Episode 26: Next on Nitrogen: Fall Applications and Smart Sources

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, farming’s go-to informational resource. I’m here to break down the latest crop nutrition research, use, and issues, helping farmers make better business decisions through actionable insights. Let’s dig in.

(00:33)
Hey, everybody. I’m Mike Howell. I work with Nutrien. I’m the senior agronomist and I also host The Dirt. It’s a weekly podcast where we talk about agronomy and soil fertility-related issues. I came up from South Mississippi yesterday and I brought the warm weather with me. I hope y’all enjoy this nice, warm, humid conditions I brought. We experience this every day. I hear y’all don’t get it that often. Everybody has gone all out. This is our 100th episode. I never dreamed that we would get to 100 episodes, but they went all out. They got me a new shirt that’s already got dirt on it. My wife can’t even fuss at me about having the dirt on my shirt anymore. We’ve got cookies over here. They’re giving away cookies. The kids got to asking him what I was doing this weekend. We talked about the hundredth episode. They said, “Where are you going to be?” I told them, “I’m going to the Farm Progress Show. We’re going to do it live. Have never done a live edition before.”

(01:25)
They said, “Well, how many folks are going to be there?” I said, “Well, look it up.” They googled it and they said, “There’s going to be over 300,000 people here.” I don’t know how good these speakers are, but everybody here has got the ability to hear this episode of The Dirt so we’ve got 300,000 people. I said, “You know how many people go to a concert?” Anybody ever listen to George Strait? We got some George Strait fans here. George went down to Kyle Field at Texas A&M, did a big concert a few months ago. He had 129,000. There’s some female that’s running around with a football player now, Taylor Swift I believe her name is, I don’t listen to her but they said the biggest concert she’s ever done is 179,000. You do a little math there, that makes The Dirt just as popular as those two put together so y’all are making history today. This is the biggest concert that’s ever been done, and y’all don’t even have to hear me sing.

(02:12)
I’m excited about this week coming up. It’s Labor Day weekend. Everybody gets to take a day off, but that also means it’s the start of college football. We’re not going to talk about college football today. We have done that a little bit in the past, but I’m excited about college football and dove season is opening up at my house so we’ve got a lot to go through this weekend. I got a busy weekend, but we want to get this hundredth episode of The Dirt out today. I appreciate everybody coming in. One last thing before we really get kicked off, I talked about the 300,000 people. The kids decided that I could sign autographs for all 300,000 people so if y’all want to start a line right over here, we’ll be signing autographs, and if everybody will come in and let me sign that and give me $100, you can do that as a tax deduction and I can retire at the end of the day. Okay. Let’s go ahead and get it kicked off. Y’all didn’t come here to hear me talk all day. I’ve got two guests here with me today, and I want to take just a minute and let them introduce theirself. First we’ve got Dr. Richard Roth. Richard, welcome to The Dirt.

Well, thanks, Mike. Happy to be here. Welcome to Iowa.

Glad to be here.

Yeah. I am an assistant professor at Iowa State University in the Department of Agronomy. I guess my official title is Extension Nitrogen Specialist, so I focus mainly on nitrogen management, also air and water quality, do a little bit of sulfur work, cover crops, things like that. Just joined Iowa State back in September. Before that, I was down in South Georgia so down in the Southeast.

You’re used to the heat and humidity.

Used to the heat and humidity. I don’t appreciate you bringing it up here to us, but I do appreciate the invitation to be here with you today.

Our next guest is Jeff Hink. Jeff, if you would introduce yourself and tell us a little bit about what you do.

Yeah. My name is Jeff Hink. I’m a dad and husband. We have four kids. Graduated from Iowa State in 1990. Got my CCA in 1999 and I’ve been working in ag retail for about 27 years now.

Okay. Well, y’all may have guessed by now since we have the nitrogen specialist here we’re probably going to be talking a little bit about nitrogen today. Richard, if you would, remind everybody why nitrogen’s so important for crop production and kind of describe how we can lose this nitrogen after application. We know that’s one of our biggest problems with making nitrogen applications.

Yeah. Thanks, Mike. First of all, nitrogen is key to the development of chlorophyll in the plant, so if we want to photosynthesize, give the plant energy, we got to have chlorophyll, so that’s number one. Number two is nitrogen is really the building block of amino acids, and amino acids help develop proteins and enzymes in the plant. Proteins are like the building blocks and enzymes are what make things work, so they help facilitate the chemical reactions in the plant. You can imagine that without those, we aren’t going to be able to build the plant and we’re also not going to be able to convert light into energy the way that we need to.

