UMN Extension Nutrient Management Podcast

This episode of the Nutrient Management Podcast is our annual fall fertilizer outlook. After such a challenging growing season throughout most of the state, how do things look headed toward harvest? Since most of the state went from being too dry last year to too wet this year, how should this affect the approach to fertility management? What role will fertility play in sound financial management this fall? What advice do our panelists give growers as we head into the fall?

Guests:
  • Daniel Kaiser, Extension nutrient management specialist (St. Paul)
  • Brad Carlson, Extension educator (Mankato)
  • Jeff Vetsch, U of M researcher (Waseca)
  • Fabian Fernandez, Extension nutrient management specialist (St. Paul)
Additional resources:
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What is UMN Extension Nutrient Management Podcast?

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:
“Title in sentence case”

September 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 University of Minnesota Extension's Nutrient Management podcast. I'm Jack Wilcox, in communications here at Extension. Today's episode is our annual Fall Fertilizer Outlook. We have four panelists here with us today. Could you each please introduce yourselves?

Dan Kaiser:
This is Daniel Kaiser. I'm a nutrient management specialist located out of the St. Paul Campus. I work a lot with phosphorus and potassium and soil testing, which is I think an important thing to be looking at right now with the way fertilizer prices are at is getting those fields tested to see where you're at before you start making some decisions this fall.

Brad Carlson:
Brad Carlson, extension educator out of the Mankato Regional Office, works statewide extensively with a lot of nitrogen issues.

Jeff Vetsch:
This is Jeff Vetsch, I'm a researcher at the Southern Research and Outreach Center here in Waseca and primarily do research in nutrient management in corn and soybeans.

Fabian Fernandez:
Hi, I am Fabian Fernandez, also a nutrient management specialist located in the St. Paul Campus with research and extension responsibilities, and I work primarily or exclusively, I would say, on nitrogen management for corn cropping systems.

Jack Wilcox:
Okay, if there was one word to describe the growing season in most of the state it would be “challenging”. How do things look headed toward harvest?

Jeff Vetsch:
Well, the good news is Southeastern Minnesota looks really good, especially corn. The corn research studies I have there, primarily nitrogen studies, they have really good yield potential, 240 or greater. I think there's going to be combines that are going to be going through the field that are going to hit 300 over there. We did do some SPAD meter readings at R1 on our sites over there, and three of the four sites looked like they were going to respond to split application of nitrogen. Interestingly though that the crop today in that region looks a lot better than it did at R1, and I think that's pretty typical across Southern Minnesota because it was just so wet early throughout May, June and the first half of July.

Unfortunately, South Central Minnesota does not look as good as most people know. It's quite variable, lots of drowned-out areas, dead spots, but there are some good corn and beans and I've seen corn improve considerably here over the last three to four weeks in our area, but unfortunately, all these bare dead areas are going to drag field averages down, so I would expect less than long-term average yields for corn. Soybeans are always hard to tell. Visual and deficiency symptoms were really common in end-rate studies here at the SROC, studies that Bobby and others are doing and others are collaborating on. Some of these data visually would suggest back in July that we'd maybe lost as much as 50% of our pre-plant applied N. I will though say that these areas have improved, especially over the last month, but recognizing that our May and June were extraordinarily wet and we had a significant amount of end loss.

Due to those end losses, we started a couple of supplemental end studies on July 11th when the corn was about B12. Both visually responded and looked better with the 40 pounds of N applied at that late sidedress. It'll be interesting to see what the yields are on those here in about a month. Corn maturation in South Central Minnesota, and I would say throughout most of the states, at least a week behind normal and probably two weeks behind last year. Our mid-April planted corn is about a quarter milk line for most hybrids and our May plantings that are full season or mid-season hybrids are just full R5 or full dent, but a lot of these hybrids still do not show a visible milk line. Typically, we'd be expecting a quarter to a half milk line already at this point in the growing season, so we'll see. It's going to be a little later and going to be a little wetter crop to harvest when it comes to the corn side, anyway.

