Cation exchange capacity & nutrient management: What does the data say?
Welcome back to University of Minnesota Extension's nutrient management podcast. I'm your host, Jack Wilcox, in communications here with Extension.
Jack Wilcox:Today on the podcast, we'll explain cation exchange capacity and cation balancing. Balancing. Complex topic, and we're glad to have three guests with us today who know a lot about it. Could you each please introduce yourselves?
Daniel Kaiser:This is Daniel Kaiser. I'm a nutrient management specialist. I specialize in commodity crops, nutrient guidelines, and I'm located at the U of M campus in Saint Paul.
Fabian Fernandez:Hi. I'm Fabian Fernandez, also a nutrient management specialist at the University of Minnesota located in the Saint Paul campus. I do research and extension work related to nitrogen management for corn cropping systems across the state.
Carl Rosen:Hi. I'm Carl Rosen. I'm extension soil scientist at the University of Minnesota, and I work on nutrient management. I focus a lot on irrigated crops, but I also get get into other agronomic cropping systems as well.
Jack Wilcox:Let's start off with just a general simple definition. What is cation exchange capacity, and what is cation balancing?
Fabian Fernandez:For the listeners, you know, trying to figure all these things out, I would not be surprised because if you if you come to the university and you take classes, you will spend a whole bunch of time. I've taken some so chemistry classes where basically the whole semester, we were more or less talking about CEC and how it works. And so it's very complicated. Really and truly for the purposes of this podcast, important thing to keep in mind is the CEC helps you determine the holding capacity of positively charged ions in the soil. And, typically, the higher that CEC value, the more nutrients you can hold and the more fertile the soil tends to be.
Fabian Fernandez:But the other part that gets confused sometimes with these balances and things like that is that I think people forget that plants have active and passive uptake mechanisms. Just because a nutrient is in high concentration in the soil, it doesn't mean that it will just, you know, passively get into the plant. The plant has the ability to determine what nutrients it needs. This whole idea of the, the balance of different cations in the soil, I think it's important to a certain degree. But, the only place where it really becomes a problem is if you are way over fertilizing, like tons of fertilizer of one kind and not applying something of the other nutrients where you can really create a huge disparity, that could be a problem.
Fabian Fernandez:But, you know, in agronomic settings where you're applying, you know, normal amounts of fertilizer, that balance is not a challenge because, again, the crop can discriminate on what it needs, and it will take what it needs, not just because it's available. It will just end up in the plant. The plant will will determine what it needs, and it will it will just take that.
Daniel Kaiser:So, yeah, Fabian, there's some good points there because, you know, by by passive uptake, what we generally mean by that is, you know, the plant, we see this with sulfur and nitrate, where the the crop is just taking it up, whatever's there that's dissolved in the soil solution. So if it's there, it's taken up. And we know that, you know, particularly with potassium too even though that, I think some of that might be inactive. I can't remember if that's active or passive or what it is, but there's this concept what we call luxury consumption essentially where the plant, if it's there, it takes it up. It doesn't really limit itself.
Daniel Kaiser:So it has the ability, to take up higher quantities than it than it actually needs. So that is, you know, something you kinda think about, especially with some of these higher application rates that many cases that, you know, even in situations if the we don't increase yield, we can actually uptake and removal of some nutrients because the plant just will take up more than it effectively needs. But, you know, this this this balancing issue really is it's complicated. And, you know, we could probably could talk for quite a while about the chemistry as Fabian said because we spend a semester usually talking about these things when it comes to, taking classes on these particular topics. But, you know, Carl mentioned, you know, calcium, magnesium, potassium.
Daniel Kaiser:You know, One of the the issues that a lot of people I mean, when you're trying to change some of these ratios, it's it's not as simple as some people might think it is. And some of that has to deal with, the cation exchange capacity and the fact that some ions, calcium, magnesium are, you know, prefer I don't know. It's preferentially selection or it they're they're sorbed. They have they tend to be sorbed more than potassium, and it affects essentially, if you add one, it can affect how others are sorbed. And, I mean, it's complicated.
Daniel Kaiser:And and I guess really is the key point that it's not easy to change these things. One major comment or question I get from a lot of growers in Western Minnesota is growers that have high mag contents of their soil. They're really worried because there's a lot of information out there about mag and lower yield. And, you know, we know there are if you look at magnesium and and potassium, there is a relationship in uptake where potassium uptake tends to go up. Magnesium goes down.
