Read Full Transcript
[00:00:00] Mike Howell: The dirt with me, Mike Howell, an eKonomics podcast 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 use, and issues helping farmers make better business decisions.
[00:00:30] Mike Howell: Through actionable insights. Let’s dig in.
[00:00:39] Mike Howell: Well, hello again everyone. Welcome back to The Dirt. You have an exciting episode in store for you today. I’ve got my good friend, Bobby Golden on the recording with us today. Bobby, welcome to the Dirt.
[00:00:49] Dr. Bobby Golden: Glad to be here with you, Mike. It’s been a while. Good to catch up again.
[00:00:52] Mike Howell: It has been a while. We’ve been working forever.
[00:00:54] Mike Howell: It seems like trying to get this episode nailed down and get it recorded, and between your schedule and my [00:01:00] schedule, it’s just been tough getting together. Bobby, before we get started, if you will kind of introduce yourself to our listeners. Let ’em know what you do.
[00:01:07] Dr. Bobby Golden: Yeah. For those of y’all out here that don’t know me, my current profession, I’m employed with Simplot Grower Solutions as the director of agronomy for the sales enablement team.
[00:01:16] Dr. Bobby Golden: And what that entails is I have about 12 regional agronomists out there embedded in each one of our business units that are out. To give the best agronomic advice to our crop advisors on a daily basis.
[00:01:28] Mike Howell: When I first met Bobby, Bobby was the soil fertility specialist and rice specialist with Mississippi State, and we did a lot of work together, but that’s been several years ago.
[00:01:36] Mike Howell: Bobby, a lot of water under the bridge since then.
[00:01:39] Dr. Bobby Golden: Yeah, and there’s water under the bridge right now. If you go to Greenville, Mississippi, I still get to reside down home and the river’s high and water’s rolling. It’s been about 10 years at Mississippi State. Made a lot of good friends. And Mike, you’re one of them,
[00:01:52] Mike Howell: Bobby, that water’s high.
[00:01:53] Mike Howell: I don’t know how much rain y’all got up in Greenville the last couple of weeks, but I’ve had in excess of about 15 inches on the south end of the [00:02:00] state is making it awful tough to do anything in the field.
[00:02:03] Dr. Bobby Golden: We weren’t that high, but we had at least four to five where you’re standing in spots.
[00:02:08] Mike Howell: Bobby, let’s go ahead and get this thing kicked off.
[00:02:10] Mike Howell: When I first started working in row crops, and that’s longer ago than I care to mention today. I know you’ve been doing it almost that long, but I thought cotton was the only crop we could grow in the state of Mississippi. We had fields that had been in cotton production for over a hundred years, and some things happened and we started making some changes.
[00:02:27] Mike Howell: Talk a little bit about the history of row crop production in the Mid-South and how we changed our production systems a little bit.
[00:02:34] Dr. Bobby Golden: If you really get to looking at the history of row crop production in the mid southern United States, we are predominant of cotton and rice culture for numerous years.
[00:02:42] Dr. Bobby Golden: And then in 1998 when the advent of Roundup ready crops started coming out as well as. We made a major shift in the way we looked at soybeans with Lanny Ash Lock and Larry Heatherly implementing the early soybean production system. [00:03:00] What that did is turn a crop that we used to think of as poverty fees into something that brings ROI to the farm gate.
[00:03:07] Dr. Bobby Golden: Somewhere at around 1998 to 2000, we really started thinking about getting away from cotton production into more of a grain based system. Now that change didn’t. Really occurred till 2007, and that’s when we saw the sharp decline in cotton acreage and soybeans become the next king, especially in the Mid-South.
[00:03:27] Mike Howell: There was also a critter in there that was attacking our cotton crops at the time. The cotton bull worm became resistant to most of our insecticides and. That kind of made a lot of people want to get away from cotton production as well.
[00:03:38] Dr. Bobby Golden: And if you also look at it when we talk about cotton and rice production, those are two very intense labor driven crops from start to finish, right?
[00:03:49] Dr. Bobby Golden: Much more so in my opinion, than a corn and soybean crop.
[00:03:52] Mike Howell: No doubt about that. A lot of people wanted to grow corn. They thought all they had to do was go out and irrigate it once every week or two and didn’t have to worry about it. I think they [00:04:00] learned a valuable lesson that first year or two, but it’s definitely not as labor intensive as cotton or rice.
[00:04:05] Mike Howell: Bobby, when we made this shift, everybody thinks that if you have crops in a rotation that’s going to improve your soil and improve your soil health and. That’s true to a large extent, but a lot of these fields have been growing cotton for years and years, and you started introducing new crops in what happened to our soil fertility levels after we made this change.
