UMN Extension Nutrient Management Podcast

University of Minnesota Nutrient Management Podcast Episode: Spring fertilizer outlook: Key decisions after a warm winter
March 2024
Written transcripts are generated using a combination of speech recognition software and human transcribers, and may contain errors. Please check the corresponding audio before referencing content in print.

(music)

Jack Wilcox:
Welcome back to the University of Minnesota Extension's Nutrient Management Podcast. I'm your host, Jack Wilcox. I'm a communications generalist here at U of M Extension. Today is our annual spring fertilizer outlook episode, and we have four panelists with us here. Can you each give us a quick introduction?

Dan Kaiser:
This is Daniel Kaiser. I'm a nutrient management specialist. My area of focus is the fertilizer guidelines for most agronomic crops in the State of Minnesota, and I'm located out of the St. Paul campus.

Fabian Fernandez:
I'm Fabian Fernandez, also a nutrient management specialist based in the St. Paul campus and focus mostly on nitrogen management.

Lindsay Pease:
And I'm Lindsay Pease. I am a nutrient and water management specialist, and I am stationed at the Northwest Research and Outreach Center in Crookston.

Brad Carlson:
And Brad Carlson, I'm an extension educator. I work out of our regional office in Mankato, but work statewide a lot with nitrogen and water quality issues.

Jack Wilcox:
Lindsay, let's start out with you way up there in Crookston. What are the field conditions you're seeing in your area?

Lindsay Pease:
Yeah, this has been the topic that's been on everybody's minds this year. We've had a much warmer winter than usual with less snow cover, and I think all of that is pointing to us being able to get in the fields a little bit earlier this year because, for a couple of reasons. First, that we don't have quite as deep of a frost depth, so it's not going to take as long for that to clear. But also that also means that we're not going to see the extent of spring flooding that is really typical for the Red River Valley because that water's going to be able to move north, but also going to be able to move downward into the soil profile a little bit more. So even if we get some late snow or rain, it's really not going to cause that sort of devastating delay to planting that it usually does in our region. So yeah, I think we're really looking at being able to get in the fields a little bit earlier this year, particularly compared to the last couple years.

Brad Carlson:
Yeah, it's equally dry down in southern Minnesota and actually probably a lot even warmer than it is up there. I guess just geographically we're that much farther south. Probably the most unusual winter in my lifetime. The lake that I lived by was only frozen for about three weeks. It was still open between Christmas and New Year's Day, and then it reopened completely again about a week ago. And so that was just a kind of an odd situation. When you look at some of the benchmarks of the winter and spring when it comes to field conditions, really didn't see frost in the ground to any extent all winter here. We had people putting tile in the ground still after Christmas. That's almost unheard of. In fact, most of them that I talked to just simply quit. They got sick of it's like well ate enough and they're just ready to be done with it. So there was that and there really is no frost in the ground to speak of anywhere.

The commercial syrup producers started tapping maple trees already the last week of January. That doesn't run if the ground is frozen, so that's been going on. And then beyond that, the research stations in Lamberton and Waseca planted corn on the 26th of February just to see what would happen, and the conditions were fit where they actually were able to do that. And it was not a particularly muddy or challenging. Obviously the calendar says there's a lot of time between now and typically we look at tracking the growing season on May 1st. A lot of things can happen between now and then, but at this point in time there's a lot of capacity and the soil profile to hold moisture. So the weather pattern would have to change drastically in order for us to start thinking differently about management, at least as we're seeing it right now. Because right now we're looking at I guess the way we would view management in or following a drought, and that's kind of where we're at.

Dan Kaiser:
And I don't think there's been a whole lot of talk about tile line running, I know. But Brad, I know just kind of in some of the meetings we've been at a few people questioning just with the rainfall. This actually stretches up to Lindsay up north, too. Some questions up around the Menominee area with the rainfall that came in December about potential for nitrate loss. If the tiles aren't running, we obviously know that loss is dictated by water flowing out, so there should be the nitrogen at some point somewhere in the profile. It just might be a little deeper, moved it down a little bit farther with some of that water. So that's been one of the, I guess, the good things about it not being completely frozen, at least that the water that has come has been able to recharge things.

