Circles on the Map: What GIS Tells Us About Manure and Cropland in Iowa

Dan Andersen is joined by Cain Bynum to discuss the spatial analysis of manure management in Iowa using GIS to align manure nutrients with crop demand.

Transcript

Dan Andersen: 0:06

Hello and welcome to Talkin' Crap, a podcast by Iowa State University Extension and Outreach. This institution is an equal opportunity provider for the full non discrimination statement or accommodation inquiries, go to www.extension.iastate.edu/legal. In this podcast, we discuss insights into the science technology and best practices surrounding manure management. Our objectives are to build awareness about the challenges farmers and the broader agricultural industry face around manure and to demonstrate solutions and areas of innovation. Hello and welcome back for another episode of Talkin' Crap. Today, we're going to be talking about circles on the map and what GIS tells us about manure and crop land in Iowa. When we talk about manure in Iowa, we usually talk about in pieces, one barn, one field, one application pass, one complaint, one nutrient management plan. But manure doesn't really work in pieces. It works as a system. Iowa raises a lot of livestock. We also grow a lot of corn and soybean, and somewhere in between those two facts is an assumption that we often don't test, that the manure we produce can be used responsibly, economically and locally on the land we farm. But is that actually true everywhere? How much manure do we have? Where is it produced, and how far does it need to move before it is land applied at agronomic rates, and what happens when multiple farms are looking at the same acres as their outlet? Those aren't philosophical questions. They're logistical ones. They drive hauling costs, nutrient value, application, timing and ultimately, whether manure is seen as an asset or a liability, today's episode zooms out and focuses on this system. We're talking not going to talk about manure at the scale of counties, regions and the entire state of Iowa. We're going to talk about circles around farms and where their manure needs to go and their land base. This isn't to point fingers, but to understand the system we're actually operating in and how well we can utilize manure. If you've tuned in the past, you've probably heard me say something like about 25% of all the nitrogen, phosphorus and potassium that the state needs to support crop production can come from livestock manures. Or you maybe even seen some colored figures that show you what percent of nutrients in any given county comes from livestock manure. And that's a great starting point. But I think what Cain, my special guest today, has been working on to try and understand this more locally, and how that scales up really provides some new insight. So I'm excited to have him here today. So my guest today is Cain Bynum, a PhD student here at Iowa State who's been working with me to pull together livestock data, crop data, estimated nutrient availabilities from manures and GIS analysis to ask pretty simple but powerful questions, does Iowa have the right amount of land in the right place to use the manure we produce the way we want to and the way we say we do? Cain's work is helping us move past assumptions and county level analysis into evidence about what's happening locally that can inform future manure management decisions, nutrient management planning and maybe even some technology investment. So with that, I'm excited to introduce Cain here for us, and I want to get Cain to maybe share a little bit about his background and who he is. But as we get to that, Cain really what got you interested in manure, and coming to Iowa State.

Cain Bynum: 3:22

Well, I thought about my abilities to focus on technology, and my background in technology and growing up on a really small farm in Tennessee, I thought about, how could I apply technology to the agricultural world? And this felt like an amazing opportunity, coming to a school like this, working in one of the best programs in the world for trying to solve big problems with tech.

Dan Andersen: 3:47

Okay, so a little bit on your background. You grew up on a small farm over in Tennessee. When you first got to Iowa, what was the biggest difference you noticed between Iowa and Tennessee?

Cain Bynum: 3:57

Definitely the lacking of hills and the dedication to row crop. You know, over 90% of the land being dedicated to corn and soybeans is quite amazing, especially when you look in Tennessee, where you have to kind of carve out against the forests to grow, whereas here there they've the whole state is designed for agriculture. So it's quite amazing.

Dan Andersen: 4:21

Yeah, the scale is vastly different. And some of the livestock farms that we've shown you during your time here just they look similar to Tennessee. It's the landscape around that that really makes a difference, because you grew up in an area where there was swine production.

Cain Bynum: 4:34

Yeah, we there's a big company called Tosh farms back home in Tennessee that does a lot of pork production and but the scale is obviously dramatically different here. I mean, it's it's amazing to be able to go down a road and just see pork pig farms after pig farms, and the concentrations are definitely different. It's amazing to see a state that's so dedicated to its field.

Dan Andersen: 4:56

And then how about a little bit on your educational background. I know you've taken an interesting path to maybe get to the world of manure, but let the listeners know a little bit about how you got here.

Cain Bynum: 5:05

Yeah. So I have a bachelor's in history with dual minors in Chinese and law. Was working on a master's in history, and then got a master's in cyber security. Worked in cyber security for a little bit, eventually came to Iowa State to work in agriculture tech.

Dan Andersen: 5:22

Yeah, and I think that you sort of got into the tech world through cyber security, and then this opportunity presented itself, and you said that's at least moderately interesting to you. What do you think of the world of manure?