[00:04:23] Mike Howell: I think
[00:04:24] Dr. Bobby Golden: what we see across the United States right now is a decline in soil test potassium a lot in our southeastern soils. And one of the things that led to that in the Mid-South was when you look at nutrient removal rates, cotton monoculture versus a corn and soybean rotation, what you’re really seeing is monoculture cotton removes about half the amount of potassium out of the soil, as does.
[00:04:52] Dr. Bobby Golden: Corn and soybean, so about two x removal rate of potassium in the grain as compared to when we remove cotton [00:05:00] seed and lint.
[00:05:01] Mike Howell: Bobby, we had Cowell, my counterpart that covers a Canadian region on two or three weeks ago, and he was talking about the same thing. They made some crop rotation shifts in that part of the world and that was one thing he was cautioning.
[00:05:13] Mike Howell: They’re seeing the same decrease in potassium levels that we’re seeing across the mid south.
[00:05:18] Dr. Bobby Golden: Well, you look at that, Mike, and when you had that change in 2007 and we were learning to be grain-based farmers, then you had a rise in potash price and those acres that we were fertilizing, we maybe backed off on and we started in a hole and we’ve been playing ketchup ever since.
[00:05:37] Mike Howell: Bobby, you mentioned the high price of potassium fertilizer, and that’s something that’s raised its head again here in the last three or four years, we’ve had record high prices and. We have seen a lot of growers that backed off of that. Now, if you had that soil test inventory built up and had your K levels where they needed to be, you could get away with that for a year or two.
[00:05:55] Mike Howell: Are you seeing the same thing people that backed off and what are those levels looking like after they [00:06:00] backed off for a year or two?
[00:06:01] Dr. Bobby Golden: What we routinely see is if you’ve been following a sound fertilization program based on build and maintain in those really tough years, like we experienced a couple years ago, or in 2008, you can back off a year.
[00:06:15] Dr. Bobby Golden: But that doesn’t mean you need to eliminate potassium fertilization. So you’re gonna have to come back to it. And if you look at soil test summary, I think the last soil test summary that was put out was in 2020. We’ve got a new one coming out, but the majority of soils. Are testing below soil, chest critical values in the Eastern United States, and most of the states in the southeastern United States test below critical levels, which suggest that we don’t need to take a year off.
[00:06:46] Dr. Bobby Golden: But that’s averages, right? That’s not specific farms.
[00:06:49] Mike Howell: Bobby, we had Antonio Malino on last year, and we talked a good bit about that, actually had two episodes dedicated to that. Why do you think these soil test inventory levels keep declining? [00:07:00]
[00:07:00] Dr. Bobby Golden: I think as we’ve improved genetics, as we’ve improved fertilization practices, we’ve grown more crops, and when we grow more yield, we remove more fertilizer.
[00:07:12] Dr. Bobby Golden: For instance, if you look at what we’re removing in soybeans, and depending on whose data you look at, can range from 1.3 to 1.8 pounds, a K, two O. Per bushel removed. When you see these 80 to 90 to a hundred bushel yields that we’re pulling out with soybeans routinely, maybe not farm averages, but routinely we can get ourselves in a hole really quick because in all honesty and coming out of the previous academic world, there’s not a lot of dollars out there for soil test work.
[00:07:44] Dr. Bobby Golden: If it’s not coming from people like you and I and some great commodity board support, when I was at Mississippi State University, all the commodity boards supported us very well in that, as well as when I was at the other research institutions that I worked at. [00:08:00] But we’ve gotta keep up pace with genetics on our crop removals, and that means putting the work on the ground, doing the work, and figuring out what those removal rates are.
[00:08:10] Mike Howell: Bobby, we’ve talked a little bit about soybeans and some other crops as well, but what I wanted to do today is focus in on soybeans. I know you did a lot of work looking at K deficiency in soybeans. How can we diagnose a K deficiency if we get into the season and things just aren’t going right? I.
[00:08:25] Dr. Bobby Golden: If we’ve elected not to fertilize in the fall or not fertilize in the spring, or we’re worried we can always come back with tissue sampling and determine if we have a hidden hunger where we’re at with routine tissue samples.
[00:08:39] Dr. Bobby Golden: Because one thing we do know from recent work published in the state of Arkansas is we can get. A lot of yield back, but once we see a visual symptom, we fell off the yield curve instead of that hidden hunger curve. So I always like proactive tissue sampling when we start getting into those early reproductive stages so we know where we’re at and we [00:09:00] don’t fall off that yield.
