Nitrogen conservation and water quality, Part 2: Precision conservation, and future efficiencies
Welcome back to Advancing Nitrogen Smart, the special podcast series from University of Minnesota Extension, where we unpack and examine research based data to help farmers and ag professionals make the best decisions for their operation. I'm Jack Wilcox at the communications desk here with Extension. Today, our panelists are Brad Carlson, Extension educator, and Jeff Vetch, researcher at the Southern Research and Outreach Center in Waseca, Minnesota. Today is part 2 of Brad and Jeff's big picture discussion about nitrogen conservation and applying a variety of different solutions to address Southeast Minnesota water quality issues.
Jack Wilcox:To recap, last time, Brad and Jeff talked about how proactive nitrogen fertilizer management is more effective and less expensive than nitrogen mitigation after the fact. They discussed cover crops, changing crop rotations, incorporating perennials, and edge of field practices, and that's where we'll pick it up.
Brad Carlson:You know, the other area that that there's been a lot of talk about is is some of these these passive sensors, that are looking out and grabbing an image. You know, the the they they too can be inexpensive, whether we're talking about drone imagery or or particularly satellite imagery has gotten incredible lately, you know. And, of course, that doesn't involve having to run out to the field and and put a drone up in the air and so forth. You know, and so a lot of people, you know, anytime this technology comes out, there's a lot of people say, oh, look at how are we gonna use this, you know.
Brad Carlson:The problem that has been with these passive sensors is a real timeliness issue that that so if you're talking about a drone, you gotta go out there.
Brad Carlson:You gotta fly the thing. You gotta take the picture. Now you gotta come back. You gotta download it off of whatever memory device was on that. Now there's other you you don't have a usable image because it's probably was at an angle and there probably was some distortion.
Brad Carlson:So now you gotta correct your image to the field boundaries, and then you've got to go and interpret the differences you found. So if you went up with a with a crop canopy and you were looking at color differences, some kind of software has gotta be used to pick out those color differences and interpret those things. And then, you know, as you already mentioned, the whole algorithm deal. So now what do those differences mean? Are we gonna make a recommendation about it?
Brad Carlson:You've gotta create this application map. Then you gotta send that over to your dealer, and they gotta apply it. And you're on the waiting list because they've already got other customers. And so that's been one of the real problems with some of this kind of sensing is it can be a week before you actually can get out there and make that fertilizer application versus those active sensors that could be making an adjustment on the fly.
Jeff Vetsch:Yeah. You're exactly right. And I think that this is where some of the research focus has been for the last, you know, I would say 5 to 8, 9 years. And using AI and using other software, really sophisticated software that can do this do this integration, do this mapping, this kind of calibration rapidly on the fly, stitching these photos together, all that stuff. And that they are making tremendous progress in that.
Jeff Vetsch:But at the same time, there are a lot of steps. It does take time. It takes computing power. It takes people with the knowledge and skills to do it, and then get it to back to that retailer to make that prescription. I think the other advantage of imagery, whether it's done with a drone, a really sophisticated one, or whether the farmer just, you know, does it as a hobby, or maybe they get download satellite imagery, and you we either pay for it or you get maybe poor quality, but you don't have to pay for it.
Jeff Vetsch:It's just looking at it. You can use it to identify field areas of your fields where you need to go scout. It can really help in in kind of guiding your scouting. You know, the farm size has increased so much and and not everyone has an independent crop consultant. But if you're farming thousands of acres of corn, you're not gonna walk every one of those fields.
Jeff Vetsch:But if you can use imagery or some of this technology to kinda clue you in as to where, hey, this is something something I gotta go check out. That can be a huge advantage because once you ground truth it, that data is a lot more valuable.
