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Talking Crop is a row crop production podcast that brings current trends, actionable management considerations, and research updates from guest experts to farmers, agribusiness representatives, and agriculture agency professionals.
Hello, and welcome to the Talking Crop Podcast. I'm Kathryn Seebruck, Commercial Agriculture educator with University of Illinois Extension serving Jo Daviess, Stephenson, and Winnebago Counties. Talking Crop is a seasonal crop production podcast with episodes occurring every other week during the growing season between the months of May and September. In each episode, I bring on a guest speaker to discuss topics related to their areas of expertise. Today's episode is the final of this first season of Talking Crop, and in it, I am joined by Dr. Andrew Margenot, Associate Professor of Soil Science in the department of Crop Sciences at University of Illinois Urbana Champaign.
Kathryn:Andrew was also the Director of both the Morrow Plots and the Alma Mater Plots at U of I. He and I discuss the Illinois Centennial Soil Archive Project as well as his work to update the phosphorus and potassium recommendations in the Illinois Agronomy Handbook. The story behind the Soil Archive Project is fascinating as it involves century old soil samples found in an old building on campus and will lead into a really interesting project that will uncover valuable information about Illinois soils across the entire state. And producers around the state are going to hugely benefit from updated phosphorus and potassium recommendations and may even get to play a role in the research that will result in these updates. Listen on to find out more.
Kathryn:An exciting update about the podcast as a whole is that we are adding it to the Illinois Extension website. If you're listening after the fact, you may be a little confused to hear me talk about adding links to the video description as the podcast originated on YouTube. Just a little FYI there. As I mentioned before, this episode wraps up the first season of Talking Crop. I'm really appreciative of the guest speakers who joined me this season and for all the great conversations that we've had. I hope you, the listeners, have also enjoyed it and have gotten something valuable from conversations as well. I'm already looking forward to next season, which will come back around in May 2025. Without further ado, please enjoy this final episode of the first season of Talking Crop, talking 100 plus year old soil samples and their implications for Illinois with Dr. Andrew Margenot. Andrew, thank you so much for joining me today for the Talking Crop podcast. I appreciate you taking the time to be here.
Dr. Andrew Margenot:Of course, Kathryn. Thanks for having me.
Kathryn:The two main things that I want to talk to you about today are two of your big projects. The first being the Illinois Centennial Soil Archive Project and the second being your work on updating phosphorus and potassium recommendations for Illinois. I wanted to start with the soil archive project. I know I've heard quite a bit about this and I've seen some things you know floating around here and there and it's a really interesting project so could you start by explaining the background of this project and what all it entails?
Dr. Andrew Margenot:I'd be happy to. The project, as the name might imply, has to do with a really rare collection of soil samples as far back as the 1800s. The oldest sample we have is 1861, and the most recent samples are from two years ago. This is a soil archive that was developed from the original soil sampling of the Illinois State Survey. We know that we've got soil maps of any given farmland in the contiguous lower 48 states.
Dr. Andrew Margenot:That was a long, long effort that began in the 1800s. Like in our state, with scientists from the land grants going around describing soils, where they dig a soil pit. They look at every single layer in that pit, these different horizons as we call them. They describe soils, they give them a certain classification, and over time this led to the development of these maps, soil type maps. Well, it turns out that the samples for the Illinois survey were kept on campus and stored. It seems like they exchanged different hands and different storage places.
Dr. Andrew Margenot:They used to be at one point in Davenport Hall on the main quad, then they were put into the tunnels beneath Turner Hall, and they ended up at a dilapidated pole barn on the South Farms where we rediscovered them in 2018. There's over 8,000 samples, and these correspond to 460 locations across the state because keep in mind each location has multiple depths and thus multiple soil samples. This is exciting because the samples go back with pretty high coverage of the state through the 1910s and 1920s, through the whole twentieth century. In sum, this is what we believe to be the world's largest in terms of area coverage, but also the oldest archive. It's a huge resource for us to understand soils across the state.
