The OSU Ag. Safety and Health group is placing another large bulk order for these hats.

Use the order form at this link to purchase this wide brim, lightweight, quick drying, mesh hat - The cost of the hat is $25.00 (plus $3 for shipping), and it’s available in two colors, sage (light green) and fossil (lighter khaki), with the OSUE logo embroidered on the brim. A link to photos of the hat:

The deadline to return orders is November 12, 2008. There is a 4-week processing time. You can expect your hats to arrive in Columbus the second week of December, or be shipped to you at that time. Please email Kathy Henwood, with any questions.

New Schedule for Delivering CORN to You

This issue is our last regular weekly issue of the Crop Observation and Recommendation Network Newsletter for 2008. We begin now with an every other week newsletter through the winter months to keep you up to date with summaries of research results, winter meetings and other information. Our next newsletter will reach you on November 18th.

Do you know someone who should be getting this newsletter but not sure how to tell them to subscribe. Just have them send an e-mail to Greg LaBarge,, with their name e-mail address and county in which they reside.

Looking for a Career Opportunity with OSU Extension

Several job announcements are now being advertised in the Agriculture and Natural Resource program area with OSU Extension. The Human Resources page at list available openings Application deadline for current positions listed below close on November 9. Complete job announcements and application information can be found with the link above.

Current Openings are:

Extension Educator, Agriculture and Natural Resources
Holmes County
Erie County
Wayne County

Program Coordinator, Agriculture and Natural Resources
Clermont County

Archive Issue Contributors: 

State Specialists: Ann Dorrance, Pierce Paul and Dennis Mills (Plant Pathology), Ron Hammond, Andy Michel, and Bruce Eisley (Entomology), Peter Thomison (Corn Specialist), Mark Loux (Weed Science), and James Noel (NOAA/NWS/OHRFC). Extension Educators: Roger Bender (Shelby), Harold Watters (Champaign), Todd Mangen (Mercer), Mike Gastier (Huron), Les Ober (Geauga), Bruce Clevenger (Defiance), Wesley Haun (Logan), Steve Foster (Darke), Gary Wilson (Hancock), Marissa Mullett (Coshocton), Suzanne Mills-Wasniak (Montgomery) and Jonah Johnson (Clark).

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.