Brad Carlson:You know, the the other area that's kind of a comes on the emerging technology side too, Jeff, is whether there's something that is sensible, maybe not with the naked eye, that's telegraphing a a problem. So we you know, for instance, we're looking at near infrared, a color band that we can't see. You know, is is is there a near infrared signal that's, that's showing us there's a pending nitrogen deficiency prior to the crop turning yellow? You know, some of that kind of stuff, may be coming and and I guess we'll we'll just have to we'll just kinda have to see as the technology is is developed and all there. Unfortunately, there tends to be a lot of, fatigue with some of this stuff.
Brad Carlson:Like, it came around and all this everybody got excited and then, oh, well, it didn't really work the way we thought it would or it didn't really pay off and, you know, now it's 10 years later and people are like, oh, are you still working with that? Well, I mean, if we're gonna make this stuff if we're gonna get a breakthrough with it, you can't just walk away from it. You know?
Jeff Vetsch:Well, and I and I would put that towards the fact that it's it's hard. It takes a lot of management. It is moving away from what I would call the easy button, and everybody wants the easy button.
Jeff Vetsch:They don't want it to be hard, and you have to really make a commitment to to do it because it's gonna be time concern time consuming and it's gonna be it's gonna take management.
Brad Carlson:So another technology that kinda came and went, I guess, technically, I don't know that it completely went, but the the crop models, we refer to them as crop models because that's what they were. They were not necessarily marketed to farmers as a crop model, but but, there were a number of technologies that were out there that were kinda following the crop as it grew. They they were doing some math as far as accumulating heat units and and looking at water. In some cases, they were using soil test values to kinda use some a balance of where we were at nutritionally in the soil and kinda predicting them. You know, this technology came and went too fast, in my opinion.
Brad Carlson:I think I think, you know, there was some issues with some farmers felt like it was a little inaccessible for the way they farmed. I think there were some farmers that had concerns. This this was really on the forefront of the whole who owns my data, issue that kinda reared its head about a decade ago, and so forth. And and really, though, what these these crop models were doing was they they had an algorithm that was mining datasets. They were looking at performance of specific hybrids.
Brad Carlson:They were looking at what happened on your fields in the past. They were looking at what happened to you on your neighbor's fields, and then they were looking at what the weather was giving us and they were making predictions. It was really kind of a black box to us on the research side because the companies that developed these were never really wanting to share with us how they were coming up with these recommendations. That's completely understandable because that was proprietary information. And if it worked out and it leaked out, somebody else could copy it.
Brad Carlson:You know? So all we were ever kinda left doing was evaluating these things. The thing about it was we kinda discovered that they were doing a pretty good job, particularly at predicting places and situations where we needed less nitrogen. You know? And that's one of the areas that's been very difficult, psychologically for a lot of farmers.
Brad Carlson:You know? It's it's easy to say, here's a spot you need 30% more nitrogen, because they can look at it and say, oh, yes. I know. We've had deficiency. I can go put that on.
Brad Carlson:But when you say, here's a spot that needs 30% less nitrogen, you know, now it's like, oh, well, I've always done really well out there. Boy, am I putting myself at risk by doing that. If this technology could kind of help build confidence that, no, we've actually got enough information that, yes, these these are your best parts of your field and they need less nitrogen, you know, we were seeing some some pretty impressive reductions in nitrogen application without them hurting yield.
Jeff Vetsch:Yeah. And, you know, the the models initiated from plant physiology and crop physiology models that were developed, you know, by fundamental long term research that was probably done in the sixties, seventies, and eighties, and and continually updated as genetics changed. But what was new about these things was that they they linked, you know, live weather data efficiently. They linked, you know, like you mentioned, Brad, genetics because they were coming from companies that that were working in that area. And they were putting those things together and developing these kind of, you know, prescriptions of how the crop is doing, and I think there is potential for that.
Jeff Vetsch:And you think with the AI technology that might be coming in the next 10 years, you think there'd be way more potential for that in the future. Are they temporarily gone? Maybe they were because they were marketed before they're confident before people had confidence in them. But will they come back? I kinda think they will.
Brad Carlson:Yeah. I agree.