But I know it has resulted in some questions and in particular fall applications, as long as the thing to always remember, as long as the fertilizer is in the ammonium form, you shouldn't have an issue with loss. Ammonium is held, nitrate is not. Obviously we're still going to get some nitrate accumulation even if the soils are close to freezing. Really we don't see much of that stop until they completely freeze. But I wouldn't say there'd be any greater risk for loss. And we've seen this, I think in the last 10, 15 years. This question's come up a few times. We've had a couple of years with some tile lines flowing and if we lost anything essentially it'd be just what I would assume we'd have lost in the spring at some point. So we just lose it a little bit earlier if there was nitrate left in the profile. But I think that's been the advantage being so dry, at least the soil's been able to take a lot of the water that's come down on it.

Fabian Fernandez:
And there has been, as you mentioned, most of that water that we received that has been to recharge the soils, we were dry and so we have some studies with tile lines and they've been dry. We are getting ready to get things going again just because we suspect that there may be some spring flush and we want to be ready to capture that for research purposes to understand how much water they create may be moving out. But at this point, really the potential for loss has been extremely low. One thing to keep in mind though is that the mineralization process, the transformation of organic nitrogen from soil organic matter into ammonium starts basically once the soils are about freezing temperature. So I suspect that depending on how things go, we may get a little bit more nitrogen built up just from that mineralization process this year, especially if the conditions continue to be warm. I suspect that the soils are already starting to maybe mineralize a little bit. The rate is pretty slow, but it is already happening with soils being with no frost in a lot of situations.

Brad Carlson:
And it's worth noting that the loss of nitrogen is water-based, as we've talked about for years, that leaching and denitrification both happen after the soil is completely saturated. Your typical soil profile will hold 10 to 12 inches of water based on current conditions. And my experience, I'm guessing we're at a water deficit of four to five inches in a lot of places. And so that's an awful lot of precip we would need before we reach that saturated condition. So I just don't think the risk for loss is very high right now.

Jack Wilcox:
What options for early fertilizer application should Minnesota growers consider?

Fabian Fernandez:
That's a really important question to be talking about right now because, and leading off of what just Brad mentioned about the low potential for loss is true, we do have the biggest potential for nitrogen loss happens in the spring, so it's to be seen. We could have an extremely wet spring and in those situations we could lose some nitrogen. Denitrification happens when the soil is saturated, and we normally tend to think about saturation when we see standing water in the field. But you do have, especially in finer-textured soils, you could have micro sites where it may be saturated before the soil is completely saturated. And in those situations you can start losing some nitrogen. Again, based on what we've seen in the last several years, the fact that the soil still has quite a bit of capacity to absorb water without being saturated, I suspect that we will not see a lot of potential for loss. But with the spring, the way that it’s coming, I would not be surprised if folks are planning to get their crops planted early and applying nitrogen early.

And so I would just be cautious a little bit about it again, because we don't know what May and June will bring. If it's weak, we could get some potential for loss. And so in terms of nitrogen, I would say, well first of all, pay attention to the fact that you might have some important amounts of residual nitrogen that could reduce the total amount of nitrogen that you need. And then the other one is the nitrogen source. Actually, this winter I got a number of questions about using UAN, and I would highly discourage using UAN anytime before sidedress time. And hydrous ammonia will be my preferred choice, especially if you're going to go early in the spring. If you're thinking of planting early, getting united in application before the planting is done, I would say an ammonia would be your best friend and then urea would be... Or other dry sources would be okay, but definitely don't apply anything with UAN because what you're applying there, 25% of that nitrogen is already nitrate, and so you want to use that as a side-dress option if you're looking into that.

