Managing Late Planted Soybeans

As we watch the calendar slip by, patiently waiting for an opportunity to plant,  many of us know from past history that delayed planting = lower yields and there is nothing we can do about it.  Right?  Well not necessarily.  On a recent conference call , we spent some time reevaluating the history of late plantings and a very valid comment has come to light.

We have all been seeing that lower planting populations in soybeans has been the talk of the winter newspapers and researchers meetings.  This is possibly a valid point when we are beginning to learn that we can plant soybeans as early as we plant corn.  Many growers have risen to that challenge and planted soybeans in mid to late April and have been very successful.  So now you are probably thinking,  “where is this going and why are we discussing this when it is now moving to late May and we still have very few acres of anything planted let alone soybeans!”  So growers have adapted to early planting.  Awesome! So now we need to rethink about the physiology of a soybean plant all over.

We have said that we need 6 fully expanded trifoliates to get the highest possible yields for our soybean crop in a given year.  Basically this means we will have many nodes where flowers can bloom and a pod can set. 

Here is what we know about a soybean plant.

5-6 days to emergence (under warm conditions and longer when we plant in April)

5 days for unifoliate leaf

5-6 days for each trifoliate leaf

June 21 is longest day of the year

Longer day soybeans will start to flower about a week after the longest day of the year

 

Well here we are.  It is May 20, and the weather man has been less than kind.  So we have only 31 days until the 21^st of June and approximately another 7 days after that gives us 41 days to work with and that is assuming we can plant within the next few days.  I know some of you are laughing saying “Are you kidding me!  I gotta plant corn yet!”

So at best , we may plant May 27.  (I gotta pick a number).  This gives us only 34 days to build our soybean factory before it starts to flower a week after June 21. 

Best case scenario, plant May 27… emerge June 1.

5 days to unifoliate – June 6

6 days  to first trifoliate- June 12

And so on to next trifoliate – June 18

And the next one……………. June 24 (here we are past longest day already and it feels like we have not seen spring yet).

So now we have 3 trifoliates and we will likely see the fourth before the plant starts to get the message that the days are getting shorter and I better start to flower.

So we said we want 6 fully expanded trifoliates before first flower and we only have 4.

So how are we ever going to get a decent soybeans crop, you say?  Remember when we used to plant 200000+ plants per acre and plant our soybeans on May 25 and get a decent soybean crop.  I think this is the year we need to reassess our soybean planting rates to try to have more plants and more nodes to put flowers on and give us the best chance of having enough pods there to get a reasonable yield.  Now we know Mother Nature has more control that we do, but it is something to think about… at least on those heavier clays that don’t let us plant as early as we want and we don’t have white mold and lodging to worry about.  It makes very good sense for a lot of acres in a late spring.

Just some food for thought as we patiently wait!

 

And if you are bored and need something to cheer you up, I thought we would include the following link for your entertainment.  Something I saw on the tube this past winter, you may have seen this already but I figure you can’t watch it too often!

www.youtube.com/watch?v=wkDvqQKGgDA

 

Hopefully we can get rolling soon!