Kathryn:You were mentioning that they were originally collected to develop those soil maps of the state. Are these the same soil maps that you see for example like on the web soil survey online?
Dr. Andrew Margenot:Exactly right. The soils that were taken from this effort were the basis for the pedon characterizations. A pedon is simply a soil individual, and so these characterizations of soil properties etc, and where you find certain kinds of soils were then used for the SSURGO as well as the NCSS data set. Simply the data set from which the NRCS pulls the properties like CEC or clay content.
Kathryn:These were obviously taken a long time ago, and I know we'll talk a little bit about how you're getting these repeat samples now. Way back when do you have any information on how those samples were taken in terms of I think something you got your team might struggle with is getting permission to go back and re sample. Back in the day, did you know if they had any issues with that or if it was mandated that they were allowed to do so?
Dr. Andrew Margenot:That's a great question. It might help to think about the two phases of SOUL survey Basically, it's before and after NRCS. Really, NRCS was at one time called the Soil Conservation Service, SCS. It's really pre SCS/pre NRCS or post. It began with states.
Dr. Andrew Margenot:It was first a state endeavor to map soils. The first soil survey ever was in 1899 in Illinois, in Adams County specifically. That was the first documented county effort. Now there were efforts before that, hence our 1861 sample. Then after the 1940s, don't quote me on that, we have the feds helping cooperate, so this is called the Cooperative Soul Survey.
Dr. Andrew Margenot:For the latter, I believe, it was a combination of networks, and also as part of a federal effort, then the permissions could be gotten. The idea was that mapping a resource was part of federal rights to get onto private property. Now, pre or let's say the phase one pre NRCS, I don't know. That's a good question. My sense was that it was a lot of knocking on doors and asking for permission to sample.
Dr. Andrew Margenot:This is also at a time, Kathryn, when soil science was in its infancy, and it was a big deal to get a researcher from the U of I come knocking to help understand soil types. We have the notebooks by Dr. Hopkins, the first soil scientist in my office right here in front of me. These are the notebooks in that pre NRCS stage. They're in Quillink, and they've got dates.
Dr. Andrew Margenot:One actually says 09/04/1901. These are thousands of pages of entries and it seems like from his notes that he was knocking on farmhouse doors because we have notes like by the red farmhouse 200 feet away from its oak tree in the front lawn, those kinds of things. It sounds like it was based on personal interactions. To back up to today, we do have the challenge of finding permission from the landowner to sample, and we are able to find who owns land that's public record, and there's apps like OnX for hunting, where they pull into the public database from the tax records who owns the property. There's two issues there.
Dr. Andrew Margenot:One is that a lot of land is now owned by investment firms. Not a lot, but more and more land is owned not by a person, but by a corporation or LLC, and that's a dead end for us. The second is that even if we have a name, we would like a way to get in touch with them directly like a cell phone and that proves to be the bottleneck in finding or asking for rather the permission to resample.
Kathryn:Like I said at the beginning I've heard quite a bit about this project and are you guys putting in a lot of effort then to try to get the word out so that you can hopefully find those folks and subsequently their contact information?
Dr. Andrew Margenot:We sure are. Here we've tried different approaches describing this effort on social media like Twitter through the Farm Bureau. We've given a lot of talks at the county level Farm Bureau offices at field days where we had talked about this project. And so it's been pretty successful. I want to point out that a lot of alumni especially had been fantastic in reaching out and giving permission. Because of their efforts, we have either sampled or have gained permission to sample this fall roughly 130 of the 460 sites. That's a little bit more than one third of the way there. That's a big deal. For the remaining two thirds, I think that's where, we've picked off the low hanging fruit, and it might be folks who have not heard about the effort, or might be landlords who don't live in The States, and thus haven't heard about the effort.