Jeff Vetsch:The question is will will they be marketed differently or will people still have will they be reluctant to use them because, well, they tried that before and it didn't nobody bought it or didn't nobody followed it. So that'll be interesting. I think they still have a lot of potential.
Brad Carlson:Well, you know, I I think from my interactions with producers, I think the big problem was I think there were a lot of people who thought, you know, oh, I've got these spots in my field that are underperforming and I'm going to use this technology. I'm going to get these big yield gains because I'm going to find all these spots. And what they discovered was they were probably their management was probably sufficient to get the performance level that they could achieve across their fields already. And in most cases, it was telling you to reduce inputs, not to increase inputs. You know?
Brad Carlson:And I and I say this, it sounds a little flippant and it sounds a little like an oh, duh, but you're never going to increase your yield by putting on less nitrogen. K? And, you you know, the the idea there is that you just simply didn't need that nitrogen, and you still got the same yield. So when you're not increasing the yield, now the profit you're making by adapting that technology is strictly related to reducing inputs since, you know, instead of looking at increasing corn production at 4 or 5, 6, $7 a bushel, wherever the price happens to be at the time, now you're reducing nitrogen inputs at 50¢ a pound and it just it makes it a lot harder to pay for it that way. And a lot of producers kinda felt like, you know, maybe it did make some money, but it didn't make a lot of money and it was just extra management.
Brad Carlson:You know? And so I I think that's really one of the big reasons why this stuff kinda disappeared off the market, and it's really kind of, it's really unfortunate because a lot of the research I did a lot of on farm testing with this stuff, and and we were finding really good results. I mean, we were we were pretty well finding that in most cases, you know, a lot of these products were actually finding places where you legitimately could reduce nitrogen fertilizer applications without hurting yield. And in the future, that's probably a direction we're going to have to go in order to achieve these water quality goals. So the kind of the last thing that's that's out there, has been out there, is this in season testing.
Brad Carlson:You know, I think there's there was a lot of buzz. I know the the yield 360 people brought out their SoilScan 360. You know? A lot of farmers kinda thought like, oh, you know, all of a sudden now I don't have to send my soil samples off to be tested. I can just do it myself.
Brad Carlson:And, the the idea was that you might just put that thing in your pickup truck and set it up on the tailgate. You'd run out, take it take a soil sample, come right back in, and take a take a soil nitrate test, and you could be on the phone with your fertilizer dealer right then and there and order up, you know, a a sidedress application. It never that's another one that never really materialized very well. We kind of we did have a chance to play with one of these units, that a farmer that I know that has one, let us use it for some different things. The technology was good on them.
Brad Carlson:They they actually did do the appropriate extraction and measurement to test for nitrate. There were some accuracy issues. I think probably our biggest concern there was really 2 big concerns. 1 is it didn't account for soil moisture. It was metering out the same amount of its extract and whether the soil was wet or the soil was dry, and so, it had the opportunity to kinda dilute the numbers out if you had a wet soil that you were testing.
Brad Carlson:And the other was their their, app that they had on a, that you put on a tablet, was maybe not and that was for using for making fertilizer recommendations based on the numbers. That was really not well calibrated for Minnesota. That that was probably more reflective of southern places, central and southern Illinois, Missouri, places like that. You know? However, we did kinda discover that that technology, it could work.
Brad Carlson:I mean, the farmer we borrowed these from told me, he was drying all of his soil samples and then testing them all dry. And so he was getting fairly consistent results and but but primarily, he was using it just sort of in, advisement. I mean, he was kinda just looking at it to see where he was as far as his nitrogen status. He wasn't using it to actually make, real time decisions. It was almost like he was playing with it because he found it interesting.
