Production Blog

Have You Cultivated Lately?

Pam Smith
By  Pam Smith , Crops Technology Editor
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There are actually soybeans in this photo, but waterhemp gave this Illinois soybean field some tough competition in 2012. (DTN photo by Pamela Smith)

DECATUR, Ill. (DTN) -- I've been watching a case of weed resistance unfold for the past several crop years. The field is conveniently located near my home and has become the equivalent of a nursery for almost every weed species we have in central Illinois. I keep thinking I'll meet the farmer who cares for this field while I'm photographing weeds, but all I've ever seen are sprayer tracks -- lots of them.

Common waterhemp has become the predominant weed species. What started as a small patch has spread throughout the field over the past three years. I watched flush after flush emerge during the 2012 growing season. I'll swear the stuff grew stronger with each sprayer pass. So far, I've noticed no change in cultural practice other than crop rotation.

Last spring, I had a flashback moment when I saw an old-school field cultivator working in a soybean field just south of Bloomington, Ill. It was one of those rare moments when I was without a camera and I yearned to capture the vintage scene as the farmer toiled toward dusk. I rubbernecked until I couldn't see the tractor and implement -- which come to think about it, was a move reminiscent of cultivating. I could almost smell the Bengay ointment I once relied on after long days spent looking over my shoulder in the days before guidance.

In a recent news release, Kevin Bradley, University of Missouri weed scientist, warned that in the war between waterhemp and producers, waterhemp is winning. "It is our driver weed," Bradley wrote. "We pretty much make every decision on that one weed.

"If you've just got glyphosate-resistant waterhemp, you should consider yourself lucky," he added. Waterhemp with multiple resistance to available herbicides makes life even more complicated.

While waterhemp has survival strengths, Bradley noted that it also has weaknesses. The main one is that waterhemp seed is relatively short-lived in the soil. "If you've kept waterhemp from producing seed and returning seed back onto that land for four years, you are probably going to virtually eliminate waterhemp from your field," he noted.

He also pointed out that waterhemp seed does not emerge from low soil depths. That translates to deep tillage -- something that can't be recommended for every situation.

Bradley is trying to get a read on how growers are changing cultural practices in the face of herbicide resistance challenges by conducting an online survey. "Currently, there are very few (if any) sources where we can obtain this information," Bradley told DTN in email correspondence. "USDA cut much of the funding where we used to get this data on tillage practices, etc. so this [survey] is what I came up with to try to get some information.

The survey is only 12 questions long and specifically aimed at Midwest growers. Let's give Bradley a hand at gathering this information and we'll report back on his findings.

The survey can be found at….

Pamela Smith can be reached at


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