Kathryn:Sure. Part of your guys' reasoning for doing this, at least what it states in the the promotional materials I'll call them that you put out, are that reasoning is to look at how soils have changed in the state between when these original samples were taken and now. You said you have these notes and records way back question then is were the things that you guys intend on sampling for testing in these samples were those same things tested for back then or are you going to have to sample those original samples yourselves subsequent repeat samples?
Dr. Andrew Margenot:A mix of both is the short answer. It's a great question. I will back up here and give a bit more on why we want to re-sample these, just to give folks some more rationale. The samples that we have already are a treasure trove, because we have samples that precede a lot of important innovations in ag technologies, like fertilizers. We used rock phosphate as a state by the 1910s, but really, it was a small total amount of phosphorus being applied as rock phosphate.
Dr. Andrew Margenot:Potash was rare. It was more common by the 1930s and 40s, but really, we don't see large scale application of NPK until post World War II. For example, MAP or DAP weren't really available at scale until about the 1960s when we have USDA beginning to keep records on sales for the reason that they're now exploding. The soils that we have, for example, that predates the wide scale use of NPK let us test questions about what was the native stock of P and K in soils. Because we have every layer going all the way down, we can come up with a pound per acre of the total amount, what we call a stock of a nutrient, pounds per acre.
Dr. Andrew Margenot:These are not gray or mel like, it's the total concentration. There's value in things like that. We can look at the emergence of contaminants like lead or microplastics, when they first become detectable in soils. There's all kinds of questions. Think about weed herbicide resistant.
Dr. Andrew Margenot:We can look at weeds, sorry, at the seeds of weeds in the archive jars, which are unground soils, and then pick them out and sequence them. A lot of potential here. Now we want to also resample soils. In the resampling we can understand by comparing the original soil property when it was sampled at that time with our re-analysis of a newly sampled soil, what has changed. Your question then is, have some of the soils that were taken originally been measured for a certain property of interest? The answer is sometimes, but not always. When we have a physical sample from the past, we can reanalyze it. A good example here is P and K. We have interest in mapping P and K levels across The States before the advent of inputs of MapDap and Potash. For this, there weren't a lot of samples, there just were not a whole lot, that were sampled for total P and K pre-nineteen forty. For those we can remeasure that, or let's just say measure on the archive sample. It doesn't present an issue of how these jars were stored, because there is no gas phase for PNK. There is for carbon, for nitrogen, and for sulfur. And because of how these soils are stored, air dry, which is important, it's critical, but they weren't exactly temperature controlled, being in a pole barn for at least twenty years. We may have lost some of the carbon and or sulfur through gaseous phases over the past centuries or decades of storage. We do have some samples that were measured for C, N, and S, those three elements that have a gas phase, and we can reanalyze that sample to look at the change as a function of storage. There's two kinds of measurements. Samples that were originally measured at the time of sampling look at the susceptible to loss nutrients, C, N, and S, by remeasuring that, that decrease that we would maybe see is due to how it was stored. And then we can correct any fresh first time analyses we do on the original stored samples. So that would be how to back correct for those artifacts of storage. Then on the new samples we run everything as is. So we have pretty high confidence. Now that would be for fertility, for things like properties of CEC or pH or clay, those are agnostic to storage, and we can remeasure those in a sample from 1860, no problem. The third kind of analysis that we're planning to do that's a bit more contentious would be soil health tests. As you might imagine, these are largely emphasizing the biology of soils.
