Soybean School: Five clues to high-yield sulphur response

Welcome to the Soybean School Bernard Tobin here at the Midwest Agricultural Conference here in Kitchener. We're going to talk sulphur and soybeans today. We're going to catch up with Omafa soybean specialist Horst Bonner in a moment. We're going to. But we're going to kick things off with Mazex agronomist Henry Princeton. Henry, how's it going? It's going great, Bern, how are you? I'm good, I'm good. Hey, we want to talk about sulphur. You've been working on it now at Mazex about three years. Give us, I guess, a top line of what you've seen over three years. You did more trials in 2025. Yeah. Burn. So sulphur we're seeing at some of these sites is consistent responses to sulphur. It's predictable. Now we know we're going to get those responses at those sites and it ranges, you know, 10, 15 on the occasional over 20 bushels on those sites. So it's, you know, what we're working at and trying to figure out is why those sites and why, you know, what are the components to the soil or what's the environment that really causes that. Right. So we've seen it at Tupperville on a mid textured soil, right? Mid CCS, 15, 16, 17. And we see a good response year in, year out in Simcoe, Ontario on A11CEC sandy loam. But what we talked about today at Midwest Ag here is that idea of SCN actually contributing, confounding a sulphur response when we're stressed and we can't get good root development with scn, you know, colonising the roots, we're getting a better response from sulphur. So our Simcoe site is both light, probably deficient in soil sulphur and we have SCN. So then we're seeing those 15, 20s plus responses. So that's really unique and I think that's maybe what we're seeing in Tupperville as well. So that's kind of the new, kind of maybe the forefront. And then it's that combination and Horst will probably talk to it. But when we have situational sulphur responses, we have sites that always respond and then we have these sites that sometimes respond and those sites, when we see that, we see that, you know, early planted cold soils, lack of mineralization, maybe a carbon tie up of sulphur, my C to S ratio, not my C To N ratio, my C to S ratio, you know, it's actually even higher than the C to N ratio in corn stover. And we. That's when we sometimes get those situational responses. But the great thing with sulphur is when we get a response, it's not 1, 2, 3, bushels. It's usually 7, 10 plus bushels. Bushels. So that's what's exciting. And rate £100. £100. And the key. And you know, we spoke about that. It's broadcast up front early, so we can find out that we were maybe deficient in the season with our tissue testing. We've seen that with tissue testing a bit, but it has to be up front because we're starting that roots. We're starting those roots off with good nodulation right from the get go. And that's actually getting us higher sulphur levels in the plant later in the season. You gonna do some more work this year? Where do you take it this year? Do you maybe move into some different textured soils? What do you want to do? Yeah, so I think we are. We have a few new sites and we're actually gonna pull out of my continuously responsive site, mostly for the, you know, the point that we've done it three years, we always get a response. We know. So we're gonna work at that. And then maybe some lower testing soils. And we saw at sofofteg conference, I was listening to Adrian Coronado talk about phosphorus response. So maybe we'll look at some sulphur only treatments, some, you know, phosphate products and then some of the combinations and see if we can, you know, maybe drive that even further at some of our new sites. So, yeah, we're going to keep doing that. We'll definitely keep doing the tissue testing. You talk about R3, we look at that N2s ratio. If it's 18, 19 to 1, we're probably fine. If it's above that, it's definitely a concern that we were short on sulphur. R1, R3, when are we doing that test? Yeah, so R3, we're doing the tissue test. We're looking at the newest trifoliate. Fully formed trifoliate. And we're looking at that end S ratio. Right. So if you're running a 20 to 22, maybe even plus N to S ratio, you're probably responsive. We want to see that 19, 18 to 1 or lower. So if you're below that 18, 19 to 1, you're probably not responsive. So the challenge there is that's an in season, we're already past the chance to, you know, use sulphur. So it's more of a. Okay, looking back, looking forward, this is what I probably should be using sulphur. But if we look at soil types or, you know, what situations from the spring, let's start on those light textured soils, soils with scn, and then soils that we plant early, that are cool, that might lack mineralization. That's. Those are the combinations where we're most likely to see a sulphur response. We're joined now by Omafa soybean specialist Horace Botter. Hey, thanks for dropping by. Oh, it's great to be with you. Hey, great presentation this morning. You talked about, you know, sulphur research in the ministry. You've been doing it for 20 years. Back then, you really never saw a whole lot of impact on sulphur. Well, because, of course, sulphur is closely associated with protein. And, you