The latest regarding risks for and management of iron deficiency chlorosis (IDC) in soybeans

Drs. Dan Kaiser and Seth Naeve discussed iron deficiency chlorosis (IDC) in soybean on today’s episode. IDC is a result of the plant not being able to take up sufficient amounts of iron, which results in leaf yellowing with leaf veins remaining dark green. Kaiser and Naeve discussed soil conditions across the state that can result in IDC that result in high pH conditions that limit the availability of iron such as compaction and soil drainage.

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Anthony Hanson: Alright, welcome everyone, this is that space to teach a farming field notes program and we're glad you could join us this morning.

Anthony Hanson: The latest risks regarding the management IDC or iron deficiency close this focus of today's program we're going to talk a little bit about what's going on with our sweet beans in the general health those today.

Anthony Hanson: So these sessions are brought to you by University of Minnesota Extension, as well as generous support from the Minnesota Soybean Research and Promotion Council.

Anthony Hanson: As well as the Corn Growers Research and Promotion Council. I’m Anthony Hanson regional extension educator in crops and integrated pest management.

Anthony Hanson: And we also have Angie Peltier extension educator northwestern Minnesota and today we're going to team up to talk to hopefully to folks right now we have Seth Naeve he is with the.

Anthony Hanson: University of Minnesota department of agronomy professor and extension agronomists there and then we will hopefully have Dan Kaiser on later.

Anthony Hanson: he's an associate Professor with department of soil, water and climate and both these folks are going to be looking a little bit of what goes on, with iron deficiency chlorosis.

Anthony Hanson: And with that I think I’ll turn it over to you Angie.

Angie J Peltier: Thank you Anthony welcome to everybody that's tuned in to participate in this webinar today.

Angie J Peltier: First, I would like to again introduce Dr Daniel Kaiser he is.

Angie J Peltier: A Professor that works on soil fertility issues and.

Angie J Peltier: Dan Would you mind turning on your camera and.

Angie J Peltier: getting ready for a question so.

Angie J Peltier: Just to lay the foundation here, please, if you wouldn't mind take a few minutes to remind us all of the soil characteristics that really favor iron deficiency chlorosis or IDC in our soybean fields.

Daniel Kaiser: Well, the majority of the issues, if you look at it.

Daniel Kaiser: You mean soils prone to it are either going to be one of two things hiring carbonates or higher and salts I mean it tends to be kind of what we see.

Daniel Kaiser: In the red river Valley, even though a lot of soils are formed on carbonates they don't always have as much near the soil surface, but they tend to still yellow up in the moose are getting this particularly this timeframe June, when we have.

Daniel Kaiser: Conditions favorable for it see that the interesting thing when you look at IDC is the fact that it isn't necessarily that those soils are always going to get IDC I mean environmental factors really play in a lot to what's going on.

Daniel Kaiser: Because a lot of the issues isn't as much we start talking about carbonates as it is by carbonate, which is something that's formed in the soil.

Daniel Kaiser: When carbon dioxide is trapped in the soil typically when we have water log sales tend to be what we see in West central.

Daniel Kaiser: Or you know Southwest Minnesota areas that have high lime is really to buy carbonate issue, more than anything, by carbonate isn't stable so when you get to aeration it's going to break down for carbon dioxide and it's going to leave so that's again why.

Daniel Kaiser: At times we see it see but we don't always see it so one of the things with it we can't measure by carbonate in the soil, so, in the end it's.

Daniel Kaiser: not something we necessarily contract We just have to know where soils are prone to it and then kind of manage accordingly one thing going into this year.

Daniel Kaiser: I think that favorite a lot of our issues is nitrate, there is a linkage, you know Seth can talk a little bit about that between high nitrate and IDC and there is a lot of work.

Daniel Kaiser: By john where's my know up in the Northwest part of the State where they were inducing iron clauses are making it worse by adding.

Daniel Kaiser: Nitrogen to the soil, because we know there's a link and within the plant and then also as the plants taking up iron nitrate can.

Daniel Kaiser: cause some problems so I’m not going to get into the weeds of that, but we knew kind of going into this year with some of the residual nitrates that are out there, that there may be an increased risk in some of the fields, particularly up in the red river Valley.

