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Welcome to Episode 26 of The Spokesman Speaks podcast. In this episode, Iowa State University researcher Dr. Mike Castellano shares the results of a new study about the environmental benefits of updating Iowa's 100-year-old drainage system.

The episode also includes a conversation with Shawn Richmond (Director of Environmental Technology with the Iowa Nutrient Research and Education Council) about the water quality progress he’s seeing in the research he’s conducting and observing.

Click here to view the transcript +
Narrator: Welcome to The Spokesman Speaks, a podcast from Iowa's leading agricultural news source. Brought to you by the Iowa Farm Bureau. Now, here's your host, Laurie Johns.

Laurie Johns: Welcome to The Spokesman Speaks Podcast. This is our November 18th edition. Thanks for joining us. Well let me just start off by saying what happened to fall? Record low temperatures crashing the thermometers all across the state. Certainly I find myself speaking with a bit more base this week. You know Iowa's changing weather impacts us all and our environment and this week's episode features a couple of experts on Iowa's water quality including Dr. Mike Castellano an Iowa State University researcher who has an interesting new study about the environmental benefits of updating Iowa's 100 year old drainage system. Dr. Castellano is the star of the latest Iowa Minute, which you'll see on TV news stations all across the state. Of course, as we've always said, there's more to the story than we can possibly cover in a minute. So we wanted to give you, our podcast audience, more from Castellano's interview. I started out by asking Dr. Castellano about the importance of Iowa's drainage system. As most of you already know, much of Iowa wouldn't even be habitable, let alone farmable without it.

Dr. Mike Castellano: So, in the early 1900s farmers installed tile drainage pipes underneath the fields in Iowa. And prior to those tile pipes we couldn't grow the types of crops that we grow now or nearly the amount of production that we have now. Those tiles enable us to have the agricultural system that we know of today and the installation of tiles, drainage pipes underneath our fields allowed farmers to grow the types of crops that we grow today and to dramatically increase the production in the state.

Laurie Johns: But that was 100 years ago. Clearly Iowa's needs are different today.

Dr. Mike Castellano: Yes. In Iowa, our drainage pipes are ready for an upgrade and rehabilitation because they've run out of capacity. They're over a hundred years old now. In most situations, farmers have been slowly upgrading them over time, but in the coming decades there's going to be a growing increase because here in Iowa, precipitation has been increasing over the past hundred years as well. So we have a situation here where the pipes are old and they need to be replaced because they're deteriorated. And in addition to that, the amount of precipitation we're getting now is much greater than it was in the early 1900s. For both those reasons we need to improve our drainage systems in the state.

Laurie Johns: That might sound like a daunting challenge, but Dr. Castellano also sees opportunities.

Dr. Mike Castellano: Yeah. Increasing the amount of drainage in fields. It will increase the amount of water loss from the field. It also increases the amount of space that the roots can explore. As a result, they can increase their nutrient use efficiency and it can actually allow us to reduce the amount of fertilizer inputs to the field.

Laurie Johns: And that's not all.

Dr. Mike Castellano: Now as we upgrade tiled drainage systems in the future and we understand our water quality challenges, we can pair practices that both increase water quality and increase crop productivity. And we can do that with a lot of practices. Bioreactors and also wetlands which increase wildlife habitat and also serve to remove that nitrate before it hits the waterways.

Laurie Johns: Dr. Castellano is talking about some significant benefits to water quality. We're talking practices that are going to benefit water quality for the next 100 years.

Dr. Mike Castellano: One of the great opportunities of linking improvements in drainage to conservation practices at the edge of field is that these edge of field conservation practices are some of our most effective opportunities to reduce nitrate loads downstream. Once we put in a wetland, it's there to stay. They're engineered for 150 years. More wetlands would really make an impact on reducing nitrate loads downstream because they're one of the most effective practices we have to reduce nitrate loads. They can reduce nitrate loads by up to 80% whereas our goal is to reduce nitrate loads by 45%.

Laurie Johns: Another perhaps unexpected benefit of thoughtfully updating our drainage system is the potential to decrease greenhouse gas emissions.

Dr. Mike Castellano: So an additional aspect of the improved drainage, which is largely unknown, is that by reducing the need for nitrogen fertilizer input and by increasing the aeration of the soil, increasing the crop growth, we also reduce greenhouse gas emissions from the soil surface to the atmosphere, in particular emissions and nitric oxide, which have a heat trapping potential of 300 times carbon dioxide in the atmosphere.

Laurie Johns: Did that finding surprise you?