Dan Kaiser:
So Fabian, just general opinion right now, anhydrous ammonia, if you get, have anybody that could get out there and put it on say here in March inhibitor or no inhibitor, because there was one question that came up when we just recently did nitrogen smart over at Farmington, some growers talking about he likes to get out early, but then he generally uses N-Serve with his anhydrous ammonia. So I'm just curious on your general opinion because normally I would say with spring applications, the need for the inhibitor becomes less and less, but that's factoring in maybe that the application is mid-April up and through May. So I'm just curious on your opinion on that.

Fabian Fernandez:
Yeah. Like you said, the potential for that inhibitor to do a benefit to you gets less and less the closer you are to planting and the time the plant will use that nitrogen. And so I would say that this will be a year where you have a slightly bigger potential to get a benefit. Again, we need to consider that in the frame that what we were talking earlier, that right now the potential for nitrogen doesn't look too big for this spring because of the soil has a lot of capacity to absorb that water. But if I were to say using an inhibitor, I would say yeah, this spring if you're planning to go now sometime mid-March, really early April, that would be a situation where you might consider using an inhibitor because it will protect nitrogen longer. And the fact that the soils are not super warm, means that that inhibitor also will stick around longer. It will not degrade as quickly as it would degrade if you were to apply it late April, early May.

Lindsay Pease:
Yeah, and I think it's important to note too, this is a pretty unusual scenario for Northwest Minnesota that you would actually have time to apply some fertilizer before your planting. And in addition to what Fabian just said, I also wanted to kind of note some of the research that happens further east, Illinois, Indiana, Ohio, really shows that if you can apply that nitrogen as close to planting as possible, that really does maximize how much is getting to the plant. So even though you can be getting out early, as Fabian said, use an inhibitor or maybe even still consider waiting a little bit longer just because you want to maximize your return on what you're applying.

Dan Kaiser:
Lindsay, interestingly, I had a call from somebody up in Northwest around the Twin Valley area. They're asking about P and K right now and I'm less concerned at this point about P and K, especially the nitric component. If you've got MAP or DAP going down since it's ammonium, you really shouldn't have any volatility issues with it. The question then is whether nitro is, and it's actually there, I don't know with that, but I'm not as concerned with P and K at this point in time. The only thing that would concern me slightly that this is Minnesota and it is generally uncommon for everybody to get really excited and get the planters out and then end up with two foot of snow on top of the planters. That's the only thing that would concern me with any fertilizer at this point, just would be getting enough moisture to dissolve it, particularly with P and K, that's very important to get it to dissolve enough where it isn't sitting there where you get a large amount of water on top of it, that would run off quickly because then that becomes a bigger problem.

So it's one of the things that I'm looking at here in March. If it'd be a situation where you're trying to get a jump on things, I think I would probably look at starting with something like P and K first and then waiting on the nitrogen if you can. But there are some issues and again, we just don't know because I just said I've seen this enough. I've been in Minnesota for 17 years. I haven't been as long as some people that are probably listening have been here, but I know that we could easily get a two-foot snowfall event sometime in April. So it's just kind of hard to say moving forward on that. If you can incorporate it, actually it would be probably your best option.

Fabian Fernandez:
That was going to be my question then with this early application, I think it's great to do the P and K and I was just wondering what your thoughts were in terms of incorporation because again, if you have a lot of rain you could potentially have some runoff issues. But anyway, what are your thoughts on that?

Dan Kaiser:
Well, I try to do it if can. Obviously if you've got any issues with moisture deficits in the soil, I hate to overwork the soil just becomes a little bit of an issue, but it's still kind of a BMP. That's one of the things that I'm not necessarily, I think there's some benefits of no-till, but putting fertilizer on the soil surface does present some risks. If you've got a water-soluble product, if there's something there that generates a lot of water, it will move with the water. So that's one of the things that if you can do it, I would try. But it just kind of depends if we get some nice rainfall where it's enough where it can dissolve. Although phosphorus is a little bit of an issue because it's not as soluble as some of the other fertilizers, so it can take it a little bit longer to dissolve with that.

