Sarah, welcome back to the war against weeds podcast. This is Alyssa Essman, Weed Science extension specialist at Ohio State, and today my co host is Sarah Lancaster, coming to us from K State. How's it going Sarah?
It's fantastic Alyssa, we haven't blown away this spring yet, so we're still doing good.
That's all we can hope for as of today, the first day of spring. So Happy first day of spring. And as we kind of gear up for spring and planting and the weed management considerations that come with that, we're talking about a pretty timely topic today, and that's, you know, the use of fertilizers as herbicide carriers. And so we've got two folks here who can provide us some pretty great information
and background as we work through this topic. And so we have Aaron Hager from University of Illinois and Caleb Wepprecht, also from that program. So Caleb, you want to start us off and tell us a little bit about your background and what you do? Awesome. It sounds like you're the perfect
Yes. Thank you, both you for inviting me on here. I hope all of our listeners are gearing up for another spring, because, as always, it's sneaking right up on us. Once again, as Alyssa said, my name is Caleb Wepprecht. I am entering my third growing season as a field research specialist with Dr Aaron Hager here at the University of Illinois. Previously, I was a certified crop advisor for an independent retail fertilizer location about
an hour and 20 minutes or so north of Champaign. I worked there for five years, being involved in the mixing and blending of various fertilizers and pesticides. Found myself at the blenders and mixed bowl quite a bit. So that's why I was asked to be with you here today. Before that, I had received my bachelor's and master's degrees from Illinois State University
in Bloomington, normal. So that's kind of a little bit of background about host to tell us all about, uh, fertilizers as carriers, and then Aaron, you're, you're a repeat guest here, but you want to tell us and give the folks some reminders about what you
Yeah a lot of people ask me that, what is what do. exactly do you do these days? So no, my name is Aaron Hager. I'm the extension Weed Scientist here at the University of Illinois, and starting, I think, year number 32 here. So been a very, very interesting career, seen a lot of change over the time, and we'll talk a little bit about as we get into the conversation. Today. You know how we've actually seen the use of either fluid fertilizers as carriers or fluid fertilizers as
spray additives? Let's change a little bit over time. So looking forward to the conversation.
Awesome So thank you both for joining us, and we'll, start at the top here. So can you describe, you know, some of the types of fertilizers that are used as carriers in this way?
Well, the good news is, I don't have to talk about clay based Atrazine with 1034 Oh, that was something that had happened years and years ago when dry starter came off of planters. You know, before my time, but I certainly heard all the nightmares. But since that time, we've kind of focused on UAN or urea ammonium nitrate, 28% or 32% we're going to talk a little bit about ammonium thiosulfate, as we gain more acres, getting sulfur applied early on so but I would say
those are the main ones. When we talk about pre herbicide applications, they're 28% or 32% with a little bit of ammonium thiol in there as well.
They're historically now it's not very common practice, but historically there also has been impregnation on dry fertilizers. Now, again, that's a very, very less frequent practice relative to, you know, using the fluid based fertilizer, but in some applications, that was somewhat, you know, common, maybe I don't know, 25-30 years ago, relative to how it is
So in terms of commonality in those practices that are the most common, what? What do you see as being the most common products and type of application. Well,
Well again, I mean, it's, it's pretty common to see high, high volume of UAN being used pre the thing you got to watch with, you know, if you're adding ammonium thiosulfate, is compatibility in terms of, really your total volume of your tank. So I always use the 20% rule personally, which just means that you don't want your thiosulfate to be 20%
or higher of your total tank volume. But I've, you know, recently heard 10% and I've even had a few people tell me five, just because you can run into issues with mattressing based products and our corn pre mixes. So that's probably one of the main, main topics of this. I had two examples about that, actually, as I'm flipping through here, basically a little bit of background on the. Thiosulfate is it's a 12 oh 26
grade, and it weighs just over 11 pounds per gallon. So in every gallon of ATS, you are getting 1.3 pounds of nitrogen and 2.8 pounds of sulfur. So you typically see rates between two and five gallons per acre. But I've seen as much as seven used. I've used seven personally on my own, but mainly see ATS get added to our pre corn tank, mixes with UAN and whatever pre