Daniel Kaiser: Where drought conditions you're falling wheat or corn or something that may not utilize all the nitrogen if that was hanging around this year there be some risks so.

Daniel Kaiser: I said it's an interesting issue because you can we know we're kind of things are prone it's not necessarily just a high pH issue there's got to be other factors that in play, but you know environmental factors really are kind of the triggering point where we see a lot of these issues.

Angie J Peltier: Sets did you have anything to add on that.

Angie J Peltier: Net sort of topic about the nitrate this year or carbonates or any other soil related issues that influence IDC development.

Seth Naeve: know, I think, Dan covered it really well, I think the only.

Seth Naeve: Everything I have is kind of anecdotal and, and so I don't know that there's any science that I can add to it, except you know the story that I kind of appreciate from the valley is.

Seth Naeve: Is when I started working on IDC 15 years ago we talked a lot about rotations and soybeans following beats was a little bit of a new.

Seth Naeve: phenomena, but people found that soybeans following beads did a lot better so we really thought this was all about water.

Seth Naeve: early in the year, and that the beats really drawn out a lot of that excess water out of the profile or.

Seth Naeve: We had better at water infiltration and that still could be, but you know it's quite likely to that we just have less nitrogen carry over after our beads so.

Seth Naeve: I think, as farmers start looking at some of the spots that show up a radically, they should be thinking about what they had last year, and whether those areas were you know flooded out or maybe they.

Seth Naeve: Maybe they actually lost nitrogen and some of those areas that greened up this year or, if so, looking at it a little bit differently, through the nitrogen lens.

Seth Naeve: I think, can help explain some of the things going on, but also, I look at this a lot by water and where water is moving in the profile and water is moving salts and.

Seth Naeve: And nitrates around up and down to the soil profile and I think especially early in the season, we are it's, we have to remember that's why being plants, really.

Seth Naeve: utilizing a very small part of the soil profile early on, now we're developing a decent rut going down but were both the location of that route is going to affect IDC.

Seth Naeve: But also it's access to iron and moving down through the soil profile, so you know I think this whole interaction between.

Seth Naeve: bicarbonate it's calcium carbon it's by carbon it's nitrates, salt and water all together that's probably explaining this but there's a lot of things going into those few factors.

Anthony Hanson: To add another complicating factor there now, at least for parts of the State June has been one of the driest months even drier than last year.

Anthony Hanson: So when we talk about water how with a set interaction possibly come into play, or is there much to talk about at least in the month of June that might have been developing variety see related to how dry it's been.

Seth Naeve: yeah it's a good question I don't and I don't know specifically you know, sometimes we get and that's why I think it depends on where we're at in that soil profile where.

Seth Naeve: Where are our salts have moved where that nitrogen is sitting and sometimes we're kind of chasing things around with the soil profile.

Seth Naeve: I think a lot of times when we get into this time of year and we get that really hot dry weather, we tend to push through IDC pretty well and it, it could be that we're just forcing a wrote down into the soil profile deeper that it has access to.

Seth Naeve: Available iron in the soil down deeper, but it also could be related these other factors as well, so I don't have a good answer for you, maybe, maybe Dan can help you.

Daniel Kaiser: yeah it's a good question, I mean I said just looking at the differences across the state, I mean normally would say okay well flooded soils are going to be or issues but typically we get up to the valley that isn't always the case.

Daniel Kaiser: And you'll end up with particularly all your whole fields going yellow compared to.

Daniel Kaiser: Just the rims around some of the potholes in the southern part of the States, so I guess yellow Madison county to come across it to where we get some.

Daniel Kaiser: Some fields going completely yellow so it isn't necessarily they're just that it's just a water log situation it's complicated issue and that's really the problem, and I think a lot of the issues valley probably.

Daniel Kaiser: boil down to nitrate because you tend to see a little bit more residual nitrate carried over from one year to the next and then interacting with.

Daniel Kaiser: Some assaults because, again, you look at some of those soils well there is carbonates in there, I mean it isn't necessarily 100% of carbonate issue but.

Daniel Kaiser: As cephas saying the rich growing down, I mean they're going to encounter carbonate layers Karina see that deeper in the profanity but it's not at the top six inches so.

