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Welcome to University of Minnesota Extension's Nutrient Management Podcast. Each month we bring you the latest research in nutrient management for crops and how you can incorporate the latest tips and best management practices to your farm.
University of Minnesota Nutrient Management Podcast Episode: “Supplemental nitrogen fertilizer: Is it time to pull the trigger?”
June 17, 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)
Paul McDivitt:
Welcome back to University of Minnesota Extension's Nutrient Management podcast. I'm your host, Paul McDivitt, communications specialist here at U of M Extension. Today we have a very timely episode on the topic of in-season nitrogen application. We have four guests. Can each of you give us a quick introduction?
Fabian Fernandez:
Hi, I am Fabian Fernandez. I'm a nutrient management specialist here at the University of Minnesota, working on primarily nitrogen management.
Dan Kaiser:
This is Daniel Kaiser. I'm also a nutrient management specialist with the University of Minnesota. My area is in crop nutrient recommendations.
Jeff Vetsch:
This is Jeff Vetsch. I'm a researcher at the Southern Research and Outreach Center.
Brad Carlson:
Brad Carlson, extension educator work statewide, but out of the main Seattle regional office, primarily focused on nitrogen management issues.
Paul McDivitt:
All right. Starting off, what are you seeing around the state?
Jeff Vetsch:
Here in South Central Minnesota, we have a lot of fields with nitrogen deficiency, unevenness, or uneven uniform corn across the fields. I think some of this is obviously a result of lack of oxygen as we've had a lot of rainfall in the last three weeks. From May 21st through June 6th, we had about six and a half inches, and during that period we had saturated soils for much of that period, so see a lot of poor looking corn in between tile lines and better looking corn over tile lines. So we know some of that's related to oxygen, but some of it's clearly related to nitrogen. We've also collected a lot of tile water samples in our research drainage study and submitted them and got some results back last week from the lab. In early April, the nitrate concentrations ranged from about seven to 15 part per million in this continuous corn field with and without cover crops.
By mid-April, they crept up to maybe 10 to 20 part per million. By late April up to 15 to 25 part per million. In early May, we're looking at 15 to 30 part per million, and the ones that were taken in late May, which was May 22nd, now we're at 15 to 45 part per million among treatments. So clearly we've seen some nitrogen move down through that profile. In this study, the nitrogen management in this study is just a small starter amount of nitrogen with the planter and then the rest is side dressing. And we side dressed on June 7th, so the majority of the nitrogen had not been applied to this study prior to that.
Brad Carlson:
Jeff, and that kind of corresponds with some of the messages we were giving this winter, that coming of several dry years, we did expect to have a fair amount of residual nitrogen, whether it was from mineralized sources post-growing season or unused fertilizer from last year. That does kind of explain that deep nitrogen that's going out now. They physics of the situation suggests that most of our applied fertilizer should not be leached at this point unless you have coarse textured soils. I happened to be on vacation last week and I was actually down in Tennessee and Kentucky and things don't look a lot better down there. Driving home across Southern Indiana and southern Illinois, it looks fairly poor. Things get much better when you get into Central Illinois, but then as you get into Northern Iowa and across kind of came home through Austin and back towards where I live in [inaudible 00:03:58] County and things looked relatively poor.
I think the thing about it is that it's not consistently poor. It's some fields and then in the same area where you would see same soil types in the same weather, there's better-looking fields, and so clearly there's also a management aspect regarding what looks better and what doesn't.
I know we had had some conversation yesterday regarding west of Mankato and I had not been west of Mankato. I did drive a little loop. I went up to St. Peter. Kind went around through Nicollet and Lake Crystal. I didn't have all afternoon to just drive around, but things actually look a lot better when you get up in that area and around west. And so it seems to me like a lot of the worst parts, kind of Mankato is kind of the northwest corner and it kind of goes south and east from there, although I do know I have also gotten some calls from kind of the Litchfield-Hutchinson area too. So I think there's probably some worse spots up there also.
Fabian Fernandez:
Just to mention about drainage and what we've seen over the last few years, this is coming from Southwest Minnesota at Lambert and we have a drainage site there. And in 2021 we had very, very little leaching about two pounds for the whole season, if you can imagine that. Really little. And then the next year, 2022, we got about three times that amount, and then last year was wetter and we got about eight times the amount that we had in 2021, so it's still even eight times it wasn't that much. But we know that nitrate leaching, it's related to the amount of drainage that we get, and I haven't quantified that for this year, but I can tell you that last year we had in the spring we had more drainage in the previous two years combined, and I suspect that this spring we probably had about as much as the last three years combined up to this point in terms of drainage.
