Introduction
Harvest is slowly getting back underway following last week’s extensive rainfall.  Much of west-central and N.W. IA received in excess of 3.0 inches of rain on already wet ground.  I would expect soil compaction (see last weeks newsletter) to be a problem this fall as heavy combines and grain carts travel across fields.  Figuring shrink following drying of corn grain isn’t as simple as just subtracting the % moisture removed; use the following table to calculate the actual shrinkage when drying corn to storage moisture.   Newsletters from neighboring states often address problems we may be experiencing here in IA, I’ve included some of their observations and insights into this newsletter to address some harvest-time questions you may be having.

How much corn-grain weight will I have after drying to storage moisture?
Weight loss due to drying is referred to as “shrink”.  Shrink is comprised of weight loss due to removal of water and miscellaneous handling losses.  Shrink factors used by grain handlers typically account for both water shrink and handling loss.  Of course, weight loss due to water shrink is by far the largest weight loss factor.  There are several mathematical equations and methods to determine “water shrink”, but to simplify the process, the water shrink factors have already been calculated and are presented in table 1.  The “water” shrink factor to use depends on the desired final moisture content of the grain.  A good estimate of handling loss is 0.5%, which is added to the water shrink to obtain “total shrink”.

Water Shrink = (percentage points removed) * (water shrink factor)

 Total Shrink = [Water Shrink + 0.5%]

Example:  You plan to dry shelled corn from 25% to 15.5% moisture (a removal of 9.5 percentage points), the water shrink would be [9.5 * 1.183 (from table 1)], or 11.24% of the original grain weight.  Total shrink would be [11.24% + 0.5% (handling loss)], or 11.74%.  So if we started out with 1000 lbs of 25% moisture corn, we would end up with 882.6 lbs of grain dried to 15.5% moisture; [1000 lbs * 0.1174 (total shrink loss) = 117.4 lbs of lost weight; then 1000 lbs – 117.4 lbs (lost weight) = 882.6 lbs of dry grain]

Source:  Calculating grain weight shrinkage in corn due to mechanical drying, D.R. Hicks and H.A. Cloud, Univ. of MN.  NCH 61.  http://www.extension.iastate.edu/Publications/NCH61.pdf

I often look to other newsletters for topic ideas and information to problems we are experiencing here in northwest IA.  The following bits of information were taken from OSU’s C.O.R.N and Nebraska’s CropWatch newsletters.

Ear Drop in Corn
Excerpted from CORN Questions, written by Peter Thomison; http://corn.osu.edu/index.html

There are several factors that may be contributing to "ear retention" problems in corn fields. In many fields, European corn borers (ECB) may present in the shank or in the stalk near the ear, and ECB feeding and injury may be causing ears to drop.  Another explanation may be due to drought and lodging stress and premature plant death which may have affected shank strength. It's been suggested that the ear shank may be cannibalized for carbohydrates by the ear just like the main stalk, which can lead to shank deterioration and eventually ear drop.  The loss of one "normal" sized ear per 100 feet of row translates into a loss of more than one bushel/acre.

Purple soybean seed  Loren J. Giesler, Extension Plant Pathologist, University of NE.  October 4, 2002 Nebraska CropWatch; http://cropwatch.unl.edu/

As this year’s soybean harvest is well underway, you may see an increase in occurrence of purple soybean seed. In most if not all cases this seed discoloration is due to a fungal disease referred to as “purple seed stain”, caused by Cercospora kikuchii. This disease is widely distributed and occurs every year at low levels. However, this year we have had excellent conditions for development of this problem. While this disease generally does not reduce yield, it will reduce seed quality and can impact seedling quality if planted next year.

Purple or pink streaks on the seed coat are the primary symptom of purple seed stain and discoloration can range from streaks to large blotches. The fungus grows into the pod and spreads though the hilum, resulting in seed discoloration being centered on the hilum. In some cases the entire seed may be discolored. The fungus over winters on soybean residue. Spores are splashed onto plants during the growing season and the fungus grows into the pod.  Conditions that favor purple seed stain develop when wet weather delays harvest or warm, wet weather hits when plants have begun to reach maturity (growth stages R7 and R8) or when pods are completely brown.  Rapid dry-down prevents seed infection and cool weather slows the rate of fungus growth, but if moisture continues into harvest there to be an abundance of this discolored seed.

Livestock Compensation Program – United States Department of Agriculture
Excerpted from OSU CORN Questions; http://corn.osu.edu/index.html

Approximately $752 million is being made available for a new program, the Livestock Compensation Program, for cattle, sheep, goats and buffalo producers in counties that have received primary disaster designation due to drought in 2001 and/or 2002. In addition, producers in counties which have disaster designation requests pending as of September 19, 2002 which are subsequently approved will also be eligible to participate in the program. Sign up will begin Oct. 1 at county Farm Services Agency offices, with payments made soon thereafter.  The payment rate is $18 per animal consuming unit, which is indexed against beef cattle. Types of livestock adjusted by these factors are:

Beef Cows $18.00/head
Dairy Cows $31.50/head
Stockers $13.50/head
Goats $4.50/head
Sheep $4.50/head