ISU Extension
Agronomy- Extension
IA State Univ.
IA Dept. of Ag
IA DNR

Northwest Area Extension

September 2004

In this issue
Fall Cornstalk Test - Post Season Nitrogen Assessment
Hoop Barns and Bedding Systems for Livestock Production National Conference
Harvest Prep
Beef of Merit Grid Marketing Class
Store A Large Crop?
McEowen Seminars Scheduled

Fall Cornstalk Test – Post Season Nitrogen Assesssment
By Todd Vagts, ISU Extension Crop Field Specialist

With the excessive amount of precipitation across much of N.W. Iowa this year, nitrogen availability to the corn crop has been questionable.  If you are wondering if corn yields may have been reduced by the lack of nitrogen, the nitrogen (N) status of a corn crop can be assessed by measuring nitrate concentrations in the lower portion of cornstalks at the end of the growing season.  The test is called the “end-of-season cornstalk test.”

Corn plants suffering from inadequate N availability remove N from the lower cornstalks and leaves during the grain-filling period. Corn plants that have more N than needed to attain maximum yields, however, accumulate nitrate in their lower stalks at the end of the season.  The use of the test enables a producer to ask if the crop had adequate N late in the growing season. 

Interpretation of stalk nitrate concentrations can be divided into four categories; low, marginal, optimal, and excess. The low category indicates high probability that greater availability of N would have resulted in higher yields. The marginal category indicates that N availability was very close to the minimal amounts needed. The optimal category indicates high probability that N availability was within the range needed to maximize profits.  The excess category indicates high probability that N availability was greater than if fertilizer N had been applied at rates that maximize profits.

The concentration of nitrate in the stalk at the end of the season reflects all factors (including weather) that influenced N availability and N needs during the growing season.  Lower than desired concentrations should be expected in years having unusually large amounts of in-season rainfall that results in unusually large losses of N and (or) high yield potential.

The time for sampling is between one and three weeks after black layer has formed on about 80 percent of the kernels of most ears.  Sampling is easier during harvest, but interpretation of results may be more difficult past the optimum sampling period.  The portion of each plant sampled is the 8-inch segment of stalk found between 6 and 14 inches above the soil.  Fifteen 8-inch segments should be collected to form a single sample to be sent for analysis.  Concentrations are expressed as parts nitrate-N per million parts of dry stover (PPM).

The test does not directly indicate how much N rates should be increased or decreased, but continued use of the test for several years provides information to make adjustments toward optimal rates.  For more information on the cornstalk test, refer to PM-1584 available at ISU Extension offices or online at:  http://www.extension.iastate.edu/Publications/PM1584.pdf

Adapted from PM-1584:  Cornstalk Testing

 

Hoop Barns and Bedding Systems for Livestock Production National Conference
by Jerry Weiss, ISU Extension Swine Field Specialist

If you are a swine, beef or dairy cattle producer looking for low-capital cost, competitive returns and exploring process-verified or niche market production as well as addressing animal welfare issues you may want to attend a day-long conference. This conference will be held September 14, 2004 at Gateway Center in Ames. The opening session begins at 9 am. with sessions concluding at 5 pm.

The keynote session will provide an overview on the use of alternative livestock bedding systems, where the industry is at, how animals respond, and reasons why hoop structures are a viable alternative for consideration.

The agenda is setup with three breakout sessions during the day. Topics include: Deep bedding systems for Dairy and other Livestock - Marketing Swine from Deep bedded systems - Deep bedding systems for Sows and Piglets - Animal Welfare Issues - Pork Quality - Interfacing Hoops with Conventional Systems - as well as other topics.

Pre-registration fee of $25 before September 1 - after September 1, pre-registration fee is $35.  A brochure may be picked up at your county Extension Office or by contacting Ag & Biosystems Engineering, Iowa State University, 208 Davidson Hall, Ames, IA  50011 (515-294-0557) or online at http://www.abe.iastate.edu/ABLS/
 

Harvest Prep
by Kris Kohl, ISU Extension Ag Engineer

By this time next month, the harvest push will be on.  It has been a long time since we have had to deal with a wet crop, but this one looks like we will need to review the basics of corn drying.

Corn is about 30% moisture at black layer and dries down in the field at about:

2 points per week in September

1 ½ points per week in October

            ¾ point per week in November

            ¼ point per week in December

Harvest losses are the lowest at 20% to 24% moisture.  Above these levels, the corn does not shell off the cob clean and a lot of damage is done at the germ end of the kernel which will allow mold to enter and reduce the storage life.  At lower harvest moistures, ear droppage and shelling at the head increase.

Drying Basics:

There are two ways to dry corn:

low-temp -  which is less than 60 degrees

or

high-temp -  which is greater than 120 degrees

The real danger zone is between 60° and 120°where the corn may sprout and spoilage happens fast.  Air flow is the key to drying.  Our drying bins should have at least 1.2 cfm (cubic feet of air per minute) when full.  A good rule of thumb is that a fan will produce about 1000 cfm per horse power (hp).  Therefore a 10,000 bu bin needs 10hp.

If the bin is only ½ full, you will increase your drying capacity by about 50%.