(05:06)
Oftentimes nitrogen can be the limiting factor in crop production because we know it’s tied pretty well to yield up to a certain point, and so to help overcome this a lot of times we add synthetic fertilizers. We also get nitrogen from the soil in terms of organic matter, mineralization, things like that. Now, nitrogen is extremely dynamic in the soil profile, meaning that it can move, it can transform, and it can go through different processes and we can end up losing it, just like you mentioned. Typically when we think about nitrogen losses, we think about leaching, which is the downward movement of nitrate through the soil with water below the root zone, we think of denitrification, so in scenarios where we have waterlogged fields the microbes need oxygen from somewhere so they pull it from nitrate, they respire nitrogen gas into the atmosphere, so denitrification is the loss of nitrogen gas, and then finally we think about volatilization. Generally that occurs with ammonium, so we think about that a lot of times with fertilizers like urea or manure, UAN, things like that where the ammonium converts into ammonia gas and is lost to the atmosphere as well.

Okay. Well, Jeff, I know you’ve been working here for, what, 25 or 30 years now in the field of agriculture. What’s the main form of nitrogen loss that y’all are worried about? What are your growers most concerned about?

Well, in Central Iowa where we had the biggest issue would be big rain events. Just like you were saying, anytime you have ponding and water sitting in that field, you’re going to have nitrogen loss through leaching of the soil.

We have problems at home, and we can actually lose nitrogen all three ways we have such a unique system down there. If we spread broadcast urea on the surface of the soil, it’s going to be 60 degrees just about any day we have even in the middle of winter so we can lose that nitrogen.

The other thing I would highlight here is unfortunately, it’s a bad stat for Iowa, but we are the number one contributor of nitrogen to surface waters that end up in the Gulf of Mexico. Down in the Gulf of Mexico, we have what’s called the hypoxic zone, so an area of water where there’s no oxygen, leads to fish kills, algae blooms, things like that. Unfortunately, Iowa is the number one contributor, but we are working to correct that through what’s called the Nutrient Reduction Strategy in the state, which is guidelines for basically practices that we can use to help reduce those losses. Yeah, we lose a lot through leaching, but we’re trying to get better.

Well, that’s what today’s episode is about and you kind of led me into my next question. What can a grower do to reduce the amount of nitrogen that they’re losing, whether that be the leaching or volatilization or denitrification?

I would say the biggest thing we use here is… I mean, obviously our usually number one source of nitrogen is fall-applied, and I would say almost 99 to 100% of the growers that I’m using are putting on nitrogen stabilizer. But I would say the bigger thing is that we’ve seen over the last four or five years there’s a lot more trending of nitrogen to spring-applied and then following that back up with more in-season nitrogen as the crop is closer to needing it, and when it’s there and it’s actually growing, that’s when it’s pulling it up.

Yeah. To add on to what Jeff mentioned, nitrogen stabilizers, there’s actually multiple different forms. We think about nitrification inhibitors, so that blocks the conversion of ammonium to nitrate, which is the form that can be leached out of that system. We also have urease inhibitors, so if you’re using urea, UAN, even manure, less so with manure, but you use these and it helps keep the nitrogen in the urea form, gives time to hopefully get some rainfall washing the soil. Those are really the two main big ones. We also have some extended release fertilizers, so coated fertilizers. They have a coating on them. Over time it breaks down and releases the nitrogen into the soil, so that helps keep that nitrogen in the form that we want to keep it in the soil to where the plant can use it.

(09:13)
To also add on to what Jeff mentioned, we still see a huge trend for fall-applied anhydrous ammonia in the state of Iowa. Unfortunately, it’s kind of an inevitability infrastructure-wise. We don’t necessarily have the infrastructure to switch everybody to apply in the spring. It just… Right now, that’s not possible. There’s also concerns surrounding, “Can we even get into the field in the spring versus having time in the fall?” When you think about actual losses of nitrogen in the system through tile drainage, which we have a lot of here in Iowa, switching from fall to spring nitrogen, it helps but not to the extent that you would naturally think. We’re talking maybe 5 to 10% difference, but when you get into starting to do some split-applied nitrogen, things like that, putting the nitrogen out when the corn has its highest nitrogen demand, that really can help increase that reduction that we see. The other thing is with the stabilizers, that really does help with those losses that can occur over the winter with the fall-applied nitrogen. Yeah.