Fabian Fernandez:
The general thing that I've seen South Central, Southwest Minnesota is that a lot of the yield potential was reduced because of the really wet conditions early on, whether it was nitrogen deficiency or poor root establishment, poor crop development. Then because the summer has been fairly consistently, getting rain very consistently and cooler temperatures, but no, extremely cool. I think there was a lot of mineralization happening later in the season, but the challenge of course, is that you are already sitting at a lower yield potential and so those crops will not recover.

That's what I've seen in general for those parts of the state. Then the other one that it has been interesting to see, I lived in the Northwest Metro where we have a lot of sandy soils is that, I mean a lot of people irrigate, but then there is quite a bit of corn that is not irrigated as well and that corn actually looks phenomenal this year because of all the rain that we have received in most years. You need to irrigate to get good yields in sandy soils because we run a deficit, but this year with the pretty evenly distributed rainfall that we have through most of the summer, some of those fields, non-irrigated fields actually look really, really well.

Brad Carlson:
I think another thing, and we were kind of talking about this a little bit in the middle of summer is obviously, we saw a lot of nitrogen deficiency on account of how wet it was. We've talked for years about the loss processes of nitrogen being water-based and so we had some fairly extreme conditions for that. We did expect that when the summer got a little warmer here that the mineralization would kick in and the crops would look a little better. They did, but I expected it to regress a little backwards again as we got towards Labor Day. That also has happened in some of the worst areas, which is right where I live. I think it's worth noting that we know that the corn didn't root very deep on account of how wet it was, and so we're probably not accessing the full amount of nitrogen that might otherwise be available in the profile.

In addition to that, I think it's also worth noting, it's been relatively cool this summer. I mean we only reached 90 degrees just a couple of times and then as of late, it's gotten really cool. We've throttled back on the amount of mineralization. We're not pushing the crop very far as far as getting hot during the day and then a lot of those drown-out areas, well for one thing, a lot of those areas drown-out twice, so a lot of farmers got in there, planted some soybeans in there and then they drown-out again. However, some of those areas that didn't get drown-out the second time, a lot of those replant soybeans just never got very tall. I think that was again, was just a factor of the weather just being cool this summer. I've seen a lot of those replant soybeans, maybe only about eight inches tall, they're really not going to produce much this year.

Jack Wilcox:
Most of the state went from being too dry last year to too wet this year. How should this affect the approach to fertility management?

Brad Carlson:
Well, I think people that listen to a lot of our product know that the last several years we've been beating the drum on residual soil nitrates, and that's because we had three relatively dry years in a row and that's the conditions under which we accumulate nitrates and then they just get held in the profile. They stay in the profile because there's nothing to push them out, so we've been talking about that. That certainly is not an issue this year with as wet as it's been, we don't anticipate there being a lot of residual soil nitrates, so that's not something to be looking for. I think the other thing is, I guess I've talked most of my career about the benefits of doing a debriefing on your crop when you get to this time of the year as far as when things don't look great, what caused that.

We've talked a lot about different management practices, how you can get away with a lot of stuff when it's really dry and then things don't look so good when it gets wet. Fall nitrogen application in general for a lot of the state is okay. However, we do know that when it gets extremely wet that, that's a practice that tends to lag behind. A lot of the data we've had over the years at Waseca has shown that where maybe it's all the same three out of five years and then two out of five we get some yield reduction with that fall application. Similarly, you think about other practices you might've done relative to timing and product and so forth, and so I think it's worth looking at that. Another X factor that I hear a lot of farmers talking about was that there was a lot of difference between planting date, nothing you're going to do about that.

However, it's important to keep that in mind if that was a factor in your crops that, that's not really much you're going to manage your way around, so just disregard that as far as what you experienced this year. Then I think the other thing is as we move forward here, we're at the time of year where there's starting to be a lot of conversation about booking fall fertilizer, and so it's time to start looking at some of those practices and then deciding again, whether fall application worked or whether you had some problems. We've talked for a long time about the areas that are most prone to loss, that being lighter-textured soils or areas that are very wet avoiding fall application. This was a year where that probably set itself up as being a problem.

