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Mike Howell (00:08):
The Dirt, with me, Mike Howell, an eKonomics podcast, where I present the down and dirty agronomic science to help grow crops and bottom lines. Inspired by eKonomics.com, farmings go-to informational resource. I’m here to break] down the latest crop nutrition research, news, and issues helping farmers make better business decisions through actionable insights. Let’s dig in.
(00:38):
Listeners, welcome back to The Dirt. We’re going to continue our series on Ag sustainability. We’ve spent the last couple of weeks talking about sustainability and what it means, and today we’ve got Dr. Carl Rosen with the University of Minnesota with us today, and we’re going to dig in on a little different aspect of sustainability. Dr. Rosen, glad to have you with us on The Dirt.
Dr. Carl Rosen (00:59):
Yeah. Thanks, Mike. Happy to be here.
Mike Howell (01:01):
Dr. Rosen, if you will introduce yourself to our listeners. Tell them what you do there at the University of Minnesota?
Dr. Carl Rosen (01:07):
Sure, Mike. I’m a professor and extension soil scientist in the Department of Soil Water and Climate at the University of Minnesota, and I’ve served as department head there for the past 13 years. I’ve got a master’s degree in horticulture from Penn State and a PhD degree in soil science from UC Davis. And for the past 36 years, my research and extension programs in Minnesota focused on optimizing nutrient management for a variety of crops with particular emphasis on irrigated cropping systems, especially those that include potatoes. And in recent years, my research has also focused on water quality issues related to fertilizer use, as well as ways to improve soil health. And I also co-teach an undergraduate class in soil fertility.
Mike Howell (01:54):
Okay. Now, Dr. Rosen, when I think about potato production, I naturally think about Idaho and that seems to be the center of potato production, but I do know that there’s a lot of potatoes grown in Minnesota. Tell us a little bit about the potato industry and how they’re doing this year. What are yields looking like and what kind of challenges they may be looking at this year?
Dr. Carl Rosen (02:12):
We have about 45,000 acres of potatoes in Minnesota. In terms of the growing season, it was a cool wet start, but then quickly dried up, especially in the central part of the state. Diseases were largely kept under control with adequate spray programs and leaching losses were minimal due to relatively low rainfall. I’d say that the yields are probably average to slightly above average this year. But because of the heat, potato quality could be an issue due to that hot July and August during the tuber bulking period. I’d say most potato harvest will be complete by the end of this week or early next week.
Mike Howell (02:52):
I know a lot of the country has been under this drought you were talking about. I didn’t know if it extended quite that far North or not, but sounds like y’all had some pretty dry weather this year as well.
Dr. Carl Rosen (03:02):
One of the ways we grow potatoes in Minnesota anyway, most of it’s irrigated, so lack of rainfall is usually not as much of a concern. Yeah, I think we had a fairly good growing season because we have that irrigation ability.
Mike Howell (03:16):
Well, Dr. Rosen, this is part of a series that we’re doing on sustainability in agriculture, and I’m starting each episode off asking our guests the same question. And if you would just tell us in your own words what sustainability means for you?
Dr. Carl Rosen (03:30):
Sustainability to me means achieving yields that can provide profitability to the grower, while at the same time, minimizing the impact to the environment. So to achieve these goals of profitability and minimal environmental degradation, it’s important to use what I consider best management practices. For example, optimizing fertilizer use and pesticide applications. And when possible, it’s also very important to minimize soil disturbance to keep the soil covered.
Mike Howell (04:01):
That’s something that typically doesn’t go hand in hand with potatoes. I understand you really have to dig those potatoes out of the soil, and that’s really going to disturb that soil, sir. How can we incorporate sustainability into the potato industry?
Dr. Carl Rosen (04:14):
That’s the $1,000,000 question with potatoes. It’s quite a challenge. When I think about sustainability, the reason why it’s important is that we’re not just farming for this year, we’re also farming for future generations. As we know, soil is the foundation for farming, and if it’s not managed properly, eventually yields will decline along with environmental degradation. And this can include contamination of surface water and groundwater, soil loss due to erosion and increases in greenhouse gases which can impact climate change. So when we think about potatoes, we need to think about not just the potato year where we really can’t get by without disturbing the soil, but we need to think of the entire rotation, what goes on in between the years of growing potatoes. And when possible, when we grow potatoes, try to minimize that disturbance as much as possible.
Mike Howell (05:07):
Okay. Well, Dr. Rosen, I understand that you’ve been working a lot with potato growers and trying to help them become more sustainable. Can you talk a little bit about your research and this program that y’all are working on in Minnesota?
Dr. Carl Rosen (05:18):
I’m the director of a project that started in 2018, and it’s being funded by the USDA Specialty Crop Research Initiative or SCRI. The title of the project is Enhancing Soil Health in US Potato Cropping Systems. It involves 24 collaborators, as well as graduate and undergraduate students, postdocs and research technicians. We’re assessing potato fields and nine major potato producing states cross country, and we bring together agronomists, soil scientists, plant pathologists, eKonomists, and extension experts in this project. It’s a highly integrated project that includes basic and applied research, eKonomics and outreach, and we have periodic stakeholder meetings to receive input on our approach and future directions. Now, we’ve already talked about potatoes and soil health and how challenging it is when it comes to managing soil health with potatoes because of the soil disturbance. But if we go over what soil health actually means, there are four principles that I’d like to just briefly discuss.
