Bob’s Bits June 5th, 2026 | Nitrogen Timing, Weed Pressure, and Crop Stage

Nitrogen Timing

Well, we are hard and fast into post corn spraying and corn side dressing.  It sounds like the side dressing has been going well for everyone, and is well over ¾ done, according to the amount of Nitrogen that’s been delivered.  These rains we’ve gotten on Sunday, and last night have been great to get that nitrogen moved into the soil (hopefully you didn’t get too much rain and encountered some washing of soil).

Weed Pressure

We’ve also been doing a lot of post spraying in corn.  No two years are the same, and I can tell differences in our pre-emerge herbicide control this year versus last year.  In 2026, the pre applications that were made early enough to get rain on them in April, or lightly incorporated, are working better than those laid on top, especially those sprayed on top between April 28 to May 15^th.  We had a dry stretch where the herbicide laid on top without enough rain for incorporation, and some of the weeds germinated and emerged before the pre was “activated”. 2025 was the opposite, with all the spring rains we had after planting last year, the incorporated herbicides didn’t work as long as the ones laid on top and rained in.

I always say farmers don’t have 40 years experience farming, they have 1 year of experience 40 times, as every year is different.

I’ve seen more grass escapes this year which is very understandable as our Group 15 herbicides (Dual, Harness, Zidua, etc) are mostly “shoot inhibitors”, which means they have to be taken into the shoot of the grass as it grows to the surface, not necessarily through the roots.  So if it had a good shoot on it, and emerged before an activating rain, it was able to survive.  Sometimes after a rain we see a little curling or wrinkling of the grass from the little bit that is root absorbed, but it is not enough to take emerged grasses down.

Waterhemp has also escaped the pre herbicides that didn’t’ get rained in or worked in.  This has led us to use more dicamba in corn earlier than normal, in order to take down some of these waterhemps that I feel are too big or thick for our Group 27 (Callisto or Impact containing products) to take down on their own.  In the scouting I’ve been doing so far this year, I can tell where a dicamba product like Status or Diflexx was used last year, as there is less waterhemp emerging this year.  That means we got more complete kill of the waterhemp last year.  In many fields that had emerged waterhemp in 2025, and we relied only on the Group 27 herbicides, we may not have gotten complete kill, which led to some late emergers going to seed under the corn canopy.

I have also been seeing less overall weeds in the rotated corn fields, versus the continuous corn, as we are able to rotate our chemistries each year, and utilize Enlist and/or Liberty in the beans, whereas in the corn, we are pretty limited to the different modes of action we can rotate to each year.  Once a little waterhemp escapes in a corn field, it gets harder each year in the continuous corn fields to get it under control.  We must stay aggressive on the front side for long term control.

On the soybean side of the farm, we encouraged farmers in April to plant beans first, and many did.  This led to the pre-emerge herbicides going on early as well.  In some cases, it has been over 6 weeks since that application, so the residual is starting to run out.  We have started to spray these fields again, with the planned Liberty or Enlist program along with another Group 15 residual (Anthem, Dual, Outlook) for extended control hopefully until canopy closure.  A worry I have is that some of these fields may need another application over the top of Liberty or Enlist right at canopy closure time, around early July, to give season long weed control.  That is the flip side of planting so early, we get increase yields, but may have to make a third herbicide application.

Crop Stage

Corn stands look great this year, as do most soybean stands.  The seeds that had been planted and laid in dry soil have mostly emerged now.  Some corn plants will be a little behind, hopefully not too far to be considered runts or weeds, but the beans that are later emerged will fill the canopy in nicely, and still add to overall yield.

Corn is generally in the V4-V5 stages now.  This is just after the primary root system has taken hold from the seed roots.  Corn will now really start to grow quickly, as it focuses on above ground growth.  The growing point is just about out of the ground, so a bad hail storm, or running over the corn could kill the growing point.  Corn is also starting to develop the ears at this time, so stress on the corn can have longer term negative effects later on.  We do not want to stress the corn between V5-V8 when a lot of the ear shoots and ear size are being determined.  This is a good time for foliar applications like Zinc in corn, as Zinc is responsible for helping with cell division, which is taking place rapidly in the ear shoots.

Soybeans are mostly in the V2 stage.  This is where the nodules are beginning to grow on the roots, in order to fix nitrogen for the plants.  The plants may be off color and yellow until the nodules get going.  If you used our seed treatment, JumpPoint Complete, you got a good rate of Bradyrhizobium bacteria, which are the nitrogen fixers, and the process of producing nodules started earlier than those planted without it.  This helps jump start the N fixation process on the roots.

It seems like overall we are ahead of the normal crop stages at this time of year.  The heat we’ve had has pushed this crop along.  Here are the total GDU’s we’ve collected compared to average.

Heat Units Accumulated

And Rainfall, this is at New Hampton, which understandably is different for everyone.

RainFall Totals

As always, reach out to me with any questions or concerns you have.

Bob Sobolik

641.330.1815