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Ohio State University Extension


C.O.R.N. Newsletter 2013-38

Dates Covered: 
November 19, 2013 - November 25, 2013
Steve Prochaska

Managing Temperature in Dry, On-farm Stored Grain

To maintain the dollar value of a bin of dry grain (corn or soybeans), one must manage the condition of the grain throughout the storage period.  Although storage problems commonly occur more frequently during a bad harvest year, many also result from poor dry-grain management practices in good harvest years.  This management begins with the loading of the grain into the bin, followed by managing temperature and moisture content of the grain mass and having a regular observation program of the grain to detect development of problems before they get out of hand. 

Recommended, safe-grain moisture contents for storage vary with type of grain and projected length of storage (Table 1).  

Table 1. Maximum moisture contents for safe grain storage.   These values are for good quality, clean grain in aerated storage.

                                                              Maximum moisture content

Grain type & Storage time                      for safe storage, %*


Shelled corn and sorghum

          Sold as #2 grain by spring                        15 1/2

          Stored 6-12 mo                                         14

          Stored more than 1 yr                               13



          Sold by spring                                           14

          Stored up to 1 yr                                       12

          Stored more than 1 yr                               11


*Reduce the moisture 1% below table values for poor quality grain resulting from drought, frost, blight, harvest damage, etc.

Good grain storage management should have started at the time of filling the grain storage structure which is usually a cylindrical bin of various sizes.  Grain should have been cleaned as it was being off-loaded from grain carts and loaded into the bin.  For ease of management practices such as controlling temperature and moisture content of the grain using aeration fans, the grain should be free of dirt, weed seeds, fines and chaff.  Not cleaning these materials out of the grain mass can result disruptions of air flow through the entire mass.  Areas of heavy deposition of these materials can be so dense that moisture and temperature cannot be altered.  Coring the grain mass occasionally while it is being filled can reduce the amount of fines, etc. that accumulate in the center of the grain mass.

One error that many grain managers allow to occur after grain has been loaded into a bin is leaving a peak of grain in the head space area and/or over-filling a bin to the point that there is no room to work in the head space area.  One should be able to enter the head space area of a filled bin to level the grain to a common depth across the entire diameter of the bin.  Peaks on top of the grain mass are difficult to manage with aeration.  Air, like water, will travel the path of least resistance.  Air will more quickly exit a grain mass through the lowest edges of peaked grain leaving the center of the peaked grain not aerated.

Aeration fans should be started as soon as the bin floor is covered with grain and operated continuously until the grain is dry or the average air temperature is below 35 F for extended periods.  Leave all roof hatches open to provide a large air exhaust opening, approximately 1 sq ft for each 1,000 cubic feet per minute of air delivered to the bin.

Adjusting the temperature of grain in a filled bin should be done in steps.  The movement of a temperature front (zone) completely through the grain is one cooling or warming cycle.  Each time an adjustment is made; one must run aeration fans continuously until the zone moves completely through the grain before shutting down the system.  Failure to do so can lead to major problems in the grain mass wherever the front was allowed to stop.  How long that takes varies with the number and sizes (airflow rates) of aeration fans attached to a bin, as shown in Table 2.

Table 2.  Approximate times for one grain cooling or warming cycle.*


    Airflow               Fall                 Winter               Spring

     rate                  cooling             cooling             warming

    cfm/bu              hours               hours                 hours


     1/20                   300                    400                    240

     1/10                   150                    200                    120

     1/5                      75                     100                      60

     1/4                      60                       80                      48

     1/3                      45                       61                      36

     1/2                      30                       40                      24

     3/4                      20                       27                      16

      1                        15                       20                      12

    1 1/4                    12                       16                      10

    1 1/2                    10                       13                        8


* Times are based on 60-lb bushels in the Midwest and 10-15 degree temperature changes.

Grain drying or rewetting is usually insignificant during grain aeration.  Because the cooling (or warming) front moves through the grain about 50 times faster than a drying or wetting front, only a small fraction of the grain is rewetted during an aeration cycle, even with high humidity.  As a precaution, operate the aeration fan only long enough to accomplish the grain cooling or warming cycle. This is particularly important with higher capacity aeration fans.

When the daily average temperature drops below 35 F, cool the grain to a uniform temperature and turn the fan off.  If moldy odors are detected or the grain starts to heat, turn the fan on until the conditions are corrected. 

After cooling is completed, close the roof hatches and cover fan inlets to prevent migrating air from adding moisture to the grain.

If grain has been dried correctly for the storage period intended, problems with grain condition usually result from:  1) Improper grain cooling; 2) Inadequate observation of the stored grain for early detection of developing problems; 3) Poor initial grain quality; and 4) Improper insect control. Each of these problems can be minimized with good management.

Remember, working around flowing grain and grain in storage can be very dangerous.  Follow safety rules at all times while working in or around grain bins.

For more information about managing dry grain in on-farm storage bins see factsheets at the following URLs:

Managing Dry Grain in Storage. (Purdue University)

Natural Air Grain Drying in Ohio FactSheet AEX-202-06 (The Ohio State University)

Bt Transgenic Corn Update

The Bt corn trait table that is available on our Agronomic Crops Insects web site ( has been updated as of November 1, 2013.  This table lists almost all of the hybrids available for growers and the pests they manage, along with the refuge requirements.  However, make sure you read the bag label and information for all needed information and requirements.