(06:27):
That includes minimizing tillage or soil disturbance, keeping that soil covered, increased crop diversity including cover crops and perennials, and that’s part of the rotation that I talked about. And then integrating animal agriculture when possible. And as we’ve already mentioned, it is difficult to grow potatoes without disturbing the soil. And current practices include hilling at planting, so you’re actually hilling that soil up around the tuber that’s planted. And then obviously to harvest potatoes, you have to undercut the potatoes and then lift them out of the soil. So as I mentioned, one of our approaches is to look at rotation crops to try to make up for the soil disturbance during the potato year. And by following some of the soil health principles, not only during the potato year, but also during the rotation year, one of the goals is to enhance soil organic matter and maintain a beneficial microbial community of bacteria and fungi that might help promote better growth.
(07:31):
And this is where it also gets interesting with potatoes because, soil-borne diseases are a major limiting factor in potato production. And therefore, a common practice is to fumigated the soil to control these diseases. Fumigation. The reason it’s used is because it can be beneficial to plant health. It helps that root system grow, you don’t have the diseases that attack the root system. But, fumigation is not specific. It kills not only soil pathogens, but also some of the beneficial soil microbes. So one of our objectives is to identify management practices that can promote a soil microbial community or population that might reduce the incidents of the bad pathogens, the soil-borne diseases without total reliance on fumigation. So for example, are there specific microbial communities and soil health indicators associated with better soil health and potato yields? And what rotations and amendments might benefit that microbial community or population?
(08:38):
So our approach is to evaluate various practices using small plots in two and three year rotations. And in those studies, we’re monitoring soil health indicators such as various carbon and nitrogen fractions in the soil, and also measuring soil DNA to determine what microbial communities or microbiomes might make up a healthy soil for potatoes. We’re also monitoring grower fields in each state with similar measurements that we’re using in the small plots. So we’re making good progress. We’ll be summarizing the first four years over the next few months. However, bringing about positive changes in soil health through improved management practices can take time. We need to consider not only the potato crop, but also the rotation crops in the years between the years that we grow potatoes. So to get a comprehensive idea of what our practices are doing, it’s going to take several cycles to see if our treatments are having an effect on the soil microbial community, the disease incidents and potato yields in general.
(09:45):
So over time, growers will benefit from this project, because we’ll be able to identify practices as well as various soil health indicators that promote a soil microbiome that will be associated with better potato yields and hopefully lower disease incidents. And we’ll also be able to provide recommendations for appropriate inputs that continue to enhance soil health. I think it’s safe to say that soils are complex and what works in one area may not work in another. So, we’re not looking for any silver bullet. We’re really looking for an integrated approach in this project, one that works in regional areas. That’s in a nutshell what we’re trying to do.
Mike Howell (10:28):
Dr. Rosen, you mentioned a lot of the rotational crops and trying to rotate different crops in what kind of crops are you looking at as far as a rotation?
Dr. Carl Rosen (10:36):
So a conventional rotation might include corn and soybeans. The problem with those crops is that they’re full season crops, and once you harvest those crops, it’s difficult to get any cover in afterward. So, we’re looking at specifically the year before we grow potatoes as maybe a shorter seasoned crop such as edible beans or field peas where we can then put in a mustard cover crop for example, that might be able to provide some fumigant properties. So, that’s one approach that we’re looking at as one of the principles integrating livestock. So we’re looking at some manure additions to see how those might work. Mainly composted type manure for potatoes and seeing if that can enhance some of the carbon or microbial activity in the system. We’re always looking for some rotation crops that we can grow, that will allow us to provide a cover for either subsequent potato crop or crops that are grown during the rotation years.
(11:41):
We’re also looking at maybe some perennial crops. Intermediate wheatgrass or kerns is a big one, so maybe that can be used in between the years that potatoes are grown. So, there’s a lot of new crops coming out that we’re going to be testing.
Mike Howell (11:55):
Okay. Dr. Rosen, talking about animal agriculture and incorporating that into the mix. That reminds me of… And I’m going back 20 years now to a project that I was working with with the University of Florida when I was working with peanuts in the extension service in Mississippi. What we were looking at was a rotation with peanuts and cotton and then two years of Bahia grass and Rye grass during the winter. And we weren’t really looking at it from a soil health perspective. That wasn’t the trend of the day, and nobody was really talking about soil health back then, but we were looking at it to benefit the peanut yields and see what we could do to increase peanut yields. And that two years of grass crop before the peanut year really helped get that soil back in shape. And I know that’s what it was. We were increasing the soil health and getting the microbes back in there to help with the peanut crop. They were able to show some really good benefits to doing that even 20 years ago down in Florida.
