Green Stem Soybeans Continue To Generate Questions

Green Stem Soybeans Continue To Generate Questions

In Iowa, "green stem" disorder has been seen in many soybean fields the first two weeks of October 2013.

Agronomists and soybean growers are calling up Iowa State University Extension crop specialists this fall asking: Why are the stems of so many soybean plants still green and "chewy" in my fields this fall? The soybeans are otherwise ready to harvest. Farmers along with seed company agronomists are wondering what to do about this situation. How can you prevent green stem problems, otherwise known as green stem syndrome disorder, from happening again next fall?

GREEN STEM SYNDROME: Why are soybean stems still green and "chewy" for the combine at harvest in areas of many fields this fall in Iowa? Green stems are hard on the threshing mechanism of a combine. What can you do about this problem? How can you prevent it? ISU Extension agronomists are gathering information, and that's a place where you can help them.

"What little we know or speculate is discussed in the recent ISU Integrated Crop Management newsletter article that ISU's Darren Mueller and I wrote last week," says Clarke McGrath, an ISU Extension field agronomist based at Harlan, in western Iowa. "So, if you have questions about green stem syndrome, you should go online to the ISU ICM newsletter site and read our article."

McGrath adds, "What we really need help with from farmers is information gathering." ISU is working with the Iowa Soybean Association to gather agronomic information about as many of these GSS fields as possible, in an effort to see if there are any commonalities or trends that may impact GSS. "We are starting with a simple online form to gather information about the fields," he explains. "Please pass our request along to ISU Extension crop advisors and others who are dealing with GSS—encourage them to fill out this form for their fields. It is really pretty short and easy to fill out."

Here are other crop production updates and related information from ISU

Palmer Amaranth weed update:  In August, a weed named Palmer amaranth, a new weed that has marched north into Iowa, first showed up in a field near Modale in Harrison County in western Iowa. After the discovery near the town of Modale, county Extension director Rich Pope found a palmer amaranth infestation in another Harrison County field…..also, palmer was recently located in a field in eastern Iowa as well. For an update, readers should visit Palmer Amaranth Update.~~~PAGE_BREAK_HERE~~~

Another discovery of significance was recently made in south central Nebraska, between the towns of Lincoln and Hastings. Some Palmer amaranth is resistant to some of the chemistry farmers will be leaning on in the future to help manage both waterhemp and palmer amaranth control in our part of the world.

For more information, click on Palmer Amaranth Resistant to Atrazine and HPPD Inhibitors Confirmed in Nebraska to get an update.

"We are hoping that this is an isolated biotype of the resistant weed, that won't find its way to our part of the world," says ISU's McGrath. "Meantime, your best bet is to use the integrated pest management strategies that we have shared, to control this weed. We will continue to fine-tune and discuss our recommendations with growers and agronomists this fall and winter in meetings and in ICM newsletter articles."

Revised Nutrient Management recommendations now available from ISU

Advances in soil-testing research has led Iowa State University Extension to revise ISU's recommendations for phosphorus, potassium and lime. Antonio Mallarino and John Sawyer, agronomy professors and Extension agronomists, have updated "A General Guide for Crop Nutrient and Limestone Recommendations in Iowa" (PM 1688). It is available to download at no charge from the Extension Online Store.

Cover crop plots: ISU field agronomists are getting a lot of questions on cover crops and the progress of cover crops this year, given the dry summer and fall. "From some spot checks I've done in fields, it shows that we needed more rain than we received—to get the cover crop plots going like we had hoped for," says McGrath. "But there are some species of cover crops that were planted in late summer and early fall that are coming along. We'll be taking fall measurements sometime in the near future so we will update you on those."

Harvest update: A lot of soybeans are coming out of the fields last week and this week, and some corn too. "As expected," says McGrath, "the early yield reports were on the high end. And then as we get more bean acres harvested, we are getting a clearer picture of yields across the area. Variable is the term we can probably lean on for this year's yield."~~~PAGE_BREAK_HERE~~~

"I just returned from harvesting a plot this afternoon, a 15-inch vs. 30-inch row soybean study," he adds. "The main part of the trial was on a high flat land, and was doing well over 60 bushels per acre. While I was there in that field, we checked a few strips on the sidehills. They were yielding around mid-40's. I am hearing this type of report a lot across our entire area this fall."

Adds McGrath: "Harvest reports of early maturing corn are telling us the same thing. A check of some fields the last few days indicates that most corn is still standing relatively well, but as expected there are areas that could go down pretty easily if we had more storms. Good luck, be safe and stay after it while the weather is decent is about all we can say for now."

Fall Herbicide applications: "We are starting to get some questions about this topic too, so I will write an article about it in the next week or so," says McGrath. "In the meantime, feel free to shoot questions on them to me or to ISU's Aaron Saeugling."

Welcome to October—while the saying "in like a lion and out like a lamb" is typically associated with the month of March, let's hope it applies to October as well. Last Friday's (October 4) severe weather that struck a 35-mile path, is hopefully the last we'll get for a while. We need a few good weeks to get the beans out of the field before they get too dry, and the longer the corn is out there the greater the chances it won't be standing as well as we'd like. High winds and/or snow like parts of the Midwest and Upper Great Plains suffered last weekend, would certainly not help us out."

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