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Agronomic Crops Network

Ohio State University Extension


C.O.R.N. Newsletter 2012-23

Dates Covered: 
July 23, 2012 - July 30, 2012
Amanda Douridas

Near Normal Rainfall in Forecast

Summary: There is some good news going forward. Above normal temperatures will continue for the rest of July into August but the hottest weather is behind us. Rainfall will see some improvement with near normal rainfall possible the next two weeks. Drought conditions appear to have bottomed and some improvement is now possible.

Outlook Week 1 through July 28: Above normal temperatures with near normal rainfall. Normal highs are in the 80s and normal lows in the 60s. Normal rainfall is near 1 inch. Most of this week will see highs in the 80s northeast to 90s southwest. There is a chance of above normal rainfall with the preferred area in the east half of the state where 1 to 3 inches is forecast. Normal to below normal rainfall will occur in the west with 0.50 to 1.50 inches for a state average of near normal.

Outlook Week 2 July 29 through August 5: Temperatures will remain above normal but only by a few degrees with highs mostly in the 80s. Some 70s are possible northeast and a few 90s are possible west. Rainfall will average around 1 inch for the state. Isolated totals in thunderstorms will be higher.

Outlook into Autumn: Above normal temperatures will relax to near normal with rainfall near to slightly below normal. This combination in a relaxation in heat and more rainfall should allow drought conditions to slowly improve into autumn as was discussed last week.

Winter Outlook: An El Nino, warming of the eastern Pacific Ocean, is forecast to occur. This tends to bring a cold start with a warm finish to winter along with below normal precipitation. We will monitor this development.

Stress Degree Days: The National Weather Service Ohio River Forecast Center calculated historic Stress Degree Days. Stress Degree Days (SDDs) for corn, which are calculated by taking the maximum temperature near where you live minus 86 added up since May 1, has risen to 235 for Ohio as of July 21. On July 15 it was 203. Usually above 140 for a growing season means below trend line yields. How does this compare to historic data:

Rank      Year       SDDs through July 21              SDDs for the year
#1          1936       252                                         471
#2          1934       249                                         373
#3          1988       240                                         358
#4          2012       235                                         ???

We are currently in 4th place and only slightly behind the top 3 years right now. It looks like we could finish the year anywhere from #2 to #4. bottom line, this has been a stressful year on the corn crop from not only the dry weather we had but also the heat.

You can stay on top of the next 30-90 days for risks of droughts, floods and everything in between by going to

At that page you can sign up for alerts send to you via email or go to:

2012 Ohio Wheat Performance Results Available


The purpose of the Ohio Wheat Performance Test is to evaluate wheat varieties, blends, brands, and breeding lines for yield, grain quality and other important performance characteristics. This information gives wheat producers comparative information for selecting the varieties best suited for their production system and market. Varieties differ in yield potential, winter hardiness, maturity, standability, disease and insect resistance, and other agronomic characteristics. Depending on variety and test site, yields varied between 56.6 and 123.1 bushels per acre, and test weight ranged from 55.2 to 63.2 pounds per bushel. Selection should be based on performance from multiple test sites and years. Results of the 2012 wheat performance evaluation are available at: and

Western bean cutworm eggs found, continue to scout corn

Western bean cutworm eggs found, continue to scout corn


The first WBC egg mass for 2012 was collected in Ashtabula County, which is also first for this area of the state.  The field where the egg mass was collected was well under threshold (5% of corn with egg masses), but yet suggests oviposition in underway.  Based on our trap counts, peak flight is starting to wind down, but remain high in the northwest and northeast portions of the state. All corn should be inspected for WBC egg masses, especially corn that is untasselled as these are preferred hosts for WBC. See our article last week ( about egg scouting protocols and egg identification.

Manure Movement through Soils


Livestock farmers and commercial manure applicators need to be extra cautious applying liquid manure to dry farm fields this summer. While it may seem that dry fields can absorb larger amounts of liquid manure, there are other soil conditions that must be taken into consideration. Dry soils often crack and deep cracks can create a pathway directly to subsurface drainage. Worm holes can also have the same effect as night crawlers and even crayfish tend to burrow directly down to field tile.

Manure reaching field tile through soil cracks, worm holes and other direct conduits is referred to as preferential flow. Taking measures to prevent manure from reaching tile outlets is crucial to avoid contamination of water bodies.