Daniel Kaiser: it's one of those things that we just know we got to manage for and what's the best way to manage, for it is really the key i'm trying to figure out how to do that and.

Daniel Kaiser: You look at channel planning a tolerant Variety is usually our suggestion, although it's not perfect scenario, you can see, you know some issues with that as well, but that's kind of a number one and then looking at some of these other practices, the infernal Pilates.

Daniel Kaiser: If it's an add ha ortho key late it's going to be effective there's some other ones out there you look at some of the work that Jay goose done up and.

Daniel Kaiser: And de Su I mean you look at kind of the effectiveness of it and I guess George dream, you know before me did a lot of work, looking at some of these key lights and really getting the right one, is critical and there's a lot of options out there.

Daniel Kaiser: At one point, sorry green was kind of the go to although there's some other ones out there, I mean that the key with a lot of these, though, is that correct key late source we that's why I think the rates and some of these go up and down because.

Daniel Kaiser: The ortho percentage of whatever is key late it does change on some of these but that's critical, because we know that Pilates has better stability at higher pH is and that's really the issue with a lot of these iron.

Daniel Kaiser: products is the stability, the way they released the iron if it's too quick keep it around and the iron to form it's going to essentially be worthless once it hits the soil.

Daniel Kaiser: So that's been kind of the issue with a lot of that and, at this time a year, I mean unfortunately we start seeing fields go yellow I mean yeah you could go out and spray.

Daniel Kaiser: On some folio key lights it worth ortho me make green it up, I think it's largely going to be cosmetic.

Daniel Kaiser: At this point, because you have to remember that iron and the plan is not mobile, so it my Green up the tissue that hits but it might still grow out with new.

Daniel Kaiser: vegetative growth might be still be yellow with it so that's kind of the challenge of this, I mean it's something that really needs to be taken care of at the initial stages of.

Daniel Kaiser: planning is, we found that it's more effective concentrating some of these key light sources near the road where the plant can continually feed off them.

Daniel Kaiser: So that's been kind of the the big thing and that's what sets been working on a little bit looking at you know different placement option just some different methods for treating this.

Daniel Kaiser: But number one is still a tolerant variety and then start looking at some of these other practices which can get pretty expensive because a lot of these products that they aren't free so they do come with a cost.

Seth Naeve: i'll just jump in really quick and you know, we do have study Minnesota soybean growers are.

Seth Naeve: The research promotion Councils funding a project i've got a graduate student that's working on this project, right now, and second year.

Seth Naeve: And we're looking at the questions that Dan just raised varieties iron key layouts and then we're also looking at populations, too, because we've seen a lot of farmers really pull back on populations.

Seth Naeve: So I guess the big picture for me as farmers really have to know what they have to look very carefully at risk from a risk management standpoint.

Seth Naeve: Because that's the question I always get from farmers, as they say, well, we have IDC we know these fields have IDC.

Seth Naeve: But it's not everywhere in the field and it's not every year, so we hate to spend the money and putting good iron key laid down on every acre every year.

Seth Naeve: So, then, I just really emphasize the farmers, they really have to have good notes good.

Seth Naeve: Look at their yield maps and have a good idea where they were hit by IDC and how much yield last they had over time.

Seth Naeve: so that they can pencil it out, because iron key lights, really, really do work and varieties do work populations help a little bit, but they all have some costs to farmer, and so we have to.

Seth Naeve: They just have to really have a good handle on what their losses are, but it is something that it's really one of the best applications for a variable rate system, farmers can.

Seth Naeve: turn on and off an iron key late with a switch they don't have to have a really high tech variable rate system, as long as they know where those spots are they can manage either rates or.

Seth Naeve: or just switching on and off fairly easily and that's another way they can test these things to they could very easily leave strips and so that's one of the beauties of IDC is that we have a visual symptom.

Seth Naeve: That is pretty well correlated with yield and so farmers can do some strip testing and look at these things in the field and get a very good this time of year, they have a pretty good idea.

Seth Naeve: How those varieties are doing or how their iron key lights are doing or how populations are doing for them that will translate to yield pretty well so it's it is something that we could do some on farm testing with at a pretty with low cost of the farmer.