Daniel Kaiser:I still don't know if there's much out there telling us, you know, what drives what. Is it MAG driving potassium or potassium driving MAG? It seems to me always, when I look at my data, it's more of a a potassium uptake thing than than magnesium, but it's you know, people look at these ratios and and try to and really change these things, and I don't know how physically you do it because if you get soils with a high canine exchange capacity, they're what we called highly buffered, or they they really are are hard to change. That's kinda what we call the buffering capacity is the the ability to change these soils that you need to essentially be able to displace these ions one for another, but then they try to leach these things out of the soil, which isn't easy. And that's kind of the thing when when I always start talking to people about these things is that really, I mean, yeah, it might be possible to do it, but the actual investment you would have to do to make these things is pretty substantial.
Daniel Kaiser:And I'm gonna talk here a little bit later about potassium because I've got some some data in looking at this this case saturation ratio stuff, and so I'll talk about that here in a little bit. But, that's kind of the big thing. I mean, it's really magnesium is always looked at, you know, calcium. You add calcium. You tend to what I found is tends to drive some of the potassium off the CEC, so you get more of that into solution.
Daniel Kaiser:So the it isn't simple that we can easily change these things because you add as you're adding these these elements, particularly for liming, that can impact particularly for those that are trying to maintain these optimal k base saturation ratios. So I I guess the the main thing here is that it's complicated. It's more complicated than people think that, these things can easily be affected because they're typically if you look at your ratios that are in your soils, they're there because, you know, that was, you know, really, I think, more dominated by the parent material and what was there at the point those soils were formed more than anything else. And a lot of them are really based on the CEC, which you can't really effectively change. So so looking at that, these ratios, it's it's really hard to get these optimal ratios.
Daniel Kaiser:And, you know, the question is whether or not we actually need to.
Carl Rosen:Yeah. Just a quick, comment on, uptake and, versus the ratio. So as Fabian mentioned, plant roots are selective in what they take up. So just because those ions are in the soil, you will not take them up in the same ratio that they're in there. In fact, most plant roots will accumulate a lot more potassium, in the in this cell sap than they will calcium and magnesium.
Daniel Kaiser:The thing about, you know, some of our soils, if you look at cation exchange capacity, it's really related to texture. So, you know, if you look at we'll just go kinda the Anoka sand plane. You know, common we have is a Hubbard, which is a is that a loamy sand, Carl?
Carl Rosen:It's a loamy sand. Yeah. It's a Hubbard loamy sand.
Daniel Kaiser:So the your your CEC on something like that would be around, you know, around roughly five, maybe 10 would be probably really good. But a lot of times, you know, since we've got a lot of sand, your CEC should be dominated by the little it's a little clay that's there, but also organic matter. But if we get into, you know, some other areas of the state, like your silt loams, Southeast Minnesota, those, I mean, CEC maybe 15 to maybe upwards of 20. And then our our higher clay soils, especially in the central part of the state, are twenty twenty five, 30, somewhere in within there. So it it really I mean, clay is really the thing that dominates a lot of what we see, and it it affects the nutrient holding capacity.
Daniel Kaiser:And what it really does and what I've seen too for some of these basic cations is impact how well they're retained. And, you know, in fact, when we start talking about potassium, a lot of people would talk about potassium being a nonmobile nutrient where we don't get any leaching of that nutrient in the soil. But with these lower CEC soils, we know that there can be some movement because there just isn't the ability to retain it. And it so there's there's a lot of things when it comes down to CEC. It can it can impact in terms of of nutrient retention, but it isn't always something that we're we're focused on for nutrient management.
Daniel Kaiser:The exception that's out there, and I think that's kind of the major topic to talk about here really is when we start talking about cation balancing. And that's one thing I hear, from some groups out there, and a lot of it comes from there's a book, and I've got it by Neil Kinsey that I need to look back at it that looks at some older research that focused on balancing of the nutrients. And, specifically, what a lot of people focus on is what we call the the potassium, the base saturation ratio, which essentially is the, percentage of the total CEC that potassium is part of or any of these other nutrients. And, you know, the fact that there's some thoughts out there that there's this optimal ratio that we should have for crops, for them to get maximum yield. And I think we need to we we really hammer on a lot with in the soil fertility community is, we that we don't really use this particular type of approach for making nutrient guidelines.
Daniel Kaiser:And I'm sure, you know, that's gonna get a lot of hate from people in terms of the comments for this particular podcast because there's a lot of people out there that really buy into some of this. And, you mean, a lot of this data really goes back fairly old with, some of the this charge balancing.