And so there definitely has been some nitrate leaching. And so the other thing that I've noticed in the study is that the places where you have drainage, so just under the tile lines, the corn looks better than in the areas farther away from the tile. So we definitely are losing some nitrogen more so than the last three growing seasons, at least for some parts of the state. And then the one that we haven't really mentioned much about is sandy sites, and that's also where there's a lot of yellow looking corn in sandy sites.
Paul McDivitt:
What practices do the worst looking fields seem to have in common?
Brad Carlson:
Well, one of the things that I've noticed, and this is particularly in my neighborhood because I'm familiar with how my neighbors manage their nitrogen, is the fall applied anhydrous and particularly the fall applied manure are the fields that are really looking fairly poor. I know my neighbors that did some spring urea applications, those tend to look pretty good, and it just seems like those fall sources are kind of the problem. The other thing that I'm seeing in some of these fields is places where the hillsides are looking worse. I think there's a number of things going on there. We kind of already alluded to that a lot of the loss is going to be due to denitrification, at least maybe not in the overall perspective, but as far as what the crop is seeing right now, the roots aren't deep enough to see what's down at two or three feet.
So it's really that top layer that's causing the crop issues right now. And that's denitrification, so we would see that possibly on the hillside with our heavy clay soils with it continually raining and staying saturated like that. The other thing that I'm seeing in some of these fields that I know had manure applications on them are some of the intangibles related to manure application that I think a lot of people are familiar with in tough years. Some of the patchiness that may be relative to either compaction or maybe uneven application, in some cases, you tend to wonder about whether there was adequate agitation. I personally tend to wonder with a lot of manure now being loaded into trucks and then moved, if there's some separation that goes on in those trucks, it was agitated under barn pits and then it got put in the truck, and I don't know that it necessarily was well mixed at that point. I think that's also possibly explaining some of the issues in some of these fields that had manure application.
So overall, it's a difficult situation to really get to the bottom of it because it requires a lot of soil sampling to see what's there. For nitrates, it would require some digging of roots to see if you've got root restrictions and so forth. It actually would be quite time-consuming to really get to the bottom of every situation.
Jeff Vetsch:
What I would add to that, Brad, is the timing of the fall manure, especially for us, mostly liquid swine manure, it seems to have made a difference. Swine manure that we put on here at the S rock and in mid-October, last fall does not look very good as you said. But we did have a couple of fields that got manure much later around the 10th or 11th of November, and those are still hanging on and don't look nearly as bad. The other areas that I've seen that look poor are any fields that we put bedding manure on that has a high amount of corn stover or biomass in it, a lot of bedding, those fields look bad. It's understandable. There's just a lot of carbon there and probably not a lot of nitrogen, a lot of immobilization going on. And then corn on corn, it's always the ugliest this time of year. And some of that, a lot of corn on cornfields do not get a starter nitrogen placed near the row, but the ones that do, we've got a couple of studies where we're doing that here. They look better than the ones that do not get a starter nitrogen.
Dan Kaiser:
I think a lot of that too, Jeff, when you bring up the timing aspect, I think is pretty critical because we look at what we have now with the saturation. I mean that's one thing, but if you look at, going into last winter, I mean we were pretty warm and even the spring we were pretty warm. That was kind of one of the questions that I had when I started getting some calls back late February, early March, about people starting to think about putting fertilizer on just because the soils are fit at that point. So looking back at that, waiting a little bit probably would've been a better option, especially for some of the sources, but time will tell on this, and that's the thing that... I was getting questions about the end of May about supplemental end and some of these fields with saturation. And at that point, we really didn't know.
We really didn't know how much that nitrogen had converted from the ammonium to the nitrate form, whether or not they should be thinking about it. But I think certainly now, just with the overall saturation continuing, that's really more of an issue. Just a little tangential here though too. I did have another consultant call me and was wondering about sulfur, whether or not that could be contributing to it, certainly it could be, but I think the bulk of the issue right now really is nitrogen. I mean, that's really the thing that the crop's going to be needed the most. I mean, certainly we could have some issues in some fields with some of the other nutrients that have some limited availability, but if you look at just where we're at right now, particularly with the crops going in, and I don't know, what growth stage are you generally seeing most crops out there right now?
