Considerations for Early Plant Soybeans
Warm weather this week has everyone itching to get moving. Sprayers are making tracks in the field, and before we know it, planters will start rolling. For the past could years we’ve done some exploring of early plant soybeans. We know many of you are thinking of putting some acres of soybeans in early this year as a way to spread out the work load.
Early plant soybeans have been shown to increase soybean yields by giving plants more time in the vegetative stage before day length triggers flowering. Giving more time in the vegetative stages means more nodes per plant and pods per nodes. As we increase our total number of pods per plant we increase yields.
Studies from the University of Nebraska suggest that there is a yield decline between ¼ to 5/8 bushel per day for every day past May 1 that soybeans are planted. However, this article is more geared toward early soybean planting during the first half of April, rather than just as we approach May 1. Here is a short list of what we have learned over the years as possible considerations for early plant soybeans.
1. Seeding Rate and Depth
We can pretty much guarantee that you will end up with a higher percent of soybeans that did not emerge the longer they sit in the ground. This of course is highly dependent on what early spring conditions are like. We generally suggest upping your seeding rate by 10-15% to compensate if you are planting before April 15th. As we approach the start of our soybean insurance date in KS, April 26, we can back off that rate increase and plant our normal seeding rate. It will be important to maintain planting depth. Many people are tempted to shallow up the planting depth to hopefully get the seed up sooner. Maintain planting depth of 1.5 inches. Planting this depth will help insulate from any dramatic temp swings. In all reality, we are okay with planting a little deeper and letting the beans sit there for 2 weeks.
2. Seed Treatment
With seed sitting in the ground waiting to germinate, its extremely important we do a comprehensive seed treatment package. This time in wait means a larger possibility of seed rots, early season seedling diseases, and insect damage. Treating with PPST as well as a full rate of iLeVO will be essential. We suggest a full rate of iLeVO due to the increased risk of SDS with early plant soybeans.
You shouldn’t have to make any variety adjustments with early plant soybeans. We do however suggest that you plant some of your fuller season soybeans first as a way to maximize our vegetation/flowering before the summer solstice. As long as you’ve selected robust, high yielding soybeans with good disease package, you should be in good shape, regardless of when you plant soybeans. Our lineup of Pioneer A series beans is well suited to hit the fields early. Ask any of the guys for more details on specific varieties.
4. Planting Window
Some care does need to be taken when selecting a planting date. If you are going to be planting early, be sure to look at the 48 hour forecast. Soybeans will imbibe water the first 48 hours after planting. If this water the seed is imbibing is very cold, it will result in imbibitional chilling and seed death. If temperatures are warm and dry for the next 48 hours after planting, imbibitional chilling won’t occur. Plan you early planting date with the next 48 hours in mind.
5. Planting Date Study
In 2018 we helped conduct a planting date study near Hamlin with four different planting dates: March 22, April 11, May 7, and May 22. The latest date was the highest yielding at 67 bpa. So why are we still discussing early planting soybeans. First, an exceptionally cool April resulted in extremely delayed emergence. May was one of the hottest on record and provided quick germination and optimum conditions for the two May planting dates. Secondly, droughty conditions in June and July disproportionally impacted early plant beans. Later planting dates were better able to utilize August rainfall. Given the current forecast, it looks like we have good potential to get some soybeans off to an early start this year. University studies have shown that planting before May 1 results in the highest yields. Every day soybeans are planted past May 1 results in a ¼- 5/8 bushel per acre reduction in yield.
We don't share this unusual data to confuse you more about whether or not to plant early. We feel like we did learn a lot from the study including that even in very unusual and stressful conditions, the early plant beans did remarkably well. Here is the link to that study: Planting Date Study.
With these excellent weather conditions for the next 10 days many of you are anxious to get to the field. This year would be a good time to try out some early plant soybeans before switching over to corn. As always, leave comments below, or call or text with questions.