Brad Carlson:You know? In addition to that, there's been a number of of various fertilizer dealers that have offered in season testing, you know, what we call pre side dress nitrate test, and, Jeff, you and I have worked on a number of projects, with that, and and it this predates, predates us. I know the doctor Mike Schmidt worked on this, and Giles worked on this a long time ago. And it continues on. Fabian Fernandez is still working with this stuff, and I think they are getting, a little bit closer to making recommendations. But, this is something that's not really caught fire really well either.
Jeff Vetsch:Yeah. And I think, you know, the the pros is that I think if you get a good sample and you send it to a refutable lab, you get accurate results. The challenge are 3 things. I think first is the timeliness. I mean, it the samples have to take be taken, you know, v 4 to v 6.
Jeff Vetsch:In Minnesota field conditions, that might be a week and a half, you know, and and you wait much longer after that. And and Bobby and his grad students and and I've done some of these studies too where we look at at nitrate concentrations and fields. And once you get past that v six point, they can plummet really quickly. So the calibration as you get into kind of the middle of the season is is very, very weak. But early on, it can work, but getting those samples taken, turned around in a in a time period in the field where it's really busy.
Jeff Vetsch:I mean, it's times when you're putting on herbicides. It's times when you are making side dress applications. And for a farmer to try to do that themselves, it's gonna be very challenging. They wanna hire a consultant firm or someone someone else to do those things for them. That's certainly a good way to go. Where it's most likely to work is where you're most likely to expect that you have some carryover in. Is it a corn on corn field and the last year was dry? Is it a field that has a long term in our history? Those are places where it's probably gonna work. If you're a 100% corn soybean rotation, I wouldn't waste my time taking a PSNT because there just isn't gonna be enough to justify any kind of correction.
Brad Carlson:Yeah. I guess I I even look at some of my own property. We had a few of these dry years. We've had some longer term manure history on on those fields, some land my father-in-law used to run and he had beef cattle and, you know, and and there had been alfalfa and so forth. And I know even, like, just taking fall samples a a couple years ago, we didn't find much of anything in there, you know, and and, that's not to mention it being in season after you went through, you know, the whole spring and the start of crop uptake.
Brad Carlson:And so, you know, it it can be difficult actually finding a credit in those ways. And and, you know, the the calibration of this, if you're, say, for instance, applying a half rate and now you're trying to figure out how much more you need, that gets extremely difficult because, you know, now the question is is that nitrogen you applied, where is it? You know, was it fall anhydrous that was in a band? Did you spin spread urea over the top? So how deep is it?
Brad Carlson:Did it, you know and and, I mean, that that can be really problematic as far as using these and and accounting for, you know, a a 60 pound application. Now how much more do I need? That can be really tough.
Jeff Vetsch:Well, and is it is it all nitrate? You know? So it might still be in the ammonium form and and if you didn't measure that or you didn't use that in your calculation, that could be a big problem.
Brad Carlson:Well, and you and I found that the one the project we did about a decade ago, we found the numbers were highly variable in the exact same location 10 days apart. And we speculated a lot of that was because of immobilization, because it was corn on corn. It was decomposing corn stalks, and suddenly that nitrogen all all got taken up by microbes decomposing the corn. It was still there, but it wasn't measurable because it wasn't nitrate anymore. So I guess we're kind of wrapping this whole thing up.
Brad Carlson:You know, as far as where is some of this technology going to go in the future, you know, there's been continues to be a lot of talk about nitrogen efficient hybrids, breeding. You know, we keep getting these questions. How far away are we from from corn that fixes nitrogen? You know, heck, that was discussed 35 years ago when I was an undergraduate. You know, the the point that I like to make about that is, and most farmers realize, that if you apply nitrogen to soybeans, their response just simply is to not nodulate.
Brad Carlson:From the corn side, if the corn is going to nodulate let's just say we genetically engineer corn and it fixes its own nitrogen. If it does not fix the whole amount of nitrogen it needs and you have to supplement it, every bit of nitrogen you apply to it is going to stimulate it to nodulate less until it's not nodulating at all, and now you're applying the full rate of nitrogen. You really didn't get anything out of it. And so that's really a a dog chasing its tail there with that one. You know, the other issue is, you know, and this is an area we've talked about with with, nitrogen smart and before is for decades, we were not seeing the need for increased amounts of nitrogen because of increased yield.