mix you you so choose. You're probably not going to see it very much as a starter fertilizer due to the potential for seedling injury, but I have seen it used in a two by two situation at a lower end of the rate spectrum. Now, when you add it to your tank mix, and I cannot emphasize this enough, make sure it's added last. I don't care if there's UAN water, your herbicide, all three of those. Potentially, if you're trying to get to a specific rate, you're going to want to
add your ATS very, very last. And you know, like I said previously, you want to watch your volume. Again, I always use the 20% rule, but last year too, I've heard 10% and even some say 5% so again, what I mean by that is you can get in real trouble if your ATS volume gets over 10% your tank mix. So let's say you're spraying 50 gallons of 28% I would probably advise you not to put more than five gallons of ATS in that load. So it's not a given that you'll have issues, but it's certainly
a strong possibility. It has the potential to cause product layering, where, when the sprayer gets in the field, pulls in the field and takes off, making it's a B line, one of those products is probably going to settle to the bottom of the tank, so there's no even tank mixture at that point, which will cause issues of all kinds, obviously. So before someone counters that and says, Well, stir your tank, I would strongly advise against that as well. Typically, you stir your tanks
during post spray season, not so much during pre emerge season. A couple of years ago, for whatever reason, and it was early in the morning, but we had a truck driver that, again, for whatever reason, decided to stir his tanker that morning, and it had UAN was in there, of course, with ATS a 10% volume. I had to go back and look at that tank mix, and then Atrazine pre mix. And when he got to the field, we had some of the healthiest looking cottage cheese you could imagine. So I would strongly
advise against stirring the tank. I don't have any literature to support that scenario. I don't know if any university has ever done research on that, but I can tell you from my own experience, I would not stir the tank with ATS in it. So and the other thing I wanted to point out was we had a situation. So Bill Johnson at Purdue did a similar study to this in 2019 I believe it was looking at thiazol in your burn down tank mix for pre corn. So we had a customer that was strip
till non GMO corn burned down. And again, it was UAN ATS and a pre mix with burned down activity with a quarter round of Power Max as well. And he had come into the chemical shed, like seven or eight days after we sprayed it, and said everything was smoked except the downy brome in one field that was known to have downy brome pressure. Downey Brome can be tough to kill anyway. But I drive to the field, and you can
tell the UAM burned. It real bad. But, you know, you look at the crown of that plant, and those plants, they they were
green as could be. Then the real problem was, you know, by the time you figure that out, that, you know, your glyphosate was probably, you know, messed with by your ATS, that non GMO corn was emerged, so now we just bought 80 acres of accident Q, so you really have to be careful on on your volume of ATS with that so and that one again, Bill Johnson did a study on that, looking at wheat termination in the spring, and Pretty much reported everything that I seen that day.
Yeah, really good thoughts. There. You've brought up a couple things that kind of lead us into where we're going next year. So all of us look at herbicide labels a lot, and this is one of the things that sometimes we see on a herbicide label, one way or the other, right? And it's very dependent on what we're looking at. So can you walk us through some of the pros and cons, or the risks and benefits that come with fertilizer as a carrier versus water?
Well, I think timing wise, probably you know, if we're talking pre corn, I never you know did anything fertilizer, carrier on a pre bean situation, but I did, I did try thiazol once with two pints of boundary and six ounces of a generic self venture zone once. And you know, it was 15 gallons per acre total. So it was seven gallons of ATS and eight gallons of water. And believe it or not, didn't. Into any issues. There was no yield bump across that growers fields. But it's not
something I would recommend doing. I didn't feel that comfortable doing it, but we did, because he wanted to try it. But in terms of pre corn, it's really about timing. I mean, you look at your options, you could do fall, applied ammonia, you know, spring applied ammonia. If you can, you know, have the time to get in the field to do that this, this is one of those springs that we actually probably did have time
to do that, or still, still could. But it's really about timing, I think, you know, and in a burn down situation, it's probably going to help your herbicide activity on eMERGE weeds.