Cain Bynum: 5:32

I think there's a lot of potential in manure, because it's something that's with us, and it's something that's not going to go away, and I think that it has a lot of utility, especially when it comes to nutrients.

Dan Andersen: 5:46

Yeah, and I think one of the things you've mentioned to me is maybe there's a lot of contention or myths around manure, that people think things, but we don't always have the data to back that up. For instance, I know you have this perception that a lot of people say manure is a waste product, and you feel quite passionately at the moment that it really is a fertilizer.

Cain Bynum: 6:04

Well, yeah, I mean, it has value, and I think that that's an important part of anything. And the most common thing I've seen, I've been told, here in Iowa since I came here, is we have too much manure. And that is far from the truth. We actually don't have enough, yeah.

Dan Andersen: 6:21

hear there's too much manure. From me. I love every ounce of manure we have, but there is oftentimes news articles that say there's a lot of manure. How are we managing it? How people are just trying to get rid of it? And and I know that bothers you a little bit, especially as you've looked into maybe some of the spatial analysis, or how much fertilizer we really need to support crop production relative to the manure resources we have.

Cain Bynum: 6:43

Yeah. I mean, manure is a it's something that can be extremely useful, especially in Iowa with all the row crop farming. And I think that using it, using it efficiently, is, I mean, that's the goal, is to use this product that we have that is a part of having this kind of animal production systems. And it's not a, I don't think of it as a negative. I think of as an opportunity.

Dan Andersen: 7:02

Perfect, and that sort of gets us at what I have you working on for a project. So really, in the next couple minutes, I want to talk about, what are you trying to do and why. And I think when I asked Cain to come here, I'd done these county level nutrient budgets before, for manure budgets, and I was like, that's helpful. It lets me know maybe areas that have a fair amount of manure relative to what they use and what they can't use, but decisions are made on the farm. They aren't made at the county.

Cain Bynum: 7:29

Yeah. And when you look at how people deal with manure, you can see that the effect that, like the legislation side has had, and how governance has played a major role here in Iowa, because manure management plans.

Dan Andersen: 7:42

Yeah, and I think that sort of sets a land base equal to manure resources for most places. All right, so at a big picture level, what are you trying to do?

Cain Bynum: 7:52

Well, we're trying to look at, how do manure man, how do manure nutrients align with the crop demand spatially? So for example, in some of the counties we have here in Iowa, we have quite a concentration of manure that helps to deal with the nutrient requirements that we have on the farm. And then in some counties, we may not have as much. And when that happens, you can see that there's a difference in how people are dealing with that situation, because corn needs nutrients, corn needs nitrogen, and manure has a nitrogen with it, so the more nutrients that we get from manure, the less they the farmer has to bring in from outside.

Dan Andersen: 8:29

Yeah, so it's really about that circularity concept. How well can we recycle some of these nutrients? And in particular, what you're doing is you're trying to figure out the attributes for each farm, how many livestock they have, what that means for manure production, given the storage systems they're using, the nutrient content that we'd estimate they have and how many acres they need to put manure on.

Cain Bynum: 8:49

Yeah. So when we look at these animal feeding operations here in Iowa, a big part of it is, what kind of animal are they using? What kind of manure system, storage system are they going to use with that animal? When you store differently, with when you store your manure differently, you get different results, because there's losses with manure storage, for example, when you deal with manure, with swine manure, you're tend to think of deep pits here in Iowa. So that has an effect on manure, just like anything else does, but lagoons would have a separate effect. Taking that into consideration is a part of what we're trying to do with our circles, is we're trying to bring into account the exact type of manure storage system they're using on these AFOs, because that gives us a more accurate understanding of how much manure are we actually getting from these animals after we take them out of storage. Because as we've as I've learned here, we have as excreted and as removed, and that is a very important difference between the two.

Dan Andersen: 9:42

Yeah. So I think one thing I want to make clear is we're not trying to replace manure management plans. Manure management plans are a farm tool, to understand where they're going to put manure, how to match it with their crop nutrient needs. And what Cain is working on is really saying we don't care about any particular operations actual decisions, but we want to do the best we can, to say generally, what we given what we know about these operations, where's the manure probably going? Not absolutely, where it's going, but where is it probably going. So we can understand, sort of where we type, where we maybe can build more livestock feeding operations, and maybe, as we look to the future, where would we think about doing different things with our manure? So I think there's a lot of data that needs to come together to sort of answer this question. And I want to start first on that farm or livestock side, to really understand production of manure as a resource. What Where did you get data to understand what livestock we have in Iowa, what types, where they are, and then how much more manure they make?

