If you call Rick Rottinghaus at the right time, you might be invited to his farm near Jesup, Iowa to help. Most likely, this will be a request to run an air seeder just behind the combine. “We can always use help if you’re available,” he jokes. But his real job is the constant improvement of the land he cultivates, including some innovations in water management.
This pneumatic drill is the key to his cover crop program, a decision he made several years ago in part because of a labor shortage. “We were on ridges, and I couldn’t get anyone to grow crops,” he recalls. “We moved away from the ridges. Then I started working with cover crops.”
More on these cover crops and what he learned later. What brought Wallaces Farmer to the Rottinghaus farm was an innovative installation he made on his farm. Rottinghaus installed a saturated buffer zone in a waterway – not near a stream, which is more common.
Rottinghaus is a member of the Miller Creek Water Quality Project Advisory Board. It is an education to understand how water flows in the area and how the watershed empties into the Cedar River which runs through eastern Iowa and empties into the Mississippi.
The bigger picture
The Miller Creek watershed is part of the larger Middle Cedar River watershed, spanning 1.5 million acres in east-central Iowa. All of Rottinghaus’s land is in the Middle Cedar watershed.
PERFORMANCE MEASUREMENT: Clark Porter, an environmental specialist in the Iowa Department of Agriculture and Land Management, stands next to one of the measurement locations where samples are taken to measure the water leaving the Rottinghaus waterway. Kent Heikens, USDA, Ames, Iowa, took measurements from these wells. (Willie Vogt)
Clark Porter, an environmental specialist with the Iowa Department of Agriculture and Land Stewardship, is posted to Miller Creek and works with colleagues as needed in the larger Middle Cedar watershed. “The Miller Creek watershed covers approximately 61,000 acres of this area,” Porter says. He explains that the Middle Cedar watershed is one of many priority watersheds in Iowa that have been targeted for water quality improvement. Targeted projects in the watershed receive additional state, federal and even private funding through various programs and sources. Along with concerns about excess nutrients flowing into the Mississippi and Gulf of Mexico, the town of Cedar Rapids sits at the base of Middle Cedar and relies on alluvial wells in the Cedar River Valley for drinking water. Porter appreciates Rottinghaus’s expertise, support and innovative thinking.
Porter explains that the Total Watershed was funded by a $ 97 million grant to the state from US Housing and Urban Development, under the title “Approach to the Iowa Watershed.” The money is used to better manage the watershed and measure the water quality in the region, which accounts for about 73% of agricultural land.
Rottinghaus was looking for opportunities in watershed management and he looked for ways to reduce runoff and improve water quality for everything that drains from his farm. “I’m looking for things that will also benefit the farmer; saturated buffers or bioreactors don’t directly benefit the farmer but benefit the environment,” he says.
He considered the saturated buffer the right choice for his operation, as it keeps nitrogen from leaving the farm at a lower cost than the alternatives.
Additionally, Rottinghaus sees a lot of these mitigation efforts focused on the edges of the field. “You want to do more than at the edge of the field to improve soil quality, water quality, and retain nutrients,” he says.
Choose this buffer approach
The saturated pad installed by Rottinghaus – without financial assistance from the USDA, as it only comes when these pads are placed near streams or rivers – was his investment in the farm. “I was going to install it in 2017 and waited for support, but it didn’t work out,” Rottinghaus says. “I installed it myself.”
Rottinghaus was leveling the waterway and came up with the idea of installing a saturated buffer zone. Essentially, the saturated buffer “traps” the water, slowing its discharge into a pipe or stream to allow natural processes to run through the nitrogen that might come from the farm.
Kent Heikins, of the USDA at the National Laboratory for Ag and the Environment in Ames, Iowa, shares that saturated buffers show promise. “We have been using saturated buffers for 12 years in our lab and are confident that they work,” he says. “Nature itself eliminates this nitrogen and we take the opportunity to send water into the saturated buffer.”
COVER CROP DIFFERENCE: Rottinghaus plants cover crops which they sow after harvest with a pneumatic seeder. This practice has already reduced the measured level of nitrogen leaving the farm according to Kent Heikens, with the USDA in Ames, Iowa. (Courtesy of Rick Rottinghaus)
While saturated buffers near water bodies are common, Heikens says his lab has looked at different types of landscapes where they can be deployed. He recalls being alerted by Porter that Rottinghaus was going to use his own equipment to install the system.
“He bought the boxes and made the tile himself,” Heikens says. “He had to redo a big tile in the stream.”
Rottinghaus installed a 10-inch waterproof pipe that basically flowed “up,” the water that poured into it was carried back to the top of the stream, where it would then descend. Two boxes – one at the top and one at the bottom – would slow the water out of the stream. This enabled the natural process of denitrification.
“You cannot cross the waterway when the buffer zone is full,” says Rottinghaus. “But it’s dry at the top.” It’s a cost he’s willing to pay on his farm.
Rottinghaus notes that the cost of the two boxes for the saturated pad was around $ 700 each, along with his own time and materials for the tile line. He estimates the total cost to be around $ 1,800 to install the buffer zone, and he is considering the practice in other parts of his farm.
While Rottinghaus may be considering another saturated buffer zone in a waterway, the idea could gain traction in other parts of the state. Heikens says the USDA is looking into other parts of the state where this could be happening. “We’re looking for more waterways to do it and doing a little more monitoring,” he says. “If we want to remove a nitrogen charge, we have to get a flow. We are looking at it in more depth.”
Heikens says given the drought of 2021, it hasn’t been a good year to study saturated buffers; but even though it was dry, the flow to the Rottinghaus buffer was good.
He adds that Rottinghaus’ use of cover crops puts him ahead in the work of keeping nitrogen on the field where it has been applied. “The water flowing through these boxes was at its maximum at 12 to 14 ppm, and the two-year average was 10 ppm,” he says. “He’s already sort of ahead of the curve with the quality of his water entering the row of tiles.”
Heikens is working on doing more tests at the Rottinghaus farm to explore how water moves through the tile lines. The waterway is part of the drainage of a 740 acre field.
Cover crops make the difference
As Heikens puts it, Rottinghaus was ahead of his use of cover crops. He was a long-time user of ridge plowing, but switched to no-till as it became difficult to find labor for the cultivation. And he switched to a corn-soybean rotation.
Rottinghaus was looking for ways to improve soil health and turned to cover crops. “I flew 60 pounds per plane in the crop,” he recalls. “But I only saw 10% germination. In five years, I had two years of a decent position.”
Knowing he needed a better approach, he turned to using an air seeder after the combine in the fall. He notes that he only uses 30 pounds of ryegrass seeds in the fall, compared to 60 pounds, and sees a higher germination rate. “I’m getting at least 40% germination and better coverage,” he says.
Labor is always an issue, as this air seeder follows two combine harvesters to harvest. “I need someone to execute it,” he says.
As for the costs? He thinks he pays $ 6 an acre for seeds at 30 pounds an acre, and he uses what he calls a “cheap” pneumatic planter. Its application cost is approximately $ 14 per acre. “We get a better position that is more consistent with the exercise. He plants the drill in a 10-inch gap with a 20-inch gap. He plants in that 20-inch gap in the spring, then finishes the cover crop afterwards. planting and uses a burn application with a residual herbicide to get the crop off to a good start.
Using no-till crops and cover crops works for Rottinghaus. It’s all about lifelong learning for him. He remembers an eighth-grade textbook from the 1930s that said, “Moldboard plows save moisture.” When Rottinghaus read this he said, “I burst out laughing. We learned a lot.”