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Mike Howell (00:08):
The Dirt, with me, Mike Howell, an eKonomics podKast where I present the down-and-dirty agronomic science to help grow crops and bottom lines. Inspired by ekonomics.com, farming’s go-to informational resource. I’m here to break down the latest crop nutrition research, news, and issues, helping farmers make better business decisions through actionable insights. Let’s dig in.
(00:38):
Listeners, welcome back to The Dirt. Glad you’re joining in with us today. We’re going to continue talking about our different crops and their nutritional needs. Today we’re going to be focusing on soybeans. To help me do that, we’ve got Dr. Trent Irby with Mississippi State University. Now, Trent and I have been working together for quite a long time. We actually overlapped in graduate school a little bit there. I think Trent was actually a TA in a class or two I took. But he is a couple of years younger than I am. We won’t get into that.
(01:05):
Trent, thanks for joining us today and sharing your expertise with us. If you will, tell us a little bit about yourself and what you’re doing there at Mississippi State.
Dr. Trent Irby (01:12):
Yeah, man, thanks for having me. I always enjoy visiting with you and certainly welcome to the opportunity to talk about soybeans every chance I get. My role is a 100% extension specialist for soybean production in Mississippi. I’ve been in this job for several years now and I’ve seen some ups and some downs. My primary responsibilities are to the grower and to the clientele of the state and try to do whatever I can to help improve yield where I can, but certainly profitability every chance I get.
Mike Howell (01:40):
That sounds like a full-time job. I know when I was growing up, soybeans were kind of the stepchild. We just kind of threw them out there after everything else got planted and they were on some of the roughest land that you could imagine. If we got 20 bushel yield off of them, we were really excited. Things have changed in the last 20 or 25 years. Tell us a little bit about the change that took place while we’re growing soybeans on the better land and what’s our yield average in Mississippi now? How many acres do we have? Things like that.
Dr. Trent Irby (02:09):
I remember those days too. I grew up on a farm. I remember trying to finish planting soybeans by the 4th of July. That was my dad’s goal in those days. It’s just quite amazing to look back at that and then look where we are today and just to see the change that you’re referencing there. People always ask me about our acres. When you look back at those days as a state, we still had a lot of acres of soybeans. There was still a million and a half plus acres in Mississippi even those days where soybeans wasn’t necessarily the favorite crop to grow. I think a lot of that probably was land that was less suitable for cotton production.
(02:44):
Soybeans is what a lot of that land went to. Then one day some guys that predate us here in this business discovered some things that really revolutionized the way that we can produce some particularly here in the region. One of those was a change in maturity group and the other was a change in planting date. Those two things really changed the whole mindset, I guess. It wasn’t just those two management factors, certainly those were the two that made the big impact. But along with those things, we started paying attention to insects and diseases and making sure that our weed control was under solid management and as well as irrigation and all the other facets of production.
(03:25):
Probably more what we’ll talk about today, the nutrient side of it. So long story short, we really started just managing the crop instead just planting it and coming back and looking at it and maybe harvesting it later. With that intensive management applied to it, we really revolutionized it. Even in the last 10 years, we’ve gone up from the low 40s to the mid-50s as a state average soybean yield. I believe the last three out of four years, our state average has been 54 bushels. We have a record at 54 and we’ve tied that record twice since. Me personally, I’m ready to see us get over that hump and move above that record and break it again. But it’s just been really a wild ride to see the success that has come along with it.
Mike Howell (04:05):
We know we’re growing a lot of soybeans and that’s true across the country. There’s going to be a lot of soybeans grown this year. Trent, you mentioned planting date. One thing that I keep seeing in some of the popular press and on Twitter is some ultra-early planted soybeans. I’m hearing that as early as the 1st of March, maybe even late February, there were some beans being planted even as far north as Kentucky. That just seems really early to me. Why the push for trying these early soybeans and is there some research data out there that says we may benefit from doing that?