Dan Kaiser:
If we look at some of those areas, Brad, in Central Minnesota, we talk about residual nitrate. The only areas I would likely expect to be some potential if you've got some of those drowned out areas that nothing was growing out there, certainly there could be some residual there, but I agree with Brad. We've been beating the drum on looking at residual fall nitrates and this isn't really going to be the year in many circumstances where we're going to have some residual. Maybe some inert ground would be some area to look at. There's been some interesting things though, especially as of late, having some questions from growers on some yellowing of beans, just some things going on where we're dealing with some of these wet soils lag into August. We're seeing some problems, although a lot of the issues I've seen have started to green up.

A lot of questions this year on things that don't look like stereotypical nutrient deficiencies but might be nutrient related, but it's really hard to say. Really, this thing was a good year if you saw some stuff happening in fields to look at things like tissue testing or something to look at comparative samples in some of those areas to try to figure out what's going on. We'll see what happens next year really on the P&K side. Really, it's nitrogen that's been more of the carryover aspect where we see some of that residual. We do expect some P&K to carry over, but I wouldn't really make any changes at this point just based on what's happening out there. I think we had a talk here a little bit about prices here. I think that's going to be the main question going into this fall is going to be some of the pricing. Looking at a lot of the stuff, I've seen sulfur, we got a lot of questions this year on sulfur just with some of the wet conditions.

I think nitrogen was our larger issue and if we did see any problems with some of these other nutrients that potentially a lot of it was probably related to nitrogen deficiency and uptake of those nutrients. The interesting thing was on, as Fabian was mentioning on some of the irrigated sites is some of our irrigated, we've been running the irrigators a lot the last two years in some of these fields and I've seen some things that pop up that I haven't seen in the last couple of years, particularly nitrogen deficiency with the leaching. Normally, we get some nitrogen through the well water, seeing a little bit more of that in some of my non-nitrogen studies, unfortunately, and sulfur deficiency this year. A few things that kind of interesting this year when you go from that dry to wet, what you see with that, and I think it's an instance where looking at some of these other tools may have been a good option to try to figure out what's going on.

Fabian Fernandez:
This year compared to the last couple of growing seasons, I think we are back to what we normally say normal for nitrogen. I don't think there is a lot of residual. The caveat here will be those fields where the yields are low. As we mentioned earlier, there has been quite a bit of mineralization, but the crop was not really able to make that into yield. The yields will be low, but the nitrogen is definitely there in those fields. I have seen some corn that looks really great, very green, but the yields are probably still lagging. That's clear evidence right there that nitrogen mineralized, the plant used that nitrogen, took it up, but it's not able to really make much yield with that because he came later. That nitrogen will be available, but I would say for the most part, there is not really a lot of residual out there.

If you do expect to see residuals in those lower-yielding fields, then maybe taking a look at how much nitrogen is there is probably a good thing. Again, as Brad mentioned, and I want to mention again, be cautious about fall nitrogen applications, the potential for loss is fairly large in most years. The last three growing seasons were dry, and so people start to get a little lax on that and feeling like, well, it's not going to go anywhere. The reality is that more often than not, applying in the fall will result in nitrogen loss, in some nitrogen loss. If you have residual, that will be definitely an area where I would say don't look into a fall application, wait until the spring to do the application because as we have mentioned many times, there's not a lot of nitrogen need early in the spring. Typically, what the soil provides through mineralization or any small amount of residual is sufficient to get the crop going in the spring.

Dan Kaiser:
This will be an interesting year though, I think. Talking to some consultants and growers, just the attitudes toward farmers towards some of those supplemental end applications, there's a lot of times when I heard people say, "We're not going to make the yield with this, these additional ends. I'll take the insurance payment and be done with it, not put through any more of this crop." It'd be interesting this winter to go around and hear some of this from growers, but also some of Jeff, what you're doing with that supplemental end trial to know whether or not they made any difference. I mean if you look at the years, this is a year that I would think that you could make some difference, and that's just because we've gotten more consistent moisture to get the nitrogen to the roots.