The reason why this table is not completely up-to-date is that Pioneer just announced last week the release of a new Bt product in their Optimum family, Leptra.  Leptra is a combination of Herculex 1 (Cry1F), YieldGard Corn Borer (Cry1Ab), and Agrisure Viptera (Vip3A).  However, Ohio growers should know that this product is intended for the southern U.S. where it will help in the management of the numerous above-ground lepidopteran pests in that part of the country, including various corn borers, corn earworm and fall armyworm.  Thus, Ohio growers should not expect to see this available anytime soon in our state.  Currently, it does not contain a Bt protein for rootworm control.

North American CCA Exam Registration

The next North America Certified Crop Adviser Exam Date is February 07, 2014. The Registration Period closes on December 06, 2013.

Keep in mind, to become eligible for the CCA certification, you must take and pass both the North American and your local (state/province) board exams. For us in Ohio, Indiana and Illinois that is the Tri-state exam. A group of educators and practicing CCAs from each state gathers regularly to update and verify the exam.

For more information and to register for the exam: The cost for the International (North America) exam is $175 and the Tri-state exam is $50. The Ohio site for the February 7th CCA exam is in Reynoldsburg at the Ohio Department of Agriculture.

The CCA program is truly international with CCAs in the US, Canada, Mexico and India. This program started 20 years ago from industry and university interest in documenting the continuing education that crop advisers and agronomists need to have to best provide advice to their farmer clients. After the exam is passed, the candidate documents their education and experience and provide references from their employer and clients. The last item to becoming a CCA is to sign the Code of Ethics. Once a CCA, there is a requirement to participate in 40 hours of continuing education every two years. For more information, see:  

OSU Extension will be offering a CCA Exam preparation class January 15 & 16, 2014 beginning at 9:00 a.m. on the 15th and to adjourn by 5:00 p.m. on the 16th in Sidney, Ohio at the Shelby County Extension office. Registration for the program is now open. Registration is on a first-come, first-serve basis. The fee is $225 per person, which covers the cost of instruction, lunches, handouts and other costs associated with the course over the two days. All instructors are CCAs. Pre-registration by January 8th is requested for meal planning and for handouts to be ordered and/or printed in sufficient quantities.  No registrations after the deadline, we expect a full room. See the AgCrops calendar for registration and agenda: For more information please contact Harold Watters at 937 604-2415, or by email

Modified Relay Intercropping – Lessons from 15 Years of Field Trials

Modified Relay Intercropping (MRI) is the planting of soybeans into headed wheat that may occur up to 7 weeks prior to wheat harvest.   MRI is system where two crops, wheat and soybeans can be harvested in the same growing season.

In 2013 in the MRI system, soybeans averaged 54 bushels/acre and wheat 70 bushels per acre over 12 different small plot field trials (randomized complete block, 4 replications).  This year, soybeans were above the long term average MRI yield and wheat below the long term MRI average yield (soybeans 30 bushel/acre; wheat 76 bushel per acre).  

After 15 years of field trials, the following are observations of the MRI system:

1.            MRI (planting of soybeans into wheat) can be conducted with many different common farm implements (some fabricated on farm).  Equipment used includes drills, tool bar planters, corn planters and variations. The key concept with equipment is to plan for and if possible, practice in the fall prior to wheat planting with the tractor/soybean interseeding equipment into practice wheat rows.  Tram lines in the wheat are essential to allow not only for precision soybean planting but also wheat management (weed, disease and fertility treatments).  Most tram lines are set up to facilitate tractor and sprayer tires.

2.            Wheat row spacing may range from 10 to 20 inches.  Wheat rows greater than 10 inches may experience a small wheat yield drop. This drop in wheat yield is relatively small up to 15 inches (from 5 to 7%) over various studies conducted in Ohio, Kentucky and Ontario.

3.            Attempt to sow wheat at or soon after Hessian Fly Free Date; for example, by Oct 7 in North Central Ohio. Plan to use an appropriate soybean variety that is harvested early enough to permit timely fall wheat planting.  There is not any merit to planting wheat prior to the Hessian Fly free Data (for example: Sept. 26 in Crawford County, Ohio).  Plant wheat seed to achieve 1.6 to 2.2 million seeds/acre or if in 15 inch rows not more than 25 seeds per foot of row.

4.            Select wheat varieties that are:  high yielding; disease resistant; early maturing and short if possible.  Confirm that wheat seed is treated with appropriate fungicides.  Go to http://agcrops/ and check out the OSU Wheat variety performance trials and the 15 inch wheat row trial.

5.            Apply fall fertilizer per soil test and Tri- State Fertility recommendations for at least 76 bushel wheat and 30 bu/soybeans (our 15 year average). Spring wheat N should again follow Tri-State recommendations.     

