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Battle for the Belt: Episode 11

Episode 11 of Battle for the Belt is now available:

In Episode 11, we are in the field with Dr. Alyssa Essman, Ohio State Extension Weeds Specialist, to learn about early season weed management and the effect of planting date. Weed management considerations can influence the decision about whether corn or soybeans should be planted first. Weed control in soybean has historically been more difficult compared with corn, due to the overall better selection and effectiveness of herbicide options for corn. Additionally, soybean has a greater risk of injury from preemergence herbicides. This risk is increased following wet weather and cool temperatures, conditions that are common early in the planting season. The most common and troublesome weed in the state year after year is giant ragweed. Giant ragweed has a biphasic emergence pattern, with an early and late flush that need to be managed (Schutte et al. 2008). One tactic that can be used to manage giant ragweed is delayed planting, allowing for the first flush of weeds to be controlled before crop emergence and reducing competition with the young crop plants (Goplen et al. 2017). Much of the giant ragweed in Ohio is resistant to group 2 herbicides (ALS inhibitors) and there are really no other good options for preemergence control. This means burndown applications or tillage are critical for control of the first emergence flush. Delayed planting of soybeans allows for more of the early weeds to emerge, which can make weed control easier throughout the rest of the season and reduce the need for a second POST application. Waterhemp and marestail were second and third, respectively, in our preharvest survey in terms of frequency in 2022. Both species have a prolonged emergence window and continue to emerge later into the season than some other summer annual species (Hartzler et al. 1999; Main et al. 2006). PRE options exist for control of waterhemp and marestail that can help manage these weeds well into the growing season. Delayed planting facilitates this, by allowing later PRE applications of residual herbicides and extending control even later into the growing season. For these reasons, from a weed management perspective, it may make sense to plant corn before soybean.

Battle For the Belt Location Updates

he third planting date (May 11) at all three locations germinated with their first root (radicle) and shoot (Figure 1).

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Figure 1. Planting date 3 corn and soybean germination.

The first and second planting date at the Western Research Station has progressed farthest with the corn at V2 and V1 for the first (April 13) and second (April 27) planting dates, respectively. The soybeans for planting date 1 are at the VC stage, moving close to V1 and the second planting date is at VE but close to VC.

At the Wooster location, planting date 1 (April 14) in corn has reached V1 with planting date 2 (April 27) in the emergence stage. The soybeans for both planting dates 1 and 2 had emergence problems. However, this crop is between VE and VC.

At the Northwest Research Station, corn at planting date 1 (April 12) is at V2 and planting date 2 (April 26) is at V1. The corn crop at this location is showing purple coloring on leaves (Figure 2). This symptom is likely caused by being exposed to a wet and cold environment which causes poor root development, along with cold night temperatures making sugar processing difficult in the plant (learn more about corn purpling here). This sugar build up can cause the development of anthocyanins. Purpling of corn is a temporal effect and it should not impact yield potential. The soybeans at this location for planting date 1 reached VC and planting date 2 have emerged.

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Figure 2. Purpling of planting date 1 corn leaf at the Northwest Research Station on 5-18-23.

Planting date 1 and 2 for most of these locations are expected to be very similar in stage throughout the summer because of the slow emergence of planting date one.

Table 1. The planting date 1 and 2 in the trial at all three locations with day of planting, soil, air temperature averages, and Growing Degree Days (GDDs). Information from CFAES Weather System,


2-inch soil temperature
(May 15-May 21)

Air Temperature

(May 15-May 21)

Planting date




Wayne County

Mean: 62°F

Minimum: 55°F


Mean: 58°F

Minimum: 30°F


April 14

April 27

May 11





Clark County

Mean: 64°F
Minimum: 57°F


Mean: 61°F

Minimum: 41°F


April 13

April 27

May 11




Wood County

Mean: 62°F
Minimum: 49


Mean: 62°F
Minimum: 49


April 12

April 26

May 11


















As a recap, this research project includes five planting date windows, 1) Ultra early = late March to early April; 2) Early = mid to late April (reported here); 3) Normal = early to mid-May; 4) Late = late May-first week of June; and 5) Very late = mid to late June. Weather permitting, the fourth planting date (late) would occur toward the end of this week or in the following week.

Keep following the ‘Battle for the Belt’ this growing season to learn more and get further updates! You can  find the full video playlist of Battle for the Belt on the Ohio State Agronomy YouTube channel.


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Goplen JJ, Sheaffer CC, Becker RL, Coulter JA, Breitenbach FR, Behnken LM, Johnson GA, Gunsolus JL (2017) Seedbank Depletion and Emergence Patterns of Giant Ragweed (Ambrosia trifida) in Minnesota Cropping Systems. Weed Sci 65:52–60

Hartzler RG, Buhler DD, and Stoltenberg DE (1999) Emergence characteristics of four annual weed species. Weed Sci 47:578–584

Main CL, Steckel LE, Hayes RM, Mueller TC (2006) Biotic and abiotic factors influence horseweed emergence. Weed Sci 54:1101–1105.

Schutte BJ, Regnier EE, Harrison SK, Schmoll JT, Spokas K, Forcella F (2008) A Hydrothermal Seedling Emergence Model for Giant Ragweed (Ambrosia trifida). Weed Sci 56:555–560


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.