Dr. Trent Irby (04:35):
I think the whole mindset around some of the success… And again, this success stretches outside of even our state lines. It’s been recognized in multiple other states, including further north, adjusting that planning date a little earlier and shifting some of those things and then capitalizing on some of those early… more favorable environmental conditions on the early side of things to get the crop going. But long story short, I think that our mindset is focused around early planting date equals greater yield, right? While that is certainly a very true phenomenon, there is a side of it that is too early.
(05:13):
I’ll reference Mid-South Project. This was probably eight or nine years ago. There were several scientists involved in this big project. But it was a big planting date and maturity group project. A lot of data that came out of that and the take-home message for planting date was that if you look at… I’m going to use March as the first example. If you look at planting soybeans in March and then you wait and plant soybeans, same variety, plant them in April, do it again in May, do it again in June, your peak yield potential is going to happen in April.
(05:46):
Then if you look at your yield potential as a result of that march planting date, it would actually be pretty similar to what the May planting date yield potential would be. You’ve got this curve here with the peak of that curve being in April for us in our part of the country. That’s not to say that you can’t successfully plant even earlier than that, but you’re actually not capitalizing on your greatest yield potential by planting super early.
Mike Howell (06:10):
Well, we have to worry about those late frost as well. I’m a couple of hundred miles further south than you are and where our big production area is. But even as late as March 20th, we had a killing frost. I think I actually lost my blueberry crop this year from that late frost. And soybeans aren’t like corn. They won’t recover from that frost nearly as well.
Dr. Trent Irby (06:29):
That’s right. That’s a big risk certainly because it seems like especially in our part of the world, if you don’t like the weather today, wait until tomorrow.
Mike Howell (06:37):
That’s it. It’s always going to change. Trent, let’s dive in and talk a little bit more about fertility now. Back in the day, we didn’t do a whole lot about soybeans. We just kind of planted them and forgot about them. But now with these high yields, we’re going to have to fertilize these soybeans. We’re going to have to get the nutritional needs met. To keep building these yields, we may even need more nutrients than what we’re accustomed to putting out. The first thing we always think about is soybeans are a legume and they’re going to fix their own nitrogen. But we know there’s a limit to how much nitrogen they can produce. What can you tell us about nitrogen and soybeans?
Dr. Trent Irby (07:11):
I’m going to say there’s two sides of that fence that a lot of growers will look at. You’ll have the grower that focuses on the fact that it is a legume and it’s absolutely unnecessary to consider any additional nitrogen. Then you’ll have a different thought process behind that where they realize that it’s fixing its own nitrogen, but they also want to push the limits with it and test to see what would happen if you add supplemental nitrogen to it. I think there’s been a lot of work done over the years looking at supplemental nitrogen not as a rescue treatment specifically in situations where adequate nitrogen is present and then adding even more nitrogen to the crop to see what would happen.
(07:49):
The summary of that would be just a… It’s a mixed bag of results. There are times where it absolutely does have a response to that and you can gain yield from it and then there’s times where you see no response to it. It’s a hard thing to put your finger on to figure out when it would have that response and then also whether it would become economical to do so. I think there’s situations that it absolutely is, and then there’s other times where you’re not going to see any kind of… you may see a tiny bump in it, but it may not be an economical kind of response.
Mike Howell (08:21):
I’m sure timing of that application is going to play a big part as well. What can you tell us about when we need to make that application if that’s something growers are wanting to experiment with?
Dr. Trent Irby (08:31):
I think as late as R2 going into a full bloom, there’s a lot of things that that crop can tolerate early in the season when it’s much focusing on vegetative growth. But when you shift gears and you go into reproduction, there’s a lot of things that are going to tell on itself, so to speak, and any kind of nutrient demand is right there in peak demand when you’re going into pod set and seed fields. So as late as R2, I think that if you were going to try something like that, that would be the timing to focus on the traditional train of thoughts to avoid early season nitrogen application because you don’t want to influence the nodulation process. I know that too much nitrogen being readily available might cause a nodulation failure and certainly want to avoid that because then we’d lose that free nitrogen.
