Heard about the Haney test and want to learn more about how it might be used in Wisconsin? Listen in while we chat with leading UW researchers and outreach specialists Chris Bandura, John Jones, and Andrew Stammer on this topic. We dive in deep discussing how the Haney test can be used practically on-farm, how it calculates fertility recommendations differently than other soil tests, and what that means for Wisconsin cropping systems.
Photo by Chris Clark
Transcript
Will Fulwider 0:00
So we’re talking about the Haney test today on field notes. And one of the things that we realized after recording, the initial episode was that this is a really dense topic. It’s kind of hard to wrap your head around your brain around. And so we decided to make a little prelude a prologue of sorts to the original episode. And for that we’ve brought in Chris Bandura, the A one of two Conservation Cropping system specialists with UW Madison extension, to talk a little bit about kind of a little bit more practical terms, how can you use the Haney test in your operation are with your clients that you work with? And so thank you, Chris, for being so gracious to come on as a last second addition to the Hain test episode and break it down to a little bit more building blocks, terms and approaches for how you can use this test on your operation. Thanks for coming on.
Chris Bandura 0:54
Yeah, absolutely. Thanks for having me.
Michael Geissinger 0:57
Yeah. So Chris, it’s great to have you on today. I think How about we just like start this out? At like a 40,000 foot level? Maybe? What are some ways that farmers can apply the Haney test or use information they get from the Haney test as a tool on their farm?
Chris Bandura 1:15
Share? Yeah, good million dollar question that that a lot of us at UW had been being asked over the past few years. I do want to preface this discussion with the university currently doesn’t have formal recommendations and guidelines to this tool. But big picture. Thinking about it as a nitrogen management tool. As you’ll hear in more detail, from John and Andrew, this test is looking at water extractable nitrogen, organic nitrogen. So think of it as, as the full gas tank, all the nitrogen that’s there, the biggest chunk of it, and respiration. So we’re looking at the biggest, you know, fuel source. And we’re looking at the amount of bugs that are there to use that fuel source to drive nitrogen cycling and specifically mineralization in that soil. And so, you know, if you step back and think about it in a broad picture, you know, the more organic nitrogen we have, the higher the respiration, or the you know, the bug activity that we have, the better, right, so just thinking more is better in this case, and looking at what the Haney test is doing from a nitrogen rate guideline tool. We’re looking at that gas tank, and what’s their burn it right, the engine, the bugs, and we’re trying to predict how much and we think is going to come out of that soil environment throughout the course of the season. And so based on what’s in that gas tank, and how big our engine is, is going to determine how much we think we can credit off of a base nitrogen recommendation. And so that’s kind of the high level, you know, theory or premise of what that Haney test and credit, that’s where it’s coming from more or less.
Michael Geissinger 3:01
I think that’s great. I mean, that’s one of the best ways I’ve kind of seen it used as like, at least it’s getting farmers to think about their nitrogen in new ways are really just thinking about nitrogen for the first time. And I think some people are using it also like as a soil health tool. And so what does that look like for farms?
Chris Bandura 3:19
Yeah, so thinking about soil health, we can kind of focus in on some of the same pieces or components of the Haney test. So again, that water extractable nitrogen that that gas tank, if you will, that it’s measuring, we know from other research that’s been done in both in the state and out of the state, that what we do on any given soil, and any given farm can influence how much of that is there. And so you think about conservation practices, such as reduced tillage, use of organic materials out on that field, cover crops, all those kinds of things. Generally, those will increase the amount of nitrogen that’s they’re thinking about the respiration kind of the same from us, right? So respiration is talked about a lot in the whole soil health space, in a lot of the conservation practices that we promote, can build or enhance that respiration value over time.
Will Fulwider 4:21
So you can use this test as a way of gauging soil health on your farm. And I’m just wondering, can we talk about that a little bit more deeply? How might a farmer go about doing so on their farm? What is the format that they would need to be able to test it into kind of more replicated slash more sciency way to be able to see if it is giving them the right recommendations? Like we’ve been chatting about?