So, Caleb, I'm going to throw a little bit of a curveball, right? So I'm at K State, where the wheat state, how much wheat and feed do you guys do? I know you have limited wheat acres compared to what we have here, but you know, how much wheat and feed type of things do you have for top dressing wheat? And you know, do you see, how many like parallels or differences do you see between that scenario and a burn down scenario. Does that make sense? Yeah,
Yeah I think I know your estimates are, so I'll be honest my my herbicide activity on wheat experience is very limited. That was actually, I told Dr Hager yesterday. He probably knows more about that than I do, because we had sprayed, you know, we had sprayed plenty of nitrogen on wheat, but we never really ran into a situation where we had to, you know, put any two, 4d in, or anything that it's spring of 2019, of course, everybody remembers we had planned to do
that. And then, of course, it got wet. And then by the time we actually could, the wheat was, was way too tall to do. So I actually don't have a lot of experience with herbicide, you know, on post emerge wheat, when it comes to fertilize security. But I know Dr Hager does
actually, Sarah, when, when I first started here at Illinois, I think we had somewhere around a million acres of winter wheat here in the state. Now we're not anywhere near that, and still, the vast majority of the wheat grown in Illinois is grown in the southern, probably third of the
state. Well, that also happens to be an area of the state where wild garlic is very common, and so fairly common practice in those geographic areas where the threshold for garlic is essentially zero, given the potential for Dockage at the elevator when they when folks are top dressing their wheat in the spring of the year, usually, you know, UAN solution, they'll use either harmony or harmony extra. And with that UAN to try to control that wild garlic. Now either, they probably use both
about equally. But a couple of things to think about. You know, if you look at the labels of the products, they will tell you that if the volume of UAN is less than 50% of the total solution, you probably should add additional surfactant to it. However, if it's over 50% then the labels will caution you that you might actually see increased injury to the wheat if you do
add the surfactant. So it's not just about adding it. It really you need to consider what is going to be the the volume of the UAN in terms of the total solution that you're going to be applying to the wheat crop, and then whether or not, if you are using something like a harmony, Harmony extra, or any other, any other herbicide, for that matter, what the label would suggest that you use for any additional spray, additive or caution against using,
yeah, I think that's Interesting. A lot of times when you're looking through those labels, sometimes it will say you can use UAN as a carrier full stop. Sometimes it says you can use UAN up to a certain percentage of the spray volume. And then you have all these caveats, like you said about mis and crop injury versus weed control and all the things we talk about with adjuvants. So yeah, yeah,
and you probably the folks in Kansas use a wider variety of herbicides in their spring wheat. And what we do here, again, vast majority of it would be treated with something like a pipe and sulfur on containing herbicide, much less so with everything else. So
what are you we've all touched on, kind of this injury component. What are some specific situations where using fertilizer as a carrier can cause issues? I know Caleb, you got the cottage cheese story. Is there any other interesting stories or situations you've run into where you've had some issues with this?
I don't, I don't think so, as long as you you just watch the the ratio of the ATS with your total tank volume. I never really had any issues. I mean, I've seen post, post corn, side dress foliar with UAN, which you can't miss that. I mean, if you're driving in the countryside, you will certainly tell that. That's what happened there. But other than that, there really wasn't anything, as far as burn goes,
that I would be too worried about. I mean, the UAN by itself, with our modern day pre mixes and that I really haven't heard of any true design. Masters happening in the countryside. It's always basically been when you throw thiasel into that mixture. And the thing about thiasol is it's it's sometimes can be inconsistent. Sometimes this tank mix worked last year and then this year it doesn't. Or sometimes it worked yesterday and today it didn't. It's just
kind of one of those weird things. It's just something that can be a valuable tool to, you know, feed your crop, but you really got to be careful with it. So, and that's just one of those things. I think experience probably is going to play a big role.