Brad Carlson:And we were in a lot of ways, we were relaying that to reductions in grain protein that there was actually less nitrogen in the corn itself. That can't go to 0. And more recently, we've seen in Minnesota, our nitrogen rates, you know, the response has been increasing. You know, you and I were just recently at the North Central Soils meeting. We're seeing other states are telling us that their nitrogen recommendations are increasing.
Brad Carlson:You know? So it is possible that we've kind of reached the basement level as far as the nitrogen content in that grain, and now increasing yields are going to increase nitrogen demand. And so that's gonna kinda go in the other direction with that.
Jeff Vetsch:Yeah. And I don't I see what the industry has been doing the last 5 years, and you see all the biologicals on the market and every major ag industry has got a biological or they're developing biologicals. It seems to me the writings on the wall that they think that's the way to go and the inefficiency of hybrids is probably as close to perfect as they're gonna get it. And I I think the, you know, is it ever gonna fix its own nitrogen? It would have to be some kind of other biological thing that they would enter or use in the soil.
Jeff Vetsch:And and the research on those, at least in the upper Midwest, has not been super positive yet. So there's still probably a long ways to go with those as well.
Brad Carlson:Yeah. And so we've talked a little bit about, changes in nitrification inhibitor technology. The the problem with with that one is, and I've said this before, nitrification inhibitors work. It's just a matter of are they working long enough and at the right time to make a difference. You know?
Brad Carlson:And and a lot of times, that's weather related. And so, you know, that gets back to now can we predict the weather to make the nitrification inhibitor most effective when you need it to work.
Jeff Vetsch:Yeah. And not only that, you know, making sure that you're using the right mode of action or the right product for the right use. You know, if you're worried about broad top dressing, urea, or UAN on the surface of a no till or strip till cornfield, you're not worried about a nitrification inhibitor. You're you need a urease inhibitor, making sure that you're picking the right product. I don't really think we're gonna see a lot of new modes of action of inhibitors, either urease inhibitors or nitrification inhibitors.
Jeff Vetsch:I think what we're gonna see in the next 10 years is more of what we see in the herbicide industry where we're taking a current active ingredient. We're trying to make it work better. And whether that's with some other chemical technology that they put into it or how they deliver it or how if it's encapsulated or something like that, that's where I see the that industry going. And then recognize that most of these products, they've been around for a long time, so they're not held by companies anymore. They're basically anyone that wants to try to make them can make them And produce them, but usually the companies that initiated them have the efficiency of making them at at the lowest cost because they've been doing it for a long time.
Jeff Vetsch:So that's where I see that going. But enhanced efficiency fertilizers, I still think they're gonna be a big thing on the market. There'll be more of them every few years. Trying to find where they work is kind of our job.
Brad Carlson:Yeah. And so moving forward, you know, I guess a few of the other things, you know, we've talked a lot about crop models. You know, the the flip side of that is is looking at environmental models. What parts of the landscape do we it's probably for sure that there are places that are disproportionately contributing to water quality issues. We have not gone very far with discovering where those areas are.
Brad Carlson:I mean, if we do start talking about land retirement or kind of, I don't wanna use the word forcing, but, like, strongly encouraging perennial crops, I mean, it's it's likely there are places that are gonna be higher benefit than others, and so we would call that precision conservation, kind of targeting it into places that are gonna see a higher benefit gets you more bang for your buck. I mean, really, this stuff is going to be expensive enough. We need to be efficient, you know, economically with with where we're targeting our changes and our practices. You know? So that's something that's out there.