So really it's looking at a lot of the data. I remember I did work before I came here to Minnesota and Iowa looking at rainfall stimulation where we looked at poultry litter compared that with dry fertilizer and there is a time component in there. If you leave it long enough on the soil surface, it'll generally react enough where the risk for dissolved phosphorus will decrease over time. But it just said it's a guessing game because it's just amazing how quickly weather can turn in this state and you can end up with a lot of snow out there in the field. So that's kind of where again, I would be worried about the ground If it's frozen, I definitely would try to avoid it, but if the surface isn't frozen, I think you could do some, I would just be a little bit careful with what fertilizer and you said P and K would probably be the first ones to start with.

Brad Carlson:
I think switching back to nitrogen, I think there's one other thing that we do need to talk a little bit about and that is that there's been an increasing trend towards side-dress applications over the last decade or so. Remember that side-dress is primarily a tool for hedging against nitrogen loss. If you've got a soils or situations that are inclined to lose nitrogen, whether that's because they're sandy or because they are heavy soils that we would see denitrification on, those are the soils we would typically see a response to side-dress because you could lose some of if you apply it all pre.

I guess the point this year is now sandy soils, I don't think we need to change the way we manage based on our current situation. However, most of the rest of our loamy and clay loam soils that we have in Minnesota, the likelihood of seeing a response to side-dress this year is not very high. There's a lot of general concerns right now about just overall economics in agriculture this year that things are off a lot from the last few years. This is probably a good year to maybe save some money and skip that side-dress application and just get all your nitrogen put on pre.

Fabian Fernandez:
One thing that I was thinking when Dan was about soil conditions for tillage, I was also thinking about anhydrous ammonia, and that is one where you need to pay attention to soil conditions. It's kind of an unusual time to be doing anhydrous ammonia applications for us and conditions can vary drastically from field to field. Make sure that you look at if you're doing anhydrous, that you're getting a good seal so that you're not losing ammonia off to the atmosphere. And then the other thing that I did not mention, but for kind of an earlier application, if you're thinking of planting a little bit earlier this year and want to get the nitrogen in before planting, polymer-coated urea is maybe a good option for that.

We have seen some pretty good results with it because it does take a while before the urea inside those granules get dissolved and into the soil. And so that would be a situation where it may work. It's obviously a little bit more expensive of a product compared to urea, but certainly something that can protect nitrogen for a while. And the only caution that I would give with that is the polymer has to be intact in order for it to work. And so if you are running this product through as the first thing that you run through and you're basically having rusty pipes or things like that, that can be a big problem because you'll end up basically applying urea at that point. We've seen that it is the biggest issue. You have to send something through the pipeline before PK or something like that. You clean it up, get rid of the rust before you send this polymer-coated through.

Jack Wilcox:
We've kind of hit on this a little bit, but what practices should be really avoided and why?

Dan Kaiser:
One of the things that Fabian didn't cover and this one of the things that guess concerns me early on is early urea and especially without incorporation that with the moisture that we have out there, it is enough to start dissolving the granules that are applied and there is some risk for volatility. We don't always talk about volatility, but we know that's there with it and it's not as easy to detect with urea because it's a slower process and like anhydrous, if you're not getting good knife sealing, you'll notice the volatilizing ammonia just by smelling it coming off the field. But with urea, that's not always the case and I got to get a crop news out. I'm going to talk a little bit more about this because it does concern me slightly with early applications because I have heard of potentially some fields getting urea applications here in February, which seems like a good idea just based on the soil conditions.

But looking at a lot of the data, we know that essentially the process that controls the volatility, which is an initial hydrolysis of the breakdown of the urea, which urea, if you know a urea is an organic molecule that'll initially break down into carbon dioxide and ammonia gas. And that's the problem where volatility occurs and that breakdown is mediated by an enzyme called urease, which is in every soil in plant materials, it's in much higher concentrations. So it's always there. You can't stop that process unless you're dealing with something like a urease inhibitor, which will slow it down, but it won't completely stop it. So that's of some concern of mine. Just looking at some of the data, there was a study out west where they looked at surface applications. There was three timings.

