2018 Summer Field Tours--Stand Counts, Herbicide Options  05/03/18 8:45:41 AM

Wiles Brothers Inc.

Calendar of Tour Dates Summer 2018


2018 Summer Field Tour Details


The 2018 tours will start with a “Stand Establishment Tour” on Wednesday May 30th  at our plot on the West side of Mynard Nebraska—1 mile South of our plant—1/4 west on Mynard Road OR 1-1/4 mile West of HWY 75 on Mynard Road—South Side of the Road.   The tours would last no longer than 1.5 hours and address any current agronomic issues as well as allow the attendees to monitor developmental progress of Asgrow and Dekalb genetics throughout the growing season.


Our Tentative Summer Tour Schedule


Date                                        Time                            Location

Wednesday May 30th              9:00 a.m.                     Mynard

Tuesday June 12th                   9:00 a.m.                     Mynard

Tuesday June 26th                   9:00 a.m.                     Mynard

Tuesday July 10th                    9:00 a.m.                     Mynard

Tuesday July 24th                    9:00 a.m.                     Mynard

Tuesday August 7th                 9:00 a.m.                     Mynard

Tuesday August 21th               9:00 a.m.                     Mynard


Wednesday August 29th ,WBI  Fall Mtg.  –Stay tuned for details


Seed Supply—Corn and Soybean supply of high yielding hybrids and varieties are still available.  I realize that this might be more of a soybean situation rather than a corn scenario.  WE still have Asgrow AG33X8, AG36X6, AG37X8, in good supply with seed tenders available for your use to complete your soybean planting this Spring.





Corn fields intended for liquid nitrogen/preemergence herbicide combinations sometimes emerge before herbicide application.  While certain preemergence herbicides can be applied after crop emergence, they are not labeled for application with fluid fertilizer after emergence, due to risk of injury.  Emerged corn is more tolerant to a point with fertilizer-herbicide mixtures.  Some growers may accept the injury in return for accomplishing two jobs at once.


Injury to corn is more serious with atrazine combinations.  The tolerance of emerged corn to liquid nitrogen and these herbicides is greatest in the spike stage and decreases as the plants grow.  Minnesota experiments have shown that atrazine applied to 4-leaf corn with 60 lbs N/acre caused heavy burning with widespread necrosis on the 2nd, 3rd and 4th leaves.  This injury, from which the corn recovered, was similar to injury caused by 150 lbs N/acre applied by itself.  Injury to emerged corn is usually more severe with herbicide combinations in liquid N than fertilizer alone.  If nitrogen must be applied as liquid N to emerged corn, early post herbicides should be applied in water several days prior to the application of liquid nitrogen.  Cool, wet weather can be expected to increase the injury caused by such treatment.



Preemergence Herbicides Applied Postemergence—Now that we have had some rain,  many fields will soon experience weed pressures and/or some areas experience pre-emergence treatments that fail to control certain weed species.  Most chloroacetamide herbicides may be applied postemergence to corn, but if weeds have emerged, the addition of POST-active herbicides is necessary.  Many of the chloroacetamide herbicides are pre-packed with atrazine.  Atrazine is commonly used as a pre and post-emergence treatment however, the addition of crop oil concentrate as a tank-mix additive increases the herbicide activity on grasses up to 2" in height.

The following table lists corn herbicides that are commonly used in Nebraska and can be used both preemergence and early postemergence.  The table depicts some of the more common treatments but is not all-inclusive.  Label limitations prevent certain soil-applied compounds from being used after crop emergence.  Only herbicides that can be used after crop emergence are listed below.


TREATMENT                     CROP STAGE                                  WEED STAGE            



Aatrex®/Atrazine                                0-12"                                       1.5" grass

Acuron                                                            0-12”                                       3”

Armezon Pro                                       0-30”                                       4”

Bicep II Magnum®/Cinch® ATZ        0-12"                                       2-leaf

Balance Flexx                                     V2                                           1.5”

Callisto®                                              0-30"--8 leaf corn                   broadleaves <5"

Corvus                                                 V2                                           1.5”

Dual II Magnum®/Cinch                     0-40*                                       unemerged

Dual® + Aatrex                                   0-12"                                       2-leaf

Expert                                                 0-12”                                       6”

Guardsman MAX®                             0-12"                                       1.5"

Harness®/Degree®                               0-11"                                       un-emerged

Harness® Xtra/Degree Xtra®              0-11"                                       2-leaf

Hornet®                                               0-20”                                       2-8” broadleaf

Keystone/Keystone LA                 0-11”                                       un-emerged

Lumax                                              0-12"                                       3”

Outlook®                                             0-30"                                       unemerged

Prowl® H20                                         0-30”                                       1"

Python®                                               0-20”                                       6”

Surpass® 100/Keystone/Fultime®    0-11"                                       unemerged

Topnotch                                             0-11”                                       unemerged

Warrant                                               0-30”                                       unemerged

Zidua                                                   V4                                           unemerged


TREATMENT                     CROP STAGE                                  WEED STAGE            



Dual II Magnum                                 3rd Trifoliate                            unemerged

FirstRate                                             up to ½ flower                         see label by species

Outlook                                               1st to 5th trifoliate                    2”

Pursuit                                                 up to ½ flower                         3”

Warrant                                               prior to R2                              unemerged

Zidua                                                   V1-V3                                     unemerged


Corn and Soybean Stand Counts—With corn planting finishing up and soybeans beginning to get into the ground, stand assessment is a logical next step for this year’s crops.  The following tables are handy to have not only to see what your final stand is from what you planted, but also, to determine IF replanting is a consideration. 