Because I think where we tend to fail a lot of times with these rescue end applications in some of these years, it just gets too dry and it just sits there and it just doesn't get taken up efficiently by the plant. It'll be interesting to see what happens because that's one of the things you see a lot of people talk about and really pushing for more in-season N applications. There's a lot of assessment you've got to do in these years to figure out whether it's even worth it. Just that price attitude was the interesting one this year because I don't think I've come across a year where I've heard a lot of growers or consultants talk about just not going in and putting supplemental N on, and just that attitude where people don't want to throw a lot of extra money at this crop was really different from what I've seen in some of the years past.

Jeff Vetsch:
Yeah, that's a great point, Dan. I think a couple of things that come into play was so many of these fields, they just couldn't get in them until so late. We did this, we set these studies up on June 11th and 12th and applied N on June 12th, and that corn was B12, B13, already chest high. You start to wonder, am I going to get a return on investment? Especially like you said, if it stays dry after that and you don't get that end in the profile. We did get a little bit of shots of rain to get it into the soil, and then about 10 days later, we got a significant amount of rain to make sure that it was in the rooting zone where the plants were taking up roots. We had two rates, I don't see big differences between the higher rate. I don't think that's going to give us an added benefit, but it'll be interesting to see when we harvest them, if we get a return on investment. I think we will base it on how they look, certainly at the lower rate.

Dan Kaiser:
That's an interesting point, Jeff, because you look at some of the earlier points you're making where you think that we lost close to half of our nitrogen with those lower rates, that isn't half the end. 30, 40 pounds is typically a good target number for much of these rescue end applications. It's one of those things that there's a lot of things that we don't probably know where that nitrogen is. It might still be accessible, some of it, but just what you can do with a lower rate and not have to worry about putting some of these high almost full N rates on in season, it's amazing what you can do.

Fabian Fernandez:
I was reminded when Jeff was mentioning some of these effects of two studies that I think are contrasting in the fact that one has mineralization potential, the other one doesn't. We have a study in Becker and one at Rosemount, and both soils are highly leachable, they have high drainage, but the one in Rosemount has more organic matter, more potential for mineralization. The one in Becker, by early July, mid-July, there were substantial differences due to the source of nitrogen that we had in there and the rate of nitrogen. At Rosemount, by the end of July, I could hardly tell the check compared to anything else with no nitrogen.

Later as we progressed through a August and the crop was taking up nitrogen, then you started to get more of a differentiation of nitrogen rates where the lower rates were starting to show the efficiency. That, I think illustrates an important point that we saw this year is that the fact that there was enough precipitation there, enough heat to produce all this nitrogen that then the crop took up later in the season. I'm actually not surprised, Jeff, that what you mentioned, that maybe the higher rate of that rescue would not necessarily make much of a difference because you have that additional buffer with whatever is mineralized in those systems.

Dan Kaiser:
Well, and I think a little context, Fabian, in Rosemount, I know they hadn't run the irrigators up through around the first week of July yet. We had hybrid rye out there and I haven't looked at that data. That hybrid rye yielded between 130 and 150 bushels on that irrigated ground, and I put it there because I wanted another irrigated comparison and they never had to irrigate. It's amazing when you get the consistent rains and you don't get the flooding rains where it's ponding in these fields, what we can get. I'm intrigued, particularly the corn yield this year and also, the soybean yield, just to see what we're going to get off of some of these studies here when the combine start rolling here in a few weeks. It's going to be interesting to see what we're getting because I was getting sick of the dry years in dealing with some of that. It was getting pretty severe in some of the areas with some of the yield depressions we're seeing because of the drought the last year or so.

Jack Wilcox:
Let's talk about farmers' finances. Crop prices and overall farm profitability have been cycling downward. What role will fertility play in sound financial management this fall?