Chris Bandura 4:45
Yeah, good question. We’ll so again, you know, with the lack of any, you know, formal University RECs and research being done specifically to Haney I think the biggest bang for the buck is going to be through onfarm race. surge be that, you know, between you and your agronomists, you on your own producer led groups. But I really think the best way to evaluate this tool to understand that, number one, can it help inform our n rate decisions accurately both from an economic and economic outcome frame of mind? But also from does it accurately predict end rates? And does it help us on the environmental side of things too. So I think the best way to do it, although it’s it’s a little bit labor intensive, and it might throw a wrench in the farm operations, doing full nitrogen rate trials that are replicated, which is an important piece of this. So what we’re talking about is like a zero nitrogen through some non limiting nitrogen application rate, that number or that rate is going to be different everywhere. So you know, using your practical experience and your farm, you should kind of have an idea as to what that is, but zero through let’s call it 250 pounds event with maybe four or five rates in between it, you want a full response curve to see how yield is changing with and over time or over that over those rates, then what you do is you randomize that, do that a couple of different times three or four times across the field. And here’s where the Haney test part comes in. So what we’re going to do, or what we’re recommending you do, do the nice regenerate trial, regardless of what the Haney test results are, just simply get the samples taken. If your if your normal application timing is like at or pre plant, pull the samples, at that time before you put the nitrogen trials out there, pull your handy samples, get them sent off to the lab, start your trial. If you’re more of an inseason type, nitrogen user, you know, go out at V five or whenever you’re about to normally apply nitrogen, pull the samples at that point in time, and then you know, put the put the NRA trial out on the field. Fast forward to grain harvest, with the help of someone at extension or your agronomist, based on your yield data across those rates of nitrogen. And again, across those replications, we can determine what your site and year optimum end rate was, then what we can do is look at the results of that any test and say, what did it recommend we credit off of our dates application. So this is kind of evaluating, you know, our own base and recommendations that we’re making for ourselves, or that we’re going to do ourselves and look at how that test helped inform that decision. And so based on it, let’s say the the true optimal rate was 100. And our rate was 150. And the Haney test recommended a 50 Pom credit. Well, our system was perfect this year. But reality says next year is going to be different. So we would recommend doing a series of on farm trials like this over the course of many seasons. And also across different soil types and maybe even cropping systems are so you really want to it’s a lot of work but to do it right. And to truly know how to use this tool in the box, we got to put a fair amount of time into it.
Michael Geissinger 8:28
Yeah, and I think that’s a great like, let’s, let’s use the test that we have proven in Wisconsin already to sort of figure out if we can ground truth this either on our own individual farms or statewide. And so I really liked that. And the NRA trial you’re talking about is really great. And probably the best day that you get to do something like that probably what I would call maybe the Cadillac of enfrente trials. Another option too, that maybe wouldn’t give you as much data to like validate, but could maybe be used as like a nitrogen management tool, or give you some helpful data that’s maybe a little simpler is just setting up like a nitrogen use efficiency trial. And like we can help people do that from extension. And it’s pretty simple as far as just like leaving a zero and stripped basically and managing the rest of your field the same way that you kind of would and identify and like how well do your hybrids in your area on your soil actually use nitrogen and then help that to like inform nitrogen decisions that we’re making, again, not quite as good data as those full nitrogen rate trials like Chris was talking about, definitely an option. And then layer in those pre plant nitrate tests and preside juries pre sidedress nitrate tests on top of that to get some additional data so besides those things, though, Chris, is there anything else that farms can be using to help manage their nitrogen that comes to mind?
Chris Bandura 9:53
Yeah, so you know splitting away from from Haney and soil testing, you know, there are a couple other tools out there that we can use to manage nitrogen. One is plant analysis. So, you know, banking on plant analysis as a sole tool for and management decisions limits you to indices and applications to to address any potential concerns. So there, there combs, you know, got to make sure you get out there before the corn is too tall and your equipment can’t get out there, you have to rent some equipment maybe from the coop to get out there some high clearance. But looking at plant analysis is an option. And there you know, the best recommendation would be really to take more than one time point. As we as you know, pretty well documented nitrogen status and a corn crop, for example, can change pretty significantly in a very short amount of time. So taking a sample today, it might show that that field is deficient and then but in a week from now, when it warms up, and we get some good timely distributed rainfall, soil is going to kick out a bunch of nitrogen for that corn that could change. So starting early in the season and taking another sample, maybe you’re on that V eight v nine time period, if you’re seeing that trend, continue, you might get out there and apply a little bit of nitrogen in the season to help overcome something. And then, you know, just in general, taking good credit for, you know, previous manure applications, you know, understanding how much and was in that manure, and using the, you know, estimated amounts of availability from that as well as from legume crops would be great at nitrogen management overall.