Mike Howell (09:22):
That’s exactly right. I used to do a lot of work with peanuts, a similar crop as far as the nitrogen needs. We don’t ever want to get into this situation where we have inoculation failure or don’t get the inoculation we need so that plant can’t produce its nitrogen. But talk a little bit about if we do have that failure, what we need to do, how much nitrogen is it going to take to get that crop from planting to maturity if we don’t get the nodulation we need?
Dr. Trent Irby (09:47):
That’s a major thing. Unfortunately, I do see that about every year. I can’t think of a single year that I’ve been in this job that I haven’t walked a field where that was the case, a field nodulation situation. Of course, there’s various reasons for it. I’ve seen it where you would think you would see it, behind 80 years of cotton where there’s never been a soybean. That’s the most obvious. But I’ve also seen it in areas that were prolonged flooded environments with too much water being out there. I’ve seen it several different scenarios.
(10:16):
But I’ve made the comment to people before that’s one of the most heartbreaking conversations that I can think of that I have to have with a grower. If we’re standing in a field and see this situation and then you start adding up how much money it’s going to take to correct that problem. A 60 bushel soybean crop can use almost 300 pounds in nitrogen. If there’s no nitrogen there, I mean, you can do the math on that depending on the year to see what that’s going to take. Our general recommendation in that true field situation is to try to get 120, 140 units out there.
(10:49):
Ideally, it would be something where you could split it maybe and have two applications. But oftentimes, we don’t really know we have a problem until we’re at full bloom. That’s when the symptoms start showing. At that point, we need to put that full amount out and see if we can get it watered in and hope that that crop can overcome some of that potential loss.
Mike Howell (11:10):
That’s not a good situation to be in, that’s for sure. So let’s switch gears a little bit and talk about phosphorus. What can you tell us about phosphorus nutrition and how much phosphorus do we need to make sure we have out there?
Dr. Trent Irby (11:22):
Phosphorus is one of those that… For me, I use the term stick to the basics. I feel like as long as we are doing a thorough job of sampling our fields, soil sampling that is, and making our applications based off those recommendations… In my experience, I’ve not seen a whole lot of issues specific to phosphorus as long as we’re doing those basic management techniques and doing the sampling on a rotation at least every two or three years and then just making those applications as necessary.
Mike Howell (11:52):
That’s something we’ve talked about a lot on this program, is making sure we get those soil samples in and follow those directions on that. It sounds like we’re not really going to have any issues in soybeans as long as we’re doing those samples on a regular basis and making sure we make those applications when we need them. I guess the next big one is potassium. I know there’s been a lot of work going on at Mississippi State about potassium in soybeans in the last five or 10 years. What can you tell us about potassium?
Dr. Trent Irby (12:20):
Potassium is one of those that I would rank there with nitrogen in terms of its importance in the soybean crops. It’s one of those things that we remove a lot of potassium. For us anyway, we have quite a few acres of continuous soybean production. We’ve also got quite a few acres of corn-soybean rotation going on. It seems like in the last 10 years, both of those crops have had exceedingly high yields compared to the 10 years prior to that. Problem with that is is higher yields removing more so the demand to put more back is there in its presence.
(12:54):
I’ve seen of course your basic situation where you have textbook definition of deficiency. You could almost drive by in a truck and see it from the highway, just the symptoms on the leaf, the symptomology that you would see for potassium deficiency. In those cases, I’ve seen guys make some corrections. Even back to the timing conversation, even as late as R2, almost R3, making… flying on some application and being able to overcome at least part of that potential loss and correct some of that issue as well. But that goes back to the same comment I think that I had about phosphorus back to the basics and sticking to the sampling.
(13:31):
But also on the flip side of that, I feel like that potassium’s one of those that could be in the future looking at, for lack of better way, spoon-feed that type of nutrient into the soybean crop to help further enhance yields in particular high-yield environments where we’re trying to boost yields with some of these supplemental applications.
