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August 27 to September 3, 2001
C.O.R.N. 2001-28
In This Issue:
A) Testing Drought Stressed Corn For Nitrate-Nitrogen
B) More Information on Drought Damage in Corn
C) Bean Leaf Beetle Update
D) Tri-County Agronomy Field Day
E) Soil and Water Protection Through Certified Crop Advisor
Education
This year the corn crop is under drought stress in many areas of Ohio. If the corn forage will be used as animal feed, it would be wise to test it for the concentration of nitrate-nitrogen. When a corn plant is severely stressed due to lack of sufficient moisture, it will tend to accumulate nitrate-nitrogen to levels that can be toxic to animals. Nitrate-nitrogen levels can be especially high if substantial nitrogen was applied at side-dress time and the plant did not continue to use the nitrogen in the development of protein because of the lack of sufficient moisture. Corn reaches toxic levels when nitrate-nitrogen is equal or greater than 0.34%. Special precautions for feeding corn may be needed when the concentration of nitrate-nitrogen is between 0.20 and 0.34%. To be on the safe side, it best to test the corn plants for the nitrate-nitrogen concentration.
When testing for nitrate-nitrogen samples can be taken and sent to a laboratory for analysis. The highest concentration of nitrate-nitrogen will be in the lower 9-10 inches of the stalk. Since the corn is usually ensiled or fed green chopped, it is best to sample the whole plant to obtain the most accurate concentration. Approximately 12 plants that represent the plants in area of interest should be selected for the test. The plant samples should be cut at the same height at which the field chopper is set. The whole (12) plant samples need to be chopped and mixed thoroughly before taking a sub-sample and sending it to the laboratory. The sub-sample should be sent to the laboratory as soon as possible so that the concentration of nitrate-nitrogen does not change.
It is important to communicate with the laboratory prior to sampling to determine if there are specific sample kits that they provide. It is also important to find out what to expect in turn-around time for the analysis. The laboratory should be able to provide the nitrate-nitrogen test results, along with interpretation, within 24 hours.
The following is a list of laboratories that test corn samples for their nitrate-nitrogen concentration:
A & L Great Lakes Laboratories
3505 Conestoga Drive
Fort Wayne, IN 46808
Phone: (219) 483-4759
Brookside Laboratory
308 S. Main Street
New Knoxville, OH 45871
Phone: (419) 753-2448
Holmes Laboratory
3559 U.S. Route 62
Millersburg, OH 44654
Phone: (800) 344-1101
Michigan State University
Department of Crop & Soil Science
East Lansing, MI 48824
Phone: (517) 355-0210
Spectrum Analytical Laboratory Inc.
P.O. Box 639
Washington Courthouse, OH 43160
Phone: (800) 321-1562
For more detailed information concerning feeding corn with high nitrate-nitrogen concentration, refer to the Ohio State University Fact Sheet AS-0003-99, entitled "Nitrates in Dairy Rations". This fact sheet is available on the Internet through Ohioline http://ohioline.osu.edu/as-fact/0003.html. Also, for additional assistance, contact your local county extension office.
Silk Emergence to Pollen Shed: At this stage, leaves and tassels are fully emerged and the cobs and silks are growing rapidly. This is the most critical period in terms of moisture use by the plant. Four days of moisture stress at this stage has the potential to reduce yields 40-50%.
Blister Through Dent Stage of Kernel Development: About 12 to 36 days after silking, the cobs, husks and shanks are fully developed and the kernels are increasing in dry weight. Moisture stress will reduce kernel fill from the ear tip down. Four days of drought at the blister stage has the potential of reducing yields 30-40%, and at dough stage, 20 to 30%.
Where dry weather has contributed to corn stands with uneven emergence, and development, yield loss may range from 5 to 20% depending on various factors such as the length of emergence delays and the percentage and distribution of later emerging plants. Where there is considerable variability in plant size, smaller, stunted plants will be at a competitive disadvantage with larger plants for nutrients, water and sunlight.