know, we're growing a protein crop with soybeans. It's not a new idea. So people have tried it down through the decades and, yeah, about 20 years ago, we had a nice experiment set up and we probably had 30 sites and essentially there wasn't. Wasn't anything worth talking about. But now you're seeing pretty similar results to Henry. It's hit and miss, but there's some significant impacts. Two trials this year. Tell us about what happened at Ridgetown. Yeah, so that's right. We have now, in the last six years, compiled a data set. Some of that stuff is Henry's, some of it is ours. Soil and crop pioneer have all contributed whatever trials they have been doing with sulphur. And the really interesting part is that things have changed. Right. Totally different than it was 20 years ago. We're having sites with a big response and even at sites that aren't just low in organic matter or sandy soils, which is the traditional storey. Right. Because, of course, there's less sulphur in those soils. It's leached away. But what's really intriguing is that we're seeing a nice response at places like Ridgetown. Big surprise to me this year, you know, and if you look at this data, incredible response. 11 bottles. Right. It's amazing. And. And, you know, in the soybean world, it sounds kind of sill. You know, we can't sleep at night when we get over 10 bushels because there's nothing in the world that gives you 10 bushels in soybeans. Unless, of course, you've got a disease problem or a real nutrient problem. That you're addressing. But if, if, if the soil fertility is good and, you know, it's a normal field, you don't get 10 bushels out of something. And open at Laura, you got eight bushels. Oh, yeah. And again, you know, loam, silt, loam soil there. I was not expecting anything. And now in that case, of course, it was no till, lots of corn stalks, and planted early. We had two dates there, and the earlier date did show a little more. So that gets us thinking about, you know, what's going on there. And there is this conversation about the carbon and the cold soils. And so early planting can, especially if you've got a lot of residue, show a little higher response. Now, overall, I mean, you put up a statistic today, 22% of the sites had a 10.3 bushel jump. I mean, that's, you know, 20%, 22%, you know, that's significant. I guess the challenge now is finding those fields that will pay. And you had five tips on how to identify those fields. And, you know, what is, what are characteristics of those fields? Let's, let's dig into it. You mentioned already sandy, low organic soils, right? So traditionally, that's always what we've said, is that those fields are most likely to respond for pretty obvious reasons. Right. Because there's not much sulphur in that soil. That's why. And if we're not getting the deposition, then of course we're more likely to see a response. And that is still true. Those are kind of the. That's your number one thing to think about if you're on one of those soils. Ah, maybe, maybe I could get a. Response, some early planting and heavy residue. So that's. That's right. So that's kind of a newer thing that we have seen that there seems to be, even on soils that aren't sandy. Right. Ah, there's more of a response in that early planting window. Significant scn. Oh, this one. Henry talked about that this morning as well. Yeah, yeah, that. This one really is exciting. There's a real correlation to soybean cyst nematode attacking those roots, reducing nodulation. And there's a physiological response within the plant that's stressed by the SCN requiring more sulphur. We know that now. So there seems to be this correlation. Now, it's not to say that if you have SCN that you're guaranteed to have a response to sulphur. That's not what I'm saying. But if the numbers are significant for scn, we're getting more correlation there to a sulphur response. So it's kind of neat. Right. And you also noticed a bump in fields with no sulphur applied the year before. Yeah. And that's logical, of course. And of course we're trying to do is help growers think through. Like, if I put on sulphur in my corn or on my corn, rather, and on my wheat, chances are that the beans will be able to scavenge that. There's still enough there. That's what we think right now, but it's an ongoing science here. We're trying to figure this one out. Right. And obviously I look at the soil test, the low test. Yeah. Now, the interesting thing about the soil test is that there is no accredited soil test right now in Ontario. And the University of Guelph is working hard on that to try and come up with an extractant that will actually work. And there is some hope. The data that John Lauzon has pulled together, the challenge is it's. It doesn't look like it's going to be a perfect answer. Right. In other words, if you're above a certain level, you may not get a response, and if you're below a certain level, you're more likely to get a response, but it's not a guarantee. Some great conversations here this morning about sulphur, of course. Thank you for stopping by. Always. Great to see you. Very good. Nice to be with you. You can find more episodes of the Soybean School by going to soybeanschool.com or finding the Real Agriculture YouTube channel.