Michael Geissinger 0:02
What happens to nitrogen when you put it in direct sunlight?

Will Fulwider 0:07
I have no idea.

Michael Geissinger 0:10
It becomes day-trogen

Will Fulwider 0:10
like, no, that’s, that’s that’s actually the worst yet.

Michael Geissinger 0:17
Oh, come on.

Will Fulwider 0:23
Welcome to Field Notes from UW Madison Extension, I’m Will Fulwider. And I’m joined by my co-host, Michael Geissinger. We bring farmers, experts, and agronomists to the table to talk about research-based approaches to the issues facing agriculture in Wisconsin.

We’re gonna slowly, you know, scale Michaels jokes out of this program, eventually, with the declining quality therein. And but we’ve got Diane Meyerfeld on the program today, Diane is a, is the Sustainable Agriculture Research and Education statewide coordinator for UW Madison Extension. I’ve worked a lot with Diane on in the past and excited to have her on today to talk about nitrogen management and climate change. Can you give yourself a little bit of an introduction and talk about kind of what you’ve been working on?

Diane Mayerfeld 1:20
Sure. Thank you, Will, and thank you, Michael, for the opportunity to talk today. I’ve been doing this work, actually, since the mid 90s. So, I’ve been around for a long time, not specifically on climate change, but on sustainable agriculture. And that covers everything from economic sustainability, environmental sustainability, and social sustainability. And we’ve looked at things like grazing and local food systems and things like that. But it’s become clear in the last three to five years that dealing with climate change, is a really, really big challenge for agriculture as for every other part of our society. And so, increasingly, I’ve been trying to think about that and come up with things that farmers can do.

Will Fulwider 2:16
And there’s a lot of money being thrown under right now with the recent recent climate smart commodities, partnership grants and more legislation passing at the federal level for technical assistance for engaging in carbon credits and the upswing in carbon credits that has been seen for agricultural practices and such. So there’s definitely a rising tide surrounding not just nitrogen management and climate change, but kind of practices geared towards mitigation of climate change from an agricultural level. So it’s definitely in the rising tide of things for sure.

Diane Mayerfeld 2:54
Yeah. And it’s very exciting. Having been concerned about climate change for a long time, it’s wonderful to see that across the spectrum, people are starting to think about what realistic things can we do in this?

Michael Geissinger 3:09
Yeah, absolutely. Well appreciate the introduction and having you on the call today, Diane, and maybe just to kind of kick things off, we keep saying we’re going to talk about nitrogen management and climate change, but maybe not everyone understands how those two things could even be related to each other. And so maybe you want to give us a 30,000 foot overview and just briefly describe how nitrogen or nitrogen management on farms is related to climate change.

Diane Mayerfeld 3:40
Thank you. Yeah, that’s a great question. Yeah, we there are three main greenhouse gases. There’s carbon dioxide, which is what we hear about all the time. There’s methane, and there’s nitrous oxide. And so if you look at the US as a whole CO2 emissions, carbon dioxide emissions, account for about 79% of our human-caused greenhouse gas emissions. And so that’s why we all hear so much conversation about carbon. Methane accounts for about 11% of those emissions and nitrous oxide, which is one form of nitrogen accounts for about 7% of human greenhouse gas emissions. And if you’re doing the math, the other 3% are primarily fluorinated gases like refrigerants. So that’s why people talk about carbon all the time. But if we narrow down to looking at the agriculture sector, those proportions change a lot. Nitrous oxide and methane really dominate and carbon dioxide plays a relatively small role, though it’s still pretty important. So, if you look across the US in agriculture, nitrous are oxide emissions are 50% of, we account for 50 to 51% of the greenhouse gases emitted by agriculture. Caveat, always it depends what things you’re counting and what things you’re not counting. But that’s so thinking about it roughly half of agriculture’s emissions are in the form of, of nitrous oxide. And one of the things to keep in mind is, as we talk about these different greenhouse gases, they each have different qualities. Carbon dioxide is because it’s by far the leading one is what we kind of use as our standard. And so when we talk about these other greenhouse gases, we compare them to carbon. And when we compare nitrous oxide to carbon as a, as a greenhouse gas, it is way more potent. So one, nitrous oxide molecule has around 290 times the warming power of one carbon dioxide molecule. And the other thing we keep in mind when we talk about greenhouse gases is how long they last. And nitrous oxide last in the atmosphere, we typically predict it will last in the atmosphere over 100 years.

Will Fulwider 6:32
So it’s both more potent. And as far as a warming degree goes goes and it lasts longer in atmosphere than carbon dioxide does.

