Fall field day gives glimpse into research

It’s been over 100 years since the Kansas State University Southwest Research-Extension Center was established in Garden City, Kansas, and researchers have found what works in their part of the state.

SWREC head Bob Gillen said if you look through the old records, the first seven years of the center’s existence, “they couldn’t raise a wheat crop.” Things are much different now, and the center is working diligently every year to find the best ways for farmers to remain profitable.

“I don’t know if that was just we didn’t know any better than that or the weather was probably against us at that time,” Gillen said. “Then technology just wasn’t all that great either. That’s part of the reason why the station was established.”

Gillen said the Garden City, Kansas, station has only received about half of its normal rainfall for 2019. Many surrounding areas are at about the same precipitation levels.

“It was really good early on, maybe not so good since then,” he said. “Hays was kind of that same way, and then we had an inch and a half the rain just before our field day up there.” 

Weeds in corn

Randall Currie, a SWREC weed scientist, has no trouble raising good weeds for his experiments. He calls them his “state fair weeds” and they give him the best environment to test herbicides. Currie has trials with weed control in irrigated corn as well as weed control in irrigated grain sorghum.

“All the stars lined up on that one to get us the best weeds possible,” he said. “I think there’s something to planting in the cooler soil to avoid palmer amaranth, and as you get later and later the palmer amaranth pops up quicker.”

Currie thinks it gets a little tougher as the season goes on to control weeds as it is earlier in the growing season. On one trial he tested pre- and post-treatments in the corn.

“The objective on this one is we’ve already decided we know that a pre followed by post is always better,” he said. “Very seldom a pre out performs a total post or very seldom does a post out perform a pre followed by a post.”

He’s found, in some instances, a two-pass program might be worth the hassle. One “remember when” product offering had 75% of the herbicide rate applied on one date and the remaining 25% put on at a later date.

“But that worked well enough to justify the added expense of making the separate application,” he said.

Currie said one of the biggest nightmares of a weed scientist is when all the treatments work. This was the case in some of his plots at Garden City.

“I’m having real difficulty telling these treatments apart because they all work so well,” he said. “So you try to put a positive spin on things when that happens.”

But it also allows him to critically analyze the treatments and ask, “What’s the economics of the treatment.”

“I’ve always said, I can kill the weeds, just how big a pocket book you’ve got,” Currie said. “We have to kind of keep that in mind when we look at this.”

He warns though, if the herbicide mix worked “really, really well last year,” to not do it again. Why? Resistance.

“You need to have more than one bullet in your gun,” Currie said. “I think that herbicides are a whole lot like of a piece of equipment. You didn’t just wake up one morning and know how to run that planter, or that piece of equipment. Somebody taught you how to do that, or you taught yourself the first time you ran it, it maybe didn’t run as good as you 57th time you ran it.”

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Herbicides are something farmers learn how to use them and under what circumstances to use them, Currie said. 

Weeds in grain sorghum

Vipan Kumar, weed scientist at Agriculture Research Center in Hays, Kansas, spoke about Currie’s grain sorghum plots at Garden City, and what has been reported in those.

When it comes to herbicide resistant kochia, producers are limited to three products that have been primarily used in wheat-fallow production systems to take care of kochia.

“They are kind of just surviving those treatments,” Kumar said. “It’s still it’s still a big problem, I would say especially in the fallow production system. And we have been losing tools like glyphosate fluroxypyr. Fluroxypyr is a new case for us and has been reported recently. It was pretty effective on kochia but it’s losing its control now on kochia.”

Kumar said that’s a measure of concern for those in western Kansas.

“So again, glyphosate resistant kochia, and as most of you know, is widespread in western Kansas, and our silver bullet would say but to rely on oxygenic herbicides to take care of those kochia or glyphosate resistant kochia,” Kumar said.

In one of Currie’s treatments, he sprayed the full label rate of the fluroxypyr for treatment multiple times and was not able to gain control of the weeds.

Kumar was asked about atrazine since it leaches into groundwater and its efficacy in controlling certain weeds.

“In terms of efficacy, I haven’t tested anything like that in Hays, but as per Currie, he has not been seeing any difference between atrazine and that related compound,” he said. “Again, because sorghum is such a crop where we don’t have many options—especially the post option, we definitely have to have a more solid pre-program that can help the program in terms of palmer and kochia management. That’s what he has been targeting in this study here.”

Hay and silage research

John Holman, cropping systems agronomist at SWREC, explained the summer annual forage variety trials available at Garden City, and said they started this program up several years ago.

“K-State hadn’t done this work for about 20 years,” Holman said. “We were getting a lot of requests.”

Holman and his team evaluate forages in both a silage test and hay test for yield and quality. There are three sites in Garden City under irrigation and they’re also working with cooperators at Hays and Belleville, Kansas. They also have dryland trials in the study.

“This year we have 206 entries across the three locations,” he said. “So a lot of entries.”

Holman said one of the things they started this year were trials for corn silage.

“We were getting a lot of requests for corn silage, and we held off on doing that for the first several years,” he said. “But this year, we started doing corn.”

After the Aug. 22 field day, Holman said they will get back into harvest mode in the trial. With the different forages, he’s aiming to harvest the corn silage at the black layer stage, forage sorghums at the hard dough stage and hay types when it’s reached 50 percent heading.

In the silage study, planting was done on May 17, but rain proved to be problematic.

“We planned to plant everything then but because of all the rain we had this spring, the hay test, we got too wet, we couldn’t get back in here the 4th of June,” Holman said. “We’ve applied 9 inches of irrigation and 7 inches of rainfall. So a little over 16 inches since planted.”

Holman pointed out a couple brown-mid rib forage sorghum varieties, a dwarf variety that has a higher leaf to stem ratio and its advantages to livestock.

“That increases the palatability of this product as compared to a more typical forage variety that is taller,” Holman said.

The brown mid rib trait was identified in the 1920s and has been developed for since. The naturally occurring white mid ribs have a lower lignin content when compared to their BMR counterparts.

“BMR have higher protein and higher energy content and higher feed values when you look at all the BMRs as a whole,” Holman said. “Historically they had a 10% yield drag, compared to the non-BMR, but we’re seeing a lot of that—the old guidelines are kind of changing. Some of the newer BMRs are yielding on par with the non-BMR.”

There have been some issues with lodging of the forages this year, but Holman believes it’s because of the wet conditions at planting and during the crown root development.

Look for results from this and previous field trials at https://www.southwest.k-state.edu.

Kylene Scott can be reached at 620-227-1804 or [email protected].