Dr. Andrew Margenot:We have done some preliminary analyses of the DNA, so looking at the microbial community composition using DNA sequencing and also enzyme activities. Soils are full of enzymes just like our stomachs to digest, in their case, organic matter. These are made by plants, by the roots specifically, and by microbes as a way to digest organic matter and then liberate nutrients like nitrate or phosphate. Well, these enzymes are extracellular. They're not in living cells. When we air dry soils, the enzymes persist. They simply bind to the clay surface, and then when you re-wet the soil, they are activated. For the DNA side of things, we can extract that because DNA is very stable bound to clays. Long story short, we have evidence from doing some initial tests with the Morrow Plot samples from 1904 that we can resurrect what's called the fossil microbiome. I think fossil is a bit of a dramatic word here, but it's a term inherited from all these studies in paleobiology, where they like in Jurassic Park with the mosquito that's in the amber analogous to that that's not actually possible but analogous to that extracting DNA from these older samples. That's a long way of saying that we're able to have a decent confidence, understand what things were like when they originally sampled these soils, and also by looking at the resampled soils how things have changed.
Kathryn:That's really fascinating and you answered a lot of questions that I didn't even think I had initially. I'm jumping ahead a little bit here I know we'll specifically get to that updating of the phosphorus potassium recommendations but something you said made me question. Was your team and potentially others depending on who's involved was that update of the phosphorus and potassium recommendations was that already being thought about and implemented before these soil samples were found or were the finding of these soil samples kind of the impetus for something like that since you now you know once you found them you knew you had them on hand and could kind of look at how we can update them from back then to now?
Dr. Andrew Margenot:Yeah. Well they were kind of contemporary. They both emerged within the same two year time span, and when I say both emerged, the discovery was in August 2018. I remember because I was so thunderstruck that I spent the whole day out there with my headlamp. And then at the same time, we were trying to develop what would become this larger scale project, and updating the State Agronomy Handbook recommendations on P and K. But they certainly fed off the other. One key aspect of how we think about P and K is the critical value.
Dr. Andrew Margenot:This is a number that you want to be above on your soil test. For phosphorus, it's typically 40 to 50 pounds of break fee per acre. You want to be above that number. Well, those values are in part based on soil supply power, basically how much natively occurring P and K is there in your soil. And that assumption requires really good data measuring P and K stocks across the state, and that then crosses over to the archive where, oh my gosh, we can now actually quantify what the native amounts of P and K are.
Kathryn:Sure. Yeah because I know we've kind of worked tangentially on a project together with some of my other extension colleagues looking at that chapter of the Illinois Agronomy Handbook, and you've mentioned how there's a map in that chapter that has this kind of general idea of the different areas of Illinois and what their inherent P and K values are. I know you've mentioned a couple times how that definitely needs to be updated. Did that information do you know if that information came from this sampling project or was it just kind of a generalization from some other source that maybe someone back in the day just kind of had on hand?
Dr. Andrew Margenot:I think it's the latter and I say that because in chapter eight of the Agronomy Handbook there's a figure that shows the B supply power, also called subsoil supply, and that map is based on the LOESS thickness and on the LOESS age of the state. L O E S S is the parent material that blankets the state. Soils were born out of the parent material, and so that would be lust for us largely. Think of this as the fine silty stuff that was blown in post glaciation. There's a lot of this stuff across Illinois. It's thicker on the West, more or less, and it more or less thins out as you go from a Northwest to a Southeast transect, by and large. The map that was used for the Agronomy Handbook said if you have deeper and or younger lusts, so as you go more north state you get younger lusts because the glaciations stop later, then you are going to have more native phosphorus. Well, those are based on maps that we believe are from 1940s, and we found some other maps in the 1960s on the lust age and thickness. The basis for the supply power of phosphorus in our subsoils that then informs in part the critical values, that was based on a geological concept of lust. It's less not related to any measurements that we can tell of the actual P content of these subsoils.
Kathryn:It sounds like the project that we'll talk about in just a couple minutes here is going to be a much more thorough kind of investigation into what those supplying powers or what those values actually are. But like I said I keep fast forwarding to that portion so before we do that I just wanted to talk about a couple other things with that Centennial Soil Archive project. So you mentioned how there's hundreds of samples and many locations.
Kathryn:I know you said you've made some kind of breakthroughs in getting those numbers up in the resampling, but obviously there's you know you're not completely finished yet unfortunately. So where would someone find information about I guess this project as a whole but then information about where these remaining samples are at?
