CFAES Give Today
Agronomic Crops Network

Ohio State University Extension


C.O.R.N. Newsletter 2006-07

Dates Covered: 
April 4, 2006 - April 11, 2006
Steve Prochaska

What Should Be Planted First – Corn or Soybeans?

Authors: Steve Prochaska

Farmers today are planting corn and soybeans much earlier than producers of 20 years ago. And this opportunity 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 soybean planting. Early planting in this scenario is from April 1 to April 21 for farmers located in north central Ohio. After April 21 the normal planting season would begin.

Soybeans - 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 crop development.
3. Perhaps the best seedbed of year and thus no soil compaction (only when soils are dry).
4. Spreading out of the work load (both spring and fall).
5. Seed treatments such as Apron, Maxim, Rival, and Cruiser may can help 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 replant response in the event of a poor soybean stand.
9. Soybeans have the ability to flex growth over plant stands, environmental conditions, weather extremes and planting dates and still yield well.
10. No loss of primary nutrients (P2O5 and K2O) applied needed for production of soybeans in event of crop failures.
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 (only when soils are dry).
5. Spreading out of the work load (both spring and fall).
6. Newer seed treatments such as Apron, Maxim, Poncho, Cruiser may 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 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 (soybeans generally will withstand temperatures to around 26 or 27 degrees F) after soybeans are up 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. Potential loss of applied pre-plant nitrogen via leaching or de-nitrification.
8. Corn herbicides may preclude planting soybeans in the event of corn stand failure.


One of the major attributes of successful farmers is timeliness. As farm knowledge and seed and equipment 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.

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 may not only reduce crop yields but also force 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 into dry soils may outweigh the risk of later cold weather and/or wet soils suitable to compaction.

Changes in Cruiser Label

Authors: Ron Hammond, Bruce Eisley

There are a few changes to the new Cruiser label to be aware of that are different than what is in our Bulletin 545, Control of Insect Pests of Field Crops. Early season protection of corn seedlings is now provided against black cutworm by Cruiser, compared with the earlier recommendation of suppression only. Soybean is now listed as a separate crop on the label, with Cruiser providing early season protection of seedlings from a number of insects, including bean leaf beetle, seedcorn maggot, and leafhoppers.

Spring Residual and Burndown Treatments in No-Till Soybeans

Authors: Mark Loux

We have had a number of questions lately about whether it is too early in spring to apply residual herbicides in soybeans. Our research generally indicates that the first half of April is an ideal time to apply a combination of burndown plus residual herbicides in soybean fields that will subsequently be treated with postemergence herbicides. Some relevant comments:

- we have already observed flowering in winter annual weeds in some fields, and burndown applications should be made soon to prevent seed production by these weeds.
- applying burndown herbicides this early provides more time for dessication of weeds prior to planting, which can make for a better seedbed.
- tough no-till weeds such as marestail are more easily controlled when small, so an early spring application of burndown plus residual herbicides is a more effective approach than later spring applications when plants are larger.
- Early spring application of residual herbicides often results in the most effective initial activity on giant ragweed. Rainfall and soil conditions in early spring are conducive for achieving a uniform distribution of herbicide in the upper few inches of soil prior to the period of maximum giant ragweed germination.
- longer residual soybean herbicides such as Canopy, Gangster, and Scepter are best suited for early-April application, while Sencor, Python, and Valor may be better-suited for application within several weeks of planting. Increasing residual herbicide rates can compensate for early application with most herbicides, however.
- It is possible to use a combination of residual herbicide plus 2,4-D, omitting glyphosate, in some no-till fields that are only sparsely populated with winter weeds. However, the combination of glyphosate plus 2,4-D ester plus residual is more consistently effective than 2,4-D alone on dandelion, marestail, and chickweed (which is not controlled by 2,4-D). Our research shows that the combination of glyphosate plus 2,4-D is more effective than glyphosate alone on a number of weeds as well, and should help delay the onset of glyphosate-resistant weeds.
- the combination of Gramoxone plus 2,4-D ester (plus residual) can be effective in many no-till fields in April when weeds are still small. This treatment tends to be most effective when applied with a residual herbicide that contains metribuzin, but will still be less effective than glyphosate plus 2,4-D on dandelions and larger marestail, however.
- The most effective preplant treatments for dandelion control in soybeans are combinations of glyphosate plus 2,4-D plus one of the following: Canopy, Canopy EX, SynchronyXP, FirstRate/Amplify, or Gangster. Dandelion control can also be improved by increasing glyphosate rates from 0.75 lbs ae/A to at least 1.1 lbs ae/A, and 2,4-D ester rates from 0.5 lb to 1 lb (if product label and time before planting allows).
- The most effective weed control and highest yield potential in Roundup Ready soybeans results from using fall or spring burndown herbicides, and establishing the crop under weed free conditions. Omitting preplant burndown herbicides from Roundup Ready soybean weed control programs will result in an increase in winter annual and dandelion populations over time, and difficulty in controlling large, weathered weeds with postemergence glyphosate applications. We believe that the failure to use an effective burndown treatment that includes several different herbicide sites of action also increases the risk of herbicide resistance.