[00:09:01] Dr. Bobby Golden: Cliff
[00:09:01] Mike Howell: Bobby, you mentioned visual symptoms. Let our listeners know what they can be looking for. If they see something in the field, how can they think, well, maybe this is a K deficiency.
[00:09:10] Dr. Bobby Golden: When we start talking about Cade deficiency, visual identifiers in a soybean crop, it’s probably one of the easiest to spot, right?
[00:09:19] Dr. Bobby Golden: So what we’re looking for is a highlighter yellow around the outer leaf margin. Now, when we first see that occur, generally early in the season, it’s gonna occur on the lower part of the plant because we know potassium is a mobile nutrient. So we’ll be able to translocate that potassium to younger tissue where the plant can try to remain alive and thrive.
[00:09:40] Dr. Bobby Golden: What I tell a lot of people all the time, the number one goal of an annual plant is to make babies for next year, right? So we wanted to make a lot of babies, so we don’t wanna lose on potassium. Now what we can see late in the season is if that source sink relationship, once we get into some later reproductive stages, is we’ll [00:10:00] see that potassium deficiency, it’ll manifest itself in the top.
[00:10:03] Mike Howell: Bobby, that sounds a little bit like a nitrogen deficiency, and when I’m thinking about that in these soybeans, I’m thinking about these water log conditions that a lot of the beans that you and I are looking at are in these days with all the rainfall, they go into an anaerobic condition and just can’t get the oxygen in there to supply that nitrogen.
[00:10:19] Mike Howell: How can somebody I. Determine between those two symptoms.
[00:10:22] Dr. Bobby Golden: I think when you’re starting to look at nitrogen deficiency versus potassium deficiency, I think when we are addressing nitrogen and concerns in soybeans, the two that’s really hard for me to identify a part is nitrogen and sulfur, because it’s gonna be a overall lesser green plant.
[00:10:40] Dr. Bobby Golden: It’ll be a overall yellowing of a plant. Maybe what I like to talk about is a washed out green versus this, for lack of better words, highlighter yellow only on the leaf margins that you observe with potassium deficiency.
[00:10:54] Mike Howell: Bobby, if we do detect that we have a K deficiency in these soybeans and where we’re at, we’re getting [00:11:00] soybeans that are getting close to the reproductive stage.
[00:11:02] Mike Howell: If they’re not today, they will be in the next week or so. I know other people are just trying to get those soybeans planted, but a wide range of the crop out there right now. But if we determine in season that we have a K deficiency, what can we do? How do we correct that? Is it worth doing anything?
[00:11:18] Dr. Bobby Golden: I think there’s multiple ways we can go about correcting it and there’s a lot of research that’s been published recently that suggests we can get positive ROI to corrections in season.
[00:11:29] Dr. Bobby Golden: So we can have multiple avenues. Primarily if we’re seeing a visual deficiency, we’re going to need to go out with Myriad, a pot ash, somewhere in that 60 to 120 pounds, K two O range. I think what’s more important is when we catch it, do we catch it early enough? If you think about soybean physiology and where we’re at when we start getting into those early reproductive growth stages, and you look at R three when we start forming those three 16 inch beans, right?
[00:11:59] Dr. Bobby Golden: We [00:12:00] know we’ve got that source sync relationship happening. That’s generally when we see a lot of this visual potassium deficiency. And based on the recent research, we’ve got R four in some states and R five and others to get those fertilization out there where we make that yield back up and we’re not losing a lot of yield.
[00:12:20] Mike Howell: R three is, you said is a critical stage and that’s gonna be a three 16 inch pod on that soybean plan. Is that
[00:12:27] Dr. Bobby Golden: right? Upper four nodes, if we’re talking about group four soybeans, predominantly that’s grown in the Mid-South.
[00:12:34] Mike Howell: Bobby, you said we could get a economic return on this. How much yield can a grower expect to recover if they make these fertilizer applications in season?
[00:12:43] Dr. Bobby Golden: I. Well, I think that really determines on your yield potential of the farm. And every farm is different, right? It’s not uncommon to get 10 to 15% back that you would have lost once you see that deficiency. And there’s some really great work out there. So not trying to put a number on it, because if [00:13:00] you’re on a hundred bushel field, that’s gonna look different than if you’re on a 60 bushel.
[00:13:04] Mike Howell: Exactly. We can. Recover some of this yield that we were gonna lose, and you said we can get an economic advantage to doing that. I know you did some work back in Mississippi, and this has probably been 10 or 12 years ago, but you were looking at some small plots and some large plot demos in the same field, and I think we did a video back then that still posted on our eKonomics website.