Mike Howell (13:50):
You talked about spoon-feeding it. You’re talking about making multiple applications during the growing season. That’s something we talk about in some of our other crops, putting nitrogen out, multiple applications. Is that going to be profitable, making multiple applications of potassium?
Dr. Trent Irby (14:04):
I don’t think we’re there yet. I’ve not encountered the consistent response to situations where that’s supplemental, if you will. Supplemental application is completely necessary. But I guess I’m just theorizing looking at the future and looking at our high yields, continuing to improve those yields, and then furthermore trying to sustain those yields. Now, I do think it’s something that’s worth looking into moving forward. I personally know of growers who have made that extra application with just a little bit extra and then one year leave it off and immediately wish they had done it.
Mike Howell (14:39):
Right. A lot of people don’t realize this, but you can actually lose potassium just like you can nitrogen through leaching, especially in some of our sandier soils. I know when we get into the Mississippi Delta, especially over around the river, we have some pretty deep sands. And when we get down along the Gulf Coast, we definitely have some deep sands there and can lose that potassium fertilizer. I could see where that could be a benefit, especially in some of those situations. Glad y’all are looking at that and hopefully we can get an answer to that here in the near future.
(15:09):
I guess the next major nutrient that I see a lot of problems with is sulfur, and that’s something I’m hearing a lot of talk about at every meeting I go to these days, is sulfur deficiency showing up in more and more crops. Are you seeing any sulfur problems showing up in the soybeans?
Dr. Trent Irby (15:24):
Yeah. I don’t think it’s to the extent that what you’ve heard about or seeing, maybe corn or a crop like corn. But I have seen a few instances over the last couple of years pointing to sulfur deficiency. It’s certainly one of those things that I think warrants immediate investigation and trying to figure out the best management scheme to that. In a lot of cases, it’s responsive management scheme responsive to the problem instead of a proactive management on the front end of the season, we’re discovering this problem again, R2, R3, and then trying to come up with a management scheme to correct the problem.
(16:01):
I have seen some guys that have applied some ammonium sulfate about R2, R3, and I have witnessed some pretty serious yield responses to it without question, economical application. And the first question that I ask and have been asked, is it the nitrogen or is it the sulfur? I probably feel like it’s probably a combination of both helping overcome that. I think the sulfur was the main problem to begin with and maybe got a little extra enhancement from the nitrogen in that application.
Mike Howell (16:31):
Yeah. And really the only way to know that is to do some tissue sampling. We’ve talked about that a little bit. Is that something you recommend growers do, is regular tissue sampling to know where they’re at with these nutrient levels?
Dr. Trent Irby (16:42):
Yeah, sampling at some form or fashion. I think for me, most of the time when I see tissue sampling, it’s usually reactive to a problem. I do think that it warrants that, especially for something like sulfur. So often, our problems are you see a history, you see a pattern, you see things. We see these fields that are beginning to have this problem. It’s starting in a small spot, next year it’s bigger, and next year it’s bigger, and so forth and so on. So I think just coming up with that management scheme of sampling. We keep talking about sampling. It really is the basics and the fundamentals of what we’re talking about here.
Mike Howell (17:18):
That’s exactly right. We’ve got to know what’s out there and how much of that is getting into the plants before we can make any adjustments at all or any meaningful adjustments. Trent, we’ve talked about those four major nutrients. I know soybeans need the micronutrients as well. Are there any specific micronutrients that you’re always watching out for?
Dr. Trent Irby (17:36):
Not yet. Who knows what the future holds. But as far as our production systems and rotations, and for lack of a better way to put it, typical management schemes, those that we’ve talked about are the main ones that have popped up on a routine basis year to year.
Mike Howell (17:54):
Well, Trent, we’ve talked an awful lot about soil fertility and managing that fertility for soybeans. Is there any take-home message that you want to provide for our listeners today before we wrap this up?