Tips for Planter Maintenance to Improve Stand Establishment in Corn

Authors: Greg LaBarge, Peter Thomison

Uneven plant spacing and emergence may reduce yield potential in corn. Seed should be spaced as uniformly as possible within the row to ensure maximum yields and optimal crop performance. Corn plants next to a gap in the row may produce a larger ear or additional ears (if the hybrid has a prolific tendency), compensating to some extent for missing plants. Skips can reduce yield in fields where the intended population is at or below the optimum, while doubles increase yield when populations are less than optimum. Reduced plant stands will yield better if plants are spaced uniformly than if there are large gaps in the row. As a "rule of thumb", yields are reduced an additional 5 percent if there are gaps of 4 to 6 feet in the row and an additional 2 percent for gaps of 1 to 3 feet.

Uneven corn emergence will generally have a greater impact on grain yield than uneven plant spacing. Uneven emergence affects corn performance because competition from larger, early-emerging plants decreases the yield from smaller, later-emerging plants. If the delay in emergence is less than two weeks, replanting increases yields less than 5 percent, regardless of the pattern of unevenness. However, if one-half or more of the plants in the stand emerge three weeks late or later, then replanting may increase yields up to 10 percent. Emergence delays of 10 days or more usually translate to growth stage differences of two leaves or more. When two plants differ by two leaves or more, the younger, smaller plant is more likely to be barren or produce nubbin ears. Weeds also tend to be a greater problem in those areas of a field characterized by skips and gaps in the corn rows, and slow, erratic corn emergence.

Corn sometimes emerges unevenly because of environmental conditions beyond the control of growers. However, timely planter servicing and adjustment, as well as appropriate management practices, can help prevent many stand uniformity problems. The following are some tips for improving the uniformity of seed placement during planting.
1. Keep the planting speed within the range specified in the planter's manual.
2. Match the seed grade with the planter plate.
3. Check planters with finger pickups for wear on the back plate and brush (use a feeler gauge to check tension on the fingers, then tighten them correctly).
4. Check for wear on double-disc openers and seed tubes.
5. Make sure the sprocket settings on the planter transmission are correct.
6. Check for worn chains, stiff chain links, and improper tire pressure.
7. Make sure seed drop tubes are clean and clear of any obstructions.
8. Clean seed tube sensors if a planter monitor is being used.
9. Make sure coulters and disc openers are aligned.
10. Match the air pressure to the weight of the seed being planted.
11. Make planter adjustments and follow lubricant recommendations when using seed-applied insecticides (e.g. Poncho and Cruiser)
Much of the corn seed being planted in Ohio in 2006 is treated with seed-applied insecticides (e.g.. Poncho and Cruiser). While these seed insecticides can help reduce stand losses from soil insects, it is critical that corn growers make planter adjustments and follow lubricant recommendations when using these seed-applied insecticides. Unless these precautions are followed, the extra chemical loading on the seed may adversely affect the “plantability” of seed – vacuum planters may underseed and finger pickup planters may overseed. To improve planter accuracy, talc or graphite should be used according to the planter manufacturer’s recommendations. With vacuum planters, it will probably be necessary to raise the vacuum to achieve more accurate seed drop.

For more information on planter adjustments to improve stand establishment in corn, consult: "Tips to Reduce Planter Performance Effects on Corn Yield" OSU Extension Fact Sheet AGF-150-01
Dr. Bob Nielsen at Purdue University has a good article entitled “Planter Maintenance: Less Down Time, More Yield ” (Chat 'n Chew Café, 21 Feb 2005). It includes links to the service support Web pages at Case-IH, Deere, and Kinze and is accessible online at

The Organic Certification Process for Crops

Authors: Alan Sundermeier

A new fact sheet is now available that explains how to become certified as an organic grain producer. It is found on Ohioline at:
Certification is the process of proving the truth of something, such as a statement or a method. The issue of third-party certification in the organic industry came from the need to prove to consumers that farmers did, indeed, use organic methods to grow their crops.
In 1990, Congress passed the Organic Foods Production Act that included provisions for the establishment of the National Organic Program (NOP) and the development of national standards. By October 2002, all organic farmers, processors, handlers, and certifiers had to be in full compliance with the regulation. The NOP does not certify individuals, but it does accredit certifiers to assure that farmers, processors, or retailers are complying with the national standards. This fact sheet lists those certifiers that operate in and near Ohio.

Archive Issue Contributors: 

Ann Dorance, Pierce Paul and Dennis Mills (Plant Pathology), Mark Loux and Jeff Stachler (Weed Science), Peter Thomison, (Corn Production), Bruce Eisley, Ron Hammond (Entomology). Extension Educators: Alan Sundermeier (Wood), Howard Siegrist (Licking), Harold Watters (Champaign), Glen Arnold (Putnam), Roger Bender (Shelby), Steve Foster (Darke), Steve Prochaska (Crawford), Bruce Clevenger (Defiance), Tammy Dobbels (Montgomery), Greg LaBarge (Fulton), Mark Koenig (Sandusky), Gary Wilson (Hancock) and Keith Diedrick (Wayne).

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.