[00:13:24] Mike Howell: You were looking at a 12 bushel yield increase in that. A specific environment, and I think you showed an $83 return on investment after you made that application. Definitely something that somebody can make up some loss there,
[00:13:37] Dr. Bobby Golden: and I think that when you talk about those numbers, that 12 bushels is real.
[00:13:42] Dr. Bobby Golden: I think the closer we get to R five, it starts backing down, so that’s a sliding scale. There’s some good work. Put out in University of Arkansas that’s actually got a cost, an ROI calculator on it that can show you that really, if you look at going into the season we’re at right now [00:14:00] and the price potash fertilizer, it’s almost a no brainer to be doing these tissue samples and look at where you’re at so you don’t have a hidden hunger scenario knowing.
[00:14:10] Dr. Bobby Golden: Especially in the Mid-South, the severe weather that we’ve had these beans grow up in. Right. Probably gonna have a limited root system because as you said the other day in a field, I walked in Friday afternoon, had roots coming out at the soil surface because it’s just so water loss.
[00:14:26] Mike Howell: Exactly. Bobby, I’ll remind our listeners, they can always go back to our eKonomics website if they’re interested in tissue sampling.
[00:14:33] Mike Howell: We’ve got a video on there that you and I did years ago talking about tissue sampling and how to sample plants at various growth stages. I wanna check that video out as well and learn how to take these tissue samples. That sample’s only as good as the quality that you put into it, so make sure you get a good sample if you’re gonna be doing some of these tissue samples.
[00:14:52] Dr. Bobby Golden: That’s correct, Mike. And there’s a lot of university recommendations out there as well on how to take proper tissue samples. And one thing that if you [00:15:00] specifically look in the midsouth, most of our tissue concentration correlations to yield have been conducted with just taking the triol and not that long.
[00:15:09] Dr. Bobby Golden: Peole that attaches to it.
[00:15:11] Mike Howell: Great advice there. Bobby. We’ve talked a lot about soybeans and the need for potassium in soybeans. What about other crops? We see this ca deficiency showing up or the decline in soil test inventories? I know I’ve been seeing this same thing in cotton for years. Can we recover any GU in cotton if we start seeing that in season?
[00:15:30] Dr. Bobby Golden: We’ve got some research. I guess going all the way back to prior to me joining Mississippi State University when I was at the LSU Ag Center, showing that we could recover. Cotton yields as well. If you think about cotton, right, it’s a tree. It’s not an annual crop, so it will react differently to in season potassium application than an annual crop.
[00:15:53] Dr. Bobby Golden: And we all know how cotton throws fruit, so a potassium deficiency can make it. Throw off fruit as well, [00:16:00] just like a cloud or insects, maintaining that status. When we get those real heavy bowl loads, we’ve seen that we can increase yield as well there.
[00:16:08] Mike Howell: Okay. Potassium, we’ve talked about this numerous times, is definitely one of our essential plant nutrients.
[00:16:14] Mike Howell: I hope we’ve shed a little light on how important it is today, Bobby, is there anything else that you think we need to cover today? Any take home messages you wanna leave the listeners with?
[00:16:23] Dr. Bobby Golden: Most of the talk that we’ve done today has been in mid southern irrigated systems. There’s just as much work in the Midwest out there on non-irrigated systems showing in-season potassium applications can help whether it be granular or foliar applied.
[00:16:40] Dr. Bobby Golden: One thing that we’ve always said is if you are seeing visual symptoms and it’s not environmentally induced via drought, granular potash is probably gonna be your best bet. Because the way potassium moves in the soil with diffusion and soil water. Now, if you’re in a drought situation and we can’t move [00:17:00] that potassium to the root, then supplemental applications with nutrients absorbed through the leaves such as foliar could help you get through a window in time to make that granular application.
[00:17:11] Dr. Bobby Golden: What you hear a lot of people talk about is, oh, if I’m putting, uh, muriate granules out on the ground in season. Is the plant gonna take it up? Well, obviously we’ve been talking about how the plant takes it up, but if you look at those recovery efficiencies, they’re very similar to pre-plan applied recovery efficiencies and can be as great as 80% based on small plot research.
[00:17:33] Mike Howell: And Bobby, while you were talking about that, I just happened to think of one other question and maybe should have had this earlier up in the episode, but we’ll go ahead and get it in now. We talked about how to address this problem. If we see a deficiency, is it better to address this in season or are we losing yield still?
[00:17:49] Mike Howell: Are we able to recover all of it? What I’m getting at is are we better off to make an application in the fall or the spring and address those locate levels then, or can we make up everything that we could potentially [00:18:00] lose?
[00:18:00] Dr. Bobby Golden: From my standpoint, what I’ve always talked about, being a sole fertility practitioner and allowing growers to spread their risk around, I always like a multi-tiered approach.