And Alyssa, you know, there's very few that I can think of, off the top of my head, very few labels of foliar applied herbicides that would allow you to use the fertilizer
as a carrier. And again, because of those concerns about significant crop injury, there may have been one or two, but, you know, historically, it's just a practice that really hasn't been done now, you know, years and years ago, and I'm talking probably here back, you know, in the 1980s for example, when we had a much narrower, I guess, number of products, you know, I think years ago, when I was an intern with BASF, we had bare and, you know, back way back when, if, if velvetleaf was
your target species in the field, then the label would say, you know, add 28% to that. And it may be two quarts. It may be four quarts based on the size of the velvetleaf. Whereas if you had something, maybe your target species was common lambs quarters, then it would say, Well, if you run 28% we know you're not going to control us. We would, you know, the recommendation would be to switch over to crop oil
concentrate. What really seemed to usher in the era of using ammonium sulfate in our fully applied products, is when the Roundup Ready technology came into the marketplace, and virtually every application, you know, since that time has probably included some kind of an AMS fertilizer in there with it. Now it does a couple of other you know, a couple of good things. Number one, I think the most important thing it does probably it really helps precipitate out the diving
cations from the water solution. And so if you had a scenario where you had a lot of calcium in your water supply, and that calcium complexes with the negative charge on the glyphosate molecule, calcium glyphosate is not absorbed very well. And so that's a really benefit of having that ammonium sulfate, you know, lower carrier volumes also really helped
roundup work quite effectively. And I think that was fairly common practice, you know, of course, in the great plain stage for years, just a low volume to try to reduce that antagonism of divalent cations with glyphosate. So, and there could be, you know, there has been some evidence that the ammonium part of it does, you know, maybe perhaps aid in the Trans
membrane movement of glyphosate into a cell. But, you know, I guess the way I've always thought about it, you probably get the most benefit of AMS in that, in that conditioning of the wall.
So that leads me to a question I'd be curious to pick the three of you all's brains on this one I got in my inbox A while back, guy says, I'm tired of hauling bags of AMS. I'm using ATS in my burn down. Why can't I just use ATS to condition my water instead of AMS?
I would be awfully concerned about burn on that I wouldn't go with ATS. There is liquid AMS, which I would probably be more comfortable using. I know there are a lot of facilities and locations that do that probably reduce your risk of burn. I mean, I'd have to think that, you know, ATS is probably going to be similar to what a UA interior would look like. AMS is a little bit safer in that
regard. And the other thing too, is adding to Dr hagers, point about glyphosate is, you know, the antagonistic minerals in our hard water in the Midwest, they have the potential to reduce efficacy of a lot of herbicides that we're using in the countryside these days. I mean, it's, you know, group ones, group twos, HPPD inhibitors, even even glucosinate. So a lot of you know, a lot of chemistry that would be in the countryside could be affected by that so, but yeah, as far as ATS, instead
of AMS, I really wouldn't advise to do that. I would go with liquid AMS if he wants and if that's what he's after. But a little side note on liquid AMS, it's usually 34% AMS. It's a seven, oh, grade. And I believe, I believe, it contains four pounds of AMS per gallon. So if you ever run into a situation where you're halfway through a load and your liquid tank runs dry, you run out of bags and you got to switch. You know, that's
quick math for you. Because don't ask me how I know that that does happen.
You want. One thing I've always tried to remind folks down through time is that, you know your major investment is in the herbicide right? Your less than major investment is going to be with the spray additives. Now, if you pick the right spray additive, you're going to be okay. You. Pick the wrong one, and all of a sudden that big investment that you just made in the herbicide is going to return a whole lot less on that investment.
Yeah, sometimes there's no, there's no easy button, right?
And you know, I guess it's, it's been my experience down through the years that most of the registrants when they write labels, you know, they've done the work. They know which are the best additives to include and which ones really should not be included. You know, all of our all of our field programs. I know ours is, and I'm sure Sarah
and the list is yours as well. You know, these are some of the treatments that we do look at, as we partner with our industry colleagues to evaluate what might be either the, you know, the best spray additive or the worst spray additive, or the best carrier volume, or something that would be less than best. So there's been a lot of work that goes into what the registrants put on labels in terms of recommendations for volume, for spray additives, for, you know, do this, but
don't do that kinds of things. And that's always the best place to begin. You know, your your investigation is read the label,
and if you really wanted to, you know, get down to cost, which is always a talk talking point. But I think two and a half to three pounds of AMS would be between three and $4 an acre, and ATS is going to be ATS will be more than that. So I think that that would be a much, much safer, more cost effective route, no doubt about it.
