Water and Soybeans- Late Season Effects

— Written By

I know that many people had quite a bit of water to come down here in the past couple weeks. Here is the memo that Dr. Dunphy just sent out about some of the things you may see when you start harvesting soybeans.


TO:  County Extension Soybean Agents

FROM:  Jim Dunphy, Crop Science Extension Specialist (Soybeans)

SUBJECT:  Soybeans and Prolonged Heavy Rains

I’m not sure what to expect the state’s soybean crop to do after experiencing a week and a half of heavy rains. So much depends on how long they were under water (if they were at all), the weather the next 2-3 weeks, and on how close the soybeans were to normal maturity when the rains came. Soybeans sprouting in the pods, shatter losses, seeds with serious disease symptoms, and/or significant lodging would not surprise me. The reality is that we have limited experience with soybeans that were that wet for that long. The only thing we can be reasonably sure about is that nothing good is likely to happen to the soybeans as a result of the last two weeks’ weather.

I would not expect all the state’s soybeans to sprout in the pods. I’d expect that some were far enough from maturity that they have not yet gotten dry enough to sprout when they regained significant amounts of moisture. Some may have been dry enough that they did not get wet enough to trigger sprouting. The same line of reasoning would lead me to expect that not all seeds on a plant will sprout. Thankfully, I would not expect shattering to be as much of a problem as it would have been 25 years ago. Our soybean breeders have done a good job of reducing the likelihood of shattering in our determinant varieties. The maturity group 4 varieties are most likely to shatter, mostly because they mature so much earlier than our traditional maturity groups.

Green beans could be a problem is the water killed soybean plants that were not yet mature. Most of our soybean diseases are very dependent on the weather. Change the weather, and you’ll change which diseases we’re most likely to see develop. I’d expect the past two weeks’ weather to have had more impact on the insects that were present in our soybean fields the past two weeks than the next two weeks.

I’m not aware that there is much a grower can do about what’s happening to his soybeans other than get them out of the field, and dry, as soon as he can without tearing up his field. Ruts are expensive on most of our soils. Our processors, and our elevators, are not set up to handle significant amounts of poor to lousy quality beans, so discounts will likely be a reality this year. We could even see some loads refused. Farmers who have soybeans contracted should probably talk to whomever they have the contract with in case any further marketing activity is appropriate. More alternatives are available a month before delivery than on the day of delivery.

If you have any questions or problems don’t hesitate to give me a call.