Jeff, we hear a lot and riding around through the showgrounds, here, there, every corner we turn, there’s somebody else talking about a new product that they can use to reduce the amount of nitrogen that farmers need to use or products that will actually make nitrogen in a corn plant. Are any of your growers using these products? If they’re trying them out, what kind of results are they finding with them?

Well, I would say we have three products that we have been using and having really good luck with, and one of them is Extract. Our approach is not necessarily less nitrogen, it’s, “How can we make the soil work for us and to make it so that it’s more efficient and the plant is able to pull up more of that nitrogen?” Extract would definitely be one, and we’re working on the actual amino acids. It’s developed from the rumen of dairy cattle, and it’s just increasing that microbial growth so that we’re able to have the microbes… Healthier microbes in the soil are going to be able to allow the plant to be able to pick up more nitrogen.

(11:26)
The other product that we’re using is Radiate, and I think it’s really cool about this is most of city people could roll down to their local greenhouse. It’s just a growth hormone that establishes root development, and when they’re transplanting plants, they’re actually dipping it in that hormone and it’s increasing the fibrous roots and just roots in general. It’s a pretty cool product. Then the last one that working with is called Terramar, and it would be the new C2. It’s a enhanced carbohydrate packaged together. We’re just trying to reduce the stress level in the plant. If you think about if we have a plant with bigger roots, more fibrous roots, and less stress on that plant, it’s going to be able to produce and pull more nitrogen out of the soil. When it’s in the plant, it’s not going down that river and it’s not going down through the profile.

Richard, we know there’s a lot more products out there than just the three that Jeff mentioned. Have you evaluated any of these products in your research program or seen other people that have evaluated those? What’s the data show?

Yeah. I have not personally evaluated any of these. Again, I just got here in September so I’m lucky that I have anything in the field this year. I’m going to talk in generalities here because being from Iowa State, I’m pretty much product agnostic, but there’s a lot of these products out there, microbial-type products, that make claims that they’ll provide nitrogen to the growing corn crop. Some of them are soil-applied, some of them are foliar-applied. Everybody has their own proprietary blend. There’s been quite a bit of research that’s been done here in the Midwest that shows that one of the main concerns is lack of consistency, it works sometimes, it doesn’t work others, does it actually give the amount that they’re saying that it will give, things like that.

(13:24)
I also believe that how well these products work is specifically tied to certain conditions in the field. We think about… There’s one specific product, I won’t mention names, but it’s a microbial product. It can be either seed-applied or injected into the furrow. The claim is that it will give you nitrogen. I think that in certain cases it will, but I think that especially here in Iowa our soils are just so fertile and we get so much nitrogen in any given year from organic matter mineralization that I think sometimes any effect that you might see from these products gets masked because in any given year, I mean, we might grow 150 bushel corn without any nitrogen. Just last year over in Illinois, Emerson Nafziger, who was a longtime agronomist there, he grew 230 bushel corn with no nitrogen. That just goes to show how fertile our soils are here in the Midwest. Now on the flip side, I spent a year at the University of Georgia as their corn and soybean agronomist down there. It’s very South Georgia, farming-

They don’t know what organic matter is in South Georgia.

No, no, yeah. We’re talking organic matters a quarter percent or less, farming on the beach. The soil fertility specialist that I worked with down there was doing some work with some of these microbial products and he saw pretty good results in those low organic matter soils, and I think it has to do with the fact that they’re not getting much from the soil and so it’s not masking it. There’s also been some work that looks at in those sandier soils, maybe applying some kind of organic amendment with it to help maybe jumpstart those microbes. Results are mixed on it. Again, I think the takeaway on these is that if you’re interested in using them, the best approach in my opinion would be to do some sort of on-farm research, test it on your own farm, see if it works for you, do it multiple years so you can hopefully get multiple weather conditions, things like that, and make a decision based on your own system. Everybody has their own system, people apply nitrogen differently, things like that, so if it works in your system, great, go for it, but I think you should approach them with caution until you test it on your own farm and know that it works.

Okay. Well, let’s go back a little bit. You both touched on making fall applications of nitrogen, and fall is just right around the corner. When we get this crop off, people are going to be thinking about making those applications. Jeff, is that something that’s common here? I know you mentioned that more and more people are trying to switch to the spring applications. What products are they using? What forms of nitrogen are they going to be used if they’re making these fall applications?