Diane Mayerfeld 6:42
Yeah, so carbon dioxide, how long carbon dioxide lasts in the atmosphere is actually complicated. Some of it’s on a very short biological cycle. And we know plants photosynthesize it back into carbon all the time, but some of it can last up there a really long time. And it doesn’t, when it’s in the atmosphere, it doesn’t break down on its own. But I think the idea is that the nitrous oxide will actually break down into nitrogen on its own in the atmosphere. But it’s, it’s important to keep in and when, and that more potent warming potential takes the longevity of the gas in to account as well. So when we use those numbers that like nitrous oxide is 300 290 to 300 times as powerful as carbon dioxide. That is over 100 year timeframe.

Will Fulwider 7:45
Gotcha.

Michael Geissinger 7:48
Yeah, and we know, too, that the atmosphere is sometimes people say the atmosphere is made up primarily of nitrogen, but that’s a different type of nitrogen. Do you want to talk about that at all? Or?

Diane Mayerfeld 8:00
Absolutely, yeah, again, it’s, it’s funny, it’s about 79, 80% of our atmosphere is nitrogen. But that’s just an N2 molecule. It’s just two nitrogen atoms. And nitrogen, as people probably know, has a complicated cycle. So it’s in the atmosphere as just plain these, most of it is in the atmospheres, just these plain N2 molecules. And then there’s in the sort of natural ecosystems, some of that nitrogen gets removed from the air by soil bacteria that convert it–this is called nitrogen fixation–to ammonia. And, again, as any farmer listening will know, nitrogen is an absolutely critical plant nutrient, and it’s a building block of proteins. So it’s also a critical human nutrient. So we rely on that. And then, in the soil, nitrogen can undergo a whole bunch more transformations caused again by other soil organisms, and it can turn into nitrates, which is the best form for plants to absorb it. That’s NO3. But it can also there’s a whole bunch of stages that these soil organisms can do. But then it also goes through the next stage or the final stage in the nitrogen cycle where other organisms can can denitrify it in other words, break it down into a form where it becomes a gas it gets emitted as a gas again, and either it gets emitted as N2 which is great and that’s what our atmosphere is full up but a little little bit of it dentrifies to nitrous oxide, which is two nitrogen molecules and an oxygen molecule. So N20. So, so that’s all part of nature. And a little tiny bit of nitrous oxide in the atmosphere is fine. You know, we need a little atmospheric warming. But what’s happened is that humans figured out how to synthesize nitrogen, how to artificially take nitrogen out of the air and turn it into a form that plants can use. And because it’s such a limiting nutrient for plant growth, this has been a key factor, the synthetic nitrogen fertilizers have been a key factor in our agriculture and increasing our agricultural productivity. But basically, they’ve doubled the amount of nitrogen that’s, you know, they, they’ve added 100% to the amount of nitrogen that would be added to the soils through, through just natural processes. And so that’s also doubled those emissions’ sites.

Will Fulwider 11:11
And so, when we look at it, kind of at the farm level, right? Well, let’s, let’s, that’s an awesome overview. And let’s kind of bring it down to the, to how that affects the management or the farmer decisions or the, you know, at the cropping level. What does that look like, you know, from the farmers practices, how does that influence, kind of this, this pathway, this process of nitrogen through fixation through nitrous oxide emissions? How does management affect it?

Diane Mayerfeld 11:46
Yes, well, so, as I think I just said, anytime that you’re increasing the amount of nitrogen in the soil, you’re increasing the potential for nitrous oxide emissions. So fertilizer management, and manure management are two really critical areas for farmers to focus on. But you we also increase the nitrogen in the soil when we have concentrations of grazing animals, or when particularly when we have monocultures of legumes like alfalfa. So, even though they’re I don’t think as much of a source as our synthetic nitrogen applications in our manure applications, we do need to keep legumes and grazing animals in mind as other potential nitrous oxide sources.

Michael Geissinger 12:50
Yeah, absolutely. And would you maybe, so we, kind of understand a few of these things, and just the amount of nitrogen was going into systems to be increasing the potential for nitrous oxide emissions? What are some, you know, besides obviously, cutting and scaling back nitrogen? What are some potential solutions that we could maybe employ in cropping systems to start addressing some of these issues?

