Thursday, January 28, 2016

Who Would Have Thunk that a Cover Crop Stunk?

Recently, there has been buzz on my Facebook page about a really bad odor along Route 16 in my home county.  One of my friends who is a teacher, knew my occupation, and reached out to me for help because she recently encountered an awful smell, while traveling to and from work.  It's hard enough to be an elementary teacher, but add an awful stench to her commute, and this was a bad day (as Tom Burrus would say)!  She described the smell as a "dead, rotting carcass, with a poopy, diaper smell", and yes she has small children.  She had heard that a farmer had "dying radishes" in a large field and it was rumored that this was where the smell originated.

Another Facebook friend, who is a local volunteer fireman chimed in, and said that Ameren and local police had been called and were "running around like chickens with their heads cut off" looking for a gas leak.  They were finally notified that the smell was not natural gas, but "radishes."  Even though some of my friends are still "not convinced there isn't a dead body in the field," we finally came to the conclusion that the smell was due to a cover crop or tillage radishes. 

Other reports of smelly cover crops came in from Burrus dealers, Brian and Kyra Willenborg near Vandalia, Illinois as well as Kyle Kiefer, who said that 40 acres of tillage radishes caused the entire town of Ina, Illinois to "smell like sauerkraut." 

Why would a farmer plant such a stinky crop? Cover Crops have grown in popularity over the last several years. They provide many benefits such as adding nutrients to the soil, preventing removal of nutrients, such as nitrates, which can lead to detrimental effects in the Gulf of Mexico, improve soil tilth, prevent soil erosion (much needed this year), and assist with weed control or reduce the use of herbicides.

So, let's cut to the chase. Why the smell?  Kris Reynolds, Resource Conservationist at the Montgomery County Soil and Water District stated, "The weather this fall provided an abnormally, good growing season for cover crops, especially the radishes. The radishes were planted early and grew very well. The bigger the radish the worse the smell!"  As freezing and thawing occurs, the radish is breaking down in the soil and this is accompanied by an odor.  Matt Boucher said that the smell will be worse if tillage radishes are "very thickly planted in the field, without the presence of another cover crop species with it."  David Rahe suggested that next time they might consider planting another cereal cover crop species, like oats to "thin out" the tillage radishes.  Unfortunately, the smell could persist anywhere from a few days to several weeks.

The moral of the story, is that by planting cover crops, farmers are not trying to "gas everyone out" so to speak, but be good stewards of the land for our future!

Picture of a "gigantic and stinky" tillage radish planted July 20th that was grown on the farm of Burrus Dealers, Kyra and Brian Willenborg, near Vandalia, IL.

For more information, check out this video:


Can Bees Increase Soybean Yields?

As an agronomist, I receive really interesting questions from farmers across Illinois.  Here is just one of the most recent questions that I received:  "Can bees increase soybean yields?"  This has been an ongoing question and has been researched in past years.

In order to help me sort through the online hype and data to answer this question, I interviewed a leading industry soybean breeder for his take on this question, and here is what he had to say:  "I do not know if bees can contribute to yield; however, there are a few facts that I do know.  Bees are pollinators and can be active in soybean fields.  When I have used soybean male steriles in fields, bees have not contributed to yield much, thus, most of the time there are very few pods on these plants.  Cutter bees are more efficient pollinators of soybeans than honeybees. We do know that soybeans abort a lot of pods and flowers due to plant health or lack of pollination, but mostly I think it's plant health, or how many seeds that plant can support.  I guess it is possible that honeybees can increase yield, but I don't think the yield increase is significant, but I have no data to back that up.  If you have beehives near soybean fields, be careful when using insecticides during flowering."

The following in the Corn and Soybean Digest article from 2013, gives some examples of studies from around the world that investigated bees and soybean yield. A quote from this article states, "While all three (studies) showed yield improvements, they involved honey bees rather than the native bees O’Neal’s research found.  Among the thousands of native bee species, some are more effective pollinators of specific plants than honeybees. It’s a challenge to link specific bees’ activities to the soybean plants and then to yield."