Well, I probably jumped ahead a little bit, but, like I said, main one in the fall for us in Central Iowa here is obviously ammonia, but the trend is definitely moving towards more spring application. Then I guess since we’re in the ESN booth, actually my favorite program that I’ve kind of started to really recommend the last four or five years and had the best yield results from it is running a weed and feed liquid down with the chemical for grass control in broadleaf and then following that back up with an ESN ammonium sulfate combination. What I love about it is, I mean, I know we’re on a podcast here so it’s hard to see anything, but you can really go in and see a lot of things.

(16:56)
I would say if you can get a sample of ESN… I mean, I carry this stuff around with a cup in my pickup with the water, and you will see the pellets floating on top of the water for a good 30 days before it’s entirely released out. I mean, they call it environmentally smart nitrogen for a reason. I mean, I think when you look at the history of it, it was originally set up for golf courses and you were trying to slow release nitrogen. Instead of flooding your yard with nitrogen, you slow release it. I think it’s so cool when I can have different people walking out in the field, agronomists from other companies, and they look down and they’re like, “What are these pellets?” “Well, these are these nitrogen pellets that we spread two, three weeks ago and it’s sitting there.” We usually spread it when it’s about pop can high to chest high, preferably we try and start earlier so we’re not trying to be out there when the corn is bigger, but when you figure in Iowa when we got pop can high corn in about 30 days, we’re not that far away from tasseling and that’s when the big pull for nitrogen is going to be.

Richard, back to the fall applications. We talked about logistics and people have to get the nitrogen out at some point. What do growers need to be aware of if they are going to make a fall application? I know there’s some rules, some dos and don’ts. What do they need to be aware of before they make that application?

Yeah. Like you said, there’s some dos and don’ts. A couple of the dos would be wait until soil temperatures are 50 degrees or less and on a downward trend. That’s the part that people usually ignore. They’ll see the soil temperatures hit 50 degrees but then it’s going to jump back up over the next week or so, so the soil temperature’s not going to stay down below 50. So below 50 degrees on a downward trend, that’s number one.

That’s pretty much the exact opposite of when they need to be planting corn. That makes it easy to remember that.

Yeah. Exactly. The other big one for me is if you’re going to make a fall anhydrous ammonia application because that’s basically the only fall nitrogen source that people use or that I would even recommend, you’re going to want to use a nitrification inhibitor. We mentioned them earlier. Again, I’m product agnostic. Yeah, there’s definitely research out there that shows certain products are more effective than others, but to me, I think something is better than nothing. The only nitrification inhibitor that I suppose I would maybe warn against would be for some a spring UAN application. There’s some thought that ammonium thiosulfate has some nitrification inhibitor properties. I tend to… Based on the research, you have to have such a high rate of ATS that it kind of makes it not really feasible. Putting ATS out with your UAN is kind of like going on a diet and then going to McDonald’s and ordering a Big Mac with a Diet Coke. So yeah, it’s something, but it’s not all the way there. Some other things to watch when you’re applying in the fall, make sure it’s not too wet. You don’t want-

Volatilization.

… volatilization, you don’t want smearing. You want the slits to seal. You don’t also… Too dry. If it’s too dry, it won’t seal. You’ll lose some nitrogen to the atmosphere as well. Yeah.

I guess I just like… Everybody talks about 50, but to know the importance of that is that’s when the microbial growth is starting to decelerate, so we don’t have the denitrification process started. If you’re out there pushing that limit, you’re also ruining some of your nitrogen stabilizer, which I think the bigger deal that you actually would need for it is closer to the spring versus the fall versus just saying you’re going at 60.

Yeah, absolutely. You’re absolutely right, Jeff. The efficacy of nitrification inhibitors is actually tied to soil temperature as well. You just mentioned it. Those products, over time the way that they wear off in the spring is through microbial activity, breaking those products down. If you apply those in the fall into warm soils, those microbes go to work on that product immediately and so you actually end up losing efficiency from that product, so that’s the other thing to warn against is that even if you’re using a nitrification inhibitor, that’s not a free pass to go apply before the soils get to where they should be. The other thing that I’ll mention, so I said anhydrous ammonia is the most common. People also apply manure in the fall, and with manure you can also use nitrification inhibitors. You just have to find one that’s formulated for liquid… Well, if you’re using liquid swine manure, which is the most common here in Iowa, or liquid fertilizer. Yeah.

Well, guys, we have covered a lot of ground and talked a lot about nitrogen today. Before we wrap this thing up, Richard, is there any closing comments you have for our listeners?