One was in late fall, early winter around early December. I think there was another application around February and one in April, and they were measuring the amount of ammonia loss with or without agrotain, which is the urease inhibitor. But what they saw essentially is if you looked at the application around early December and then the one in February is a substantial amount of loss, I think it goes about 30% total loss over the three time periods, which the bulk of it, I would say close to about 85 to 90% occurred essentially in the December to February timeframes. So that's telling me that that volatility issue is occurring no matter what the temperature is. And there is another piece of work that we, and I've got the graph we use for nitrogen smart talking about temperature and the hydrolysis of urea, looking at two different temperature regimes.

One's at 35 Fahrenheit and one's a soil at 80 degrees Fahrenheit and they applied I think 80 to a hundred pounds of urea and at 80 degrees after about four days it was fully hydrolyzed. So essentially it means it went completely through that hydrolysis process in about four days. If you look at the 35 degrees, it took about 10 days. So while it slows it down, the cold and the freeze, even frozen temperatures, as long as the urea can start to dissolve, if there's some of that urease enzyme present, it will start to hydrolyze. So it does concern me slightly that we start looking at loss potential that there could be a significant potential for loss for some of these earlier applications if the material isn't incorporated.

So that's one of the keys. Normally a quarter inch of rainfall should be sufficient to incorporate urea, but at this point in time, really you're looking at tillage, you need to get it down, work the ground three to four inches deep to get the stuff incorporated to make sure it sticks around. It may not necessarily be getting to surface water, but you're still losing some of that data was showing maybe upwards about 10 to 15% loss from that early February application. So there's some risk there that just to be aware of with that, and that's why I'd really kind of stress that with urea. I'd probably avoid at least applying early on. If you're putting a MS down, that's not going to be an issue, but something like urea that has that volatility concern is going to be something that I would watch out for.

Fabian Fernandez:
And the tillage deficit is important. You mentioned that they need to incorporate it, and I would stress that in fact, if you incorporate less than two inches, you can actually enhance the potential for volatilization loss because you're putting it too close to the surface, you're increasing that process because it is in contact with the soil, but it's not deep enough to prevent it from volatilization, so make sure that it does get incorporated at these three inches or so.

Dan Kaiser:
Yeah, and that's one of the things they see more of a shift towards many growers looking at some of the vertical tills systems, and that's one thing that has me a little bit with urea applications, even fall applications with a vertical till is you're not really getting it all that deep. Now, the thing to consider there if you're worried about urease activity, you could look at an inhibitor. Normally I would say most inhibitors give you... And warmer conditions maybe at, again, about two weeks or so where it gives you somewhat decent control. The thing about urease inhibitors though, if you can get it incorporated within four days after application, it's really not as much of an issue. If you look at all the data, really the activity and where things start to crank are about four days post application, and I would expect that to occur regardless of temperature at this point.

So it's just something to consider because I think a lot of people think that you look at urea and anhydrous, they're just two different animals on that in terms of the loss pathways, and urea will nitrify quicker, so the earlier it is on, that can be an issue. I don't think it's worth nitrification inhibitors though because I haven't seen any data with instinct or even with DCD that shows that great of an impact on it where I would focus on it, because I think a lot of our losses really are occurring through volatility. It's one of the things that we underestimate and it's why we see a lot of underperformance of the urea. The other thing, Fabian, too, you mentioned with anhydrous really depth of application would be probably more of an issue this year. Shallow incorporations, particularly the dryer is those bands are going to stretch out farther as that anhydrous is looking for water. So that could be something that also could come into place. So that's one of the things, these dry conditions, while they're be fit to do work could cause some issues and some things we need to think about.

