CORN
Crop Observation and Recommendation Network

For April 12-23, 1999
C.O.R.N. 99-5

In This Issue:

A) Stage Wheat Before Applying Herbicides
B) What should be planted first-soybeans or corn?
C) My Corn is not coming up!

A) Stage Wheat Before Applying Herbicides - Jeff Stachler CORN Questions

Many wheat fields south of Interstate 70 have begun to joint! Before applying Banvel, Curtail, and 2,4-D, double check the stage of the wheat. Application of these products will cause significant yield loss once the wheat has begun to joint. There are certain labels of 2,4-D that allow application up to early boot stage. 2,4-D is safer to wheat beyond the jointing stage than Banvel. The use of 2,4-D amine is also safer to wheat than 2,4-D ester, however 2,4-D ester provides more effective weed control. To minimize the risk of injury after jointing, use water as the carrier and do not apply more than ½ pint of ester or 1 pint of amine.

Now is the time to apply herbicides in wheat, as summer annual weeds have begun to emerge and wheat has or will begin to joint. Also more herbicide options are available prior to jointing. The most broad spectrum weed control program in winter wheat is Harmony Extra plus 2,4-D ester, especially at or shortly after jointing. A Harmony Extra plus Buctril/Moxy combination is nearly as effective, but not as good on dandelion, Canada thistle, and horseweed (marestail). These herbicides can be applied in nitrogen fertilizer solution when the wheat is top-dressed. This may increase injury somewhat, and some labels recommend adjusting surfactant rates to minimize injury. The Harmony Extra plus 2,4-D combination should only be applied in water if the wheat has begun to joint. Be sure to read the herbicide labels before making an application.

B) What should be planted first-soybeans or corn? - Steve Prochaska CORN Questions

Farmers today are planting corn and soybeans much earlier than farmers of 20 years ago. And this opportunity, when it occurs, to plant early into dry soils may be beneficial because the growing season is extended and soils are not compacted. However, there are risks to planting very early and the risks will vary by crop. What follows below is risk/benefit analysis to early corn and /or soybeans planting. Early planting in this scenario is from March 27 to April 20 for farmers located in north central Ohio. After April 20 the normal planting season would begin.

Soybeans - Benefits To Early Planting (only when soils are dry!)

1. Extended growing seasons with high quality sunlight (more photosynthesis possible). The maximum amount of sunlight occurs in the months of May, June and July in Ohio.
2. Adequate moisture for crop development.
3. Perhaps the best seedbed of year and thus no soil compaction.
4. Spreading out of work load (both spring and fall).
5. Newer seed treatments such as Apron, Maxim, and Rival can help to protect soybeans during time periods unfavorable for growth.
6. Weed control costs may be reduced due to earlier canopy.
7. Opportunity to plant wheat in a timely fashion in September.
8. Time to evaluate and make a mitigating response in the event of a poor soybean stand.
9. Soybeans have the ability to flex growth over different environmental conditions, weather extremes and planting dates and still yield well.
10. No loss of primary nutrients (P₂O₅ and K₂O) applied needed for production in event of crop failures (failure of early corn plantings may result in significant loss of preplant nitrogen).
11. Most favorable temperatures for crop growth and development may occur from April 15 to July 15 as opposed to July 15 to September 1 (carbohydrate deposition).
12. Opportunity to grow and harvest high yield soybeans (yields greater than 60 bushels/acre). Later planting may not allow such an opportunity due to loss of growing season.

Corn - Benefits to Early Planting (only when soils are dry!)

1. Extended growing season with high quality sunlight (more photosynthesis possible). The maximum amount of sunlight occurs in the months of May, June and July in Ohio.
2. Adequate moisture for early crop development.
3. Favorable temperatures for crop growth and development and thus carbohydrate deposition. Pollination may also occur during a period of cooler temperatures.
4. Perhaps the best seedbed of year and thus no soil compaction.
5. Spreading out of the work load (both spring and fall).
6. Newer seed treatments such as Apron and Maxim can help to protect corn in adverse soil environments.
7. Reduced weed control costs possible due to earlier canopy.
8. Can withstand a frost as long as growing points below ground.
9. Opportunity to grow and harvest very high yielding corn.
10. Longer growing season and thus the opportunity to have dryer corn at harvest.