Any measure of disturbing the soil will aid in keeping manure nutrients in the root zone. This can be tillage equipment that works the ground 3 to 5 inches deep prior to application, or injection equipment that disturbs the soil below the line of manure injection. With tillage, be sure the equipment leaves at least a 90% residue cover.

During and after application, tile outlets should be monitored for manure flow. Sometimes it can only take seconds for manure to reach tile lines. Checking immediately as well as throughout the next 24 hours is recommended depending on how dry the tile is and how far the outlet is from the site of application. Tile plugs and control structures can be used to ensure manure does not exit outlets or they can be used in an emergency situation to stop manure that is already flowing.

All soils are rated for their available water holding capacity (AWC).  AWC is exactly what it sounds like; it is the maximum amount of moisture soils can hold before runoff begins. NRCS Practice Standard 633 (available online or from local SWCD and NRCS offices) provides an easy guide to determining what that moisture level is by soil type.

If more manure is applied than the soil can hold, there is an increased risk that the manure will move offsite and contamination of water bodies could occur. When injecting manure on 30 inch centers, remember that manure is being applied at much greater volume directly behind the injectors than the soil may be capable of absorbing.  Using lower rates and covering the fields twice might be advisable.


One final suggestion for summer manure application is to plant a cover crop ahead of time. Oats, cereal rye and radishes have all been successfully used. Each can capture the ammonia nitrogen portion of the manure and convert it to plant tissue, which eventually gets released after the plant dies as organic nitrogen in future crop seasons.

For more details on preferential flow visit:

Electronic Nutrient Management Workbook


The electronic version of OSU Extension’s Nutrient Management Workbook is now available online at  The workbook allows users to quickly allocate manure nutrients and/or commercial fertilizer to cropland to meet the agronomic needs of the crop.  Farms with manure sources can enter the total yearly production of manure using book values or known farm values.  The allocation of manure to fields is tracked so users can easily see how much manure remains after each field’s nutrient needs are met.  This allows farms to balance on farm nutrients and forecast manure storage levels throughout the year.

The crops currently included in the workbook are corn, corn silage, soybeans, wheat, and alfalfa.  The nutrient needs of these crops are based on the Tri-State Fertilizer Recommendations for Corn, Soybeans, Wheat and Alfalfa.  The workbook also provides guidance on observing setbacks from sensitive areas when applying manure.  Soil and manure test information is accepted so users can fine-tune each field or book values can be used if test results are not available to create a general plan.  If test results are used, the plan may be approved by local Soil and Water Conservation Districts which can serve as an affirmative defense in a private civil action for nuisances involving agricultural pollution.

For more information on the Nutrient Management Workbook contact Amanda Meddles at or 614-292-6625.

Emergency Forages

With the current drought situation, livestock producers may be in need of emergency forages for livestock. The OSU Beef team has created the Beef Cattle and Forage Drought Information page. The page contains information on feeding non-traditional crops as well as other drought information such as managing pastures under the current conditions. The page can be found at:

High temperature effects on corn and soybean


High temperature stress is usually associated with drought.  Heat stress and drought intensify damage to corn and soybeans but either may cause major crop injury alone.  The recent high temperatures, i.e., record numbers of days above 90 degrees, and in some locales 100 degrees F, have generated questions about the impact of high temperatures on corn and soybeans. How much heat stress can these crops withstand without incurring major yield losses even when adequate soil moisture is available?

Corn originated as a tropical grass and can tolerate exposures to adverse temperatures as high as 112 degrees F for brief periods. Optimal daytime temperatures for corn typically range between 77 degrees F and 91 degrees F. Growth decreases when temperatures exceed 95 degrees F. Fortunately, the high temperatures during the past week have been associated with some much needed rains across the state.

How high is too high for corn? Dr. Emerson Nafziger, University of Illinois agronomist notes that “afternoon temperatures in the mid-90s are not a problem for corn….. if they have enough soil water available. …. plant temperatures have been raised to 110 or higher without doing direct damage to photosynthetic capacity. The level required to damage leaves depends on the temperature the leaf has experienced before, but it generally takes temperatures above 100 in field-grown plants.”