Dr. Andrew Margenot:I'm happy to discuss that. So yes we have over 300 samples left to take across the states, and I should say site, because at each site we take a deep soil core down to about three foot depth. Where can folks find more info? Well, I think the key is the map. For this, if you go to our lab website, which is my last name Margenot.
Dr. Andrew Margenot:Cropsciences.illinois.edu It's a bit long story, but if you just Google also U of I, Marganaut, you'll find it. On the lab website, there is a tab at the very top that says Illinois soil archive, and that page contains the background information on what is this, why are we doing this project, and there's a link to the Google Map. Now, we have the link in two forms. One is as a QR code, meaning on your smartphone, if you scan it with your photo app, it'll automatically pull up the Google Maps on your phone. I personally feel like the Google Map on the desktop or on the laptop is easier to navigate, and we have a hyperlink and green text for that.
Dr. Andrew Margenot:So that will also, plug you into the Google Map formats, and it looks like a Google Map. The difference is that we've got four sixty pins across the state of Illinois, and each pin corresponds to an original sampling location. How to use this map? Well, there's three kinds of pins. There's yellow pins, there's green pins, and then there's a red checkmark pin.
Dr. Andrew Margenot:As you might imagine, the red checkmark is a site that we have already sampled. So, thanks to those landlords, operatorsowners, for giving us that permission. Then there's the green pins, which are sites that, again, big thank you, we have been granted permission to resample. Then we have, of course, most of the yellow pins, which are sites that have yet to be identified for a landowner name and contact, which we would then be using permission to sample in the coming one to two years. Overall, if you look at this map, we've got some gaps in the south especially.
Dr. Andrew Margenot:So, once we're South Of Effingham type area, really South of 70, we've got a pretty large gap until we hit the very southern tip, like Alexander County. And then up north, up in the Driftless, for example, we've got some pretty big gaps, and then out in the Southwest area. You can zoom in to these pinpoints, look at fine scale resolution. It is a Google map. If you click a pin, you'll find that you get what's called the Pedon ID.
Dr. Andrew Margenot:So again, Pedon is a soil individual. It's an example soil that's been sampled, and that tells you information like the exact GPS coordinates, and the year of sampling. I just I just clicked on one right here. That is Montgomery County 1960. Just clicked one up and Kankakee from 1930.
Dr. Andrew Margenot:So it gives you a flavor for how old these samples are in terms of when they were last taken.
Kathryn:Okay perfect yeah that's really good information to have and I've perused that map and I would agree it's much easier to navigate on the desktop so I would recommend that as well. And then you mentioned how you take a three foot sample, would the landlord or landowner or tenant whoever, would they get the information that you guys obtain via these samples?
Dr. Andrew Margenot:Absolutely. So a bit more on how we sample. Once we have a contact name and phone number, we make a first call just to, you know, ask if we can get permission when we're in the same season of sample. So, for example, if we get permission to sample the sites in December, that's a bit too late for us to go out there. So that would likely be a preplanned sample.
Dr. Andrew Margenot:As things thaw out before crops are being put in, we would give a one or two month out heads up of, hey, as a reminder, if the offer still stands, we'd like to go out there. Then roughly the week of the sampling, we design the circuits of what sites can we hit. As you might imagine, we have a lot of equipment on a trailer to haul out there, so we have to design circuits, and we would give a heads up phone call that week. We get out there, we take four to six different cores. They are about three foot deep.
Dr. Andrew Margenot:We have not punctured any drainage tiles yet, and we don't think that we will because we work with the landowner operator if they have concerns about that to where can we sample to avoid a tile. And the depth that we go to will be more shallow. If there's any concerns, simply don't sink the probe down to three foot. So then those samples go back to campus. We then process them every six inches all the way down to three foot.