For help addressing other questions concerning drought damage in corn, the following are some relevant articles from the National Corn Handbook (NCH) that may help (index of NCH publications available via the web at the following address - www.agcom.purdue.edu/AgCom/Pubs/NCH/)
"Utilizing Drought-Damaged Corn" (NCH-58) - www.agcom.purdue.edu/AgCom/Pubs/NCH/NCH-58.html
"Weather Stress in the Corn Crop" (NCH-18) - www.agcom.purdue.edu/AgCom/Pubs/NCH/NCH-18.html
"Growing Season Characteristics and Requirements in the Corn Belt" (NCH-40) - www.agcom.purdue.edu/AgCom/Pubs/NCH/NCH-40.html
We should begin seeing an increase in populations of bean leaf beetles with the emergence of the second generation. Because this is the population that will feed on pods, growers should begin closely monitoring their fields to prevent significant levels of pod damage. See the CORN newsletter for August 13-19 for a full discussion concerning pod injury. Briefly, rescue treatment to prevent excessive development of seed damage may be warranted when pod injury exceeds 10-15% and adult BLBs are still present and actively feeding. The percent pod injury should be determined by sampling about 20 plants and counting the number of pods with feeding injury and the total number of pods. Adult BLB population should be estimated by taking 10 sweeps with a sweep net. Less than five BLB per sweep are unlikely to cause significant injury, five to 10 BLB per sweep indicates a potential problem, and more than 10 BLB per sweep may result in significant injury.
The Tri-County Agronomy Field Day is set for Thursday, September 6, 2001 from 2:15 p.m. til 7:30 p.m. at the Roger Kilbarger Farm near Thornville. Two and one-half hours of continuing education credit for certified Crop Advisors will be offered. The event is free of charge. OSU Extension and various corporate sponsors are involved in conducting the event.
Managing a Chemical or Fertilizer Spill, Potato Leafhopper Management, Root Development and Soil Structure, TMDLs, and Late Season Corn Stresses will be concurrent sessions. In addition, an update on the new farm bill and a presentation by TOP Producer's John Phipps on "What if This is Normal?" will be presented.
The Kilbarger farm is located off of S.R. 204 midway between Thornville and Millersport. For additional information contact Howard Siegrist at (740) 349-6900 or e-mail at siegrist1@postoffice.ag.ohio-state.edu.
An educational program for Certified Crop Advisors offering 5 hours of credit in Soil and Water Management and 1 hour in Crop Management has been scheduled for September 13, 2001.
Topics include:
1. Using Precision Agriculture to Protect Soil and Water
2. Bio-indicators of Water Quallity
3. TMDL - What is it? How are they determined? What impact will TMDL's have
on agriculture?
4. Crop Production Systems to Protect Soil and Water Quality
5. Managing Fertility to Prevent Nutrient Contamination of Surface and Tile
Water
6. Highlights and Issues With Local Soil and Water Programs
7. Crop Plot Tour
This program will begin at 9:30 AM and conclude at 4:00 PM and will be conducted
at Tom Weiler farm and Harmony Methodist Church located at county roads 20 and
123, Mt. Gilead, Ohio (1 mile west of I-71 and SR 95 interchange, turn south
on county road 20). Cost of the program is 20.00 dollars. Remit reservations
to: Steve Prochaska, OSU Extension, 117 E. Mansfield St., Bucyrus, Ohio 44820
by Sept. 11.
Readers can subscribe electronically to this newsletter by sending an e-mail message to: corn-out-on@postoffice.ag.ohio-state.edu. A successful subscription message will receive by an automatic reply from the listserv. Contact your local Ohio State University Extension Office or e-mail labarge.1@osu.edu if you have problems subscribing.
Past versions of C.O.R.N. can be found on the World Wide Web at: http:/www.ag.ohio-state.edu/~corn/archive/
C.O.R.N. is a summary of crop observations, related information, and appropriate recommendations for Ohio Crop Producers and Industry. C.O.R.N. is produced by the Ohio State University Extension Agronomy Team, State Specialists at The Ohio State University and Ohio Agricultural Research and Development Center. C.O.R.N. Questions are directed to State Specialists, Extension Associates, and Agents associated with Ohio State University Extension and the Ohio Agricultural Research and Development Center at The Ohio State University.
Contributors to C.O.R.N. this week include:Editor: Clark Hutson Web Editor: Tom Rosati
Information presented above and where trade names are used, they are supplied with the understanding that no discrimination is intended and no endorsement by Ohio State University Extension is implied. Although every attempt is made to produce information that is complete, timely, and accurate, the pesticide user bears responsibility of consulting the pesticide label and adhering to those directions.
All educational programs conducted by Ohio State University Extension are available to clientele on a nondiscriminatory basis without regard to race, color, creed, religion, sexual orientation, national origin, gender, age, disability or Vietnam-era veteran status.
Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, Keith L. Smith, Director, Ohio State University Extension.
TDD # 1 (800) 589-8292 (Ohio only) or (614) 292-1868
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