The only thing that I have is just when you’re going to make decisions regarding nitrogen, keep the 4Rs in mind. That’s the right time, right place, right source, and right rate. Each one of those is important. They all factor into how well your system is going to perform, they factor into how much nitrogen we can potentially lose from the system. As you make decisions, keep those things in mind and be good stewards of the land.

Okay. Jeff, anything you want to make sure our listeners remember?

I would just say that it’s just the overall perception of ag, and understand that farmers are out here… I mean, a lot of these guys are family businesses and they’re trying to grow the best corn crop or bean crop that they can, not that beans need nitrogen. Well, they do, but we’re not applying nitrogen on them. But we’re trying to do the right things. I would tell everybody even if you’re growing in a garden, I don’t know that there’s much more satisfaction you can get that when you’re going out and actually harvesting, whether it’s tomatoes, cucumbers. I mean, farmers are getting the same exact feeling when they’re out there running their combine and doing that, and just understand that they’re out there trying to do the best they can and to put those nutrients where they need to be, where they’re the most efficient, and so they can get the best return on their investment back.

Okay. Well, guys, I really appreciate you taking a few minutes and visiting with us today. Listeners, we hope you enjoyed this first segment of The Dirt. Want to remind everyone to stick around just a minute for segment two.

(23:25)
Listeners, I hope you enjoyed the first segment of today’s show. If you did, please take a minute and give us a rating on your favorite podcast channel or app and give us some feedback as well. We want to hear from you to help make the show even better, and don’t keep it to yourself. Please share these episodes with coworkers, family, friends, anyone you think may benefit from the information we’re sharing here. Don’t forget to visit our website, nutrien-eKonomics.com, to help find the latest crop nutrition news and research information as well as market updates, a growing degree day calculator, a nutrient use calculator, a rainfall tracker, and much, much more. It’s all at nutrien-eKonomics.com.

(24:10)
Most episodes of The Dirt are now available for CCA credits. Visit our website and click on the Agronomics tab to find these CCA credit opportunities. If you have a question, you can ask one of our agronomy team members. Simply ask your question and one of us will get back with you. Thanks for listening. Now, segment two of The Dirt.

(24:33)
Listeners, thanks for coming back for segment two. As you know, we’ve been taking tours around the United States this year and visiting different research farms associated with our land grant universities and talking about the importance of those. We’re going to forego that part of it today. We’re not going to do that, but I wanted to take just a few minutes and do a focus on safety. We’ve talked about this is Labor Day weekend, a lot of activities going on, dove season opens. There’ll be a lot of young people out there hunting with firearms, maybe never done that before, so I want to remind them about safety and make sure that we’re being careful when we do that. Monday’s going to be a big day for barbecue. I know we’re looking forward to the firing up the grill, but a lot of dangers associated with that.

(25:16)
Back home, we’re already in the middle of harvest. We’re harvesting full swing, and that’s going to be starting up here before very long. I want to remind everybody that there’s a lot of equipment moving up and down the road. These farmers are working long days and long nights, and when you start getting tired that’s when we have these accidents so I want to remind everyone to be careful during this harvest season and let’s try to get through this season with no accidents or injuries. Let’s take an extra second and make sure we take care of that.

(25:42)
Also, I wanted to take just a minute and give out a few thank-yous. I can’t do this podcast by myself. We’ve got a team of people that we don’t talk about a whole lot. We’ve got people like Aaron and Diala, Mackenzie, Suzanne. They always go through and make edits to all these podcasts, take out my Southern baubles and make it sound like something that somebody can enjoy listening to. We couldn’t do it without them. We’ve got a team of editors that make the audio come out like it should.

(26:10)
I want to thank my guests. I should have went back and counted up how many guests we’ve had, but this is the hundredth episode and I know we’ve had well over a hundred guests on the show, but nobody would want to sit here and just listen to me all day. We try to bring in the best possible guests we can. I want to thank the guests for helping make this program so successful, and I want to thank the listeners. Without the listeners, all of this would be for nothing. We’re doing this to help benefit you. In the three seasons that we’ve done this, we’ve had a little over 70,000 people that have tuned in and listened to these episodes. That’s what makes it all worthwhile, knowing that we’re helping the farming community out there. As always, thanks for tuning in. If you have any questions about anything we’ve talked about today, you can visit our website. That’s nutrien-eKonomics.com. Until next time, this has been Mike Howell with The Dirt.