Will Fulwider 11:41
Thank you, Chris, for filling us in about the different ways that you can use the Haney test on your farm and also test the recommendations that it’s giving you. So now we’re going to jump in to a little bit more of the density. I’ll call it that of this topic with John Jones and Andrew stammer, stay tuned.
Michael Geissinger 12:13
Welcome to field notes, today we are talking about interpreting the Haney test in Wisconsin. So we have John Jones with us. And he’s a researcher in the soil science department at UW Madison, and Andrew stanmer, lab manager for the UW soil and forage analysis lab to help us sort of break this concept down. So we’re gonna jump right in here head first, because we have a lot of great guests on the episode today and some great content to discuss that farmers have been asking questions about in our areas. So Hi, John. Hi, Andrew. Great to have you guys on and without further ado, maybe we’ll just kind of jump right into things. So I’ll start things off with Andrew. So let’s start with kind of the baseline of what’s what’s happening from a soil testing perspective. So how are soil nutrient tests used in nutrient planning for fertilization in Wisconsin?
Andrew Stammer 13:08
Thanks, Michael. So we have some long established methods that we use to extract nutrients from the soil. For phosphorus and potassium, we use the Bray one extraction, which is a mix of hydrochloric acid and ammonium fluoride, per soil nitrate, we use an extracting solution that has potassium chloride. So there’s several different approaches these methods use, whether it’s acid extraction, base extraction, displacement of ions with similar sized and molecular strength ions. And these results are then measured using different types of lab equipment. So with a good and well developed lab method, the next step is to correlate that to crop response. Usually the response people are most interested in is crop yield. And so, studies are conducted with differences in soil fertility, and sometimes different fertilizer treatments to evaluate how crops respond and how that response compares back to a soil test. Once the correlation to yield is understood, then what can be done to calibrate a soil test to determine the optimum fertilizer rates. So all this information goes into the recommendation you’ll see on a soil test report or from a nutrient management software like snap plus. So all these components need to work together to have an effective soil test that can reliably be used to make fertilizer recommendations. Are other management decisions on farm?
Michael Geissinger 15:03
Yeah, definitely. So when I’m talking with farmers about nutrient management, usually we’re, we kind of tend to chat a lot about the quality of the recommendations that you’ll get back from the lab really depend on the quality of the data that’s going in there. And we discuss it more from like a soil sampling protocol perspective and collecting like accurate data like that. But I really enjoy kind of what you’ve discussed here too, like the the protocol and procedures that you’re following in the lab, and like working through those correlations and calibrations to sort of dial it in for these Wisconsin farms are just as important for, you know, what goes into that ultimate recommendation in the end that farmers can interpret it for their own farm as well. So yeah, definitely appreciate that.
Will Fulwider 15:49
And so for this, you know, these are our standard soil samples that we’re talking about, that everyone knows and loves love so much. And, you know, today we’re talking about the Haney test. So is there a is there a related part of the Haney test that acts as the standard soil test, because ultimately, the goal of the Haney test is right, a soil health assessment in a way or at least that’s how it’s built out. So like, what is the component of it that kind of takes this chemical element of the soil into consideration.