Angie J Peltier: So one question and then we can get to some of our audience questions.

Angie J Peltier: i've always been curious at what point during the soybean.

Angie J Peltier: life cycle can one look at a variety, for example, and see okay indeed my crap has pretty severe IDC and know that's going to translate into a loss of overall yield potential is there a time to be looking at that, or is it if you see it you've already lost cemil potential.

Seth Naeve: that's one of the things that my students looking at we're doing weekly drone imagery and so we're trying to look at this question about recovery.

Seth Naeve: Because actually varieties do recover at different rates and we see different kinds of recovery, you know, of course, by.

Seth Naeve: By the location so that's another issue for us so it's a little bit hard we can't say go out on June 1 and if you have.

Seth Naeve: An ND VI value or, if you have a canopy closure level of X that you're going to have X amount of or y amount of appeal loss.

Seth Naeve: On the other hand, I will say as a soybean physiology guy would say that basically anytime we lose growth.

Seth Naeve: That we're losing yield potential at this time, so anytime we don't have aren't fully producing a canopy as in the green part of the field we have yield loss relative to that so it's there's we're anytime we're not capturing as the maximum amount of light.

Seth Naeve: anytime we have some yellow leaf material or we're not closing the rose by a number of days, those are that's yield loss for us relative to.

Seth Naeve: The other condition, so it is something we can you can, I think, farmers can do a gut check on this pretty well and probably have a pretty good handle on it without us getting too techie on that side.

Angie J Peltier: Okay question from our audience here is what a ride cover crop help to absorb the nitrates and less than IDC now seth I know that you've done some work looking at.

Angie J Peltier: spring oats along with planted along with soybean and I know that we currently this year up in West central Minnesota and then the crookston area are looking at IDC and.

Angie J Peltier: And cereal riaz a cover crop planted last year, but have you done any work looking at rise a cover crop for IDC.

Seth Naeve: gel just be really quick we have not we did, as you mentioned, we did a companion crop study I did that with George dream several years ago, so we planted soy.

Seth Naeve: oats with the soybean so it does help to have that companion, with the crop but.

Seth Naeve: As soon as we sprayed out the odds with around up first pass around up, then the soybeans went back to the same yellow color that the other soybeans worse, so we didn't really get anywhere forward, but I think having something out there earlier.

Seth Naeve: Definitely has a lot more potential so maybe Dan has a little more experience with them.

Daniel Kaiser: Well we've done it in its have had a couple sites were and I seen some data, where it's actually increase yield, so the main thing with it is when we've done oh it.

Daniel Kaiser: has been making sure we terminated at the right time, not letting it go beyond about 10 inches so because that's going to be the same issue with rise since we're I is.

Daniel Kaiser: You know, pretty effective at taking nitrate but also water out of the profile you let it go too long, essentially if you're in a situation or well will be probably not this year well there's a lot of water.

Daniel Kaiser: around in the spring, it can compete with your soybean crop so that's kind of the main thing.

Daniel Kaiser: That, I think there could be some advantage with that, but you've got to have the termination time down where you're not getting excessive amounts of growth and.

Daniel Kaiser: Again, the recommendation for just based on some of the stuff that George did was about 10 inch termination.

Daniel Kaiser: On that, and you know I had some fields that and some of the studies that were doing it's been probably you know 678 years ago.

Daniel Kaiser: That we got close to heading and it yield went down so that's kind of one of the things there's a balance there, while it's effective you've got to balance it without making that.

Daniel Kaiser: companion or that preceding cover crop turned into more of a weed for that, where you have an issue with the.

Daniel Kaiser: either growth or germination early in the growing season from the soybean crop.

Daniel Kaiser: But it is effective mean we know that does take a fair amount of nitrogen out and also it can impact, some of the water that's in the soil that might potentially help with drawing the soil and reducing IDC.

Angie J Peltier: Thanks, we had another question here, where somebody asks, are there any solutions that would last more than one year for IDC.

Daniel Kaiser: I get a lot of questions on acidification of soil that's been one of the people kind of talk about that and, obviously, that would be the way to do it.