Jeff Vetsch:
Our smallest corn, Dan, is probably V four, V five, but the majority of it is V six, and there's a lot of corn that's V seven or V eight already that I see that's over knee-high and getting near thigh high.
Dan Kaier:
So when we were looking at here, we were recording this June 14th, and looking at it, that's kind of that danger point really right now, especially about running out because we know we can get away for a little while with the nitrogen we've got in the soil, but we're at that point where we're hitting peak demands. So looking at it in terms of scenarios, it's just, I think, set up for a perfect storm this year. Some of the comments too, Jeff, about your increases in your water concentrations, I've been looking at some of the data from last year, I'm just getting some of our fall nitrates in, and it's kind of amazing some of the concentrations we have, and in fact that a lot of it was near the soil surface, zero to six inches. So we had a lot of dry conditions that we... We talk about mineralization late I think is definitely a key in terms of some of that nitrate we're losing early on here in the growing season, but also the last few years.
I mean, we've had just years where you've had bad crops, some poor utilization, and we've been talking about that the last couple years about loss potential. We start getting into some of these wet situations that things will really start to ramp up if we get into conditions where we've got a lot of nitrate hanging around and there's not a plant to use it.
Fabian Fernandez:
And this year, it was kind of a perfect storm in the sense that we have fairly warm conditions in the fall. There was quite a bit of mineralization. And then, of course, when mineralized nitrogen is transformed from organic to ammonium, but ammonium doesn't stick around too long, the tendency is for that to move fairly quickly to nitrate, and so we likely had quite a bit of that mineralized nitrogen in the fall transformed to nitrate even in the fall. We had a really early spring as well, so there was more mineralization happening at that poin. And some of that also nitrify, and then we started getting these wet conditions that were ideal for leaching in some situations, but I think, as we mentioned, in more soils, fine texture soils, the biggest concern is not so much leaching but the denitrification component. And so we normally have that buffer in our fields where we have quite a bit of nitrogen.
Even if we don't apply nitrogen, we have quite a bit of nitrogen from mineralization. I think that buffer this year was reduced quite a bit because of those really wet conditions. So we definitely need to keep that in mind. And then some of these low values right now, as Jeff mentioned, I think impact, especially situations where you have immobilization happening, like in continuous corn, that's where you'll have the biggest problem because not only you have already some loss through denitrification, then you also have some tie up with all that crop residue.
Dan Kaiser:
And denitrification is an issue. I mean, I wasn't as concerned going into the end of May with some of the saturated soils because we hadn't been overly warm. I mean, it's really this time of the year where it's more of an issue, particularly when we look at forecasts, temps getting into the mid eighties and nineties there, you start seeing saturation for more than four days, then we start getting some pretty significant loss potential. So that was one of the things that was just kind of weird in maize. You didn't really know how to give a straight answer yet towards late May just because our temps hadn't been overly warm and there were some questions whether or not we still had some of our fertilizer in the ammonium form. But I think we're certainly to the point now where we need to be looking at some of these things when it comes to supplemental and decisions.
Fabian Fernandez:
Yeah, and that combination, I mean, yes, it was a little cooler, but then the other important point to this was the temperature is starting to rise, but the length of saturation is also important because there is a lag period there where it takes a few days before denitrification really gets going. And so if you have only a couple of days of saturated conditions, it's not a big deal, but then if you continue to stay saturated, that's where the denitrification starts to ramp up.
Paul McDivitt:
How does a producer assess their situation?
Fabian Fernandez:
Well, that's an important question right there. I think one of the situations where we see more issues is related to drainage. I don't think we touched too much on that, but that's an area where fields that have poor drainage, they might have insufficient tile drainage for instance, those will be fields where you will see more of a problem. And as we talked about before, landscape position is important. So overall, visually looking at either just with your eyes or doing canopy sensing, for instance, looking at what part of the field is looking poor, those yellow spots, is it uniform across the field or is it more related to specific regions within that field? And most likely they will be spotty, it will be low, low areas of the field will have the more deficiency, as we talked about, tile lines, away from the tile line, the further away from a tile line or areas where you have poor drainage, that's where you will have more of a problem.