Fabian Fernandez:
I would say you're probably looking at five, six inches for the anhydrous because if it is dry, the retention zone is much bigger. Again, every field you need to look at the conditions in every field and do a strip, stop the tractor, get out, go out and smell it. If you smell ammonia, you know that you're losing nitrogen. That's the best indication. And then with coming back to urea, the urease inhibitor, that is one thing that we need to be cautious about, that the inhibitor is not a thing that will just keep nitrogen from volatility loss indefinitely. It lasts about two weeks at this time when it's cooler temperatures and stuff, I would say about two weeks. And so that's basically just giving you time for incorporating that nitrogen that is on the soil surface. If you just leave it there after two weeks, you're basically, that inhibitor, it's out of service, it is done, and you'll start to lose some nitrogen if there is no incorporation.

Dan Kaiser:
The other thing I would look at too is if you're doing continuous corn, it's one of the things I would really try to avoid right now with the amount of residue that's out there, because again, if you look at the urease enzyme, it's in much higher concentration in the residue, so the more residue you have, the quicker essentially that hydrolysis is going to occur. So that's one of the things that I would look at prioritizing fields if it was going early, stuff with high residue, if you can't get it incorporated, I would probably avoid, and those would be probably some of the last fields I do.

Jack Wilcox:
Should we be concerned about nitrogen carryover?

Brad Carlson:
This is the third year in a row where we've been dealing with this potential. We know that as we've already mentioned, that the loss of nitrogen is water based, and so when we don't have a lot of water, we tend to keep it there. Normally we don't think about carry over nitrogen or nitrogen credits because of that loss process that on a normal year, but that's only when it's normal or average. So when it's not normal or average, we need to start thinking about the things that could happen, and one of those is retaining extra nitrogen in the soil. There's really two pools of that. One is unused fertilizer from last year, and then the other is the accumulation of mineralized nitrogen that comes post-growing season. Normally speaking, we would lose a lot of that. The data shows we end up losing a lot of that in March, April and May through early water flow through the soils.

And so we don't expect that because there's a large capacity for water to still be absorbed in the soil profile where we don't think we're going to see a lot of that outflow either to tile or shallow groundwater. And so, our recommendations have been for many years now in situations like this to take a two-foot soil sample measuring for nitrates. Really the key for this, there's a few tips related to that. One is it only tests nitrate. So if you did, for instance, a half rate of fertilizer last fall, it's not going to tell you much because we don't even know what percentage of that is in the nitrate form. It's not calibrated for that. Similarly, if you put manure on, we're not going to be able to tell how much nitrogen is out there, things of that sort. So we really are only looking at situations where we've applied no fertilizer and we're going to be finding nitrate in the soil.

The other thing is, of course, that nitrate still is subject to be lost, and so we know that it may be accurate at the time you took the test, if it gets really wet after that, it's possible that that nitrogen is no longer there. Minnesota Valley Testing Labs in new ALM has shared data with us the last several years related to the samples that were submitted to them in the fall for two-foot soil testing for nitrates, and this last year the numbers were up considerably. Our old recommendations went up to about 18 parts per million in that two foot sample. If you look at 2021, 2022, they were looking at 28, 23% of the samples submitted to them that were in that level. However, if we look at just this last year in the fall of 2023, that bumps up to 46% or nearly half of the samples submitted were at 18 parts per million or higher, and that translates to 155 pound nitrogen credit.

Our old recommendations only went that high, and Dan did some work and extrapolated this, and we figure that if the nitrate concentration is 24 parts per million, there's probably a nitrogen credit in excess of 200 pounds. Thirty percent,, almost a third of the samples submitted to them, we're at that level. Now, it's worth noting this is not a random sampling. We can't say that a third of the fields out there have a 200 pound nitrogen credit. These were samples that were submitted in situations where the grower, whoever was making the fertilizer decisions, had a suspicion that there was going to be a nitrogen carryover. But the point is is that if they thought there was going to be some there, in a lot of cases, there definitely was. In fact, the credit starts at six parts per million and there's only 12% that were six or below. So almost everything had some nitrogen credit associated with it. Now, I think the other question is of course is what after that.