Carl Rosen:It goes back, into the thirties and even before, you know, some of the work by Albrecht and Bayer in the forties came up with some of these concepts. One thing I did wanna, mention is that we measure, CEC in terms of, equivalence or milliequivalence. And so that's just referring to the, amount of charge that's in there. So when we say total cation exchange capacity, there's a certain amount of milliequivalents that the soil can hold on to, and then we're looking at proportions of that with the different cations. So a a CEC of five milliequivalents would be relatively low compared to one that might be up to 20 milliequivalents.
Carl Rosen:And that means the the one with 12 20 milliequivalents or 25 milliequivalents just has more clay or organic matter relative to one that has maybe, milliequivalents, but getting back to, how this whole cations exchange, capacity and ratios became popular, and a lot of it had to do with back in the thirties where they were looking at effects of calcium in the soil. And we know calcium is important, but calcium is also can be associated with pH. So the more calcium you have, you tend to increase your pH depending on the source of calcium. Most of the calcium that's added is lime. And so when they were doing these early calcium experiments, it sometimes got confounded because the pH was changing as well as the, calcium concentration or the calcium amounts.
Carl Rosen:So the the ratios got got, somewhat, distorted, I I guess, because you're you're confounding it with pH. And so those are some some things to take into account. It it's may not just be the calcium that's important, but you're also raising pH if you're using the a lime source to raise that pH.
Jack Wilcox:Dan Kaiser, let's talk about how cation exchange capacity is measured. Are those estimates reliable?
Daniel Kaiser:So there are a number of ways to look at cation exchange capacity to actually measure it. I mean, the the best way is the way we typically do it. It's it's more expensive in the lab, is called ammonium saturation and displacement. Essentially, what you do is you saturate the soil, the CEC with ammonium, then you come back in after that and then saturate it with another ion, I think, potassium that displaces the ammonium. Then you can measure the amount of ammonium displaced to get an idea of what the cation exchange capacity is.
Daniel Kaiser:And it's a rather laborious method that takes a lot of time. It is far more accurate, though, than what most labs do is what we call the summation method. Essentially, what they're doing is they're using a procedure like the ammonium acetate, which we use for potassium, or I think most labs actually are using the Mehlich three test. They're just using whatever they routinely measure with the Mehlich three, and there's some formulas that you can use to calculate the CEC based on the nutrients that are extracted by that test. The issue though is, particularly for those that have higher pH soils with a lot of calcium, that, the test can overextract calcium, so the formulas themselves that are used to calculate these summation methods aren't accurate.
Daniel Kaiser:So what you tend to get, you know, in soils with higher calcium contents, you get overestimates of the CEC, which is a problem because if you're trying to balance, the CEC makes a bigger difference when it comes to the ratios than anything else. So the if you're overestimating, particularly if you're overestimating high, you're gonna get a really low ratio, which gonna it's gonna call for a lot of lot of fertilizer to be applied to try to adjust that particular ratio. And I'm not saying that should they should be adjusting ratios. I'll talk about that here in a moment. I just think it's a waste of time and money to be looking at these things.
Daniel Kaiser:But, you know, the main thing is, you know, the question is really the accuracy of that CEC measurement because if that's not accurate, then you've got a problem. The recommended method is, you know, at least with the ammonium acetate procedure is that the labs adjust the pH of the extraction solution to a higher pH to try to avoid over extracting calcium. So you can get the number, and think most people will get a CEC measure on their soil test report, particularly if they're doing a complete analysis. And that's mainly because the lab is using a summation method off of the Mehlich three test, which most of the labs are running. So that's just really the problem on that is, again, if you're not estimating CEC correctly, then this whole balancing issue becomes moot.
Daniel Kaiser:I mean, it's really a waste of time because that's really the the the key is that is that CEC measurement. If that's too high, you're gonna be chasing things that you're likely never gonna be able to achieve.
Jack Wilcox:Fabian, let's switch gears for a moment. What's the research that ties cation exchange capacity to nutrient management?
Fabian Fernandez:I don't know if necessarily new research, but, I mean, we continue to do research, and everything we do with soil fertility relates in some way to the CEC of the soil. The main thing to be aware of is, again, as we talked about at the beginning, the basics is, you know, how much of the nutrients that you apply that are cations can be held by by the soil. And so soils where you have more cations exchange capacity tend to be easier to work from a fertility standpoint just simply because they they have a lot of buffer. They have a lot of capacity to hold nutrients, and, you can mess things up with your management and still be okay because the soil has that buffering capacity. When you have sores that don't have that kind of buffering capacity, then you have to be more careful in terms of of how you manage nutrients.