John Jones 16:20
So up to this point, we’ve been talking about routine tests such as the Bray 1 that are used in in recommendations at Wisconsin around many states throughout the United States. The the Haney tests in its extraction component, h3, a extracting solution was developed in an intended use. And this is within published literature to mimic chemical processes that that are occurring within the rhizosphere within that zone between the root and the bulk soil, and specifically focusing on weak organic acids that plant roots do exude and do exist within that rhizosphere that release or dissolve precipitants that allow nutrients to become available to crop reps, the idea was that using a type of extractant, and process that’s more similar to what’s occurring naturally in the rhizosphere may lead to a better prediction of of crop yield response to fertilization. So that was kind of the intended use of the extracting, or extraction component of the Haney tests, as we found out in some of my work in Iowa and Wisconsin as well, specifically, that doesn’t always mean that new to new tests are because they’re they’re trying to mimic maybe a certain process or certain chemistries that do occur naturally, it doesn’t mean necessarily that it’s better performing than than our routine tests. For example, in certain, and this has been corroborated in in western states, certain instances where we have higher PHS and higher appreciable calcium carbonate within soils, we see a more buffering of that extraction, where we don’t extract the amount of nutrients that would be pulled out or measured or determined in a more neutral or acidic soil. And so there’s that inherent site effect on the performance of the test. That’s been pretty well documented. The extraction part of this of this test, and very similar to the routine tests are essentially that are some type of weak or dilute strong acid is essentially being able to dissolve some precipitants, but also simply pull off by by some mass movement, nutrients that that are going to be then determined. And we’ll be able to report some type of parts per million or pounds per acre value. The interpretation of this really, if you’re looking to use this in a system, such as Andrew just defined within correlation and calibration, the interpretation steps should be the same as a routine test. And so for the industry to be used, it has to go through that process, that research process, but then also implementation process, correlating the crop yield response and calibrating to identify optimum fertilization rates. And that’s, that’s a very complex system. We’ve kind of defined it simply here, but that’s essentially what what needs to occur. The value proposition again, as I kind of alluded to already have the Haney tests was that it might mimic or relate to naturally occurring processes that relate to organic acids and uptake of nutrients. The question is, does that make sense? Bio physically, because when we think about what a soil test represents, it’s really one measurement in time of a nutrient concentration in the soil that has to predict the crop yield response or crop nutrient uptake across the whole growing season. And so when we’re thinking about trying to predict what’s going to happen over a whole growing season of corn, soybeans, wheat, for example, with one test We don’t necessarily need to mimic what’s happening in nature, what we need is a strong statistical relationship, a strong a strong predictive power, that can reproducibly give us values that are going to predict if, if or if we do not need to apply fertilizer. And so when we think of the goal of the maybe the Haney test that was was brought about, and it’s being used around different parts of North Central region in the country, that context has to be thought when we’re going through and assessing it, if it if it can be used. And again, it really has to go through those, those research and interpretation processes to be used effectively in a production setting.
Will Fulwider 20:41
So kind of bring that round, like, the idea is that, yeah, you’re using a stronger acid than in your kind of traditional standard soil test in Wisconsin a stronger acid than maybe what the roots are doing. But you’re trying to assess it across a whole season. Whereas the weaker acids that like the h3 a for example, it’s a you know, you’re assessing it over a short duration of time in the lab. And that really can’t capture necessarily all that would be extracted over time. So it’s like kind of the relationship ship between the strength of the acid and the time in the lab, with the strength of the root acids and the time out in the field of nutrient uptake over over that period of the growing season. Yeah, that’s
John Jones 21:24
a nice synopsis. Well, and I think what it’s important to remember is nutrients exist in soil in many different phases in many different types of sometimes we define them as pools, they exist within the soil water or soil solution, they exist on the surfaces of soil colloid, or are on an adventurous cast iron or anion exchange sites. And so what a stronger acid and it is diluted but a stronger acid is probably doing is picking up those different pools and relating statistically to what a plant could use throughout the whole season. It’d be very similar to if we compared a strong acid extraction and just a water extraction, that water extraction is measuring what might be immediately available, that stronger extraction might be able to pick up what’s going to be released from soil exchange sites, what could potentially be mineralized for in terms of phosphorus, not potassium. But that’s that’s really important to consider that that whole growing season is represented or, or, or relating to one point in time where you’re measuring a soil test.
Andrew Stammer 22:37
So John, I know you’ve done work in other states where you compared the h3 extract it with other methods. When you compare h3 A to a more true, more common method, like a Breyer may look extraction, which method recovered more nutrients from the soil?
John Jones 22:56
Yeah, so that’s a great, great point, Andrew. So when we’re talking about the weaker extraction on referring to weaker extraction, like h three a, or a reference to water, extractable nutrient number, that’s extracting less nutrients or recovering less nutrients that would be in the soil sample that is processed. And so your values for an h3 A extracted phosphorus or potassium, I want to going to be lower than your brain extracted phosphorus or potassium from a soil sample. And so when we think about eventually, trying to come up with a fertilizer recommendation for these different tests, you have to remember that you can’t use the recommendation that was built off of a stronger extraction if you’re if you have lab data from a weaker extraction method or a lower lower value or a lower extracting power. And that really gets to the point, again, that we’ve kind of hit around a few times, is that any new soil test that’s going to be interpreted has to be independently field calibrated so that a recommendation or an interpretation could be available.