Risks to Early Planted Soybeans

1. Hard freeze after soybeans are up (soybeans will withstand temperatures to about 26 degrees F) may kill plants.
2. Poor emergence due to extended periods or wet, cold weather (>25 days).
3. Cost of replanting in the event of stand failure.
4. Lack of time to replant on a timely basis.
5. Additional weed control costs due to lack of early crop canopy.
6. Loss of yield due to loss of growing season in the event the initial planting fails.

Risks to Early Planted Corn

1. One chance to get good stand!
2. Poor emergence due to extended periods or wet, cold weather.
3. Cost of replanting in the event of failure.
4. Lack of time to replant on a timely basis.
5. Additional weed control costs due to lack of early crop canopy.
6. Loss of yield due to loss of growing season in the event the initial planting fails.
7. Loss of applied preplant nitrogen via leaching or denitrification.
8. Corn herbicides may preclude planting soybeans in the event of corn stand failure.

Summary

One of the major attributes of successful farmers is timeliness. As farm knowledge and technology increase, corn and soybeans have been planted earlier. With our present knowledge and experience of planting corn and soybeans, there are reasons to consider planting soybeans before corn.

First, with farm size increasing, and many working off the farm, it is imperative to effectively utilize all available planting days. Stating it in another way, one of the major impediments to large or small farm operation success is the lack of planting time on dry soils. Planting on wet soils is a disaster that not only robs crop yields but forces additional tillage to rectify damage. And, more tillage creates the potential for greater soil erosion and concomitantly reduced farm profit. Thus, realizing there are additional windows to replant soybeans or repair poor stands (you realistically have one chance to get a good stand with corn) soybeans might be a better option for very early planting. Further, the benefits (in the years it is available) to very early soybean planting opportunities into dry soils may outweigh the risk to possible later cold weather and/or wet soils suitable to compaction. Using the above reasoning, Extension personnel are presently involved in evaluating the benefits to very early soybean planting. At least two more years of testing are necessary before general recommendations in regard to very early plantings will be able to made.

C)  My corn is not coming up! - Greg Roth  CORN Questions

After all of the investment that is made in land, equipment, labor and other inputs, it's frustrating when corn doesn't emerge as well as it should. Diagnosing emergence problems early helps to identify solutions and develop replanting plans. Corn should begin emerging after about 100 to 125 GDDs have accumulated following planting. This can be anywhere from one to three weeks after planting depending on the temperature. Here's a list of a few common things to look for if you encounter an emergence problem in corn this spring.

1. No seed present. May be due to planter malfunction or bird or rodent damage. The latter often will leave some evidence such as digging or seed or plant parts on the ground.
2. Coleoptile (shoot) unfurled underground. Could be due to premature exposure to light in cloddy soil, planting too deep, compaction or soil crusting, extended exposure to acetanilide herbicides under cool wet conditions, or may be due to extended cool wet conditions alone.
3. Seed with poorly developed radicle (root) or coleptile. Coleoptile tip brown or yellow. Could be seed rots or seed with low vigor.
4. Seed swelled but not sprouted. Often poor seed-to-soil contact or shallow planting- seed swelled then dried out. Check seed furrow closure in no-till. Seed may also not be viable.
5. Skips associated with discolored and malformed seedlings. May be herbicide damage. Note depth of planting and herbicides applied compared with injury symptoms such as twisted roots, club roots, or purple plants.
6. Seeds hollowed out. Seed corn maggot or wireworm. Look for evidence of the pest to confirm. Note the patterns of poor emergence. At times they are associated with a particular row, spray width, hybrid, field or residue that may provide some additional clues to the cause. Often two or more stress factors interact to reduce emergence where the crop would have emerged well with just one present. Also, note the population and the variability of the seed spacing. This information will be valuable in the future.

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: STATE SPECIALISTS: Pat Lipps (Extension Specialist, Plant Pathology), Anne Dorrance (Extension Specialist, Plant Pathology), (Jeff Stachler (Extension Associate, Weed Science), Peter Thomison (Extension Specialist, Corn Production), and Greg Roth (Extension Corn and Sorghum Specialist at Penn State University); EXTENSION AGENTS: Steve Prochaska (Crawford), Woody Joslin (Shelby), Gary Wilson (Hancock), Greg LaBarge (Fulton), John Barker (Knox), and Barry Ward (Champaign).

Editor: Steve Prochaska        Web Editor: Nathan Watermeier

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.

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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.

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