And that is obviously if this was following corn last year, if you're rotating the soybeans, it's not of much use to us. I had a farmer friend of mine, we were chatting actually at a Christmas party back in December related to this and the potential for this. And his first response to me was, "So you're telling me I need to change to more corn on corn?" Well, that's a big overarching decision that has a lot of other implications on what happens on the farm. The thing I would say about it is though, is if you did potentially have a nitrogen credit of 200 pounds in the soil, I really would think about it. It's worth investigating and maybe making some modification to those management plans, if that's possible. And so particularly if you're looking at taking that test this spring, like I said, we recommend that down to two-feet deep. And we specifically are looking at corn on corn situations where there might be unused fertilizer from last year's crop as well as fields that have a long term in our history.

Fabian Fernandez:
Looking at the values for this last fall, I'm actually not too surprised you see some of those higher values because some of it is certainly carry over, but quite a bit of that I think is coming from the organic matter. We had a fairly dry season for the most part, attacking globally across Minnesota. But later in late summer, early fall, we did have moisture starting to come in. Again, it was dry enough that we didn't really have any potential for nitrogen loss, but that moisture and the warm temperatures definitely made it so that you had ideal conditions for mineralization. And it was warm for quite a long time this fall. So we had, I suspect, a lot more mineralization than typical. And since there is not a crop to take it up and there is no water moving through the profile, that nitrogen just accumulates in the soil.

Dan Kaiser:
And I'm wondering how many people actually that have the test taken actually utilize the data. It'd be interesting to know that, because it's one of the things that I fear is that they look at it the number and say, "Oh, that's interesting," and then just do whatever they did before. And that's kind of problematic when it comes to nitrogen because once it's there, you can't get it out without a plant. You've got to have something there to get it out of the soil. So it's then a question of what tools do we have that can help us make a decision before the nitrogen is applied? And there aren't many. I think the pre-plant nitrate test is one of them. I was just talking with the NRCS on some of their 590 standards, and I know the pre side-dress nitrate test is in there as an option, but I wish they would add something like the pre-plant test.

Because at least if you had it, you'd have something that you can make a decision beforehand and maybe cut back. And when we're talking about something like Brad was talking earlier with side-dress, say you put down a lower rate just because you have some information that would say, I've got some sort of credit, at least then you're starting at a point where you can adjust up versus you can't ever adjust back down. So that's kind of where I'm thinking is what options do we have with that? And I think we need to do a better job probably in some of our research to look at the variability from fall to spring. I'd rather have a grower habit than not because we know that the numbers will change, but then how to effectively utilize that to try to maybe hone in on the exact optimal nitrogen rate. Because that's the thing that I think we struggle with that. And really, so the options are highly limited in terms of what we can utilize beforehand, before we put that nitrogen down in terms of making a decision on what to apply.

Brad Carlson:
And I think there's another piece of this phenomenon too, and that's that we've had three dry years in a row, and so we may not just simply be looking at what was left over from last year. You might be looking at what's left over from multiple years, and particularly, even if you're going into soybeans or if you had soybeans there last year, it's possible that there was still nitrogen there from two years ago from the previous corn crop, kind of depending on what efficiency that the soybean had in picking up that nitrogen out of the profile and so forth. So it's possible that these numbers are actually just building because we've had multiple dry years in a row, so it's something worth thinking about.

Jack Wilcox:
Are there any last words from the group?

Brad Carlson:
Well, one thing I guess I would just like to bring out, and as I mentioned once already, there's a lot of conversation that the overall economics crop budgets aren't going to look as good this year, as they've had the last several. One of the pieces of information that I dig out every year is to look at the FINBIN numbers, the accumulated adult farm management records that are available for Minnesota. And if you look at the expenses for various crop inputs, if you break that out between the 20% most profitable farms and the 20% least profitable farms, it's really been a common theme. Now, ever since I started looking at this, going all the way back to 2016, that the least profitable farms are grossly overspending on fertilizer. The data for this past year for 2023 is not out yet.