First, check your stand by counting the number of live plants based on various row widths

15” row – 34’10”, 20” row – 26’1”, 30” row – 17’5”, 36” row – 14’6”

Corn Replant--Early Season--Example #1:  Using the below table—(optimal planting date of April 30th):  If you planted a 108 Relative Maturity hybrid at 30,000 on April 30th and have a viable stand now of 15,000, the yield potential is 82%.   This table is useful for all replanting decisions (hail, soil crusting, insect damage, etc)


Planting                                                          Population (1000/ac)

 Date          10                         15                    20                    25                    30                    35

Apr. 1          62                       76                    86                    92                    94                    93

Apr. 20        67                       81                    91                    97                    99                    97

Apr. 30        68                       82                    92                    98                    100                  98

May   9        65                       79                    89                    95                    97                    96

May 19        59                       73                    83                    89                    91                    89

May 29        49                       63                    73                    79                    81                    79

                         % of maximum yield

from Nafziger,E.D. 1994. Journal of Production Agriculture. &:59-62

Based of research in the Central Corn Belt by the University of Illinois.


Corn Replant--Late Season--Example #2--The following table from Purdue University using 108-110 day hybrids demonstrates late season planting yield potentials.

                                                            Population (1000/ac)

Planting Date             16                    18                    20                    22.5                 25


May 16                        86                    90                    93                    96                    98

May 21                        83                    87                    91                    94                    95

May 26                        80                    84                    87                    90                    92

May 31                        75                    79                    82                    85                    87

June 5                          69                    73                    77                    80                    81

June 10                        63                    67                    70                    73                    75       

                        % of maximum yield

At a population of 25,000 planted on June 10th a yield reduction of 25% has occurred before you have pulled out of the field.  The chances of seeing a 15-20% yield reduction due to early frost/light test weight, etc. is also very real. Planting grain or forage sorghum has more yield and economic potential at this calendar date if your location and management practices would permit this to take place.   I realize that previous corn herbicide applications or management practices may have you locked into replanting corn on certain acres.  I would suggest that you don’t go more than 10 days earlier in relative maturity if you do decide to change the maturity of corn planted.  Research and experience suggest that you are still better off using the same maturity hybrids you normally plant in your region due to their aggressive plant growth will allow the corn to “catch up faster”.  Hope for a hot summer and a late frost.


 Corn Population Chart--American Society of Agronomy

Seed Spacing

Corn Population—Row Spacings

In Inches





]4 7/8










5 1/4





5 1/2





5 5/8





5 7/8





6 1/8





     6 3/8





6 1/2





6 3/4










7 3/8





7 5/8





8 1/8





8 1/2





8 7/8





9 1/8





9 1/2





9 7/8





10 3/8





10 3/4





11 1/8





11 5/8










12 1/2










13 1/2










14 1/2










Fields with stand losses upwards of 40-50% which could be candidates for replanting.  Should you replant them?  Should you use the same maturity on the second planting?  AS we get further into the middle of May, I would replant soybeans only if I had a stand loss of greater than 40% of my original seeding rate and I would use the same maturity of soybean that I initially planted.  The last week of May, I would replant soybeans only if I had a stand loss of greater then 50% of my original seeding and I would still use the same maturity of soybean that I initially planted.  Once the calendar gets into June is the only time I would decrease the maturity of the soybean being used by ½ of a maturity point (From a Group 3 to a Group 2.5).  Yield potential in soybeans is always greater with the maturity adapted for your geography.  As we get further past June 10th, you are taking a yield potential reduction no matter how you look at it.  Still, you have the greatest potential with genetics developed for your growing region until the calendar reaches the 20’s of June.


Here is some background.


Figure 1 shows the plant population that will exist given the row spacing.


                                    Plant Number per linear foot of row in a given row width

Population                                36”     30”      20”      10”      7”


200,000                                   14.6     11.5     7.5       3.8       2.7

175,000                                   12.8     10        6.6       3.3       2.3      

150,000                                   10.9     8.6       5.7       2.8       2.0      

125.000                                   9.1       7.2       4.8       2.4       1.7

100,000                                   7.3       5.7       3.8       1.9       1.3

75,000                                     5.4       4.3       2.9       1.4       1.0

*American Society of Agronomy


Soybeans compensate for many things and a thin population as a result of flooding, hail, insects, etc., is a prime example of their biological ability to increase plant branch and pods numbers in light of lower stand counts.  University of Minnesota research suggests the soybean plants can fill gaps up to 18 inches within or between rows without sacrificing yield.  Research conducted in Madison Wisconsin in 1981 indicate that viable stands of 100,000 plants per acre have the ability to attain 90% of their optimum yield potential as long uniform plant spacing exists and the plant/replant date is before June 10th. Don’t get me wrong—earlier is always better from a yield potential standpoint. After June 10th however, the same yield potential of the same stand will decrease to 50% or normal by June 30th

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