SWOGA and Rhizobia Survival

The Southwest Ohio Corn Growers Association annual Agronomy Field Day was interesting today. My friend Bill Lehmkuhl stole the show with his root pit and the ears laid out from 17.5 feet or 1/1000 of an acre of 30 inch row corn.

He found 31 plants from a 34,600 seed drop with 28 harvestable ears and two nubbins that might fall through the stripper plates on the cornhead. He also found 3 major layers of compaction in the profile, pancake roots, the tractor wheel prints that pulled the 4 row planter and the side dresser marks.

Most attendees saw the ears and said or thought, hell, my corn sure don't look that good, compaction or not. The site received more rain than most attendees farms did. He made some very good points though that I always try to keep in mind.

We must find a way to get the same amount of soil with the same amount of density above each seed whether we no-till, strip till, rip, or whatever. It is important to have each plant at the right depth to send nodal roots down deep for moisture in a dry summer.

My corn doesn't look that good either and I probably got as much rain as they did but I am close and I know exactly what caused everything I see in my fields. This year marked 50 since I planted my first in 1963 and God gave me the chance to challenge 300 bushels per acre and I blew it. I will be happy with half that much, very happy. My April 17 blog only tells part of the story but it is all in this blog, somewhere.

Then I got to talking about soybeans and the talk led to inoculants and did they die in the heat. Here is a timely quote from Ohio State's CORNewsletter:

"The dry weather of 2012 has given cause for worry about many areas of crop production. On a recent trip to Ukraine, it became obvious that high soil temperatures and dry surface conditions there have greatly reduced rhizobia populations. This is a country where soybeans are only recently being established, first year soybeans even with inoculants applied are suffering from lack of nitrogen due to the lack of rhizobia development. While we in Ohio have a long relationship with soybean and rhizobia, conditions this year may lead to concerns for next year.

Soybean rhizobia bacterial cells survive best when they are in a moist soil environment and an ambient soil temperature of 40-80 degrees F. The drought throughout the Ohio in 2012 has resulted in the top six inches of soil becoming extremely dry and very hot in many fields. Either a very dry soil environment or a very hot soil environment causes the rapid death of rhizobia cells and the combination is lethal. Therefore, we would expect a reduction in the population of residual soil rhizobia cells in many Midwestern soybean fields in 2012 due to those soil conditions.

Although many cells will survive the extreme environmental conditions, those cells will have evolved into survival mode and will have lost much of their potential to provide nitrogen to soybean plants in 2013. That means the surviving rhizobia population will likely be less productive next year than in previous years. That reduced productivity should translate into increased yield responses to inoculating soybeans and other legume seeds in the spring of 2013."

Think about that for awhile! I sure will be!

I finished the day talking to my cover crop guru friend, David Brandt from Carroll, Ohio. I will have to continue this talk tomorrow.

Ed