Will Fulwider 24:05
This comparison of the h three a with what we do here in Wisconsin, is the routine part of this of this Haney test and is important information. But in my conversations with farmers, how people are using this is one an assessment of soil health. But if they are making a management decision from it, it’s really the nitrogen recommendations that the Haney test gives. And they’re quite a bit different than like our, you know, pre plant nitrate tests or pre sidedress nitrate tests that we have kind of more recommended here in Wisconsin. And so I’m just curious if you all have some thoughts as to what this is derived from this Haney test nitrogen recommendations and kind of how does it stack up as far as making management decisions?
John Jones 24:52
When, from my experience in working with the Haney test system, it’s really trying to assess beyond the X tracted component of a soil or extracting value or amount of nutrient, trying to predict what potentially can be a mineralized amount of nitrogen or phosphorus, for example, and we say mineralized, essentially we’re talking about some type of microbial or enzymatic process that’s moving a nutrient from an we defined pools earlier in organic pool to an inorganic pool, or a nutrient phase that would be our form that would be taken up by plant roots and utilized by crops. And so in most cases, when we look at at any test numbers that come back from labs, there’s some type of of consideration for microbial activity, usually as a as a proxy using carbon dioxide evolution or co2 respiration. There’s also a consideration for certain forms are extracted forms of carbon and nitrogen and the ratio between those we know that the ratio of carbon to nitrogen is very important for residue breakdown for microbial processes to occur because of their required amounts of carbon nitrogen individually, but then as a ratio. And so that’s that’s focused on and considered, and many of the systems that are looked at in in the Haney test. And so when we think about that potentially mineralized amount that maybe maybe reported, the carbon dioxide respiration is really what starts to drive this estimation of biological activity. And again, we talked about there’s also components of water, extractable carbon and nitrogen and potentially a microbial carbon value. And then that’s all related to an estimation of potentially available nutrients and in the future. So when you reflect back on our previous conversation about how a strong P or K extraction may try to or may essentially, indirectly estimate potentially available nutrients across the whole season. The Haney system is may be attempting to do that, but really focusing on biological activity. Andrew has got a lot of experience, running a soil testing lab that that are working with these, these lab procedures in a day to day basis, and then working with the results of these. And your when you think about the routine extractions of nitrogen, for example, in pre plant nitrate test, or pre sidedress nitrate test, how does that compare to some of the methods that you’ve seen used within the Haney test system,
Andrew Stammer 27:50
when we talk about the soil nitrogen, especially the soil mineral forms, our routine method is to use potassium chloride, a potassium chloride solution to extract nitrate and in some cases, when we talk about our routine soil testing methods are standard for measuring mineral nitrogen in the soil is to use the potassium chloride extracting solution to displace nitrate from the soil surface. And when we compare that to the Haney test, which uses a water extraction even even though the Haney test measures some organic nitrogen as well, there’s data from the University of Minnesota that shows that a routine soil testing procedure extracts more mineral nitrogen from the soil than the Haney test does. So in some ways, this is very similar to the the weak acid versus strong acid approaches that are considered when we look at the h three a component compared to some of the more traditional soil testing methods. And so there can be situations where the actual measured nitrogen in the soil is less and in some cases, significantly less than other. More traditional methods might provide.
John Jones 29:39
Andrew mentioned organic nutrients and organic nitrogen in this case, when we think about measuring an organic fraction of a nutrient what what’s the general general methodology for doing that? And how would that compare to what the Haney tests is s? relating to be organic nutrients levels that could be potentially mineralized or used by crops.
Andrew Stammer 30:07
So when we talk about measuring the organic components of these nutrients when we think about phosphorus, often we’re we’re talking about taking a color metric, ortho phosphorus measurement, and subtracting it from an ICP derived measurement, which represents more closely the total phosphorus in that extract. With phosphorus specifically, there’s some possibility that there could be colloidal or other forms of phosphorus that might not necessarily be organic in nature that could be in that pool. Similar, there could be some similar concerns. When we talk about organic water extractable organic nitrogen, because of the possibility that some of the forms that are captured in that pool may not be directly plant available.