For natural-air drying, at 1.25 cfm/bu (when full), maximum moisture contents are as follows:

24% - ¼ bin full

            21% - ½ bin full

            19% - ¾ bin full

            17% - full bin

Over filling will result in spoilage.

This September, producers should clean up the fines on top of drying floors.  Make sure there is at least 8” between the drying floor and fines below the floor.  Turn on all the fans and service the motors, fill the propane tanks and hope for some warm weather.

Harvest will be here before you know it.

Beef of Merit Grid Marketing Class
by Dennis DeWitt, ISU Extension Livestock Field Specialist

The Beef of Merit Grid Marketing Class purpose is to provide 4-H and FFA market beef exhibitors an opportunity to participate in a live show combined with a value added carcass competition where the traits that add value to a beef carcass and the industry are evaluated in a scientific way.

Exhibitors must choose which grid window they will participate in for the live show when entering. The live show will award ribbons only. The final placing will be determined after harvest and carcass evaluation. Carcass desirability and trait value as well as growth rate are incorporated to calculate beef retail value added per day on feed.

Two typical grid windows are:  

“High Cutability” and “High Quality.” 

The High Cutability Grid offers more premium for superior yield grades and less premium for quality grades.  The High Quality Grid offers more premium for average & high Choice and Prime carcasses and less premium for superior yield grades.  There are discounts for too light or too heavy carcasses depending on grid program.

The equations for calculating the retail value added per day on feed are:

• Percent retail product is calculated as follows: (65.69 - (9.931 x fat thickness) + (1.2259 x rib eye area) - (.013166 x carcass weight)  - (1.29 x % kidney, pelvic, heart fat))

• Carcass retail value added per day on feed is calculated as follows: ((Hot carcass weight at packer-(.55 x beginning weight) x % retail product x carcass price as determined by appropriate grid))/.7/days on feed.

The 2004 Iowa State Fair Beef of Merit show set a record number with 74 entries.  The number of entries has increased in the last 7 years from about 50 to now over 70!  $4200 in fair premiums were paid to 2004 exhibitors. The steers averaged 1302 pounds with a 3.20 average daily gain.  The average steer carcass weighed 828 pounds and exhibited 0.43 inches of backfat, 13.8 square inches of ribeye area, 2.7 yield grade and 64.9% retail product.  Seventy percent of the carcasses graded Choice and were yield grade 1&2’s.

Youth beef exhibitors need to consider participating in the 2005 Beef of Merit Class at both their county fair and Iowa State Fair.  This is the real world of feedlot cattle marketing.  Color of the cattle and hair coat does not matter because once the hide is removed at harvest the carcasses all have a similar amount of bone, and varying amounts of red meat and white fat!

Store a Large Crop?
by Ron Hook, ISUE Farm Management Specialist

Grain markets are nervous over prospects of record corn and soybean crops. However, there is concern for the slow maturity of crops in northern Iowa, Minnesota and Wisconsin.  The Iowa State Entomology website reports that northwest Iowa is 239 degree days below average.  This uncertainty makes additional sales of new crop grain even more difficult.  If the September 10 USDA crop forecasts show production near the August forecasts, it would indicate that farmers with on-farm storage should consider storage this fall. 

A large crop will likely keep pressure on cash corn and soybean prices and the basis during the harvest season.  A review of LDP mechanics and management strategies may be in order if LDPs are triggered by lower prices.  It is likely that there will be some price recovery from mid-December into mid-winter after excess supplies in outside storage have been reduced.  Late winter and spring prospects look brighter for corn prices than for soybeans until the size of the South American crop is known.

McEowen Seminars Scheduled
by Ron Hook, ISUE Farm Management Specialist     
 
Roger A. McEowen, the newly-named associate professor of Agricultural Law at Iowa State University, is scheduled to present a series of get acquainted seminars in several locations around the state in September.  McEowen was chosen after an 18-month search to replace Neil E. Harl who has held the position for nearly 40 years and is retiring at the end of the year.
 
McEowen joined the Iowa State University faculty in Agricultural Education and Studies on August 15, 2004, from Kansas State University where he developed a strong program in teaching, extension and research from 1993 to 2004.  McEowen received the Distinguished Service Award from the American Agricultural Law Association in 2003, the youngest recipient ever for that award.

Professor McEowen is a native of Indiana with a bachelors degree from Purdue University, a Juris Doctor degree from Drake University and a Master of Science in Agricultural Economics from Iowa State University.
 
McEowen will present a seminar on important recent developments in Agricultural Law for approximately one hour and then follow-up with a question and answer session.  Seminars scheduled in northwest Iowa include:
 
September 1 - 12:00 lunch, 1:00 seminar

Lakeshore Café
North Lake Avenue
Storm Lake, IA

For reservations contact: Tom Olsen at Buena Vista Co Extension Office, 712-732-5056
                                                                                     
September 29 - 1:00 seminar

Northwest Iowa Community College,
Rm 116-119A,
Sheldon, IA

For reservations contact: Ron Hook at Osceola County Extension, 712-754-3648
Lunch available in college cafeteria for anyone so desiring.

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