Dr. Trent Irby (18:04):
Again, not to overstate it, but people ask me, what are the most important things that I can do to make high yield soybeans? I’ve kind of revised that and would restate it as, what are the most important things I can do to make a profitable yield in soybeans? We talked about the planting date and the variety selection thing from the beginning. I would put our nutrient management right there behind those two in terms of major impact on setting up our overall yield potential for the year and doing the other things that we do for managing.
(18:34):
So I go back to the sampling thing, not to say it too many times. But I know in my experience, I’ve seen us be tempted sometimes not to spend the money on that sampling and I know that oftentimes we’ll be extremely disappointed if we don’t pay attention to the nutrient demand of these crops, especially when we’re trying to continue to push yields higher and higher each year.
Mike Howell (18:55):
That’s exactly right, Trent. The way fertilizer prices are the last few years, soil sampling is really cheap, and that’s the best way to know what you need to get out there. Trent, we really appreciate you taking the time to be with us today. And listeners, if you’ve been tuning in, you know that now’s the time that we switch gears and go into our second segment of the day. We’re going to start talking about our famous agronomist for the week.
(19:19):
Anybody that’s ever grown soybeans in the southern part of the United States is going to recognize this name that we’re going to talk about today. Dr. Edgar Hartwig is known as the Father of Southern Soybeans. Dr. Hartwig got his BS degree from the University of Minnesota and then at later a master’s and a PhD from the University of Illinois at Urbana. At this time in the early 1940s, soybean production was kind of low in the state of Mississippi. We only had about 39,000 acres of soybeans, and a lot of that was grown for hay. But Dr. Hartwig began his career working in Florida at one of the agriculture experiment stations there.
(19:57):
He later moved on to the USDA-ARS in North Carolina and started working on soybeans. In 1948, he actually wrote an article and it made the front cover of Soybean Digest. Shortly after that, he moved to Mississippi. It was a joint venture between the USDA and the Mississippi Agriculture and Forestry Experiment Station there at Stoneville. But he spent the rest of his career in Stoneville working on soybeans. One statement said he bred about 80% of the varieties that were actually grown between the 1940s and the 1980s here in the state of Mississippi and across the South.
(20:34):
Later in his career, he began to do some work with other countries in Brazil and India and helped those guys learn some of the things that he had been teaching the folks here in the southern United States. But Dr. Hartwig worked a total of about 47 years. He received numerous awards, including the US Department of Agriculture Superior Service Award and the United States Department of Agriculture Distinguished Service Award. Dr. Hartwig, I never had the pleasure of meeting him. He had retired shortly before I really got started.
(21:04):
But a great man and everybody that’s growing soybeans in the state of Mississippi has heard of Dr. Hartwig and some of his creations and his different varieties and growing practices. Now, back when he was working, we’ve already mentioned that today, that we were growing maturity groups 5, 6, 7, even some 8. We’ve made a change since Dr. Hartwig has retired, but a lot of his innovation is still going on today. Trent, if you will, tell us a little bit about how his legacy is living on at Mississippi State these days.
Dr. Trent Irby (21:33):
Yeah. So my pleasure to point that out and highlight that. Dr. Hartwig family provided a generous donation along with the Soybean Promotion Board and some industry partners to create the Hartwig Endowed Chair in Soybean Agronomy. This position was created several years ago with the goal to provide leadership in soybean research and education as a whole, not just here at Mississippi State, but also around the whole state, the mid-South, and even broader around the globe as well. It’s a really important position. We do have a chair-holder in that position right now conducting lots of different research, things that can immediately and in the future impact soybean production favorably.
Mike Howell (22:18):
Trent, once again, we appreciate you being here. We want to thank the Hartwig family for providing that support for the Endowed Chair there at Mississippi State so that we can keep these research efforts going.
(22:29):
Listeners, thanks for joining in. We couldn’t do these without you, and as always, we want to remind everybody to visit our website. That’s nutrien-ekonomics.com. We’ve got all kind of information related to soybean fertility. We actually just published a soybean fertility manual and you can find that on the website there as well. Until next time, this has been Mike Howell with The Dirt.