Michael Geissinger 31:13
Yeah, sort of kind of put it put this in a little bit of a nutshell, maybe there’s two pools and nutrients we’re thinking about in the soil, organic, inorganic and organic. And the inorganic forms tend to be mineralized from the organic forms. And that’s how they become plants available. Typical soil tests that we would use as capturing a lot of that mineral forms like in the inorganic form, but typically we’re not looking out searching for numbers just like in the organic form. But that is where the Haney test kind of goes in that direction a little bit when, with some of these other measurements, they’re doing with like water, extractable carbon and microbial respiration and things like that. There’s a lot of appeal with like this this Haney test, especially among farmers that are sort of employing conservation practices to build soil health. Because they might feel like the traditional soil tests aren’t fully capturing, like what their nutrients actually are in the soil as they’re like building organic matter over time. And so maybe, we kind of start with like, John a little bit, and just like, Do you have any context for like those farmers that are employing this as as a test of whether it’s measuring soil health or measuring organic fertility? And how how might they be able to interpret these numbers and actually use them?
John Jones 32:40
Sure. So one of the important things to review kind of back to our more routine methods is their, their performances, it’s usually not affected by a cropping system that uses maybe more conventional tillage, for example, compared to a a 20 year no till system. And that’s one have been one of the beauties of working on these tests for several decades is that you can start to compare large datasets and show that for example, a gray one phosphorus extraction amount can predict to a certain accuracy, levels of responsiveness of corn to P fertilization, for example, and no till and till systems or strip till systems or systems that are in rotate rotated pastures, that that that’s one of the functions of testing that, again, through the correlation calibration process is that you’re looking at all of these potential cropping systems that can be used and NSS unit across that area for the given geography is supposed to be used. And the concern may be on on some methods that are applied in the Haney test is that they are affected by system or site specific characteristics or properties. And so that’s something that certainly to be aware of, if you’re trying to use one of these values to make a fertilization recommendation. That’s something that’s really important to consider. Certainly, when we look at some of the data that’s been published on for example, co2 respiration or co2 Evolution, you can start to pick up maybe some some management differences, specifically when you’re looking at long term systems that have received a lot of manure that have reduced tillage compared to a tilled system that maybe is only relying on integrating inorganic fertilizer. However, it’s not always consistent, and that may change across geographies. One thing that’s really important to consider though, and regardless of the kind of stepping away from the soil tests that we’re using is considering any nitrogen inputs into your system when you’re thinking about what your your intended nitrogen application rate or guideline is going to be. And so that’s crediting the newer soil nitrogen status maybe at the beginning of the season look In net, your crop rotation and understanding what like you saw or maybe previous crops were used that may affect the nitrogen need of the crop that you’re working on for that given year. So that’s really important to consider those facts, when kind of coming up with a intended nitrogen application strategy is thinking about what is the end status of my field, what has it been throughout the last year or two of the cropping system. And then that that’ll be really helpful when when going in planning ahead for where the Haney test or even routine test play into this is trying to understand what’s happening again, at that snapshot in time, perhaps before planting perhaps or foresight, dress it aside dress application of nitrogen fertilizer in this, this example. That’s where really, there needs to be some type of formal assessment that can provide guidance that that just isn’t quite there yet. For the for the Haney test, but it’s been it’s done quite a bit when Andrew reference says as KCL extractable nitrates specifically.
Will Fulwider 36:03
So one of the things that I think is really interesting about, you know, kind of circling back a little bit to this in crediting, that the Haney test is using is how so much of it is modified by microbial respiration, biological activity, which makes sense, you know, it’s the microbes that are mineralizing the pools of organic and inter inorganic and, but trying to capture that is is, you know, is difficult. And so we the hanging tested using microbial respiration as, as the medium through which it’s doing that, and I’m just wondering, what are the factors that we see affecting microbial respiration? How does that play out? Kind of as they’re trying to nail that down with this with this test?
