As I sit here in my office I can hear the patter of raindrops outside the window. It is late May and we are still trying to get corn and soybeans planted down here. Now we will have at least another day’s delay as this little shower has to dry up. This isn’t the first time I’ve dealt with this kind of weather and I am sure it won’t be the last. It does, however, come with its own set of problems to deal with.
What few soybeans we do have planted have gone through a gamut of problems: cold temperatures, seed corn maggot feeding, crusting over of soil, and just flat sitting under water. All of these can contribute to a poor stand and that is when I get called in to evaluate whether or not to replant. I truly hate having to make that decision! I am, and always have been, a “glass half full” kinda guy. If there is any way to leave what start we have to the crop I will. Now there are exceptions to every rule, and a 90,000 ppa (plants per acre) stand of beans on April 20 I will probably recommend tearing up and starting over. However, that same count on June 15 (if consistent across the field) will be left alone and should produce enough yield to offset replanting.
There are lots of methods to measure stand and charts to determine what population on what date requires replanting. Those are great and I have used them all over the years: the hula hoop, the plants per foot of row in both 15- and 30-inch rows, etc. are proven and good indicators for the final decision. But, I always forget the hula hoop or I misplace the chart or something so I have adopted a much easier method.
My rule of thumb by this point in the season is if I can get two plants per square foot fairly evenly across the field I will leave it alone. Scientific, huh? I know that is only about 85,000 plants per acre, but that is all we really need to produce 90% of yield. If we tear it up and replant we will need about 165,000 ppa at this late date to just break even.
So don’t be too picky about not having a perfect stand. As long as you don’t have large skips in the field where there are no beans at all you will be fine at 85-90,000 ppa. You can still use the hula hoop or yard stick or whatever tool you are used to and be more exact. I will tell you though, that if you have a decent, even stand now, even if less than perfect, the management you put into it from this point on will have the most effect on yield.
I hope you all treated your soybean seed with a good fungicide/insecticide seed treatment, had great conditions and they all came up. Now I hope we get 10 days of dry weather so we can catch up with the rest of Illinois.
Mike Wilson is a Specialty Products Marketing Coordinator at Wabash Valley Service Company. For over 20 years he has been working with farmers in ten counties in southeastern Illinois to improve economic yield in soybeans, corn and wheat. Mike has been a CCA since 1994 and is enjoying being a part of the Soy Envoy program.