So 2022 is the last year we've got numbers for, but the difference was the most profitable farms in 2022 on average spent $198 an acre on fertilizer, and the least profitable farms spent $256 an acre on fertilizer. That's a 23% difference. And again, going back to 2016, those numbers are 28%, 25%, 21%, 30%, 24%, 15%, 23%, huge differences. Whereas the difference in the expenditure on seed this year was only 2% difference between those two categories. So something's going on where the guys losing money are spending too much money on fertilizer. I don't know if that's high rates. I don't know if that's using expensive product or what it is, but I think it's just important to remember if we're looking at decreased profitability in agriculture this year, not spending on unnecessarily fertilizer applications is probably one of the things you should be focusing on.

Dan Kaiser:
And fertilizer prices right now, they look like they're down compared to, I'm just looking at the numbers here through about the end of January compared to what they were a year ago. So it isn't necessarily that the fertilizer's costing more, it's just you look at crop prices. I know where the big thing, but that's one of the things I'm concerned about a little bit is just how things are prioritized, because I know a lot of growers might be sacrilege to them, but really there's probably a lot of ground out there that doesn't need dapper map applied to it, but we've kind of hooked ourselves on it where we think that we need it. And if I look at just soil testing for those nutrients, the phosphorus soil test is pretty solid, the one that we recommend in terms of predicting the overall need for fertilizer.

So if you are putting, say, crop removal down, I've got data. I've got long-term data over a 10-year period where we put on about 60% of removal, what's removed into two year corn soybean rotation. My soil test is held at a certain point at that medium to high level. So it isn't that you need to be completely specific, and we get a lot of flack because we're not just up to date on these very advanced fertility programs that some people are doing, which essentially just using a yield map times crop removal and putting that down, and you're going to spend a lot. And I think that's where a lot of it comes into, Brad, and I think it's a lot of it's P is the big one. And the thing that scares me a little bit is my K numbers.

My soil tests have been down low, and it seems like the phosphorus gets prioritized over that. And I'd be paying more way more attention to that. And like I said, unless you're dealing with high pH situations, that soil test is pretty good at predicting where you're going to get a response to phosphorus. So you're above 20 gray. The likelihood that you're going to see a response is very, very, very, very, very, very low. It concerns me on the priority side in terms of what's being done out there. So I think it's the easiest place really to look at saving on and then not just wasting your money on all these products that are out there. There's just so many of them, and I get these questions on all these things. It's amazing.

We had a meeting with Central Crop Consulting recently, and the number of questions and the number of products, I just can't keep up with them all. It's pretty simple. The crop will respond to, if you look at just that Lee's law to the nutrient that's in most limited supply, it's going to respond to the total amount of nutrient it requires relative to the amount the soil can supply. So all these other little products, when you're paying more, almost double or three times the amount per unit, say P205 or K20, it's where your economics really fall apart with them. So focus on your base fertility program, then focus on the nutrients that make most sense. That's really the big thing it can save, with economics over and over again is you just got to watch because you can really spend a lot of money when you're not going to get very little return.

Fabian Fernandez:
Your comment, Brad, about the economics also reminded me of another big expense, which is seed. And when we are looking at early planting, you can risk having to replant, and that's a big expense if you have to replant not only getting seed supply, but also the cost. And so I think memories are short. I will remind folks, I think it was 2018, late April, where we got 18 inches of snow. So keep that in mind if you're itching for getting out in the field way too early to get your fertilizer in and your planting done.

Lindsay Pease:
Yeah, and I think if there's one thing I would really encourage people to take away from this podcast, it would be, use this extra time that we're going to have in the spring to go test your soils, especially if there's any place you're not sure about. That's probably one of the best and most useful places you can use your time and your money this spring.

Jack Wilcox:
Before we go, if you have a question or comment for our panel, or a topic you'd like discussed in a future episode, please email us at nutmgmt@umn.edu. Again, that is nutmgmt@umn.edu. Thanks, and we look forward to hearing from you.

All right, that about does it here for this episode of the Nutrient Management Podcast. We'd like to thank the Agricultural Fertilizer Research and Education Council, or AFREC, for supporting the podcast. Thanks for listening.

(music)