Daniel Kaiser: If you could the issue with the majority of your soils they have like what we call it a high buffering capacity are essentially high resistance to change.

Daniel Kaiser: So the amount of carbonates and that are in the soil and many of these that are affected by DC make it such that you can try to put.

Daniel Kaiser: elemental sulfur on at a higher rate and you might get a small drop in your pH but give it a couple of years, according to some of the data that advice add.

Daniel Kaiser: And they were looking at camera what the rate was just ridiculously high.

Daniel Kaiser: level mental sulfur went down, maybe i'll point to point three, the pH drops by that much, but then it was backup within about two three years to what the original level is.

Daniel Kaiser: So that's kind of the main issue, there is, you know that would be the permanent solution if you could do it's just not going to be cost feasible, I mean you might as well look at one of these other options, because it's going to take a lot of time.

Daniel Kaiser: To do at the soils are just too well buffered that they're going to resist change.

Daniel Kaiser: And you're not going to see much benefit of some of that, but that would really be about the only way to do it is to try to get rid of.

Daniel Kaiser: Some of the carbonates leach some of it out of there.

Daniel Kaiser: But you know we still see even with tile drainage, and some of these fields, we still have the problem, so I don't think you're really going to necessarily get rid of it's just going to be trying to manage it as best you can this is really the best thing you can do.

Seth Naeve: yeah I wanted to jump in on the tile.

Seth Naeve: thing I think there's a there's you know farmers really like to tile and they like to justify that and so there's a lot of discussion around.

Seth Naeve: Putting in tile For this reason, and it seems like the most obvious one, but I think, as you heard the complicating factors at the beginning of this discussion it's I haven't seen really good examples.

Seth Naeve: Where tile has really done what we hoped it would do so.

Seth Naeve: I think we have to be a little bit cautious about it as a panacea to solve the problem, but theory in theoretically, it should certainly help a lot, especially in these saltier soils.

Seth Naeve: With with plenty of rainfall to watch some of that through the soil profile.

Angie J Peltier: So something that is particularly evident this year is you can really pick out.

Angie J Peltier: wheel tracks from our sprayers that have gone through our fields where it's very striking to see these deep green soybeans right where those wheeled tracks were in a sea of IDC yellow soybeans can you comment on that.

Daniel Kaiser: So a lot of theory behind that if you look at some of the work that's been done just looking at sampling taking soil samples in and we'll tracks isn't it's that it's a nitrate effects you got compacted soils that.

Daniel Kaiser: are going to be more prone de da de notification that would get rid of some of that nitrate that's potentially what.

Daniel Kaiser: could be creating that greening effect so essentially you've got less nitrate there are less being taken up, so the IDC should be less so it's predominantly what we see mean i've seen kind of the opposite occur at some point in time, but.

Daniel Kaiser: You know just looking at some the previous data collected in Minnesota that's kind of the thing that they were showing us the difference in the nitrate values really nothing else was different between the in and out of the wheel tracks so.

Daniel Kaiser: If you think about it with compaction you're decreasing the porosity which would increase essentially the saturation which would lead to more D notification, so it makes sense.

Daniel Kaiser: From that standpoint, but that's usually the prevailing a lot of that if you look at it sprayers are also what we tend to see more as a secondary tillage.

Daniel Kaiser: passes you seals nice angle is going across the field from the wheel track so again, a lot of that just kind of what they've indicated from some of the research has been that it's just reduction and nitrate within those zones that reduces the impact of IDC.

Seth Naeve: And so just re emphasize, I mean we're talking about a very small zone within the soil that happens to coincide with where the roots are at that time of year.

Seth Naeve: And I think everything kind of comes together to create these green real wheel tracks, you know, and so we just have to be careful with.

Seth Naeve: How we use that information there's farmers that say Oh well, then i'll just go roll my soybeans well rolling you know, gives us a compaction layer you know that's very, very shallow.

Seth Naeve: completely different location within the soil is not going to have any effect so and a very different time.

Seth Naeve: So I think we just have to be careful with how we interpret those kinds of things and know that this isn't really it helps us understand the biology and the chemistry, a little bit, but it doesn't help us deal with the real issue for us from a management standpoint.