Brad Carlson:And then, of course, you know, we've talked about this already, and it's a subject for another another podcast another day. But, the whole efficiency of cover crops, you know, ultimately, if we could take all that mineralized nitrogen that and and unused nitrogen that's laying in the soil in September October and pick it up and arrest it from coming out of the drain tile in April May, you know, that would be huge. I mean, ultimately, that probably could lead to a solution for us. We've gotta get that figured out. It's you know, at this point, what we've got, isn't adequate to actually function that way.
Jeff Vetsch:Yeah. I'm gonna go back to the precision conservation because there are there's one example that I can think of that I'm gonna mention where this really works. This can work, and it can work to benefit a lot of people, and that's what happened in the city of Perham, Minnesota here, I think it's about 10 years ago now, where they were realizing that they're one of the wells in Perham was had high nitrate. And the well drawdown area was kind of at the edge of town, and that field or the the farmland around there was in potato production. And we know that that's a high end use crop, and it's irrigated, and it's got the potential to have, you know, a significant amount of nitrate loss.
Jeff Vetsch:So the people that own that worked with the people in the city of Perham and some of the local people in politics, and they actually did a land swap, and they converted that area where the well was to perennials, and they purchased some other land from the city outside that air well, airhead area, and they moved the potatoes out there, and it was a win win for everyone. The nitrate concentrations came down in the well. They had didn't they could avoid the city could avoid having to do treatment, secondary treatment of that well water, and they moved the potatoes somewhere else where it wasn't as close to a major wellhead area. So there are options that that can work, and it can work for everyone.
Brad Carlson:Yeah. You know, another area that's probably gonna show up here in the next decade is and a lot of this isn't really on a lot of farmers' radar screen, but, it's it's kinda high on the agenda of a lot of our state agencies to increase water storage on the landscape, with it raining so much more in the last 10, 15 years than it has, you know, previously. We're having issues with flooding, flash flooding. I think a lot of farmers are keen on the topic of bank erosion and particularly in southern Minnesota, the Le Sueur and Blue Earth and Minnesota Rivers. You see all that areas where there all that cutting is, and and they're looking at wanting to just simply hold more water up on the landscape.
Brad Carlson:A lot of farmers, you know, initially, they kinda bristle at that idea, but then when you start thinking about it, you know, we all know fields that flood out almost every single year and no crop has really grown there. You know, there are places that make sense where we can do some of this stuff. We've got drainage systems that are kinda at their capacity and, you know, would require really expensive upgrades to get more water out of them, so we're probably looking at on the the bottom end of some of those places, just simply holding water, taking it out of production. You know, the the kind of the key with that is is if you completely stop the water from going in the river altogether, well, then your contribution goes to 0 at that point. And so, you know, there there's going to be some of that kind of stuff also that plays out in the long run.
Brad Carlson:So, it's it's, it's gonna be a work in progress. You know, we've, you know, we've been working on this a long time, and it's gonna happen well past your and I careers before we reach these objectives. I guess we'll just kinda keep keep working on it. Yeah. You're right.
Jack Wilcox:Extension educator Brad Carlson and researcher Jeff Vetsch. Thank you both for talking with us at the Southern Research and Outreach Center here in Waseca, Minnesota.
Jeff Vetsch:Thanks.
Brad Carlson:Thank you.
Jack Wilcox:The Nitrogen Conference is coming up on February 4, 2025 in Mankato, Minnesota. Topics will range from nitrogen management and crop production to a "boots on the ground" farmer- panel -look on lessons learned during the last growing season. You can attend sessions on everything from how farmers can do their own studies to some of the new research on production agriculture and the environmental aspects of nitrogen management. Both Brad and Jeff will be presenting too. Attend in person or virtually. Be sure to register at z.umn.edu/Ncon.
Jack Wilcox:Do you have a question about something on your farm? Just send us an email here at nutmgmt@umn.edu. Thanks a lot for listening, and we look forward to seeing you next time. Advancing Nitrogen Smart is proud to be supported by the farm families of Minnesota and their corn checkoff investment through Minnesota Corn.