[00:18:10] Dr. Bobby Golden: We’ve got a lot of people that want to apply their potassium in the fall, and if you’re a CCC is in the proper levels, that’s great. We’ve got other people that have lower CCCs that have moved to awe. Plant to end season type system and it works on their farms. So what I would suggest is get with your advisors that know your farm, know your soil textures, and they can help develop a program for you based on your acre.
[00:18:38] Dr. Bobby Golden: I think most farms out there that I deal with, we’re on a split application method. We’ll put a lot of it out in the fall. Then we’re gonna save some to come back in the spring just to hedge our bets on environmental conditions.
[00:18:51] Mike Howell: Bobby, we could keep going on this for hours, but I know you’ve got a lot of stuff going on.
[00:18:55] Mike Howell: I really appreciate you taking time outta your busy schedule to be on the program with us [00:19:00] today. Listeners, we appreciate you tuning in and if you will hang around just a couple of moments and we’ll be right back with segment two. Farming isn’t farming without questions, and now there’s a place to go for answers.
[00:19:12] Mike Howell: At eKonomics, an entire team of agronomists is waiting and ready to help for free. No question is too big or too small. Visit Nutrien eKonomics with a k.com. And submit your question with the ask an agronomist feature.
[00:19:29] Mike Howell: Listeners, welcome back For segment two, we have Dr. Alan Blaylock, senior Agronomist with Nutrien. Back with us today for another Ask the agronomist question. Alan, we’ve had you on, and we’ve talked about nitrogen management quite a bit this season, but one thing we haven’t talked about is nitrogen management in soybeans.
[00:19:46] Mike Howell: Now we know soybeans are a legume and most people aren’t putting nitrogen on soybeans. But do we still have the potential to lose nitrogen from the system even in a soybean system?
[00:19:56] Yes, Mike. We do have the potential to lose [00:20:00] nitrogen from a soybean system. Remember, the nodules on the soybean are converting nitrogen from the air into plant available nitrogen.
[00:20:08] Well, those nodules, those are bacterial colonies. Well, what do bacteria do? Well, like any other living organism, they grow. They die. They decompose, goes back into the soil, so there’s a nitrogen contribution into the soil from those systems during the season even. And then obviously when the crop is harvest, we leave all those nodules behind and we drop the residue, the leaves, and stems onto the ground and they decompose.
[00:20:31] So there’s nitrogen. In that plant residue, there’s nitrogen in the soil from the soybeans, and as that converts to nitrate, it can be lost by leaching or denitrification. As we’ve talked about, there have been some studies that show in a corn soybean rotation that leaching losses during the soybean year may be greater than during the corn year.
[00:20:50] We need to recognize that these are dynamic biological systems and that all these plants need nitrogen. They have to get it from somewhere. And yes, the soybean system is very [00:21:00] efficient. Most soybean crops in good soil conditions can fix enough nitrogen to grow good yields, but that doesn’t eliminate completely the risk of loss from the system.
[00:21:10] Mike Howell: Alan, is there anything we can do in that situation to prevent some of that loss? Well,
[00:21:15] I’m not sure if there’s much we can do. Obviously growing a good healthy soybean crop, so the soybean is scavenging as much of that nitrogen as possible, so that’s good. Lower yielding crops don’t use as much, so if they’re fixing nitrogen that the crop isn’t.
[00:21:30] Using, well that leaves more in the soil, but you know, it’s a biological system. We don’t have control over the zoa really. But I would say growing the healthy crop is probably the best thing we can do. Now, another thing that we can do, and this isn’t maybe suitable for everyone, but where possible, if we were to grow, say a cover crop following the soybean harvest, to scavenge any residual nitrate nitrogen left in the soil over winter and grow that cover crop until we’re gonna plant.
[00:21:58] Corn or wheat or [00:22:00] whatever the next year, then we can scavenge a lot of that nitrogen and keep it circulating in the organic fraction in the soil and not leave a lot of nitrate nitrogen in the soil to be lost.
[00:22:10] Mike Howell: Alan, great information. Thanks again for joining us this week. Listeners. We really appreciate you tuning in, and as always, if you have any questions about anything we’re talking about, you can visit our website at Nutrien eKonomics with a k.com.
[00:22:25] Mike Howell: Until next time, this has been Mike Howell with the Dirt. Hey guys, if you like what you heard today, do us a favor and share this podcast with someone else. It could be your neighbor, your friend, your crop advisor, or whoever you think would enjoy it. Your support helps ensure future episodes, so please like, subscribe, share, and rate the show wherever you’re listening from.
