Double Crop Soybean Needs Tender Loving Care for Best Yields

Published: June 13, 2010

I was recently listening to some old men talk about stuff that old men talk about. I understand that you may think me mentally off for sitting around listening to old men, but I find it easier to do now that I have become one of these old men. As usual, the first story told by an old man never has a chance because other old men will tell stories to top the first. The best story this particular day was about the freeze on Mother’s Day one year that killed all the crops and was so severe the radiators in some tractors froze and broke. There of course were some doubts among the other old men about the validity of this story. Most old men can’t agree on much. However, these old men were farmers and they all agreed that soybean will yield best when grown on well drained, fertile soil; when the weather is mild (72° nights and 90° days); when sunshine is abundant; and when it rains 1.5 inches every Friday afternoon. All of these old farmers agreed that these conditions usually only develop in their dreams. The conditions that typically occur are too much or too little rain, poor drainage, too little fertilizer, temperatures too high or low, and too much clay soil. These more typical conditions can make soybean farming difficult but not impossible, and soybean can grow and yield well in these conditions with tender loving care (TLC). Tender loving care will be especially beneficial to double crop soybean. Wheat harvest will begin in south Missouri has started and will begin in north Missouri very soon, and farmers will begin to plant soybean in some of these fields. I have some suggestions for these farmers to help the double crop soybean crop grow and yield as well as possible.

1. For south Missouri, plant a maturity group (MG) 4 or early 5 variety. In our tests, yields of mid-June planted MG 3 varieties were always lower than yield for MG 4 and 5 varieties. The yields for the MG 4 and 5 varieties were about the same. The harvest date for a mid-June planted MG 4 variety will be about mid-October.
2. Plant seed that has been commercially treated with a fungicide in fields where irrigation will be used to help the soybean seed germinate. This treatment will help protect the seeds and seedlings from rot that may develop due to wet soil from irrigation. Fungicide seed treatments available now are more effective that those available a few years ago.
3. Scout the crop frequently during the summer and fall to determine if insecticides are needed, especially for stink bugs and pod feeders; to determine if foliar fertilizer is needed, especially potassium; and to determine if a foliar fungicide is needed. Double crop soybean that may yield 40 bushels per acre or more may benefit from a foliar application of fungicides such as Quadris, Headline, Stratego, or Quilt.
4. Pay attention to news reports, especially beginning in August, about soybean rust development. Rust is probably a greater threat to our double crop than full season soybean.
5. Irrigate properly.

Following these suggested procedures will give farmers a better chance of realizing a profit with double-crop soybean in 2010.