On a similar note, if growers are worried about honeybee exposure to soybean insecticides at planting, you can use SuperFlow offered by Burrus to reduce dust off of seed treatments to decrease risk to pollinators, while lubricating planters.  This is the same Bayer CropScience Fluency Agent that Canadian farmers have been required as of 2014, by Canada's Pest Management Regulatory Agency (PMRA) to use on seed treated with various insecticides.  This is one contribution to improve honeybee health in Canada and could be an option for you on your farm in the United States.

Monday, January 11, 2016

Who saw Sudden Death Syndrome in Soybeans during 2015?

A common question at many agronomic meetings this winter has been: Why did we not see as much SDS in 2015?

The 2014 season will be remembered as one of the worst for Sudden Death Syndrome (SDS). This fungal pathogen survives in soybean residue and infects the roots of soybean seedlings in the spring. If environmental conditions are conducive, the fungus can continue to colonize the root cortex during vegetative growth stages. Then, during reproductive stages, if the fungus continues to grow into the vascular tissue of the root, a toxin can be released and disrupt the water and nutrient flow of the plant, which can result in yield reducing, yellow foliar symptoms of the soybean.  

Those hardest hit by the disease in 2014 appeared to have planted soybeans between May 6 and 10, 2014, and unfortunately, many growers planted at this time. The pathogen that causes SDS favors early season temperatures around 60 degrees.  If you refer to map 1, you can see that SDS was present in areas outlined that consisted of cool, early season temperatures. When comparing 2015 and 2014, the biggest difference appears to be that most of Central Illinois had warmer temperatures during early planting dates (May 6 and 10) in 2015 and this can be seen on map 2.  Therefore, later planting or warmer temperatures at planting are some reasons that we saw less SDS in Central and Southern Illinois in 2015. However, areas in Northern Illinois did have cool, early season temperatures that were favorable for soybeans to become infected with SDS fungal pathogen.
Map 1
Map 2

Along with early season cool temperatures, heavy rains can also cause SDS to intensify. You can see the areas with the heaviest rainfall in 2014 and 2015 on map 3 and 4, respectively. There is a star placed on an area with cool, early season temperatures at planting and heavy rainfall.   
Map 3
Map 4

As expected, this area was one of the worst hit by SDS in 2014 and 2015. This is just one example where the presence of this fungal pathogen in the soil combined with favorable conditions caused high SDS severity.  However, the dryer conditions later in the season in areas of Northern Illinois helped to curb the yield loss due to SDS infection in 2015.
Ultimately, soybean yield loss will depend on SDS onset and severity. SDS is usually more severe when symptoms appear before soybean podfill.  When symptoms occur early, yield loss occurs by way of reduced seed number, because flowers and pods can be aborted. Unfortunately, SDS symptoms can become more severe over time, and soybeans stressed by SDS can be more vulnerable to other root, stem, and seed diseases. Soybeans that show symptoms after podfill can suffer yield loss due to reduced seed size, reduced pods, and seed weight, because seed quality could be at risk. As soybeans reach the later growth stages, such as R6, the final yield loss can be observed.

All soybean varieties can be susceptible to SDS, but, planting soybeans with a higher level of resistance to SDS and SCN can prove to be helpful. A rotation from soybean to corn will not help to combat SDS, because the fungal pathogen that causes SDS has also been found to survive on corn roots. The SDS pathogen favors soils that are compacted, or not as easily drained, therefore, improving soil drainage and eliminating compaction will also help to reduce risk of the onset of SDS. There are no foliar fungicides that can be used as rescue treatments for SDS, but there are seed treatments available, such as the high rate (.15 mg ai/ seed) Burrus PS SDS (ILeVO®) that have proven results against soil borne pathogen as well as SCN.