Diane Mayerfeld 13:20
Well, fortunately, I think a lot of good work has been done in connection with water quality. And it’s, you know, it’s great when, what what we’re doing to improve water quality can also be helping our our climate. And so they talk about the four R’s. And you mentioned right rate. So making sure that as we decide how much nitrogen to apply, we make sure we take into account whether manure was applied, whether there were any legumes grown on that soil. Any other credits that we might need to, to consider. And then the, the other sort of thing people talk about in connection with water quality, a lot is right time, and putting that nitrogen down when the crop can actually use it. Because nitrogen is very mobile, and it will escape in our water and it will escape in our air. And so if we put it down before the crop needs it, there’s just so much more chance for it to get into the atmosphere in ways that are damaging and into our water in ways that are damaging. The other thing about timing, and this is where it gets a little complicated is that for nitrous oxide emissions, if the soil is wet or saturated, it really increases the chance of that nitrogen being converted to nitrous oxide. So you want to avoid application before heavy rain in or to saturated soils.

Will Fulwider 15:06
And so kind of for review, we’ve got four Rs, the Rs are

Diane Mayerfeld 15:11
The Rs are right rate, right source, right time and right place. And to me, right source, right source is talking a lot about, and I’m going to maybe ask Mike put Michael on the spot as well, because he probably knows more specifics, I’m not a nutrient management specialist, but you know making things like having your fertilizer in a form where it is not as mobile right away. And, to me, it’s also a little bit a subset of right rate, meaning make sure that you’ve taken all your credits into account, and that you’re accounting for them. And so there’s right rate, right source right time, and I talked a little bit about right time when the plant can take it up. And then the fourth one is right place. And that’s talking about putting it where the plant can access it right away. And I think sometimes and Michael, I invite you to chip in here, it’s talking about incorporating it, so it’s not so liable to run off. But that’s where we start to have questions about whether incorporation makes it more accessible to some of those soil organisms that will then convert it to nitrous oxide.

Michael Geissinger 16:37
Yeah, I agree with everything that you’ve already said, with the right sources, typically, the types of fertilizers that we’re using, how can we stack that in a way to make sure that it’s meeting the crop need as efficiently as possible. But given the right time consideration there, there are things that you can do if you’re applying, you know, all of your nitrogen upfront at the beginning of the growing season, to prevent it from getting released early on. And so some of these nitrogen management tools that you hear about in industry, one would be N-serve, the function is basically a barrier to those micro organisms to accessing the nitrogen until later. Another strategy to, I would say, minimize the risk of any of that nitrogen being lost either to water or to the air, it would be just even splitting those nitrogen applications. Especially in you know, when we think about nitrogen management, it often goes hand in hand with with corn in particular, I think, but any of these crops that have a have a high nitrogen need and an inability to fix the nitrogen in the soil themselves. And so I know that splitting those applications can help, you know, increase the amount of nitrogen that’s actually available to the plant when the plant actually needs it. Especially when you get into July in Wisconsin, and you can sit in the cornfield and hear the corn plants growing. That’s an important consideration, but.

Will Fulwider 18:21
So you talked about crediting and making sure that you’re you’re taking the right amount of credits, and I kind of want to drill down on that for a second and be like, how do you know if you’re taking the right amount of credits? You know, is it something that you kind of look at a book and say, I applied X amount of tons of manure to this? And therefore it’s like that, this amount of credit, so I test my manure. Is it something like your soil sampling for that even?

Michael Geissinger 18:47
Yeah, in Wisconsin, and in probably most states that have a significant amount of cropping happening. I’ll speak for Wisconsin because it’s my experience and where I live and work. There has been a series of research over decades, developing these crop need requirements, so we we really know at this point, how much like nitrogen, phosphorus and potassium, for example, we need to grow a corn crop, or a soybean crop or an alfalfa crop. And that typically has gone hand in hand with the way that we apply nutrients. What’s began changing more recently is the use of a lot of these soil health practices which intend to kickstart these microbiology biomes. And so what we’re trying to figure out right now is, do some of these practices affect potentially the way that nutrients like nitrogen come available to the plant and the soil or not? And I would, you know, some of the more static credits are are reliable. For example, a legume credit in Wisconsin would typically be like 90 pounds in the first year and the manure credits when you apply manure, we know from the research we’ve done that some of its available in the first year, and then the rest of it typically comes available in the second and third year for nitrogen. And so that’s, that’s where those recommendations kind of come from and are built in. I would say, though, too, that if a particular farmer is really interested in what the best nitrogen rate is for their system, and the hybrids or varieties they use, the management practices they follow, it can really help sometimes to just set up an on-farm trial and figure out what is the most efficient way, amount of nitrogen for your crop. And in turn, hopefully, you can reduce your nitrogen program, which Diane has pitched is a wonderful way to decrease the potential of losing this nitrogen to the environment in the water or to the atmosphere.