Dan Kaiser:
Well, Jack, that's a depressing topic to bring up at this point. Looking at the numbers, I know we're sitting here the first week of September, 2024. Just pulling up some of Russ Quinn's data off of DTN, and this is from the 19th through the 23rd of August, 2024. If we look at prices, normally what we like to see is if you look at your commodity prices, the price ratio of about 0.1 with whether it's nitrogen, phosphorus, and potassium, and you certainly look at potash and look at some of the anhydrous numbers right now, you're pretty close. The one that's really out of balance really when it comes to the price ratio is phosphate. That's I think one of the ones that I've heard some rumblings from some consultants and growers about a lot of discussions going on right now when it comes to MAP and DAP for the fall because just some of the numbers that Russ has, if you look at $816 per ton map, if you're not factoring in any of the nitrogen with that, you're looking at around 78 cents per pound P205.

We looking at a price ratio of close to 0.2 with where the current corn prices are for Southern Minnesota. That's one that it's going to be some interesting discussions. Interestingly, I was at a meeting over the summer and had several older and younger farmers there and had an older farmer get up in the front part of the meeting and they're asking what the secret is to raising high yields, and his message was not cutting back in inputs. Then we get towards the end talking to the younger farmer, and you can see there's a real dichotomy in where the younger farmer, really it was more of a return-on-investment type issue, was really the message from him with a concern. I don't know, especially if you're running ground right now, how do you balance things out with return on investment? Really, I think the bigger key is to look at where you can cut.

Now, I'll get on my soap box here and I've been talking about this for a number of years, and really to me, the easiest out of all the fertility to cut at this point is phosphorus, particularly if you've got soil tests and you've been keeping your soil tests up in that high to very high range. We know there's a very low return on investment, so putting on a removal rate, phosphorus really doesn't pan out, particularly if you're looking at some of the prices where we're at right now. If you've got manure, you've got a cheaper source, I think it changes things a lot. If I look at the numbers and I look at the data, I've got far more confidence in the soil test data we have right now in assessing where or where we don't need phosphorus. To me, as I said, that's the easiest one to cut. I know, Jeff, I think you've got a couple of other thoughts as well, correct?

Jeff Vetsch:
Yeah, I do, Dan, and I totally agree with your phosphorus contention. I've been preaching that too for a long time and it falls on deaf ears. Most of our fields, they get crop removal now, and if you've been doing that, it's very likely that your soil test phosphorus is very high and you can get by without it for a few years. Other places, I think you could save some money is probably maybe not applying liquid zinc fertilizers, they tend to be kind of spend-y. If your DTPA soil test zinc is below 0.6 part per million, try consider applying zinc sulfate instead and just applying it where you need it.

You get a lot more zinc for your money and it's probably going to give you a better chance for return on investment than these zinc liquids. Also, some of these low-salt liquid fertilizers are pretty spend-y compared to their counterparts, the cheaper liquid starters, like 10-34-0 and 6-24-6, and then recognize that you can get by with pretty low rates and still get a good starter response. Three, four gallons is probably all you need in many cases, and the starter fertilizer is way more expensive than dry fertilizers. Those would be my key points, and then the importance of soil testing now more than ever, especially going into a year like this year.

Dan Kaiser:
Well, I had a question too from a consultant in southern Minnesota recently about some of these phosphorus solubilizers, including them with your fertilizer, try to increase availability. It doesn't make a lot of sense to me in that case to do something like that with an improving product, even though the promise is that you get higher availability. Because even if it's $5 an acre for something like that, just invest it in more phosphorus. It makes more sense, it's going to have a higher ROI. It's those kinds of things. You've got to look at these things that aren't necessarily critical from it, because I mean, really if you look at what the seed cost is, if you've got land rental, that's a pretty significant chunk right there of your overall total profit, and then fertilizer is up there too. It's just amazing what will be spent on fertilizer, and I don't think we can cut nitrogen. There's situations where we can cut sulfur.

I think we can be better at rates. Fabian, I think you probably have some comments on that. We know that the ROI on some of these nutrients really are likely going to be more than certainly with phosphorus and potassium. Potassium right now, looking at the numbers of potash with what Russ had, it was close to 40 cents a pound per unit K20, so it's a lot better. It's almost half the cost per unit versus what you would've for phosphate. You can bring those numbers of phosphate down slightly if you factor in the nitrogen, but I don't know how many growers are doing that. That's one of the things that it always bothers me a little bit when we start talking about fall-applied MAP and DAP, is that the nitrogen there, isn't it available? When it comes down to it, to me, added expense if you're just replacing it with some other form in the spring. Fabian, I think you had some comments on the nitrogen side that you want to cover.