Fabian Fernandez:The one thing that I keep hearing is something that just reoccurs. Every so often, you get people talking about the importance of CEC for managing anhydrous ammonia applications. And the idea there is is just a wrong idea. It's just something that somebody came up with. It has no basis, really, is that the the soil can only hold, certain amount of anhydrous ammonia based on the CEC.
Fabian Fernandez:They they talk about CEC times 10 to calculate the amount of nitrogen pounds of nitrogen that the soil can hold, and and that's just not the case. This is important because of sandy soils. As we mentioned, they have typically lower CEC. And so if you make a calculation like that of saying CEC times 10 is a pretty small amount of nitrogen that you could apply before you start, losing some of that nitrogen. That's that's the the concept.
Fabian Fernandez:But, again, it just doesn't hold up. We've done research to look at that. And in sandy soils like a Becker where it's beach sand, you can apply a full rate of nitrogen with anhydrous ammonia. It's not a problem because what happens when you apply anhydrous ammonia is you apply an n h three, and it reacts quickly with water to transform to ammonium. And so more than anything, the important thing when you when you do these applications is to look at soil moisture and also the depth.
Fabian Fernandez:Of course, you know, if you have, in sandy soil, you have bigger pore space, and so it's easier for the ammonia that is a gas to escape to the atmosphere if you are shallow applying these these applications. So a little bit deeper application will take care of that physically because the ammonia had to travel a longer distance before it reaches the surface and escapes. And then the other part is moisture. If you are trying to apply anhydrous in a dry sandy soil, basically, that ammonia will have to travel a longer distance before it catches water molecule to react to it and become ammonium, and so you have more chance of losing nitrogen that way. But if you have adequate moisture, again, that ammonia is going to react quickly with water in the soil, and and it will be retained.
Fabian Fernandez:It's not going to be lost just because you have a lower CEC. So that's that's kind of the the main thing that, again, keeps coming back all the time about this the importance of CEC for anhydrous ammonia, but there's no base for that, really.
Daniel Kaiser:So I hear people talk about that just in in terms of all nitrogen sources. And I think as Fabian said, it's important to realize that, I mean, this came out of Illinois. There's I think nobody in the research knows where this number came from, and it was geared towards the pounds of an as anhydrous. Now I think the main thing to think about if you're looking at CEC for nitrogen management really is timing and really timing and split applications because, you know, certainly, a sand, I wouldn't, you know, go by how much you can apply or how much you would hold, but certainly, we're looking at split applications in those circumstances because low CECs do cause problems. They have better you're gonna have better drainage, and you won't you can hold ammonia, but, you know, still there could be some some issues with leaching just because ammonia isn't the the only thing on the CEC.
Daniel Kaiser:Because actually soils, you multiply, you take the actual actual formula, it can hold far more than 10 times the CEC potentially. It just I think it it's more of an issue of of looking at your timing of application more than anything else. I mean, big one I have heard really is this idea for potassium that, you know, that growers should be maintaining a k base saturation ratio of two. You know, I'm talking to some growers, more recently. They're actually talking now they're pushing them to maintain a k base at a four.
Daniel Kaiser:You know, you look at a 25, soil with a 25, centimole charge per hundred grams, 25 CEC, that would mean a soil test value of 400 part per million k, which is twice what we generally recommend at the point at which response stops. So, you know, I've I've got a study with AFRIC right now that's looking at potassium timing and rates. So I just kinda yesterday, you know, preparation for this, I just kinda went down the rabbit hole of looking at the CECs and the k based sats because I'd calculated them out, but I've never really looked at them to see, you know, what if any effect they have. So if we look at, I mean, the sites I mean, you look at the data, I mean, you look at where we're at for responses. I'll just the corn sites, I'll just kinda pick on those.
Daniel Kaiser:It's easier. I'm not gonna talk about the soybean sites. But if you look at the corn sites, there is, I mean, a direct relationship. And this is taking a sample in June after fertilizer application that, yield increases up to about a hundred part per million there. It tends to stabilize.
Daniel Kaiser:And since the soil test is part of the k base saturation ratio equation, the way you you calculate k base saturation is to take the soil test, you convert it to mill equivalence, and then you divide by the CEC that there's also a relationship with the k base sat. But, again, we're if you look at k base sat soil test, there's a direct relationship between the two. So if one affects yield, the other one's gonna affect yield. And, you know, looking at the numbers I had, I looked at the moist k test. I looked at the dry k test, and essentially at around a base saturation ratio of 1.1, yield was maximized.