6.            Control marestail and other weeds prior to planting wheat either with appropriate tillage (not vertical tillage) or use appropriate herbicides (glyphosate + Sharpen is an example of a treatment that can be used prior to wheat planting to control marestail and many other weeds).

7.            Grow the best wheat you can grow utilizing  best management practices( ie: soil testing, fall  fertility  with some nitrogen, an appropriate spring nitrogen rate applied prior Feekes GS 6, disease control as needed as needed, 2,4-D applied on wheat in the spring prior to  wheat jointing by  Feekes GS 6, etc.).  

8.              Interseed soybeans about 21 to 50 days prior to wheat harvest. The fall wheat planting date, variety, weather and wheat row spacing selected will influence the soybean interseeding date.  Interseeding can be done too early!  There must be adequate light onto the developing soybeans,

(and wheat).  If interseeding is conducted too early, there is the possibility that soybeans will decrease wheat yields via excessive competition and further the soybeans may be damaged as well at wheat harvest.   Wide wheat rows will facilitate earlier soybean planting, but a wheat yield reduction is possible.  This wheat yield loss is due to both increasing row width and the interseeding of the soybeans.  Use as late a maturity soybean as is appropriate for your locale and planting date.  In previous trials conducted a 3. 3 or later maturity soybean has been planted with not any freeze damage.  A later maturity soybean may allow for more leaf development, later flowering and pod development with late season rains.     In 15 inch rows, plant beans from 6 to 7 seeds per foot of row.  In 10 inch rows, plant 4 to 5 seeds per foot of row.    

9.            Available plant water for soybean growth and development is critical.  Stated in another way, timely rainfall in July and August are very important to soybean yields.  This year, MRI soybean yields were exceptional (54 bushels/acre) with about 25 inches of rain from the middle of May to Oct. 1.  Our data would suggest that rainfall amounts over the summer growing season and hence soybean yield in the MRI system follow a normal distribution.  What this means is: soybean yield 1 year out of 5 will be very poor and  soybean yield 1 year out of 5  will be very good;  with the remaining 3 years of  soybean yields being around  average. 

10.          Wheat may be in flower when interseeding.  This will not significantly harm wheat as long as it is not run down (there may be a small interseeding effect on wheat yield in some years).  Spreaders, fabricated iron into a V shape, attached to the tractor and/or the planter should be considered in some MRI systems that will spread the wheat at planting and allow the equipment to pass without running over the wheat.   

11.          The larger the soybeans are at wheat harvest; the more susceptible to injury or damage from the combine wheel traffic.  Significant soybean stand loss can occur and this is essentially in the area run over by the combine tires.

12.          Harvest wheat early as can be threshed,   if possible harvest wheat at 20% moisture and dry.

13.          Cut wheat at top of soybeans.

14.          Aggressively chop and evenly spread wheat residue behind combine as excessive residue on soybeans will limit yields.

15.          Control weeds.  With development of herbicide resistant weeds, glyphosate cannot be relied upon to control weeds such as marestail; however within the system, other herbicides effective on marestail can be applied.

16.          Scout for defoliators/pod feeders in late July and early August as they have the potential in some years to may damage interseeded or double crops beans and reduce yields.

As is the case every year, new information from our 2013 trials will be added to our previous experiences with this system and that new information will lead us to trial new MRI concepts in 2014.  Among the concepts up for test in 2014 are revised wheat/soybean row spacing’s, and interseeded corn and grain sorghum (the latter two concepts were conducted in 2013). 

Finally, there are many other cultural and risk management factors associated with MRI not discussed here and these factors may be associated with either the wheat or soybean production.  For more information on the Modified Relay Intercropping go to:

CCA of the Year Nominations Due by January 10th

Who is a CCA? The Certified Crop Adviser (CCA) program is the largest, most recognized agriculturally-oriented certification program in North America. This program’s professional standards are widely respected by industry, academia, and government and are referenced in statutes. CCAs work at co-ops, ag retailers, as your seed dealer, as independent crop consultants, in government agencies and even OSU Extension. Our goal is to bring crop farmers the best advice we can.

Certification is the standard by which professionals are judged. The purpose of a certification program is to protect the public and the profession. The CCA program is a voluntary professional enhancement to a person's career credentials. Farmers and employers prefer to work with Certified Crop Advisers because CCAs have demonstrated they have the commitment, education, expertise, and experience to make a difference.

Nominations are now being accepted for the 2014 Certified Crop Adviser of the Year award. The Ohio CCA Program is sponsoring this state award designed to recognize an individual who is highly motivated, delivers exceptional customer service for farmer clients in nutrient management, soil & water management, integrated pest management, and crop production, and has contributed substantially to the exchange of ideas and the transfer of agronomic knowledge within the agricultural industry in Ohio.

The winner of this year’s award will be recognized at the Conservation Tillage & technology Conference in Ada, OH on March 4th, 2014. The winner will receive a $1,500 cash award from agribusiness, industry recognition, and a plaque. 

Submit nominations by January 10, 2014 to the:

Ohio CCA Board c/o Ohio AgriBusiness Association

5151 Reed Rd, Suite 126-C

Columbus, Ohio 43220-2598

A nomination form is available at under Links or at the go address:

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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.