According to Iowa State University agronomist Roger Elmore and climatologist Elwynn Taylor, high temperatures may have a double impact on corn “The first is the increase in rolling of corn leaves in response to moisture deficiency. By rule-of-thumb, the yield is diminished by 1 percent for every 12 hours of leaf rolling - except during the week of silking when the yield is cut 1 percent per 4 hours of leaf rolling. ….The second impact is less obvious initially. When soil moisture is sufficient, as it is for the most part this July, the crop does not have a measurable yield response to one day of temperatures between 93F to 98 F. However, the fourth consecutive day with a maximum temperature of 93 F or above results in a 1 percent yield loss in addition to that computed from the leaf rolling. The fifth day there is an additional 2 percent loss; the sixth day an additional 4 percent loss. Data are not sufficient to make generalizations for a heat wave of more than six days, however firing of leaves then becomes likely and very large yield losses are incurred.  Generally a six-day heat wave at silking time is sufficient to assure a yield not to exceed trend (Iowa trend yield is near 174 bushels per acre). Should warmer than usual nights continue for a six-week period the state is assured a below trend harvest….”   

What is the ideal temperature for soybeans?  Soybeans are a temperate leguminous plant with an ideal daytime temperature of 85°F.  When air temperatures exceed 85°F, soybeans can experience heat stress regardless of reproductive stage.  When soybeans experience heat stress, yield reductions can begin to occur, especially when soil moisture is limiting.  Heat stress during flowering can result in pollen sterility and reduced seed set.  Temperatures exceeding 85°F can result in a decreased number of pods while temperatures above 99°F severely limit pod formation.  Heat stress at the R5 growth stage (beginning seed), has the greatest impact on soybean yield.  During seed fill, daytime temperatures of 91 to 96°F result in fewer seeds per plant.  Daytime temperatures greater than 85°F during seed fill can result in decreased soybean weight.

How do high nighttime temperatures affect corn and soybean production?  High nighttime temperatures (in the 70s or 80s) can result in wasteful respiration and a lower net amount of dry matter accumulation in plants. The rate of respiration of plants increases rapidly as the temperature increases, approximately doubling for each 13 degree F increase. With high night temperatures more of the sugars produced by photosynthesis during the day are lost; less is available to fill developing kernels or seeds, thereby lowering potential grain yield. High night time temperatures result in faster heat unit (GDD) accumulation that can lead to earlier corn maturation, whereas cool night temperatures result in slower GDD accumulation that can lengthen grain filling and promote greater dry matter accumulation and grain yields.

Past research at the University of Illinois indicates that corn grown at night temperatures in the mid-60s out yields corn grown at temperatures in the mid-80s. Corn yields are often higher with irrigation in western states, which have low humidity and limited rainfall. While these areas are characterized by hot sunny days, night temperatures are often cooler than in the Eastern Corn Belt.  Low night temperatures during grain fill have been associated with some of Ohio’s highest corn yields in past years. In 2009, when the highest corn average yield to date was achieved, 174 bu/A, Ohio experienced one of its coolest Julys on record. The cool night temperatures may have reduced respiration losses during early grain fill and lengthened the grain fill period.

Compared to corn, soybeans are less sensitive to high nighttime temperatures.  Warm night temperatures do not appear to increase respiration in soybean plants as much as corn.  During the day, soybean plants accumulate starch in their leaves.  At night, the starch is broken down and exported from their leaves.  When nights are cool, the amount of starch exported is reduced resulting in high leaf starch the following day which can disrupt photosynthesis.  Nighttime temperatures have to exceed 85°F before any noticeable reduction in soybean yield is experienced.  In an experiment conducted by the USDA, soybean plants subjected to a night temperature of 85°F resulted in a 10% yield loss.  Corn subjected to 85°F at night experienced grain yield reductions of 40%.   

How is soybean nodulation affected by high temperatures?  Soybean nodulation is influenced by temperature.  Greatest nodule weight and nitrogen fixation (the conversion of gaseous nitrogen to plant-available nitrogen) has been found to occur when soil temperature is 75°F.  When soil temperature exceeds 86°F, nodule initiation and growth decreases.  According to the OARDC Weather System (, maximum soil temperatures ranging from 79 to 89°F in the top four inches of soil have been recorded for July.  Under a soybean canopy, soil temperatures may be lower.  However, in fields where canopy closure has not yet occurred, high soil temperatures may result in decreased nodulation and nitrogen fixation.  Applying nitrogen fertilizer to nitrogen-stressed soybeans can increase yield in some cases, but this practice is not without risks (see this source).  Applying urea forms of nitrogen to warm, damp soils results in nitrogen loss as a gas (volatilization).  Additionally, if dry weather persists, the nitrogen may not be moved down into the soil and be accessible to the soybean roots.     