And then the other one that you could also see is areas of the field where there is compaction. The soil tends to stay wetter in those areas. I mean, once it gets saturated, there is finer porous space, and so those soils tend to hold the water more tightly. And so you can start to see some of these things... So looking at the distribution I think is where you to start first of all because while I think there is certainly a need for supplemental, and in some situations, I don't think it's just... We cannot say this as a blanket statement that we should apply hydrogen everywhere. We need to be really strategic about it. And so having this visualization is important, whether you do it with your own eyes, at this point, canopy sensing can also be a good tool to get that overview of the field. And then the other one is PSNT. I mean, we have seen low values, again, because I think whether it is denitrify or leached or simply moved down, not all the nitrogen that the plant is not seen right now is gone.
There is quite a bit of nitrogen that is within the profile, but it's deeper in the profile. And so the PSNT might not give us a very good answer just simply because we will not be tapping into those slower layers with a food sample. But certainly the PSNT could be one tool that farmers can use to assess where they are on their nitrogen budget. So those are some of the things that I would say in assessing this situation right now.
And then the final thing too, that I always kind of mention in these wet springs is that sometimes we feel that applying nitrogen will solve all the issues, and I caution against that because those areas where the crop yield potential has been compromised because of standing water, things like that, adding nitrogen is not going to bring that crop back. There will be some yield potential loss already, and the root system may be compromised. And so applying nitrogen is not going to solve the problem.
The other thing that I mentioned, deeper nitrogen in deeper layers, one of the things that is a little difficult to determine at this point is what is going to happen? Because if we continue to stay with good precipitation, those roots may never really grow very deep. But if we start to dry up, then we might have more of a chance for two things to happen. One is that the roots will go deeper reaching to that nitrogen. And then the other part is that as the soils dry up, since it's all through capillary action, the nitrate that is deeper in the soil will start to move up to the surface and closer to the roots.
But again, it kind of depends on what happens weather-wise, as we move forward in the growing season.
Brad Carlson:
So one of the things that I guess I've talked about, and actually it's something I've kind of harped on at various points in my career is if you've got fields that don't look real good and your neighbors have fields that look relatively decent, find out what's going on.
We talked about the fact that in the same neighborhood, there's some fields that look good and others that don't look so good. And Fabian, you already mentioned this, it's not a blanket statement that everybody needs to come in and put in a rescue treatment and add some rate of nitrogen. It's more circumstance-specific. And so it's kind of a matter of evaluating your fields as far as what your practices were. I know we've got our supplemental nitrogen worksheet that you can walk through that's available on the web.
But particularly as we mentioned some of the fall applications and manure applications are the ones that don't look quite as good. So that's an area where you need to kind of take a look at.
If your fields look fairly good, it's not saying that you haven't lost some nitrogen, but I guess I wouldn't be thinking automatically that I need to be applying some nitrogen to those. There's one field I was going to mention, it's a field that I'm very, very familiar with that I know had a fall anhydrous application. Now, while it was dry last year, we did have some rain periods, and this specific field that I know about had a rainfall of an inch or two, and then it froze, and then anhydrous got put on, and the field looked incredibly rough, because I know, I was deer hunting out there, four days after the anhydrous application went on, I could still smell ammonia in that field. And that field doesn't look good this year.
And so if you've got situations that you kind of scratch your head about and say, "Maybe this was a problem," those are the places particularly to be targeting.
The other thing is, and this gets back to some of the information that we present at Nitrogen Smart, is to, as Fabian said, take a look at not just the soil temperature, but also the time. We've got some basic research that we cite often in the Nitrogen Smart program related to rates of nitrogen loss and soil temperature and time.
The charts indicate that if the soil temperature is at 70 degrees and it stays saturated for four days, you lose 10%-12% of your nitrogen. If it's saturated for 10 days, it's more like 26%, or about a fourth of the nitrogen can be lost. We are in situations in some of these fields where we now have been saturated for 10 days.
When that soil temperature moves to 77 degrees, I'm not sure why it's 77 and not 80, but regardless, the amount you can lose in four days is 20%, which that's getting pretty high for a very short period of time. And it really indicates the sensitivity to this process as the soil temperatures get warm. The 10-day loss at 77 degrees is 43%, and that's pretty significant.
And so you can kind of start looking at whether your fields have been saturated and for how long, and then start coming up with an estimate.
And I know Jeff, the S Rock has the four-inch soil temperatures posted, and those have been in that 75 degree range. So again, we would expect to see some pretty significant losses up near the surface due to denitrification based on how wet and how long it's been wet.