Andrew Stammer 36:46
That’s a good question. Well, um, so anything that’s going to affect microbial activity, should should in turn, affect respiration, essentially, the activity of the microbes were that respiration value that you’d measure in the lab. And so when we think about what what is conducive for a happy microbe in the soil, we think of an optimum moisture content with our soil moisture content, we think of optimum temperature in any biological activity is very affected by soil temperature, environmental temperature, when thinking about what specific microbes are going to be prevalent, or active soil pH can affect the microbial and then also, so bacterial, but also fungal populations, and population compound composition. And so all of these factors are really affecting microbial activity and persistence. And so when we think about assessing a microbial activity proxy, like like co2 respiration, as an estimation of potentially mineralized nitrogen in this case, it’s really important to remember that we’re really doing this indirectly. And so there are, are so many steps and components of this process within the soil plant kind of continuum, that can that can affect the the readout from when the sample was taken to house equals analyzed in a lab. In many cases, there’s instances where you have a bone dry soil, for example, and it’s really wet and the microbial activity, blossoms and flourishes because a lot of the times those microbes are sitting there waiting for some type of environmental cue to start working on on that carbon and then associated nitrogen. And so environmental factors really are going to play a role, specifically temperature and moisture when we’re thinking about when the soil is sampled, and how the sample is analyzed. So if we’re considering those very strong effects of environmental conditions, that’s really going to influence that estimation of potentially mineralized nitrogen that you would use in a nitrogen credit example. One thing that’s important and that isn’t really considered within this, the system any test is is is there going to be any transformations of inorganic nitrogen back to an organic pool or immobilization within the soil? Remember, it’s kind of a two way process depending on the ratio of carbon and nitrogen and some other environmental components. So that’s, that’s really important when kind of wrapping this all up into a, an assessment of soil health, because a lot of soil health conversations, you know, usually include some type of assessment maybe using the Haney tests maybe not. And other scores given at the kind of completion or at the end aggregating some type of qualitative assessment of, of soil health.
So what do you think the the key Benefits of using the Haney tests test and the drawbacks are for Wisconsin farms.
John Jones 40:05
I think if a farmer is or agronomist is wanting to consider using the Haney tests within their, their their guidance provided for fertilization decisions, or essentially just wanting to guide, what next steps might be relating in relation to nutrient management, I think it’s important to think about, does that measured value, give a reproducible and predictable estimation of of whether a crop is going to respond to fertilization or not, again, we’ve kind of talked about that and hit that throughout this, this episode is that that needs to occur. And in most cases, the Haney test has not been been calibrated or field calibrated to provide a fertilization recommendation, especially in the areas where I worked for in fraud and phosphorus and potassium. I think one of the benefits could be to start to see some trends over space and time, especially if you are transitioning from a one system says to the other, that could be different intensities of tillage that could be incorporation of cover crop practices. I think there’s a growing population of data out there that that perhaps you can be able to, to use that to assess what might be changing in your field settings. The important thing is that if it fertilization our decisions are going to be made from any laboratory process that’s giving you an in a measured value and interpretation is that that’s gone through the rigorous process of defining what that value is and what it means for for an outcome that would be predicted within the growing season.
Michael Geissinger 41:48
All right, well, thank you, John. And thank you, Andrew is is a lot of content on kind of a difficult subject to talk about. Definitely appreciate having you guys on. And if I could just say add maybe one more potential benefit to the Haney tests that’s kind of cool is is getting farmers to kind of think a little bit more or maybe a little bit in a new way about their nitrogen, and how that all functions in their systems. And so there are resources we have at UW if you get a hold of specialists or educators serving your area, and they can help sort of shepherd that process on your individual farms as well. But John, Andrew, thanks for having thanks for coming on day and appreciate it a lot. Great, thanks.
John Jones 42:30
Great, thanks Will and Andrew, and Michael
Andrew Stammer 42:32
Thanks for having us.
Will Fulwider 42:33
It’s good to always forget about Michael we should forget about anymore.
Michael Geissinger 42:36
I know…. Really.
Will Fulwider 42:49
Thanks for listening. This has been field notes from UW Madison extension. My name is Will Fulwider, regional crops educator for Dane and Dodge counties. And I was joined by my co host, Michael Geissinger outreach specialist in Northwest Wisconsin with the nutrient and pest management program at UW Madison. A big thank you to Joe Ryan for creating our theme music and to Abby Wilkymacky for a logo. If you have any questions about anything you’ve heard today, or about your farming practices in general, reach out to the extension agriculture educators serving your region
Transcribed by https://otter.ai