Dr. Carl Rosen (12:50):
Oh, yeah. I think back then we called it soil quality or soil tilt, and we evolved to soil health. But we’re all trying to do the same thing. And any way that you can improve the properties of your soil or improve soil health, it’s going to have a direct impact on the health of your crop. And so, yeah, I totally believe that two years of a grass crop in there would be very beneficial. One of the reasons why we’re thinking something like a kernza crop or intermediate wheat grass. If we can develop a market for that, I think that would be a good thing. The problem is, we can come up with all these different rotation crops, but if there’s no market for it makes it difficult to sustain the whole rotation.
Mike Howell (13:34):
That’s right, and that’s something we’ve talked about previously. It’s got to make eKonomic sense as well as sustainability sense for us to implement these practices. If it’s not going to be profitable to the grower, they’re not going to be able to keep that up very long.
Dr. Carl Rosen (13:47):
And that’s one of the objectives of our project. We have a team of eKonomists working on this and taking a look to see if these rotations make sense.
Mike Howell (13:56):
So Dr. Rosen, I know another big aspect of this is nitrogen management. If you would talk a little bit about what the potato growers are doing to manage nitrogen and make sure they’re not leaching that nitrogen out or losing it to some other form of loss.
Dr. Carl Rosen (14:09):
Yeah, nitrogen’s critical for potato production. And the other fact about potatoes is they have a relatively shallow root system. We grow potatoes, as I mentioned, under irrigated conditions, and usually it’s on sandy soils. So particularly in our area where we have unpredictable rainfall, management of nitrogen’s very critical to prevent leaching. Obviously we promote split applications. That’s one way of managing nitrogen, so you’re not putting it all on at once. We’ve looked at various coatings on the urea, for example, to keep that nitrogen from solubilizing right away and have more of a controlled release during the growing season, and we found that that’s worked very well for us under our conditions. There’s always going to be some cases where it may not work as well as others. But in general, using polymer coated urea, for example, has been beneficial in terms of promoting yields and minimizing that nitrogen loss. So, basically split applications and use of polymer coated urea is what we recommend in our region.
Mike Howell (15:17):
Very good. Well, Dr. Rosen, you’ve given us a lot of information here today. We’ve talked a lot about sustainability and what the potato growers are doing. If you had to sum all of this up and give our listeners one key take home message, what would the take home message be?
Dr. Carl Rosen (15:31):
If you’re going to try something new, test it out on a small scale, see if it works. Try to minimize your soil disturbance as much as possible and follow those best management practices to minimize any nutrient losses.
Mike Howell (15:46):
Okay. Dr. Rosen, we really appreciate you joining us today. You’ve given us a lot of good information, and I hope that growers can implement some of this on their farms and help them to become more sustainable in the future.
Dr. Carl Rosen (15:56):
Thanks, Mike. Enjoyed the conversation today.
Mike Howell (16:02):
Well, listeners, it’s that time again where we talk about our tailgate for this week. It’s going to be a busy week at Poplarville High School this week. It’s senior week. All the seniors are going to be recognized for their service over the last four years and have a big celebration, but there’s a lot of other things going on this week, and there’s not going to be a lot of time left for doing a big fancy tailgate this week. So I thought what I’d do this week is, fix something that I can make at home and take it to the game and get it heated up when we get back to the game. So it’s finally starting to cool off a little bit here in the South and seems like the perfect time of the year to cook that big pot of chili. So this week we’re going to have chili.
(16:41):
I’m going to make that here at home and then take it to the game and have that for after the ballgame. Everybody’s got their own special chili recipe. I’ve got kind of a recipe that I use, but I just shoot from the hip, so to speak. I put stuff in and I’ll give it a taste test and add what else needs to go in. But one of the main ingredients that’s going to go into anybody’s chili is tomatoes. We haven’t talked about the tomato industry in the United States, and I thought we would take just a second and give a shout-out to our tomato producers. In the United States, there’s over 400,000 acres of tomatoes that are grown yearly. Obvious about 98% of the total production goes into processed tomatoes. Whether that’s canned tomatoes or going into ketchup, and the rest is in the fresh market. These tomatoes are produced across the United States in just about every state. Many people grow tomatoes in their home gardens, but the top five states in terms of commercial production are California, Florida, Indiana, Ohio and Michigan.
(17:43):
These states produce by far the most tons of tomatoes every year in the United States. We also import tomatoes for the fresh market, and these imported tomatoes come predominantly from Mexico.
(17:59):
Well, folks, we had another exciting week of high school football this week. Poplarville Hornets had a tough week. They played the Columbia Wildcats. They’re the defending four A state champions. They were down six to nothing at halftime. Columbia came back after halftime and scored another touchdown, put them down 12 to nothing, and Poplarville finally got things turned around at the end of the third quarter. Came back and won that ballgame by a score of 20 to 18. A great night of high school football that did clench the district championship for the Hornets. They have one more game, regular season game remaining and then start trying to march through the playoffs. Well, I want to encourage everybody to tune in next week as we continue our series on sustainable agriculture and continue our series on our tailgates of the week. Until next time, this has been Mike Howell with The Dirt.