Elmore, R. and E. Taylor. 2011. Corn and “a Big Long Heat Wave on the Way” Iowa Integrated Crop Management Newsletter Iowa State Univ.

Gibson, L. R. and R. E. Mullen.  1996.  Influence of Day and Night Temperature on Soybean Seed Yield.  Crop Sci.  36:98-104.

Hu, M. and P. Wiatrak.  2012.  Effect of Planting Date on Soybean Growth, Yield, and Grain Quality: Review.  Agron. J. 104:785-790.

Lindemann, W. C. and G. E. Ham.  1979.  Soybean Plant Growth, Nodulation, and Nitrogen Fixation as Affected by Root Temperature.  Soil Sci. Soc. Am. J.  43:1134-1137.

Nafziger, E. 2011. High Temperatures and Crops. University of Illinois.

Peters, D.B., J.W. Pendleton, R.H. Hageman, and C.M. Brown.  1971.  Effect of night air temperature on grain yield of corn, wheat, and soybeans.  Agron. J.  63:809.   

Northwestern ARS Field Crops Day July 26


The OARDC’s Northwestern Agricultural Research Station (ARS) will be hosting the 2012 Northwestern ARS Field Crops Day on July 26th from 6 p.m. to 8:30 p.m.

The field day features a wagon tour of the Agronomic Crops Trials at the Northwestern ARS.  The program includes: Anne Dorrance – Soybean Disease Management and Seed Treatments, Bruce Clevenger – Sprayer Tank Water Quality, Tony Dobbels – Weed Resistance Management and Late Season Control Strategies, and Ron Hammond – Insect Challenges Facing Producers in the 2012 Growing Season.

There is no registration required and the event is open to the public.  Refreshments will be provided.  Commercial Applicator credits will be available and CCA credits have been applied for. Contact Matt Davis at or 419-257-2060 with questions or for more information. 

The Northwestern ARS is located at 4240 Range Line Road, Custar, 43511.  2.5 miles northeast of Hoytville at the corner of Oil Center and Range line Roads.

Field Day in Michigan: Farm Drainage, Design, Installation and Nutrient Management


A Farm Drainage and Nutrient Management Field Day sponsored by the Michigan Land Improvement Contractors and Michigan State University Extension is scheduled in Hillsdale County, Michigan on August 1st and 2nd. The field day will have six tile drainage contractors doing in-field demonstrations of sub-surface tile drainage installations.  Attendees can visit with the participating companies and learn about land shaping and drainage design, sub irrigation and GPS guided installations.   Equipment dealers from farm machinery to excavators and companies from seed to agricultural service providers will be available in the exhibit area.

Along with drainage, the field day will feature topics on nutrient management. This event will demonstrate how to customize management systems on your farm to avoid manure and/or other nutrients reaching subsurface drain tiles. Advances in water control devices and bio-reactors will be on display and in use at this field day. Cover crops and manure calibration will be discussed with regard to recycling plant nutrients.

Tillage equipment to manage soil residue and break soil pores that combine technology with management to achieve high yields and protect soil and water quality will be on display.  Salford, Landoll, John Deere and Kuhn-Krause will all be there with vertical and conservation tillage machines.

Farmers, industry and University specialists from five states will be guest speakers at the various field day demonstrations.  The events will take place on the field of Bruce and Jennifer Lewis, located two miles west of Jonesville, Michigan on US 12.  To Google directions, use the address:  5211 W. Chicago Road/US12, Jonesville MI.   The same events will happen both days and run continuously from 9 a.m. to 4 p.m. with a short break over the lunch hour.   Admission and parking is free.

Certified Crop Advisor credits will be available for CCA’s that attend. More detailed times and events can be found at  For more information contact Natalie Rector,

Articles added to Agronomic Crops Team Drought Resources

Several new articles have been added to the Agronomic Crops Team Drought Resources page. We will continue to update the page as new questions and concerns arise.



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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.