Yeah, one thing we haven't really touched on yet that I think is pretty important is that, you know, most sections of the labels, when they talk about different either types of additives or tank mixes or carriers or whatever may be, you know, they would strongly encourage you before you do the 500 gallon mix load, you know, do take a little time and do
this little thing called a jar test. And it been a while since I read that part of some labels, but for some odd reason, I was reading it the other day, maybe I was trying to get ready for our discussion here today. I don't remember what, but looking at a label and how they really were very specific and very
clear on how to actually do these jar tests. It's not just you slop in a little bit of everything that you're going to throw in the tank and see what happens or what doesn't happen, but very, very specific details on what volume of an emulsifiable concentrate it should be, what volume of a SC formulation should be included in that jar test. So it's not
something that you have to kind of guess about. It's usually very well spelled out on labels on how to do this and again, as you know, Caleb's earlier reference to a tank load of cottage cheese, you know, could result in saving some pretty substantial dollars if you knew ahead of time that this is not going to be a mix, it's going to not going to flow very well out of the nozzles.
I have an agent here in Kansas who likes to say a jar test is way easier to clean up than a tank test. Yes, yeah,
there's a very wise person
from experience a time or two. Aaron, your label comment brings up another point that I and Caleb touched on this earlier, just mixing order, I think especially when we're thinking about using some of these kind of alternative fertilizer carriers that can be, that can be a thing, right? Can you guys think of any other Caleb you had that one example earlier of putting ATS in last? Can you think of any other like examples or scenarios?
Well, a lot of the a lot of the systems and chemical sheds nowadays are all automated, so you can pre program those, which makes it extremely handy. I mean, that takes some of the stress away in the spring, which is, you know, that's nothing, but a chemical shed is, is one big stress area. But, yeah, as far as mixing order goes, a lot of them are pre programmed. And, you know, it'll give you a certain amount of gallons that you can pre program ahead of time to a lot
for your mix bowl. So if you're, you know, carriers pumping faster than what you're mixing in the mix bowl, it'll stop, you know, to allow that mix bowl, you know, that that product to go in. So, yeah, mix order, it shouldn't be too big. Video,
now, of course, if growers are spraying their own. I would recommend having a, you know, printed out sheet on the wall by where they mix, or something that goes over mix order, and even have the products they're using listed on that sheet so they can't, you know, there's no, you know, mishap or misinterpretation, but yeah, thiis always went in last, or it should go in last, but yeah. I mean, a lot of those, lot of those systems are automated and pre programmed, which makes it
pretty nice. Never used to be that way. So,
yeah. So some of these comments, you know, Aaron talks about, we're making a herbicide application. We want that to be our priority. And it made me think about the number of options now, of things. Things that can be thrown in a tank mix. I'm curious if you have any thoughts on any of those special products that would have an interaction of some sort, one way or another, with with fertilizer as a carrier versus water
well, and that's, you know, any product that goes into a tank. You know, the more products you have, the more chance there is that something could potentially go wrong. But I don't think that, as far as the fertilizer interaction, I don't know if that'll be so much an issue as what other herbicide you know you might have in there, or other product you might have in there. So I guess when it comes down to that, again, you know, jar test could be your best
friend. But also, before you even look into that, make sure that whatever this product is that you want to explore with your operation is actually worth exploring. Make sure you actually understand what what is in that job would be, my advice there.
Yeah, there's examples, of course. And Sarah, I think you wrote about this in one of your last newsletter articles. You know, if you are running something like a UAN solution, esters tend to mix better in a UAN solution than
does a salt formulation. So and again, you know, you may know that you may see that on the label, but if that label is recommending that you do that jar test first, highly advisable to do that, because the last place that you want to discover a mishap is something that doesn't mix well, is when you get in the field and you flip the switch and you nothing comes out of the nozzles.