Fabian Fernandez:
As you said, Dan, nitrogen is the one that doesn't get cut and there's a good reason for that. Crops are very responsive to nitrogen. We need that, it's one of the ones that will make the most money. What I say, especially in years where things are tight is well, make sure that you use that nitrogen in the most efficient way. We touched on earlier about fall nitrogen applications, for instance. We have done so many studies comparing fall versus spring. At best, fall applications are as good as spring applications, but more often than not, they are lower than spring application. We have compared applying nitrogen in the fall with an inhibitor to protect the nitrogen, of course that adds cost. Those applications with an inhibitor in the fall typically are lower yielding and more costly than a spring application without the inhibitor. Again, weighing your options, what is the fertilizer costing you in the fall versus the spring, and what is the potential return that you will get on that? What is the potential for nitrogen loss that you will have?

Of course, nobody knows what that loss potential is, but that's where you have to go by what is typically happening. What I can tell you is that typically, you will lose nitrogen, and so being really cautious about those fall applications. Then the other part too is the source of nitrogen. We have beaten this to death already, this topic of fall urea in the southern part of the state, it's just not an option. If you are thinking of doing nitrogen applications in the fall, the only source that I would recommend is anhydrous ammonia. If you can use an inhibitor, a nitrification inhibitor, even better, but nothing else. Urea, you are going to lose nitrogen, you're going to lose profitability, and so making those decisions, you are not going to be cutting your nitrogen rate, but making sure that whatever you apply is in the best possible time and in the best possible form. It's extremely important always for environmental reasons, but in years like now, also for profitability reasons as well.

Brad Carlson:
I think a lot of people that consume our products, our blogs and other things have heard me talk about the analysis of adult farm management, economic crop budget numbers in Minnesota and just remind everybody that the least profitable farms over the last decade have spent anywhere from 10 to 30% more on fertilizer than the 20% most profitable farms. We're not saying don't apply necessary fertilizer, but clearly, the least profitable farms are doing practices are over applying and just simply wasting money. There is such a thing as buying inputs that just simply aren't returning in investment.

Jack Wilcox:
Are there any closing thoughts or are there any pieces of advice you'd like to give growers as we head into the fall?

Dan Kaiser:
Well, I'll reiterate some of this comments. I think with P&Ks, especially phosphorus soil testing, is a good option. You look at, yes, it's increased in price, but certainly, if you can save yourself a little bit on the phosphorus side, I think you can more than make up with it. For those that have just been strict removal year after year after year, we talk about this a lot, consider the soil to be a bank, which it's not really yet good of a bank of phosphorus. It does hold it, but it's one of those things that looking at in terms of building, it makes sense to build when the fertilizer price is cheap to get it to a point where you can weather some of this. Looking at it in terms of applications, it's why the recommendations I have in place looking at are looking at percentages of removal once you get to a certain point. Because we know that you can put on 40% or less of removal for a two-year corn, soybean situation and not see your soil test crash.

I think that's a lot of the people's fear is that especially farmers that have been around for a while who are dealing with soils initially when they started farming that were very low in some of these available nutrients that they're worried about them crashing back down and losing all the effort they've had to build these to the levels they're at now. The thing about it is it just doesn't move that fast. That's the thing that if there is some hesitation, 50% or less of removal isn't a bad option. It's still probably not going to be economical, especially with phosphorus if your situation is if you've got a Bray soil test of 25 or higher. I think it's better off than just going up strictly, particularly if we have high yields this year.

If we have high yield again this year in this fall in some of these areas, removal is going to be relatively high because that's all linked. It's one of the things that just being a little more moderate on some of these, it's not an exact science that we need to manage, particularly phosphorus down to the pound that's come off the field and be able to hold the soil test where you're at. I'll get on my soap box here on that, but I'm sure a lot of people think I'm crazy because phosphorus makes yields, which we know that's the case. In most cases, most of these guys with these removal systems, they're just putting back what the crop is taking out of the soil.