Anthony Hanson: Anti question for you northwestern Minnesota how widespread is IDC that you're seeing up there now for a lot of our other listeners across other parts of states like curious what you see up in your neck of the woods.

Angie J Peltier: Sure, so i'm like seth and Dan we're talking about we have very poorly drained soils up here and not last week, but the week before IDC came on strong So you can see those folks that.

Angie J Peltier: might have had a little bit better IDC tolerance in their variety that they selected for a field, you can also see those people that probably, in addition to that might have put on an iron key late, but by and large, most of the soybeans.

Angie J Peltier: crossfield fields are suffering right now.

Angie J Peltier: yeah I.

Seth Naeve: have another interesting anecdote I talked to a farmer last week in South central Minnesota that's in the zone right where we kind of transition from acid them.

Seth Naeve: High pH soils and he has almost every one of his farms has a little bit of ITC and a little bit of area where they have.

Seth Naeve: White mold shows up So these are things that I tend to think are kind of mutually exclusive, and we don't tend to see these in the same areas but it reminds us that we see a lot going on, even specialty within the same field in some areas, and so.

Seth Naeve: there's a farmer that has to really deal very carefully with populations in their farms and they're actually trying to map.

Seth Naeve: And and really reduce populations, where they have tendencies for IDC or for white mold.

Seth Naeve: And then push populations higher in those IDC areas, and so they have to be very, very careful to so that they can manage these things within the same fields.

Seth Naeve: And then, of course, a variety selection is a huge problem, because you know those those issues have been kind of selected for separately as well, so.

Seth Naeve: It it's not just a looking at this on a huge scale, but it could actually be a problem on a very small geographic scale to.

Anthony Hanson: Any last questions before we head out here.

Angie J Peltier: The only last question, I had, I know that Seth a couple years ago you had a graduate student that was working on looking at the interactions between IDC and SEM So if you could comment on that.

Seth Naeve: yeah original question was you know these are two problems that tend to show up a lot on high pH soils and.

Seth Naeve: They both tend to cause soybeans to get a little bit yellow and stunted.

Seth Naeve: So we are wondering if there's really any interactions is one making the other one a lot worse and the short story is really that we don't find that they don't there isn't a real.

Seth Naeve: interaction so each of these problems, seems to be independent of each other, except.

Seth Naeve: The one interesting thing that we found was that SDN still reproduces at a very high rate, even on sick ugly stunted yellow soybeans so this could be part of our problem is that, where we do have IDC and we have really poor looking soybeans we can still support high levels of reproduction.

Seth Naeve: it's not what we usually expect when we think about of you know kind of this parasitic relationship as you think that a.

Seth Naeve: unhealthy soybean wouldn't support I SDN reproduction.

Seth Naeve: But, but the sex probably taking advantage of the fact that the soybeans kind of standard and unhealthy and actually reproducing and high levels on it, and it could actually be why.

Seth Naeve: We have such a large population show up and in western Minnesota and high pH soils to it could lead to some of these very high population so.

Seth Naeve: In effect, we're causing ourselves a worse problem, so the only management thing I would suggest is for farmers that have small areas of fields that they just cannot grow a decent soybean crop on.

Seth Naeve: Maybe they should stay out of those with soybeans that they're not doing themselves any favor by planting a soybean and only being able to harvest 2020 bushels out there.

Anthony Hanson: Alright, well, thank you seth and Dan for joining us today and covering iron deficiency close this, and thank you angie to for an emceeing and.

Anthony Hanson: walking through kind of what's going on in northwestern Minnesota and thank you for everyone who attended as well, this is strategic farming field notes.

Anthony Hanson: And if you when you do close out remember there's that very short for questions survey.

Anthony Hanson: That helps us know just how we're doing what we can improve and also what we might be looking at for future sessions as well for potential topics.

Anthony Hanson: And with that, I would like to thank our sponsors Minnesota so did research roshan Council suppose the Minnesota corn research and promotion console.

Anthony Hanson: Next week session will be July 13 at 8am sounds like we'll be covering corn pollination, at least as well as other topics we're still looking at, and with that - Thank you and have a great rest of your day everyone.

The latest regarding risks for and management of iron deficiency chlorosis (IDC) in soybeans
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