Daniel Kaiser:You know, most people are using two or four. I think a lot of where that data is coming from is they're actually I'm using yield response, so I'm looking at a deviation from maximum yield instead of actual yield. The data I've seen, you know, posted online talking about this four number. There look there's a lot of points that, you know, what somebody did is they went and looked at the grid samples. They took the yield for each of those grids and then just plotted it with k base saturation ratio within a lot of those grids.
Daniel Kaiser:And the data that was presented, you could draw a line between a lot of the points. I mean, there was a lot of noise in the points, but, I mean, you could draw a line. But I also I was looking at that dataset, and something bugged me because you could see just breaks between sets of the points where it appeared like, essentially, it was three different fields that were measured that, you know, just by chance, the higher yielding field, which I bet was, you know, an irrigated sand because it's if I look at my data in my dataset, the only way to get about a four k base stat essentially was something with the low So my irrigated sand at Becker that had a five CEC, you know, there, it was we're at four. Everything else was, you know, about one to two within that k base saturation within the sites, and, you know, not all those sites actually responded to k. But, you know, and that's kinda what I'm wondering.
Daniel Kaiser:You know, a lot of the data now, it seems like people are just taking their absolute yield values within their particular fields and then looking at them versus the soil test values. But the problem with that is it you know, we can get into a whole another discussion on what we do for soil testing is there are a lot of factors that affect the yield potential within a given field, so you can't compare the absolute yield values and look at just all of your soil test values unless you know that what you're particularly looking at it is the only factor that's influencing yield. Otherwise, you get to the the situation where it's that old Liebig's law with if everybody kinda knows that where it's the, yield is directly proportional to the, whatever factors that's most limiting within a given field that a lot of people attribute that to nutrients, but you can throw water. You could throw pests. You could throw a number of other factors into that that set your overall yield potential that you can't just look at the maximum yield produced versus something like, the k base saturation ratio.
Daniel Kaiser:Because when I did that with my dataset, it there was nothing. It was just a it's a bunch of noise within that. But if I looked at it in terms of looking at my maximum or the the yield produced as a relative to the maximum yield produced within a field, then there's a relationship, and that's, you know, typically what we do. So, you know, while I again, I could go in and look at the k base saturation ratio and it does relate to the, you know, percentage yield produced, it's still just a proxy for my soil test at all these sites. So and if I look at it across my sites, my sandy sites looks like I might have a different optimal k base sat versus my nonsandy sites.
Daniel Kaiser:But, you know, what the common denominator across all these sites is when I get to a certain soil test, then my yield is maximized. So then in effect, I mean, essentially, the k base at really is relevant, and it's more of an issue with essentially where I'm at in terms of extractable soil test. And this thing, it just keeps having legs, and the thing that really irritates me just it really gets under my skin. It's like anything else with some of this is people talk about this stuff like it's new. Like, it's this that's this, this new, more advanced style of management and how to managing your crop nutrients.
Daniel Kaiser:But as Carl said, what? Thirties? A lot of that data for the when it first started. So, I mean, it it's it's nothing new. We just keep recycling some of the same thoughts.
Daniel Kaiser:And, I mean, a lot of this, I think, we're just at points in time where it's around when soil testing was being developed that we're just kinda scratching at ways to try to look at managing things and trying to balance a lot of these things. It really doesn't matter all that much or the numbers that are being used. It's just insane, I mean, in terms of the investment that you would have to do for potassium to get to a 400 part per million soil test. If you're out in Western Minnesota or, you know, Southern Minnesota, somewhere in those areas, I mean, you'd be spending thousands of dollars per acre, and you you may maybe you get back a couple bucks per acre, on that in terms of maximizing yield. So the thing is you need to ask questions in while it looks good when you look at some of this data I mean, really, the big thing I'd like to know, I mean, some of the data that people are using or what are some of the underlying soil principles.
Daniel Kaiser:You know, looking at the k base, it's it's it's a lot easier to change that if you can change the CEC, which you can, of a of a soil. But if you're, you know, looking at if it's underlying essentially that I've got you know, I'm looking at, let's say, an irrigated sand where I maybe add a k base out of four or four, you know, there's there's probably just an inherent higher yield potential just because of the irrigation and number of other factors, and the k is just it's just secondary to that that it's it's just more kind of that just by happenstance that it it it's higher and that it doesn't really affect anything. I remember my dad, going to some of these high yield meetings and where some of these growers that are growing, you know, 300 bushel corn were up there talking about everything that we're doing, and he was coming back and talking about just, you know, one thing that he heard from there that he thought we could try that, you know, it might not just be one thing. It's more complicated than we can just look at one factor.