Dr. Andrew Margenot:We take a separate section, and that gets analyzed for a lot of things. These are soil properties like clay content, pH, CEC. We look at soil fertility, the total and the available of everything, macros and microbes, And third type of analysis is soul health, the kitchen sink of all of them. It's about 4 to $5,000 worth of analyses that we perform. All that data goes right back to the owner operator.
Dr. Andrew Margenot:And that also is not just a data dump of a lot of numbers. We provide reports that interprets and visualizes with graphs and figures exactly what it looks like. And we also compare it to the original sample. So, then the owner can see, you know, if grandpa farmed this in 1940 and someone took a sample, how have things changed? All this data is kept on private servers at the U of I, so only our team has access to it.
Dr. Andrew Margenot:And the exact sample location is never revealed so that it cannot be traced to that property.
Kathryn:That sounds like a lot of really great information to get and for free, and on top of the fact that you get that extra added bonus of like you said looking at that historic information. So hopefully you guys can get those numbers up and get this finished in due time. A really great project. Jumping back then to what I was talking about before, I got a little overzealous and jumped ahead to our next topic, but your project like I mentioned at updating the Illinois phosphorus and potassium recommendations. So again I know we've talked about it and touched on it but can you briefly go over the background of this project as well?
Dr. Andrew Margenot:Sure thing, so this is a companion or a sibling project as you've mentioned where we're trying to update specifically chapter eight of the state agronomy handbook the recommendations on P and K, And we're not just trying to verify if the current recs are still valid, we're trying to add levels of nuance and complexity. And there's at least four different levels of complexity, but I'll begin first on what the chapter updates are. In chapter eight, we have what's called a critical soil test value, also called the threshold value. Some folks call them CSTVs. It's all the same thing.
Dr. Andrew Margenot:It's the idea that if you're underneath this number on the soil test, there's likely a pretty good chance of seeing a yield response to adding more of that nutrient. We don't do this for nitrogen. That's based on a different paradigm. We don't soil test for N rates because it rains a lot. That works out west where the rain doesn't push out the nitrate.
Dr. Andrew Margenot:But out here where it rains, we sole test for PNK. We then want to know, hey, if I spread MAP or DAB or potash, is it going to be worth it in terms of a yield response? Those critical values then vary by region due to the supply power concept for P, or due to CEC for K. For K, the paradigm is that if you're on sand like up in some parts of Kankakee, you can't really build K levels because CEC is so low. If you're in a low versus high K, then your critical value for K is also different.
Dr. Andrew Margenot:The power of this stuff, was first developed in the 1950s, is that it gave farmers at the time the first ever quantitative way to have a higher confidence approach to adding nutrients. Until then, it was kind of guessing. Now we have a way to measure what is in the soil for the crop. Now, the issue, I think, is that these values have not been updated since the 1950s, as far as we can tell. They have been modified based upon what our neighboring states do, but a lot of these racks are, number one, pretty coarse.
Dr. Andrew Margenot:We only have three different regions for the P supply power concept, and also that concept has not actually been tested. We don't really know. Is it valid to adjust what your critical grade P value is based upon whether you're medium, low, or high supply power. That's an assumption being made with no data. Other details that we have to address is that no one actually measures Bray.
Dr. Andrew Margenot:I know that we still talk in Bray P, also called the P1 test, it's all the same, But all commercial labs are now running soils for the Melec 3P test, because they also can measure K. So, we've stopped using Bray P and ammonium acetate K. We know, if you get numbers that are saying P1, they're measuring mellic three p, and they're back calculating by a correlation what the break p value is. And they're roughly comparable. They're about 35 difference in the in what the value is.
Dr. Andrew Margenot:So that's an example of how it's time to update to what the commercial labs are giving you back on your tests. Other issues include things like the depth of sampling. So what we're adding as a new expansion is we want to go to a second depth, not just the top seven inches, but the seven to 14 inches depth, because we know that crop roots can forage P and K beyond the top seven. And here's a good example, in the South Part Of Illinois we have a lot of fragile pens, clay pens, and P and K will move especially K downward. They'll leach out of the top seven inch depth from which we sample, but they'll sit on top of that clay pen at say seven to 14.
