Theorized Summary: Evidence from field observations supports the theory of large differences in final stands of corn that correlate in part to current field conditions. Over time there is increasing evidence that soybeans are also impacted by the conditions of the field at plant. I would argue that corn yield and early growth is more susceptible to current ground conditions than soybeans. However; soybean final stands are just as vulnerable if not more to loss by percent versus corn. Soybeans have a wider range of tolerance in stand loss than corn when they are planted at the locale’s average population rate. This does not negate the importance of finding the best conditions possible for soybeans and dropping populations that are lower than historically thought viable. (Current ground conditions in this document refer to the ground decisions when making decisions at plant. Final stands are stands counted at point that a replant could occur after enough time has been given.)
What we have learned:
Empirical evidence confirms that aftermarket closing wheels over rubber tired wheels return a positive ROI and can be the difference between a profitable stand vs a replant situation that is behind the ideal planting date.
Downforce of row units and the wings of a planter play a crucial role in maintaining the correct depth. Additionally, emerging evidence on our farm shows that it can affect trench closing. Wing downforce when correctly set transfers the appropriate weight to the wings where weight is the least.
Properly set opener discs, gauge wheel to disc contact, and the firming point within specs help each seed find optimum moisture and prepare the trench for proper closing.
High speed seed drop equipment is proven to allow the correct seed placement, spacing, and depth regardless of speed or conditions. (there is eventually limitations to this but most tractors will not allow this discovery unless they are pulling over 350 horsepower)
Vacuum set correctly for the conditions, seed size, and speed are basics in correctly planted seed. Central fill planters with appropriate amounts of flow agents keep seed flowing fast enough for re supply of the row unit hoppers.
Using a checklist to go over meter installation to insure that all components are set to the crop and adjusted to specs will give peace of mind that any challenges faced while planting are not some small hidden detail that was missed.
Tire pressures on tractors and equipment can also help with compaction and the case of ground drive planters the rate of seed. Keep planter bar running level.
It is worth noting that all “fancy” additions to a planter are only as good as they are set to the current ground conditions. Aftermarket closing wheels will not return positive ROI if the tailpiece is crooked, high speed has diminished return to your operation if planting while conditions are marginal, and hydraulic downforce can hurt emergence if oversight is not present by the operator. When starting to plant, it can greatly improve confidence and exploration of proper in field settings if two people work together to start planting. A ground guy to check depth, downforce, and seed start stop at headlands can keep this important decision making process manageable. How many times has a person spent time to set the planter by themself and then finally said; “I think its good enough.”?
For in depth planter settings Clayton Stufflebeam with Beck’s Hybrids PFR planter setup has a wonderful video to guide you for detailed explanations on what to look for and why.
https://www.youtube.com/watch?v=BYa5DTJqZA4&t=1026s . Precision Planting is a good resource if you run their equipment. They are well known for agronomically focused
equipment along with great development and support.
Too wet of ground conditions. Obviously, there becomes a point when no one dares to enter the field. Unfortunately, there is a window between that point and optimum conditions that is left the to “the eye of the beholder”. When a small handful of soil is formed into a ball and dropped on the ground it will fall apart if moisture is close to optimum. If our clay soils are too wet then the ball will remain mostly intact and will ribbon easily when squeezed between thumb and forefinger. Too wet of conditions accelerates disease and insects while slowing plant emergence due to strangled coleoptile, swollen hypocotyl, and roots that have been stunted due to smeared seed trenches.
Set planter with row unit downforce of minimum margin 10-15 lb.
Set closing system medium, it can take more to push shut due to wetness.
After starting, check seed trench side wall and dirt above. Compaction/smearing is a high risk while still closing out the air gaps.
Too dry of ground conditions. These conditions can be extremely challenging and require much looking ahead to manage.
Fall spraying or winter weed control are important to keep winter annuals from sapping precious moisture.
Cover crops like cereals should be terminated by the time they are in the boot stage but as soon as the first stems appear to save on water while still helping to protect wind and sun from the vulnerable soil.
If current conditions are there with faint moisture at 1.5” and ample at 1.75” one could plant soybeans up to a little below 2” but no deeper. If soil profile is too dry on bare dirt or uneven residue putting soybeans in the “dust” will only cause the seed to potentially swell with any faint moisture and then rot when the next rain comes. In soils with covers there seems to be some more forgiveness but any moisture no matter how faint will be imbibed by the seed and if it is not enough to fill the seed profile in a timely fashion will then begin the seed’s decay.
As hard as it is to wait, too little moisture in harsh conditions of heat/cold, wind, and rough tilled soils will create a heightened risk of a replant after the next rain anyway.
Too cold of weather.
Ironically, we have found planting into current conditions of cold soils are far more successful than into warm soils that are chilled in the next 36 hours. Looking at forecast and planting as you begin a warming trend reduces risk of cold injury.
In the same token, pausing 24 hours ahead of a cold front’s arrival can also give a seed enough time to fully imbibe water before the abrupt change to soil surface temperatures occurs.
Remember, the good feeling of making the last pass of corn as the rain starts to fall is too many times unwound by the realization of a replant that is now needed a few weeks later.
Too hot of weather. Planting in temperatures above 86 degrees poses a different set of challenges. Soils with ample moisture become too dry in an amazing short amount of time. If you plant it too wet it will be a brick later on.
Make sure closing system and downforce are adequate to seal. Be careful in marginally wet conditions of high closing or down pressures, this can brick road the surface and seal the soybeans in an earthen coffin.
Running long hours during this time with rotating drivers can help arrive at complete before too dry is a problem.
Too cloddy of soil. Roughly tilled dirt is an emergence problem before the seed has even imbibed its first drink of water. On corn this results in uneven emergence and corn plants becoming a weed to the other as they emerge days if not a week apart. On soybeans and corn chilled night air we receive in early spring can send the seed into shock and potentially result in cold injury. Smooth soil is a pretty good temperature and moisture buffer. For every ½” down in soil temperatures and moisture moderates rapidly.
Roughly tilled dirt should be worked finer.
Consider no till if needing to plant in drought conditions to preserve moisture.
Too fine of soil. On the flip side, tilling soil too deeply and fine will result in a soil that is prone to massive erosion with heavy spring rains.
Reduce tillage to as shallow as possible while still maintaining a level seed bed.
Weed control needs to be maintained by chemical in this case.
Too weedy of conditions. When weed control is poor, controlling the weeds becomes priority. There are times that the calendar date is late and the rain is coming and planting becomes the only choice. A decision like that is best prevented or only used as a risk mitigation with the understanding that it should be avoided in the future.
Spray ahead of planter and allow 24 hours before disturbing weeds.
Weeds grow too fast, display too much resistance, and will hurt yield not only in this season, but their seeds will cause challenges and costs on into the future seasons when we do not start clean.
Too much cover. High amounts of residue or cover crops pose challenges in planting.
Having a spring down force planter or even an old style air bag will create challenges in holding gauge wheels to the ground to provide consistent downforce.
The other factor is when row unit downforce is too extremely high; considering you have hydraulic down force, this can work against you in furrow closing. It is very important to find the right balance between enough margin on the weigh pins vs an adequate closing of the furrow.
Final Thoughts
Follow optimum conditions where possible. If not feasible to plant into good conditions, then the settings on your planting become exponentially more important. The settings that are acceptable become more narrow in their balance and position. This should cause an operator to stop and have more checks behind the planter. Using a second person to be out there from time to time on an UTV to make sure will pay you well over time.
-Wendell Koehn