You guys also have eight-inch temperatures. Those aren't posted, but eight-inch is probably a little more likely to be what most of your nitrogen is experiencing that if it was applied as anhydrous at six, it's probably safe to say it's at eight or a little bit deeper at this point. And so where are we at with that?
Jeff Vetsch:
Yeah, Brad, so like Dan mentioned earlier, in late May, we were just... at eight inches our soil temps were averaging about 60 degrees the last 10 days of May. Since early June, the first week we were averaging about 65 degrees at eight inches. And then these last several days we've been averaging almost 70 or in the upper sixties. So that's kind of where we're at at eight inches, and at four inches we're averaging right around 70 degrees over the last several days.
Paul McDivitt:
What are your recommendations going forward?
Dan Kaiser:
So I think certainly there'll probably be a fair number of fields in the south central part of Minnesota with some supplemental and applied.
I think one of the key things is some of the things I think that most of us have mentioned is that it isn't by default that all the fields need supplemental nitrogen. It's difficult because especially with the rainfall the way it's been, if the roots... we might have a lot of nitrate down deeper that the roots might be below the point which we're picking up nitrate with some of the tests we're using.
So I think that's a thing to look at. We do have some other options like the supplemental N decision tool that is more of a qualitative assessment of whether or not you need supplemental N. In most cases a lot of that test, we only recommend about 30 pounds, potentially additional end with corn following soybean or somewhere between 40 and 70 with corn following corn.
So we don't really make any fine adjustments based on something like what the Pre-Sidedress Nitrate Test would supposedly do. The issue with the Pre-Sidedress Nitrate Test, again, is you're only testing the top foot. So what if there's more nitrate down deep? If the roots go down there, it's likely going to access it.
So it's one of those things, I think it's just look at the fields and make a kind of field by field decision on what you think you might need for supplemental N. The thing right now, if we're getting into that V-eight V-nine time frame, it's really probably the optimal time to be thinking about some applications if we can make them, because we're right at that point at which the uptake is starting to ramp up.
So you're going to likely see the plant starve itself if there isn't any nitrate or nitrogen there. But hopefully we'll be getting some deeper penetration of the roots into deeper in the soil profile that if there is some nitrate deeper that some of these plants will access it.
But yeah, it's a difficult decision because when we start looking at it, one of the things that what Brad said, I think it's good to kind of assess if you are seeing some of your fields look bad, but your neighbors' look good, assess some of those different practices.
I would really stress not to just default that we need more nitrogen for a single application rate, because you really need to be looking at everything that's going on. And I think source is a big overarching theme right now with a lot of the things we've talked about, source and timing, when it comes to how some of these fields look.
And that's, I think one of the big keys there is I don't think, look at rate-wise, you're going to manage yourself out of a lot of this if we have some of these issues just by increasing rates. So I don't think I'd automatically just pull the trigger and just look at higher rates upcoming because it's really, I think, a good time to really have some of those discussions and look at best management practices and what's recommended, particularly for three other Rs that aren't rates. So we start looking at its source, timing, and placement just to see if there's some better options available to you out there, because it's the thing that kind of concerns me. We get years like this and we tend to overreact, and you make some decisions where there was probably some better decisions that could be made by some considerations, just by some people thinking that the rate wasn't too high and they need to apply more next year.
Fabian Fernandez:
The other thing, too, to consider is that we do have good moisture in the soil. That means that... and these soils do hold the moisture, is that, as we start warming up, there will be mineralization. And obviously we try to manage nitrogen to the best possible way, but one of the great advantages I think we have in Minnesota is that a lot of these soils have a lot of organic matter. They are deep, and so that mineralization that will happen from now through the growing season, it can really erase any of these deficiencies that we are seeing right now. So it kind of depends, obviously, on the growing season, what is going to happen later. The last few years, it really dried up in July and August. But if we have good conditions, the mineralization that happens during those months could very well cover the deficiencies that we are seeing now. So keep that in mind.
As I mentioned earlier, the yield potential is an important one. And so as you look at needing to apply additional nitrogen, first look at the crop. Look at where it's located. See if the crop is actually going to benefit from that nitrogen application. And then the other thing is, we have had some studies where we have replicated trials in the same location, same soil with and without tile drainage so that we have artificially created good drainage versus poor drainage.