Diane Mayerfeld 21:09
But maybe, in some cases, also, helping save some money that people don’t have to spend on on this input.

Will Fulwider 21:18
Especially with the high cost of nitrogen these days, I think everyone would like to save a little bit of money on that not and not use as much. So Michael mentioned, soil health and the practices that are kind of associated with that. And my mind immediately goes to cover crops. And I’m just wondering, is that a tool that we can use in nitrogen management Diane? Is it how do we manage that those best for nitrous oxide emissions? To minimize those?

Diane Mayerfeld 21:48
I think absolutely cover crops can be a tool. And in in two different ways, I think one way is that there are cover crops that can be used to hold on to the nitrogen that’s, that’s there at the end of the season, and keep it in the soil. And rye is kind of a classic example of that. The issue with that can be that it continues to hold on to some of that nitrogen early in the season when the corn needs it. But without that crop people were you know, that’s where it, you know, an early small application of nitrogen can make sense. And then the, as the rye decomposes, and releases some of that nitrogen, the corn can presumably use it. But and then the other thing is in certain situations, so if you’re growing wheat, you can plant a cover crop of, for instance, red clover, you can frost seed the red clover into the wheat, and it can fix nitrogen over the winter. And because it stays alive in the soil, it can substitute for synthetic nitrogen. So I think that can be a very helpful part of the cover crops toolbox as well. So you’re not having to take that very energy intensive nitrogen fertilizer and apply it as much.

Will Fulwider 23:31
That’s a good call out to our previous episode on frost seeding red clover, so you should go listen to that if you do not know what Diane is talking about. And one thing that I’ve seen recently talking about cover crops, is the fact you were talking about how kind of wet conditions, soil saturated conditions lend themselves to nitrous oxide emissions just because of the process of denitrification. And something I was just reading about, you know, one study that has there’s been several other studies out there but have shown that winter killed cover crops, such as here in Wisconsin, oats and radishes, and the such can actually lead to higher fluxes of nitrous oxide emissions because you’ve got this decomposing plant matter aka this nitrogen hanging out in really saturated soils of April, March, May time. And you know, it’s it’s very climate dependent. It’s, this is one study, but it’s it’s an interesting kind of tidbit that we need to think about is when we’re choosing our cover crops, we need to be choosing them for various different reasons, you know, there’s a reason someone plants, oats and radish and radishes rather than rye, for example, because maybe they don’t want to have to come back and terminate that rye chemically. So there’s trade offs and everything but that that winter, those winter killed cover crops are not holding on to that nitrogen to when the corn needs it then in the same way, necessarily that others like, like a red clover that overwinters and doesn’t winter kill would be so, you know, cover crops can be great, but they can also not be as helpful depending on the management strategies there.

Diane Mayerfeld 25:10
Absolutely. And yes, there, there’s so much we still have to learn because this nitrogen cycle is so complex, because the soil biology is so complex. And, you know, you get those complexities interacting with variations in soil and climate and weather. And as I said, we still have a lot to learn about specifics. But we, we also have some basics. And, you know, I’ll circle back to really making sure that as much as possible, we don’t apply more than we need, and that we apply it as much as possible when the plant is using it can can help move us in the right direction.

Will Fulwider 26:08
And so you were talking about nitrogen cycle is very complex. It is, and we’re still learning some and there’s a lot that we don’t know. But and that’s an obstacle and it upon itself to figure out what you know, the solutions are. But what are some other obstacles to kind of fine tuning these solutions is there other things that we do know that are kind of impeding our our efforts?

Diane Mayerfeld 26:31
Well, I just before I jump into the second part of your, or the main part of your question, I just want to build on you know, one of the things that that adds to our lack of knowledge is that it’s actually really expensive and difficult to measure these nitrous oxide emissions. They and they’re highly, what we do know is that they’re highly variable over time. So they vary a lot over the course of the day. And also, they vary a lot over the course of the year. So you spoke in the context of cover crops, but that’s about spikes in nitrogen emissions, when you get the soil thaws. You can also get those spikes if you have say fall applied manure and you get a winter thaw, you can have another huge spike, which can be in 24 hours, half of the year’s nitrous oxide emission from that place, as far as people can tell. And yet, you know, we don’t have good tools for continuously monitoring those emissions. So I think we have a lot. You know, the tools we have are very expensive, and people have to be there and monitor them and actually withdraw those, those samples of the gases in a little closed chamber that you put on the side, and then test those. So that’s one that’s one challenge. That’s one thing we have to overcome. Other barriers, I mean, I think always a barrier is how close to the margin farmers operate. And, you know, balancing the desire to be a good steward with those narrow profit margins. And, you know, I think lots of farmers would love to experiment with cutting their nitrogen rates or some of these things. But the economic barriers without some sort of good backstops, I think are also huge.