Dr. Andrew Margenot:So the corn or soybean is seeing plenty of K. It's doing just fine, but your soil test at the top seven would miss that underlying seven to 14 inch buildup of P and K, and you would conclude incorrectly that you got to spread P and K when in fact the crop is doing just fine. That's an example of how we should go a little bit deeper, or at least let's test whether going deeper on certain soil types improves the prediction of a crop yield response. The second major reason, or sorry, new thing that we are adding is looking at soil type. So we want to make critical value recommendations, not by broad regions, two over three, two for K and three for P, but rather by soil types.
Dr. Andrew Margenot:As you pointed out, we have these maps from Surgo, soil type maps for every single farm across this country. Why not link the P and K critical values to the soil types? This will enable VRT it just enables more precision management of our nutrients. For this, we are doing on farm trials, broken up by specific soil types, so that we can try to capture the 57 major soil associations. Soil associations are not soil types like Drummer or Verdin or Cisne.
Dr. Andrew Margenot:Instead, we get associations like Ava Cisne or Flanagan Drummer Cattlin, which are sibling soils that occur on the same part of the landscape. You often find a farm will have Flanagan and Drummer, Cisney and Ava. That's why we're breaking this out by those associations. There's 57 of those across the state that we want to try to link the critical values to. The third change that we're doing, well actually the fourth, excuse me, is the economics of P and K.
Dr. Andrew Margenot:Right now, the critical value that you want to be above this, so you should be building the test value, that's based on yield response. But as all farmers know, maximizing yield does not necessarily maximize net profit. In some cases, you can lose net profit by increasing yield because the extra P and K won't pay for itself. Mhmm. And we've seen some pretty rough, high price years for p and k, you know, back in '20 post COVID, and we're seeing non grain sorry, not great grain price years this season.
Kathryn:Mhmm.
Dr. Andrew Margenot:There might be years where there might be a yield drag of couple bushels per acre by not spreading P and K, but it'll still be more profitable because the P and K won't pay for itself. Clearly there's a point where we have to put it on because we're taking off P and K with every bushel harvested, but there needs to be, I think, some information on the economics of P and K. Does it make sense to apply from a net dollar per acre return? So that's the final novel aspect of our updates. These will all be part of an online tool just like the MRTN where you can click input your soil type, your soil test even, the prices of inputs, and the grain to estimate what might be a good input rate.
Kathryn:That's awesome. That sounds like it'll be at the end a really invaluable resource that you guys are going to be putting together when this is all said and done. So you mentioned that the study is being done via on farm research and so what then I guess what are the treatments look like on this on farm research and is it something that you're still looking for participation on or have all those kind of slots been filled so to speak
Dr. Andrew Margenot:Great question. The answer to the second one is no slots are still very much open. I want to emphasize that, that we're happy to talk to folks. This is a big effort, so we need hundreds of site years. A site year is the total number of locations and years.
Dr. Andrew Margenot:So, if you have five sites a year, it could be you have the same farm for five years, that's five site years, or five farms in one year, that's five site years. We think we need at least north of three sixty site years. That's So, quite a this, what is involved exactly? Well, we try to find farmers who want to host us, and are willing to put up with our nagging, where what they provide to us is a shapefile of their field of interest. And we're taking fields that have any sole test level of PMK.
Dr. Andrew Margenot:We, in fact, on purpose, want from very deficient to medium to adequate to very high levels. We need a full spectrum to make these recommendations correctly. So don't think that you have to have a P or K deficient field to participate. We then look at the shapefile, and our data scientist makes the prescription maps where we would be proposing the omission trials. So the way to come up with a critical value is that you compare the yield without the nutrient, versus the yield with the nutrient.