And we have had this study over a number of years, more than 10 years now, and many of those seasons were wet seasons. And in those really wet seasons we noticed that the maximum return to nitrogen, or the EONR, for those specific years between a drain versus undrained condition was about anywhere from 20 to 30 pounds of nitrogen. So even in those situations where you had a lot of potential for denitrification in those wet years and of course some leeching in the drain site, the difference between those two is not huge.
And so if you are going to be supplementing nitrogen, be cautious about it. It's not like you need to apply a full rate or anything like that. It's probably somewhere in the range of 20 to maybe 40 pounds of nitrogen. It's not a huge amount of nitrogen that you will be needing to apply. And then the last point I just want to mention too is, and I think Dan alluded to some of these, is that, in these years where things are a little bit more challenging, it really helps us to realize that we cannot be lazy about some things.
When conditions are adequate, it doesn't really matter too much what we do. Things worked out. But in these situations where you have a little bit more stress into the system, that's where good management really shows up. And we've been talking for years now about, for instance, fall urea applications. Don't do it. You are going to lose nitrogen. Well, the last two or three years, some people might have gotten a little lazy on that because we didn't really have much potential for loss in the spring. But the typical situation is what we are seeing now, where applying urea in the fall is just not a very good idea because most of that nitrogen is going to be nitrate by the time you start getting wet conditions and start to lose some of that nitrogen. So again, I think years like this is a good time to reflect on what we are doing with our management and trying to figure out better ways to do things in the future.
Brad Carlson:
And I think another thing, as I've been talking with producers who've been calling me wanting to discuss what they should be doing, is what your overall rate of application was so far. I know there was one fellow I talked to that had applied a rate that I thought was quite high for corn following soybeans, and what I suggested to him was is he could lose about 1/4 of his nitrogen and still have enough nitrogen. So that's, I guess, kind of a separate issue. But I've also talked to producers who planned to side-dress. And so they only applied a half rate in the fall. Those fields don't look very good, but because they only had, say, 80 pounds of nitrogen applied in the fall, the amount they lost is actually kind of small. And maybe if they lost 1/4 of it, they only lost 20 pounds.
And so as far as coming back with the side-dress that they had planned to do, maybe in some circumstances they'd want to bump that up an extra 20, but in some cases that extra 80 they were going to put on probably is still adequate, especially if the crop is fairly consistent. I think it's also important to recognize that, in a lot of these cases where the crops aren't looking good, it's not going to reach its full potential anymore. You're probably not going to coax it into a 280 bushel yield anymore, and so there's really no reason to try and fertilize it for that target.
Paul McDivitt
All right. Any last words from the group?
Jeff Vetsch:
I got a couple points. I think my biggest concern right now is the forecast for the next 10 days in our areas, for another three to four inches of rain. And that is not what these wet fields need. That's going to drive denitrification. And the other problem is these wet fields are going to limit options for applying supplemental land or doing other field operations. So that's very concerning, if that happens.
The other point is kind of an add-on to what Fabian just mentioned. In my time here we've done a lot of nitrogen studies where we've looked at rescue or in-season treatments, and only a few of those ever needed more than 45 pounds of N. Even though it looks bad and we think we've lost a lot of N, it doesn't take a lot to perk it back up and get it back to whatever its yield potential is going to be. It doesn't need a whole new 100, 200, 150 pounds of N to do that.
Brad Carlson:
I guess one final note is what is it that you're going to do? Probably in most cases, the corn's gotten too tall to be injecting or getting through the rows. Some guys may have drop nozzles or wide drops that they're able to put it on, but I suspect a large percentage is going to go on as urea. In some cases, we're going to see the airplanes flying that on. In other cases, it's going to be put on with a spin spreader. I think it's important to recognize that you are probably going to want a urease inhibitor in a lot of cases here because of the soil moisture conditions.
We're kind of curious whether the urea is actually going to end up penetrating deep into the soil. I think there's a potential it could dissolve on the surface and not go anywhere, and so you could experience some volatilization losses. I think the key to remember though is Fabian already mentioned, and Jeff mentioned that the rates that we need to apply probably aren't extreme. We're talking 20 to 40 pounds, and so you probably have a lot of options for that. Definitely wouldn't be thinking that I need to figure out a way to get 80 or a hundred pounds, unless, of course, that was a rate that you intended to side dress anyway.
Paul McDivitt:
All right. That about does it 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.
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