In terms of the overall efficiency of the fertilizer being applied, it's going more into that cycling aspect of the soil versus need by the crop. I'll get on this year, I'm sure we'll talk about a lot of this, this fall, and a lot of guys will walk away from these meetings saying he's crazy, he doesn't know what he's talking about. I've been doing this for 17 years, and looking at it, if you look at our data versus data across the Midwest, it's pretty similar when it comes down to it. You get to a certain point and there's certainly areas where it makes sense to cut back and under some circumstances.

Fabian Fernandez:
I will second that then, Dan, even though I work with nitrogen now. When I was in Illinois doing P&K work, that's exactly the same. The same thing that you've being saying here, I was saying in Illinois. It's pretty consistent. With nitrogen, the one thing that I just want to mention as a closing remark here is that at the university, we are doing a lot of research to try to give you the most up-to-date information. The nitrogen rate calculator is a really good resource in terms of determining the nitrogen rate that you need to be profitable. I strongly encourage people to look at that when you're trying to decide which rate of nitrogen to apply. Using that calculator can help you tremendously to know how much to apply.

The economics are there, the agronomic data is there to back those numbers. In nitrogen, there is a lot of inconsistency with a lot of things, but when you start to put all of these inconsistencies together, you start to see a clearer picture of, okay, within reason, it's not perfect, it's not a perfect science, but within reason, where is the optimum? You start to see that once you go above that optimum, you are not increasing yields, you're putting more nitrogen that is costing you money and not helping you improve your return on investment, actually reducing that investment. I would say regarding that, we continue to do a lot of work to continue to update this calculator with new data as we see issues.

For instance, the south-central part of the state, we are certainly seeing some issues over the last several years where it seems like the nitrogen rates are higher than what we would expect. We are currently doing some work with that with Jeff. We are looking at different nitrogen sources as a way to see if we can explain some of these differences, why we are needing a little bit more nitrogen with the spring applications. We are comparing anhydrous ammonia to urea as a spring application right now to see if some of those differences are caused by the source. Again, a lot of work, a lot of research going into this calculation so that we can provide you with the best possible information out there, so take advantage of that.

Brad Carlson:
I just want to remind everybody that all the water quality issues are still out there. We're going to see the revision of the state's nutrient reduction strategy show up next year in 2025. There's going to be a lot of attention paid to the contributions that agriculture is making to nitrates in our surface water. We know that the issues in Southeastern Minnesota have been accelerated because of the petition that was made to the EPA and the request for the state to do more with groundwater down there particularly, but ground and surface water are all intertwined, and so a lot of that stuff is going to cause problems for us as an industry.

That starts with just simply making better decisions. As we're headed towards fall here, there's places that fall application aren't advised. We said it already multiple times, we don't like fall urea across most of the southern part of the state. If you're using excessive rates and you're booking nitrogen and saying, "Well, I'm going to put on a little extra because I put it on in the fall and I'm going to lose some." Those are all things that are going to eventually come home to roost. At some point we really just need to start tightening up that management because we are going to bear the consequences of it.

Jeff Vetsch:
If you haven't soil tested for a while, there's still plenty of time yet this year, this fall or even before this crop gets you start harvesting. If you have a soil test and you already have your soil test results, consider taking those soil test results to an independent crop consultant and review them with a crop consultant and review them with your seed agronomist. I recommend doing this before you go talk to your retailer, your fertilizer retailer or fertilizer agronomist, and it's just always good to get a couple of different eyes or a different opinion based on that information and their recommendations.

Jack Wilcox:
Thank you to our guests Jeff Vetsch, researcher at the Southern Research and Outreach Center, Dan Kaiser, nutrient management specialist, Fabian Fernandez, nutrient management specialist, and Brad Carlson, Extension educator.

Fabian Fernandez:
Thank you, and glad to be here.

Brad Carlson:
Thanks everybody.

Before we go, if you have a question or comment for one of our guests or a topic you'd like addressed in a future episode, please email us at nutmgmt@umn.edu. Thank you. We look forward to hearing from you.

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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