Dr. Andrew Margenot:Sole tests are taken on those two plots right before the application, and then we correlate the soil test value with that relative yield, relative because it's the yield without versus the yield with. That's one data point. We need 400 of them to make decent confidence estimates. What we ask from the farmers is that if you give us the shapefile of what you think might be a good candidate field, we do all the work of identifying by soil type where these could go. These plots are about 120 foot by 120 foot, and we've got eight of those per field.
Dr. Andrew Margenot:So, four pairs of with and without, and that would be for a given nutrient, just for P or just for K. In some fields, if they're big enough, we do both P and K trials, so 16 plots total. We take care of all the soil sampling. We work with the applicator, be it the farmer or be it a co op, whoever, to make a single prescription map, so that in one single movement across the field, and one event, both the rest of the field gets applied, and then these specific plots. And then the other ask that we make of the farmer is the yield map of the combine.
Dr. Andrew Margenot:From that, we can come up with these critical values based on the relative yield. So that's what's involved. We're happy to meet with someone to visit by phone first to just talk him through, and, we're looking for either fall applied or spring applied sites. So there's still time for both for the 2025 season, and there's no commitment. If you do one year, that can be a one and done.
Dr. Andrew Margenot:If you wanna keep the same field going for all four years left, also a possibility. And finally, we can do more than one field per farmer.
Kathryn:Okay that sounds like a pretty good deal in terms of what all is being done, know not too intensive. Do they get does the farmer or landowner again whoever you're working with here directly get like any sort of compensation for being involved in this?
Dr. Andrew Margenot:Yes they get what we call nuisance fee. So we pay the farmer $1,000 per field for a single nutrient trial, If you're doing P and K in the same field, then that's $1,500 that we compensate them. We don't think that there's going to be much yield drag, unless we've got very, very low P or K values. We're talking single digit per AP. Then there might be a yield drag.
Dr. Andrew Margenot:The payment that we have would cover the loss of profit in these 160 foot square plots. We're talking pretty minor yield drags. If we see a larger one that is an economic hit for the acreage that we have, which is about one or two acres per field, we are happy to talk on how to compensate them. So, we have a flat nuisance fee of 1,000 to 1,500 per field, depending on how many P and or K trials in that field, and again the ask is the shapefile on the front end, and then they yield off the combine on the back end.
Kathryn:Okay and if someone determines that they might want to be involved in this how would they go about getting in contact with you and your team?
Dr. Andrew Margenot:Sure thing before I give that information one last note I know some folks are maybe hesitating to spread P and K this fall because of the pretty low prices on grain. We don't have to apply or the whole field does not have to be applied. So, it is possible to just have the P and K applied on these 160 foot plots. So it doesn't mean that the whole thing has to get P and K if someone is thinking about not spreading. How to get in touch?
Dr. Andrew Margenot:Well, the best way is my email. That is my last name, Margenotillinois dot edu. If you again Google my last name and U of I, you'll find the lab websites and my contact there. Myself and our data scientist Ezra would work with you to check out the fields, meet with this person about whether it's a good fit, and if so we'd move forward with all of the application prescription maps.
Kathryn:Great, perfect. And that information and any other links or anything of that nature that we've talked about will be included in the video description for those listening, so that'll be easily accessible for you guys. So Andrew thank you again so much for joining me today. This was chock full of really great information that I know a lot of people are interested in hearing and hopefully we can get some either some new samples for you guys or maybe some farmer participation in your project out of this best case scenario right? So again thank you so much I really appreciate it.
Dr. Andrew Margenot:Thanks Katherine, and thanks for having me and for letting me yap a little bit about these projects. I personally have lost sleep over both of them, but the archived one when you hold a sample from 1861 in your hands, that's pretty mind blowing, and we can learn a lot about our soils to help from applied to more fundamental questions on soils and their fertility for the state. Any help that we can get on either of these would go a long way. Thanks for having me.