Dr. Mike Castellano: It surprised us a lot. So on one hand we knew drying the soil out with the drains would reduce nitrous oxide emissions. We didn't realize just how much it would.

Laurie Johns: Well I don't need to tell you, our podcast listeners, that there's a lot riding on these upgrades.

Dr. Mike Castellano: If we let our drainage systems fail, we will not be growing crops to nearly the extent we are now, and we would lose a significant portion of our agricultural economy. You know, Iowa wouldn't have the population it does today without our drainage infrastructure.

Laurie Johns: So how can you, farmers, get involved in win-win drainage solutions for crop production and water quality?

Dr. Mike Castellano: They should call Iowa State University. We would be happy to work with the farmers and help them out. And we hope they help us out too by providing us the practical information that helps drive studies like this. It's really the innovative farmers that have been, you know, leading the way and, we know the science, right? But oftentimes we lack the practical interaction of what will work, you know, what can I actually do on my field in my place. And I think that leads to a lot of the innovative ideas that other scientists around the world don't have an opportunity to come up with because they don't have the greatest farmers in the world to talk with Iowa.

Laurie Johns: Hey, they're not in Iowa.

Dr. Mike Castellano: Yeah, right.

Laurie Johns: Hey, that's you. It's farmers like you who bring the world class research at Iowa State University to life. Well, that's not a new thing. Of course, we know that farmers have been working with researchers to make water quality improvements for decades. One expert who knows that fact well is Shawn Richmond, who's the Director of Environmental Technology with the Iowa Nutrient Research and Education Council. I recently had the opportunity to sit down with Shawn and talk about the water quality progress he's seeing in the research he's conducting and observing.

Shawn Richmond: One of the things that's important to realize when we talk about how we mark our progress is where we're starting from. For that nutrient reduction strategy. That starting point was the 1980 - '96 average period. As we look to achieve our 45% reductions in nitrogen and phosphorus, that's what we're tracking against is that past historic timeframe. We've done a lot of work with Iowa State University to help us estimate what changes have happened in our nutrient load exports over time since that past timeframe. A recent report that they came out with about a year or two ago tracking where we were at the time, we put out our nutrient strategy compared to that historic baseline shows that Iowa farmers have adopted practices that have allowed us to reduce our phosphorus exports by 21%.

Laurie Johns: That progress on phosphorus didn't happen overnight, nor will our progress reducing nitrates in the water. But Shawn is seeing growth in farming practices that drive both.

Shawn Richmond: Yeah. Cover crops is a practice that has shown dramatic increases over the past, you know, six, seven years, thereabouts. A new survey that the Iowa Nutrient Research and Education Council is working on with Iowa State University to be a statistical representative sample of adoption of practices across the state. It shows that we have close to 1.6 million acres that was in the 2017 crop year. Our new survey is measuring everything on a crop year basis. We have results coming in from the 2018 crop year as we speak, and we'll continue to do that another future so we can track the adoption levels of that practice and all others to see where we're at and compare that again to the past and measure our progress.

Laurie Johns: That's just a bit of my conversation with Shawn. I hope you're planning to join us at our annual meeting, which is December 3rd and 4th in Des Moines, because Shawn is going to join a panel of experts discussing Iowa's water quality progress and results. That meeting is just a couple of weeks away now. We can't wait to see you there. That's all for this podcast episode. Be sure to tune in for our next episode on December 2nd. Until next time, thanks for reading The Spokesman. Thanks for all the great stories and inspiration, and thanks for listening to The Spokesman Speaks.

Narrator: Thank you for listening to The Spokesman Speaks, a podcast by Iowa Farm Bureau. Check out more podcasts and articles from The Spokesman at You can also find and subscribe to The Spokesman Speaks Podcast in the Apple Podcasts app, Google Play, and other popular podcast apps. We appreciate your ratings and reviews and welcome your feedback at

About The Spokesman Speaks Podcast

Since 1934,  The Iowa Farm Bureau Spokesman has been Iowa’s leading agriculture news source, and today it is the largest circulation ag newspaper in Iowa. While the Spokesman newspaper is available exclusively to Iowa Farm Bureau members, The Spokesman Speaks podcast is available publicly, reaching farmers on-the-go with stories that matter to them. You can find episodes of the podcast here or subscribe and listen in your favorite podcast app, such as Apple Podcasts, Google Play, Spotify, iHeartRadio, Stitcher, TuneInRadio, or

We release new podcast episodes every other Monday. Episode 27 will be released on December 2, 2019.