Michael Geissinger 28:39
Absolutely. And longer term, maybe, I don’t know, 10, 20 years in the future. How might you think the use of nitrogen on farms, how might you think that will look different in the future? And I feel anyway, turned around and asked me to, but I’m curious what your thoughts are on how you think nitrogen management will look different in the future.

Diane Mayerfeld 29:05
Yeah, that’s a great question. Well, one of the things you mentioned a little earlier, Michael, is the work on soil health. And there’s some really interesting stories coming from farmers who are really on the cutting edge of soil health and regenerative management, who, who have been able to really reduce nitrogen applications or even eliminate them altogether and still maintain yields. I mean, that’s not cutting nitrogen out of their system, I think they’ve got legumes in their rotations. But, you know, if we can learn more about specifically, what they’re doing right to make that work, and we can disseminate that across the landscape. I think that would be amazing. The other kind have long term maybe idealistic vision I have is, you know, we’re we’re hearing a lot in the news about our cars switching over to electric cars and the electric fleet. And, you know, I hear that and I’m thinking about right now something like 35, or 40% of our corn crop goes to ethanol. And corn is nitrogen hungry. You know, you mentioned that, at least here in Wisconsin, that’s our, that’s our big crop that we have to apply a lot of nitrogen to. So does that transition to an electric transportation system offer us some opportunities to maybe even think about what crops we have on our landscape and whether we can shift to things like perennial pasture or just other crops that are less hungry for nitrogen? So those are my two visions. But I am really interested to hear and what you think might change.

Michael Geissinger 31:05
Well, yeah, I certainly agree with those. And even the conversation on the ethanol and what could happen to follow up, that is something that keeps me awake at night, sometimes. I’m glad that you brought that up. I would think to just I mean, generally and very pragmatically, that I think the the use of nitrogen is going to continue to go down as we develop, you know, newer hybrids that might be less apt to being as nitrogen hungry as the current ones that we use. Even you know, if we are managing nitrogen in the system, I think that 20 years from now, it’ll probably be a lot different than it is now. I, you know, the hope is that it’s not more regulated. But I think pragmatically, I think in the future, they’ll probably be a much wider use or opportunity to use nutrient management plans on farms, to actually map out what the crop needs are for a particular system. And reconcile that with the rotations that they use, and their different fertilizer sources depending on where they are. And a big part of that, too, I think, is setting realistic yield goals. And so the number one, probably determinant of how much nitrogen a farmer will apply right now is the amount of yield that they expect to get or the amount of yield that they want to get. And the amount of yield doesn’t necessarily correspond to profit margins, which we’ve kind of already alluded to earlier in the call. But the amount of yield might not even correspond to what the world needs, which is what you alluded to, with the discussion on corn, 40% of corn going toward ethanol production right now. And so if I was to spit ball, I would say that those are a few of the ways that I think nitrogen management will continue to, to look different. And, you know, there’s a lot of stuff out there right now about these biologicals, that are going on. And whatever anyone feels about them and UW or otherwise, I think there is some maybe untapped potential there that well, why wouldn’t it be realistic and, you know, 20 years from now that a corn plant might be able to fix its own nitrogen? Right now, that certainly doesn’t really seem to be the case. But I don’t know. I don’t, I don’t think it’s entirely impossible that our systems could move in that direction. But I would just throw that out there as an idea. I mean, who knows what’ll happen. That’s, that’s part of the fun of this question is we can say whatever we want, and it can be totally wrong.

Will Fulwider 34:05
Nitrogen fixing corn for all is what Michael is saying there.

Michael Geissinger 34:10
I actually have a variety in my, in my closet here at home. So

Will Fulwider 34:15
Michael, really stepping into his nutrient management position there. That’s really great. Well, I think that about does it for us today. Diane, thanks for taking some time and talking with us about climate change and nitrogen management. Appreciate it.

Diane Mayerfeld 34:33
I really enjoyed this conversation. So thank you so much for this opportunity.

Will Fulwider 34:44
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, the Nutrient and Pest Management program of UW Madison. A big thank you to Joe Ryan for creating our theme music and to Abby Wilkymaky 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