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Agronomic Crops Network

Ohio State University Extension


C.O.R.N. Newsletter 2008-36

Dates Covered: 
October 21, 2008 - October 28, 2008
Curtis E. Young

Still Thinking about Planting Wheat? Here are some Things to Consider

Authors: Pierce Paul, Jim Beuerlein, Dennis Mills

We are now in the third week of October and at the end of the recommended time for wheat planting in Ohio. We generally recommend that wheat be planted no later than the third week of October to ensure adequate tiller development before winter dormancy to minimize winter kill. Reports from across the state suggest that between 75-95% of the wheat was planted within the recommended time (within the first 10 days after the Hessian Fly-Safe Date, which varies between September 22 for northern counties and October 5 for the southern-most counties), and recent rains have contributed to a substantial improvement in the overall emergence and appearance of the crop. However, delayed soybean harvest in some parts of the state is forcing some producers to consider planting wheat during the last week of October or the first week of November.

So, how late is too late to plant wheat? There is no easy answer to that question. It all depends on the weather conditions during the fall and early winter. Wheat planted this late (generally after Oct 20 in northern Ohio) is certainly at greater risk for poor stand establishment (fewer tillers per foot of row), increased winter kill and spring heaving. However, in any given year, if warmer-than-usual conditions occur during late fall-early winter (freezing weather delayed until early December), even wheat planted as late as the first week of November may still do fairly well.

To compensate for fewer tillers developing in late-planted wheat, it is recommended to plant at a higher seeding rate than the regularly recommended rate of 1.2-1.6 million seeds per acre for 7.5-inch rows (that is about 18-24 seeds per foot of row). Plant at a rate of 1.6-2.0 million seed per acre instead. The number of seeds per pound will depend on the size of the seeds - 2.0 million seeds per acre is 30 seeds per foot of 7.5 inch row. If there are 13,000 seeds per pound, you will need 154 pounds of seed to get 2.0 million per acre or 123 pounds to get 1.6 million seeds per acre. The following table shows the pounds of seed needed per acre to accomplish various seeding rates using different sizes of seed.

Pounds of Seeds Needed to Plant 1.2 to 2 Million Seeds per Acre Based on the Number of Seeds per Pound
Seed/lb 1.2 1.4 1.6 1.8 2.0
10000 120 140 160 180 200
11000 109 127 145 164 182
12000 100 116 133 150 167
13000 92 108 123 138 154
14000 85 100 114 129 143
15000 80 93 107 120 133
16000 75 88 100 113 125
17000 71 82 94 106 118
18000 66 77 89 100 111


Grain Shrinkage in Corn

Authors: Peter Thomison

In response to questions I've received about grain shrinkage in corn during past weeks and how it's calculated, the following is some background information on the topic and an additional resource to consider. There are two components of the weight losses calculated during grain shrinkage: 1) water and 2) handling or dry matter loss.
Water removal is by far the major weight loss component during drying. But a second, smaller portion is dry matter or handling loss due to release of oils, mechanical losses from broken kernels, and respiration from the seed.

Calculation of water loss alone is straightforward and does not vary from load to load or chart to chart. But the actual amount of handling loss will depend on the initial physical quality of the corn and the handling processes during drying. This loss is not measured directly by buyers, but is added to water loss using several different methods of estimation. The most common two methods are: 1) use of drying tables which include water shrink plus a constant handling loss (usually 0.5% of the initial grain weight), or 2) a constant shrink factor in which the assumed handling loss varies depending on the initial grain moisture content.

In order to accurately compare custom drying quotes or grain sale alternatives, corn growers must determine the shrinkage costs associated with each and choose the alternative which returns the greatest dry bushels or highest net sale.

For examples of how to do such comparisons (and a more detailed description of shrinkage calculation differences), see National Corn Handbook Publication NCH-61, "Calculating Grain Weight Shrinkage in Corn Due to Mechanical Drying." It's available on-line at: (

Clinic Clips

Authors: Bridget Meiring, Nancy Taylor

The sampling season for soybean cyst nematode is just getting under way. The C. Wayne Ellett Plant and Pest Diagnostic Clinic is taking in soybean cyst nematode samples for your after harvest counts. We have received samples from Marion, Paulding, Henry, Knox, Hardin, Wood, and Fulton counties with population levels ranging from moderate (2,000 – 4,999 eggs per 200 cc of soil) to not detected. For instructions on how to sample and send in SCN samples please refer to Factsheet AC-39-98,

Weather Update

Authors: Jim Noel

Some light rainfall occurred last week and some frost was observed this past weekend. This is close to what was predicted in last week's CORN (C.O.R.N Newsletter 2008-35, October 14, 2008 - October 20, 2008).

This week will be rather dry until late in the week. A few light showers will occurred Monday night with a cold front moving through the state.

A more significant system looks like it will come through Friday and Saturday of this week. Rainfall of 0.50" to 1.00" will be the average with this system. Some places will be as low as 0.25" in the west and as high as 1.50+" in the east later this week and weekend.

Next week looks sharply colder with some rain and snow showers by the middle of next week. Snow chances are best in the north but right now it looks like most of the snow will not stick.

It looks like the normal to below average trend is still holding in precipitation for the longer term into November. We will continue to watch for a stronger change in the weather pattern for November.

Archive Issue Contributors: 

Contributors: State Specialists: Ann Dorrance and Pierce Paul (Plant Pathology), Ron Hammond and Andy Michel (Entomology), Peter Thomison (Corn Specialist) and James Noel (NOAA/NWS/OHRFC). Extension Educators: Roger Bender (Shelby), Glen Arnold (Putman), Greg LaBarge (Fulton), Harold Watters (Champaign), Gary Wilson (Hancock), Marissa Mullett (Coshocton), Mark Koenig (Sandusky/Ottawa), Todd Mangen (Mercer), Ed Lentz (Seneca), Alan Sundermeier (Wood), Mike Gastier (Huron), Steve Foster (Darke), and Curtis E. Young (Allen).

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.