Until a few years ago, producers in southeast Missouri looked at no-till production with a wary eye. “We've always had a good relationship with the people at Milan, Tenn., who put on the big no-till field day. I used to think they needed to no-till around there or they'd lose their soil through washing,” says Andy Kendig, Missouri Extension weed specialist.
Missouri Bootheel farmers don't really have that problem. But they do have the same problem farmers nationwide are facing: poor commodity prices. So, as it saves money, growers have lately been much more interested in conservation tillage.
“I'm not completely sure that ‘never-till’ is an agronomically perfect way to farm. But anything growers do to reduce tillage does save money…. If we can grow a crop without disking twice, putting up beds, knocking them down and maybe repeating the bed-building a second time, why not? You're saving money, time, diesel fuel and tractor wear,” says Kendig, who spoke at a tour stop at the Aug. 30 Delta Center field day in Portageville, Mo.
One of the downsides to conservation tillage is this is probably the worst herbicide-drift season Kendig has seen. That's especially true of burndown products moving outside designated fields.
“Corn is very sensitive to Roundup or other glyphosate products. That's just a fact. There are other products — like Gramoxone drifting onto to corn — that have caused problems, but glyphosate is the main problem.
“If you do your own spraying or are in the spraying business, you really need to be using low-drift tips. It's important to run those tips at a properly rated pressure. Sometimes that means lower pressure with older tips. Some of the more modern tips, however, require higher pressures. The important thing to pay attention to its rated pressure.”
At a field day a couple of years ago, Kendig demonstrated that a boom will make a good pattern (about 6 inches) above a targeted crop. An actual sprayer can't run at that height because the boom will begin rocking and be dragged through the crop. However, Kendig insists, there isn't any reason for the boom to be set 6 feet above the target and “blowing fog.” Lower the boom when you can and use a drip retardant.
“Be smart. If you have a 20 mile-per-hour wind blowing toward your neighbor's corn, don't proceed with a planned burndown. It's meaningless in those conditions. Despite all the fancy engineering we can talk about for hours, the key to stopping drift is simple discipline. Just don't do it. If the wind is blowing, make the tough decision and shut down.”
One of the key advantages for conservation tillage is it allows extra time. Use that to your advantage, says Kendig.
Another reason for drift is desperation. “But if you mess up a neighbor's crop, it's just going to make things worse.”
Glyphosate-resistant horseweed (or marestail) is showing up all over western Tennessee. Kendig says the weed tends to show up the second or third year a field has been in no-till culture.
“We think we might have some on this side of the Mississippi River. Traditionally, we haven't done a lot of no-till and a disk controls it pretty well. But a farmer near Portageville has been no-tilling for 10 years and it looks like he might have some resistant weeds.”
Even though it isn't a sign of the apocalypse, Kendig says, finding the resistant weed “is an important wake-up call. Conservation tillage producers in the Bootheel have been battling cutleaf evening primrose for years. The solution has been to get out in March with a 2,4-D-type herbicide. That will be a fairly good solution to any horseweed problems, too.”
Forgetting to put out 2,4-D is one of the main no-till problems Kendig sees. “Don't let that slip by.”
While recent focus has been on resistant horseweed, several other resistant weeds have cropped up in the country. “Never say never. When we use any product repeatedly, be thinking about it. Anything you can do to rotate products probably will help. I don't get terribly excited about strict rotation schemes, but anything to rotate chemistries is good. Chemical rotation is easy for me to say and harder for a grower to do, but you should at least be thinking about it.”
Roundup Ready crops
In the past, if you were no-tilling you'd burndown with Roundup since that's all there was. Then you'd use traditional herbicides in the crop. But now that producers put glyphosate on their Roundup Ready crops, the need to use a traditional herbicide in the burndown window is being studied.
In a study funded by the Missouri Soybean Council, Kendig and colleagues are looking at this question: can a grower use other products for burndown?
In controlling summer weeds, after the crop is planted and up, “we made two 13-ounce applications of Roundup Ultramax. Where we had no burndown at all, our weed control was only 60 percent. So burning down after the crop is planted isn't the best way to do things. You don't want to go in cold without knocking back winter vegetation.”
Kendig says current research shows that surfactants or crop oils plus Callisto Canopy XL, Valor, Sencor, atrazine, Cotoran and Caparol can be good overall burndown treatments in crops. But you've got to be cautious because some weeds — especially ryegrass — can sneak through.
“So the philosophy of replacing glyphosate in the burndown may be a bad one. We may need to leave glyphosate in the burndown mix.
“In no-till corn, atrazine plus crop oil does an outstanding job if there isn't too much ryegrass out there. It's weed-specific and we mustn't shove glyphosate aside. If you try an alternative burndown, do so carefully.”
Conservation tillage in southeast Missouri has grown in leaps and bounds over the last couple of years. Kendig says that growth will continue. “But we need to be more careful with it.”
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