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In: Central Sands, Justin Isherwood, Kevin Masarik, potato, potatoes, UW-Stevens Point, Water quality

Fried, baked or mashed, we love our potatoes. What we don’t love is drinking water with lots of nitrate — a form of nitrogen that fuels a robust potato crop because it acts as a fertilizer. In the Central Sands area of the state, which is where most spuds are grown, drinking water is groundwater and groundwater can bear the brunt of unwelcome potato cultivation effects.

“When you look at impacts on the groundwater system from typical cropping systems in the Central Sands, they tend to leach nitrate,” said Kevin Masarik. “Potatoes are particularly challenging because the hill and furrow system tends to promote both (water) recharge, as well as nitrate leaching loss due to the high nitrogen demand of that particular crop.”

Although he’s not armed with regulatory suggestions — or even salt, butter and sour cream — Masarik is coming for those potatoes. The researcher from the University of Wisconsin-Stevens Point and University of Wisconsin-Madison Division of Extension is armed with a one-row hand planter, and rye, millet and oat seeds. He’s got in mind science-based solutions, not potato-growing restrictions or even gastronomical intentions.

University of Wisconsin-Stevens Point student Nick Koschak plants oat, rye and millet to build biomass in the furrows between potatoes. Photo: Kevin Masarik

With two years of funding from the University of Wisconsin Water Resources Institute, he’s pursuing what he termed an outside-the-box idea for assessing whether this tasty tuber can be cultivated in a way that reduces the movement of nitrite into the groundwater.

In children six months and younger, nitrate promotes the oxidation of hemoglobin to methemoglobin that limits blood’s ability to bind and transport oxygen, depriving the infant of oxygen. Nitrate has also been linked to cancer, thyroid disorders, birth defects and hypertension. Both state health and agricultural officials name nitrate as the most widespread groundwater contaminant in Wisconsin affecting both municipal and private water systems. Because groundwater also makes its way to surface waters, rivers, lakes, streams and wetlands can see higher nitrate levels with one result being increased algae growth, disrupting ecosystems.

Masarik said for the last 20 or 30 years, when the cause and extent of nitrate in groundwater has been documented, there’s been a simultaneous gap. “We’ve been good at pointing out that there’s a problem, but we haven’t been good at pointing out what the solution is.”

He continued, “In the last five years, I’ve been trying to switch the questions that I’m interested in devoting my time and attention to, investigating potential solutions that significantly improve water quality. And that’s what this project was born out of.”

“Investigating in-season cover crops for reducing nitrate loss to groundwater below potatoes” is an aptly descriptive title of what the project is doing: interseeding cover crops — the rye, millet and oats — among potato rows to see if these added plants will take up the excess nitrate and thereby improve water quality.

Critically, the project also needs to ensure that the potato harvest isn’t hindered nor yield significantly reduced by the additional vegetation between rows.

In a study plot, interseeding crops in potato cultivation rows did not interfere with harvest. Photo: Kevin Masarik

Masarik is grateful for the cooperation of Portage County farmer Justin Isherwood who in 2020 provided a test plot. “It’s (the study) giving me the book,” Isherwood said. “We know a lot of things in agriculture. There are a few things in agriculture we don’t know. Kevin is giving me those letters and the alphabet. He’s giving me the language of the landscape.”

Isherwood is game to again participate in the study this year. “It’s exciting to be a part of the science and to be involved in the discovery.”

Discoveries of last year will be applied. For example, rye is likely to be removed from the seed mix because it put early energy into root growth, resulting in slow above-ground growth. The rye was then shaded out by potato plants. Other plants, though, “Did have some success. I think it showed that the amount of biomass accumulation and the amount of nitrogen that the interplanting, or that cover crop, was able to capture is significant enough that this could be viable,” Masarik said, as enthusiasm bubbled. He said he is energized for the coming growing season. “I enjoy talking about it. I’m pretty excited about it.”

Masarik also wanted to talk about potato growers, who he termed as wanting to be proactive on the nitrate-loading challenge. “It’s all about establishing the plots and making sure that biomass we’re able to grow in that space is successful. If it’s successful, then what is the impact on the actual crop itself. If the impact isn’t too great, it might be a viable strategy. It might not be something that growers would naturally want to do. I think they are looking for solutions.”

 Kevin Masarik is a researcher with the University of Wisconsin-Stevens Point and University of Wisconsin-Madison Division of Extension. Photo: UW-Stevens Point

This project is also about building blocks. To gauge the effectiveness of this approach on water quality, it builds on Masarik’s earlier refinement of methods to track groundwater quality by drawing samples from temporary wells dug with a bucket auger to sample the top of the water table. This establishes a baseline, then he returns in 12 months, repeating the process to check what effect the interseeding might have on groundwater quality. The goal is determining a statistically significant difference that he pegged at minimum of 20% of change.

A second and future building block is if this effort, which Masarik called a proof of concept, is successful it can be used with other crops to reduce nitrate leaching in those fields.

The post Experimental cultivation method could mean healthy potato yield and healthier water first appeared on WRI.

Original Article

News Release – WRI

News Release – WRI

https://www.wri.wisc.edu/news/experimental-cultivation-method-could-mean-healthy-potato-yield-and-healthier-water/

Moira Harrington

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In: aquaculture, Chris Hartleb, Emma Wiermaa, fish farming, Greg Fischer, NADF, Northern Aquaculture Demonstration Facility, RAS, saugeye, UW-Stevens Point, UWSP, walleye

Research at UW-Stevens Point Northern Aquaculture Demonstration Facility focuses on out-of-season spawning

Nothing says “Wisconsin” quite like a Friday night fish fry with all the trimmings: rye bread, cole slaw, French fries, and perhaps a cold beer or brandy Old Fashioned. For many people, the star at the center of the plate is crisply battered walleye.