Daniel Kaiser:So, I mean, I'll put the plug out there. I mean, if you go to the AFRIC website, our k timing trial, if you go into the section on potassium that this this k this potassium timing trial, and I'll I'll try to include some of that data if you really wanted to get into the weeds of this in terms of some of the things we're seeing.
Jack Wilcox:Dan, Carl, and Fabian, what would you like to leave farmers with as they are thinking about cation exchange capacity and their own nutrient management strategy?
Daniel Kaiser:I think the main thing for most people is, you know, a lot of these concepts, it's what I said before, you know, there isn't anything here, particularly with balancing, that's new. I mean, there's issues with some of the the stuff that was done in the past. There's as Carl brought up, you know, you I think you could argue some of the Albrecht data, essentially, what they were seeing in terms of yield increases may have been due to the the changes in pH more than the ratios themselves. So, I mean, you've gotta dig into this a little bit more in terms of of some of these topics because, you know, from all that we have seen that if you have a higher clay soil, that if you have a soil test of 200 part per million around that with potassium, there should be really no, need to go a whole lot higher than that in in to change some of these ratios. And, you know, what I've seen essentially is if you look at the soil test versus the ratio, the cation ratio, that there just really is is nothing there where the ratio is any better than using the soil test itself.
Daniel Kaiser:So, you know, that's kinda where I'm gonna leave things there, but it it's still gonna come up. And I guess and I said, we're gonna get some comments that people that aren't gonna agree with us that this is the new wave of managing things. But the, you know, the question for most of you is gonna be with fertilizer prices the way they are. And if crop prices are low, can you really afford to invest the kind of money that a lot of people are talking about to try to balance these things? Because the issue is you apply potassium one year and say, you know, if down the line you lime, then it's gonna you know, you're gonna be back at it again trying.
Daniel Kaiser:It's just gonna drive you crazy trying to manage these these ratios to these optimal levels, and that's it it just it's too much, I think, to invest for absolutely minimal gain to try to really start looking at these. Just look at your soil test. I mean, look at that. And then more often than not, that's gonna give you a good idea in terms of your availability and what you actually need with the field.
Fabian Fernandez:Yeah. Sometimes we tend to overcomplicate things, when in reality, a simple approach will just do it. As we talked earlier, looking at these ratios, it makes little sense because you have a soil plant system that it self regulates. Things in nature tend to go to an equilibrium. And so, just because you might have a different ratio in the exchange sites, it doesn't mean that you have out of whack concentrations of different nutrients.
Fabian Fernandez:You know? It's not like you will have only potassium in the solution or only calcium or only any other nutrient. You have all of them and they are in solution, and then they are in the reserves in the exchange sites. And so the plant uses whatever it needs. It will pick and choose whatever it needs.
Fabian Fernandez:It will deplete those concentrations in the solution, and then more that is in the exchange sites will come out of the exchange site to replenish that solution so that it maintains that balance. And I think we we tend to forget that when we start talking about these more complex in, quotation marks, approaches with balancing things in the soil when in reality, nature already is taking care of that.
Carl Rosen:You know, it comes down to economics a lot of times, and you start trying to change these ratios. You will be dumping a lot of fertilizer on and, also in other amendments, and, yeah, it will cost a lot of money, and you may not see a difference. As Dan mentioned, look at your soil test, follow the soil test recommendations in terms of concentration of the nutrient itself as opposed to the ratio with the other other nutrients in there.
Daniel Kaiser:The other thing too with potassium with these higher rates is you do have to be careful because I do have data showing yield decreases with high rates of potash, particularly on soybean. There are some unintended consequences some of this, and I've got some other blog posts if you wanna go back and talk about that. It's mainly on soybean. But just some things to think about with some of this that it isn't just all rosy that you can do these things where it may not actually have negative effects.
Jack Wilcox:A little bit of complex and a little bit of straightforward. Thank you guys very much. We appreciate all your information on this topic.
Carl Rosen:Thanks, Jack.
Fabian Fernandez:Thank you.
Jack Wilcox:Do you have a question about something on your farm? Just send us an email here at nutmgmt@umn.edu. Thanks a lot for listening, and we look forward to seeing you next time.
Jack Wilcox:We'd like to thank the Agricultural Fertilizer Research and Education Council, or AFREC, for supporting the podcast.