And even, I mean, we always kept just a couple jars that, you know, in the office of the chemical shed. You know, you walk by them, you know, 100 times each day thing. And I don't know, whoever use those things. And we use one one time in five years. I'm really glad we did just put it that way, that box, nobody touch it.
Take your hands off my jars.
I think we've covered a lot of these, you know, tank, mix, compatibility and other things that come up. Are there any other applications or different considerations that that we're kind of missing in this discussion here?
I guess the only other, the only other thing I thought about, you know, we talked a lot about UA hand and ammonium thiosulfate, but you know, some suspension type fertilizers, you know, we can run into issues with those kinds of fertilizer solutions, if they're using, like a clay base for the suspension agents. And, you know, something like paraquat comes into mind. You know, paraquat is strongly
adsorbed to things like clays or other soil colloids. So that could be a consideration also, but, but again, you know, those kind of things would be spelled out on, you know, for this example would be spelled out very clearly on the garbox, on
label. One thing that I had come across my desk in the last couple of weeks along this topic was nozzle selection for these types of applications, you know, so right streamers for for a fertilizer application, obviously is not going to work if our primary goal is herbicide application. So, I don't know. Maybe Caleb, you want to talk about some of your experiences around application equipment for some of these applications,
unless, unless you have a true, complete disaster. I don't think you know, nozzle plugging would be a problem. You know, there's so much pressure, and these, these flood nozzles, are hard to plug. I mean, I've never seen that actually happen. I have seen, and this is not, this has nothing to do with with fertilizer, by any means, but I have seen the, you know, like the little first rate packets that they say you can throw into the mix bowl, and they'll
dissolve. They don't always dissolve. And they can plug the sprayer screen roughly, quick, and that's not a very pleasant phone call from the operator there. So, and it's really not good when you know that you have about three other trucks sitting at the field waiting to load a sprayer with that same thing. So that that's one thing I would advise, but that's got nothing to do with fertilizers. Carrier. That was just a post soybean
application so, but, yeah, I wouldn't. I would open those little packets,
I mean. And the only other thing I guess I'd add, Sarah, you know, if you're making this application of a, let's just say a soil residual herbicide under, you know, ground has already been tilled, probably not going to be a huge issue. But if this is also going to be part of your burn down, and you are using something like a UAN as a carrier, you know its density is more than out of water, so that can affect your your flow rate. Maybe not so much with today's modern
equipment, but you know, consider the coverage also. The last thing that you want to do would be compromise your coverage. If there is a herbicide in that UAN carrier that you need to control any existing vegetation in that field.
I think that's kind of what I had for today's topic. Sarah, did you have any final burning questions or or Aaron or Caleb? Any any last thoughts? Yeah,
I guess the only, the only thing, I guess. Of the partying comment I would make, you know is, we're here at the outset of another growing season. You know, just wish everybody all the best and just be safe. You know, take your time, rest as you need to. It's, you know, it's so important to be able to, you know, do your job, to go home to your family at the end of the day. Also,
I love that reminder. Let's end on that. So thank you so much Aaron and Kayla for joining us today. Do you? Do you have any lab websites or or social media accounts that folks can maybe follow along and get more information from
you? We actually, it's funny as that. We're kind of renovating our web page right now. We're kind of bringing it up to date, up to speed, so it will be, it will be public knowledge once it's done. And it actually is now, but we're working on getting it done now where we'll have trials and data posted and that sort of thing. So that'll be, hopefully available later this spring.
I have a Twitter account. It's UI Weed Science. I actually started that in 2017 which happened to coincide with the beginning of the Dicamba use of soybean, and really wish I hadn't started it that year, but I still haven't. So
all right, so find more information from Aaron and Caleb there. Thank you all for listening along with us today, and we'll We hope you'll tune in next week to the War Against Weeds podcast. You thanks for tuning in. Just a reminder, you can find this and other podcasts and resources on the crop protection network. This network has a host of information from extension programs across the US about all things pest management. We hope to catch you next week on the war against weeds. Podcast.