Yet most of the walleye served in restaurants or purchased in grocery stores actually comes from Canada, including a sizable amount from the Canadian waters of Lake Erie, where it is netted by commercial fishermen.

These walleye, raised in a recirculating aquaculture system at the UW-Stevens Point Northern Aquaculture Demonstration Facility, are about a year old. (Photo: UWSP NADF)

One way to increase the availability of this popular fish year-round and have it come from U.S. sources is through aquaculture, or fish farming. Research conducted at the University of Wisconsin-Stevens Point Northern Aquaculture Demonstration Facility (NADF) and funded by Wisconsin Sea Grant is helping fish farmers get closer to being able to raise walleye year-round in indoor recirculating aquaculture systems.

Said Chris Hartleb, NADF Director and Professor of Fisheries Biology at UW-Stevens Point, “For the past eight years, Wisconsin Sea Grant has provided funding to tackle some of the challenges” related to domesticating walleye (Sander vitreus) and making it suitable for farming. Previous research has examined whether walleye can be raised in tanks and, if so, what the optimal density in the tank is for the fish to thrive, as well as starter feeds for walleye and saugeye, a naturally occurring hybrid of walleye and sauger.  

Hartleb and Greg Fischer, NADF Assistant Director/Research Program Manager, are the lead investigators on a new project funded by Wisconsin Sea Grant in its 2020-22 project cycle.

The project will focus on making walleye eggs, fry and juveniles available year-round through out-of-season spawning triggered by photothermal manipulation. This means carefully controlling the amount of light and the temperature to which the fish are exposed. That way, multiple crops of fish could be produced throughout the year, as opposed to the single time per year that happens in the wild.

Other key players in conducting the research are NADF Foreman Kendall Holmes, an advanced fish technician, and fellow technician Jared Neibauer. Aquaculture Outreach Specialist Emma Wiermaa will communicate research results to the fish farmers who can use them.

For the study, some fish will be exposed to an early “spring” in early February 2021, through warming water and more light. “And then hopefully those fish will be triggered to spawn, and we’ll get eggs by the end of February. And so, if it works, we’ll get juvenile fish probably around April or early May,” said Hartleb.

A control group of fish will spawn on the normal cycle that wild fish would—sometime in April—and a third group of fish will have an extended “winter” (again, due to light and temperature) and spawn late.

While this plan may sound straightforward, it is not guaranteed to work in practice. “It sounds simple enough, since those are the two main triggers for fish to spawn: light and temperature,” said Hartleb. “But some studies have shown”—such as work by Sea Grant’s other aquaculture specialist, Fred Binkowski, involving yellow perch at UW-Milwaukee—“that if you rush them or if you delay them, sometimes the embryos, the offspring, turn out not be viable.”

And not only may embryos die, so may juveniles or early adults, so that’s why it is crucial to grow the fish in the study out to a marketable size of 1 to 1.5 pounds.

Because the NADF team will need to keep producing batches of walleye, they’re working with a range of public and private partners to help them grow the fish out to full size. Those partners include the Max McGraw Wildlife Foundation in northern Illinois and Concordia University Wisconsin in Mequon, which is starting an aquaculture program. Northside Enterprises, a fish farm in Black Creek, Wisconsin, will also participate, and several other farms throughout the state have also expressed interest in raising the young walleye to market size.

Earlier walleye outreach at NADF has addressed topics like showing farmers how to feed-train walleye to consume a commercial diet from hatch. (Photo: UWSP NADF)

Said Fischer, who has worked with walleye in a variety of systems for about three decades, “The capability to spawn walleye out of season in a controlled aquaculture setting is paramount to bringing commercial walleye production to fruition in the U.S. We have got to have eggs year-round for this to be commercially acceptable. This newest project will allow us to move this species into the commercial aquaculture production sector in the Midwest.”

As with other NADF projects, outreach is a key component, with Wiermaa—whose position is jointly supported by Wisconsin Sea Grant—leading efforts to share NADF research with fish farmers throughout the state.

Said Wiermaa, “Making our projects results accessible and presenting them in ways that are useful to farmers is just as important as the research results themselves.”  This can take a number of forms, including fact sheets, manuals and videos.

Aquaculture Outreach Specialist Emma Wiermaa holds a walleye at the facility in Bayfield, Wis. (Photo: UWSP NADF)

Wiermaa has noted high interest among Midwest fish farmers looking to raise walleye commercially as a food fish. “To respond to these requests for assistance, the Northern Aquaculture Demonstration Facility recently completed a technical video series on raising walleye intensively in water reuse systems. The series compiles nearly a decade of research, and it is accessible online. Results from this newest project will be added to this video series and other outreach tools.”

Ultimately, the NADF team hopes that the research will result in more Wisconsin- and U.S.-raised fish on diners’ plates, and help expand Wisconsin’s aquaculture industry, which is currently a $21 million business that represents about 500 jobs.

“Every time we’ve concluded one of our projects, there’s just tremendous interest [from fish farmers] throughout the Upper Midwest. I think people realize that walleye are a great-tasting fish. And it’s a high-value fish, so it gets a good price on the market,” said Hartleb.

Original Article

News Releases – Wisconsin Sea Grant

News Releases – Wisconsin Sea Grant

https://www.seagrant.wisc.edu/news/new-walleye-study-at-uwsp-nadf/

Jennifer Smith