Despite all 2020 could throw at him, Romulo Lollato, Kansas State University associate professor of wheat and forages production, was able to conduct his experiments across Kansas almost like normal.
Lollato spoke during the wheat portion of Sorghum U/Wheat U, on Aug. 11. Sorghum U/Wheat U was virtually hosted by High Plains Journal, Aug. 11 and 12.
One study looked at the interaction between wheat varieties and nitrogen management and another looking at fungicide timing at various growth stages possibly influencing yield.
In the nitrogen study, Lollato had 14 locations with 14 varieties and collected “quite a bit of data” with four different nitrogen rates. Combined with the nitrogen already in the soil and the added nitrogen, rates ranged from 20 to 180 pounds of N.
“So we have a pretty nice range in which we we’re evaluating these varieties,” Lollato said.
Yield ranges went from about 20 to 90 bushels per acre.
“Essentially the varieties, they behaved quite differently in terms of their yield for the same amount of nitrogen,” he said.
Of the 14 varieties, Lollato was most impressed with Bob Dole and WB4269. Bob Dole was more adapted to lower yielding environments, while WB4269 was better in the higher yielding ones.
“They were the most contrasting ones that we found in that nitrogen study,” he said. “And what was interesting from that study is that either low yield environments, or at high yield environments—they were reaching very different yield levels at about the same nitrogen amount.”
So they looked at where nitrogen was limiting and that ranged from zero to 100 pounds, more or less. Beyond that, there was no limitation in low yielding environments.
“So in other words, we’re seeing yield increases with increases in nitrogen up to about 100 pounds of N per acre in low yield environments,” he said. “Then when we look at the high yielding experiment that we had, we were seeing increases all the way to about 200 units of N available. So that’s combining what we applied, plus what was available in the soil, and then beyond that we really saw some more response.”
In those higher yielding environments, some of the varieties were maximizing their use of 200 units of available N, Lollato said, but the yield level was very different.
“Some varieties were maximizing it at 65 bushels per acre. Others were maximizing at 85 bushels per acre. There was a very huge difference in the yield level in those varieties.”
Lollato is waiting on the data to be finalized for protein levels, but has already looked at nitrogen use efficiency. He found there were a couple varieties with very high nitrogen use efficiency, three with very low nitrogen use efficiency and the rest were kind of “in between your average.”
In the fungicide trial, he had a very similar layout with the same 14 varieties as the nitrogen study. He used four different treatments—no fungicide at all, fungicide at jointing, fungicide at heading and both jointing plus heading. This was conducted in five locations. He found some disease pressure and saw some stripe leaf rust depending on the environment.
“The reason for these trials—many growers ask me is it worth for me to go early and do that jointing fungicide application?” Lollato said. “We were trying to answer that.”
He found a bit narrower range than the nitrogen trial when it came to yield, 40 to 80 bushel per acre improvement. Across the five locations and 14 varieties, the effect of using fungicide compared to not using was pretty small. The most gain resulted from the wheat getting the treatment at jointing and at heading.
“It almost seemed like we had like a stair step where if I decide to add a little bit to joint and wanted to get the heading one, you added more and both together, was almost an additive effect that we saw there,” he said.
Lollato said it’s important to keep in mind whether the disease appears early or late in the growing season, and be cognizant of the environmental conditions when applying fungicide. Sometimes yields can be hurt if there is disease pressure.
He also looked at the different products and how the costs stacked up. He looked at the “cheaper options or a more expensive option.”
“In other words, regardless—we went from a cheaper option or a more expensive option. The response was about the same in two locations where it was quite dry,” he said.
Kylene Scott can be reached at 620-227-1804 or [email protected].