Cain Bynum: 10:39

Well, luckily, one thing I've really enjoyed about Iowa is that with the dedication to agriculture, we also have a lot of resources from like, for example, Iowa DNR, Department of Natural Resources, and they have a database of the AFOs that we have here in Iowa. And they actually have some of that data uploaded into the geospatial Clearinghouse, which is extremely useful for GIS users, and you can go through Iowa DNR to pull also to see the storage types they're using on these manures. Now these are two different data sets, thankfully, here in Iowa, the governance is really I personally think that Iowa does a really good job of giving examples for how governance and good management can really help farmers, because this is a symbiotic relationship. We're trying to everybody's trying to do the same thing. We're all trying to use the nutrients as effectively as we can. And I think that working with the farmers is the most is a huge part of dealing with manure and working with it and using it as effectively as we can.

Dan Andersen: 11:39

So you found public data on farm locations. So their larger animal feeding operations are large enough that they had to report to DNR their size, and in that they tell you how many animals they're permitted for and a little bit about facility type, but you had to find a second database to sort of link what's their manure storage type that goes with the type of livestock. Is that fair?

Cain Bynum: 12:02

Yeah. And one thing about the storage type is, when we're looking at it, it can be assigned specifically to the animal units that they're using. So that gives us more of a precise view of when we're estimating that manure. What are we going to do? How do we do it? Effect more effectively than ever before. Because when we know exactly, for example, if a farm has 1500 animal units, and 1000 of these animal units are assigned to a bedded pack, and then 500 are open feedlot, well that's different types of storage, and that plays a role in how, what the NPK, where nitrogen, potassium and phosphate that we're going to be getting from those nutrients? So having that information is really valuable.

Dan Andersen: 12:42

Perfect. So from public information, you're able to find where facilities were their animal unit numbers and the types of manure storages they were using. How do you take that data and start estimating how much manure that facility makes?

Cain Bynum: 12:56

I use a lot of Excel, a lot of data analysis that I've learned from here at this program. And basically you plug it in and then start calculating, and you take into account the variables that affect the manure. Because every what we're doing here is estimating we I can't there is no exact number in the world, but there is as close as we can get. And I think that's really important, especially when it comes to saying, just go into a farmer and saying, Hey, you have this much. We know that we can guesstimate this much. What is the best? Where are we putting this? And that's kind of the idea is to estimate where we are putting these manure, to know that way, maybe if we could do it more effectively somewhere else, or maybe somewhere has a less concentration than others.

Dan Andersen: 13:41

So you're using things like Midwest Plan Service, the American Society of Biological Engineers Manure Production Standard, some Iowa DNR resources. And my best judgment to come up with how much nitrogen, phosphorus, potassium really are in this livestock manure when it's excreted, and then, more importantly, when we remove it. So trying to adjust for losses that occur during storage.

Cain Bynum: 14:01

Yes, because the anything that has an effect on the NPK is extremely important.

Dan Andersen: 14:05

And as you mentioned, it's an estimate or an average. It might not be right for any specific facility, but we're trying to give a general, good estimate for the state and what that might make it look like. On the flip side, we have crop production. What sort of data were you looking for there, and where did you find it?

Cain Bynum: 14:21

So a lot of this has already been done in a way. You can look up the read the literature, for example, some of your papers have helped me got find something certain, like when you look at county level, yields and rotation, for example, if you're in a continuous corn versus corn and soy rotation, you're going to have different amounts of nitrogen you need. And that plays a role in the circle sizes, because when we're looking at circle size, we're thinking, I have this much nitrogen from my manure, How far can I go out from here? Where does it like? How much area can we cover? Well that plays a huge role, because the more corn we're growing, the more nitrogen we need. And then you. Using something like a yield goal method, and looking at the allowable manure application rates and nutrient constraints. For example, in Appendix A5 the corn nitrogen usage rates. It's extremely important because it tells us kind of an idea of what the corn needs in this specific area. So it goes by zones.

Dan Andersen: 15:21

Yeah. And I want to say it's not, maybe what the corn needs, but the maximum allowable rate that you can apply. So one of the things that we had to decide to start with is, what do we do this based on? Do we use ISU recommendations for nutrients? Do we use the yield goal method and what's allowed according to manure management plan forms? And you started with sort of that yield goal method and what's allowed according to manure management plans.

Cain Bynum: 15:42

Yes. And we can also further, once the data is completed the analysis side, or, I should say, as good as we can get it, and we can take that and apply that to other methods, for example, N-FACT.

Dan Andersen: 15:54

So I think the advantage of that is, oftentimes we don't fully understand what, what a policy change might do, right? Like, how much further might you have to move manure from a farm if we'd say, well, we're no longer allowing the yield goal method, we're switching to maximum return to nitrogen, or we're switching to N-FACTs as a basis for suggesting this, and what impact does that have in the farm? So really, Your work here is to sort of set that up and say, what changes in the state of Iowa if we do something like that.

Cain Bynum: 16:21

Yeah. And our circles will change the circles. The benefit of GIS is, whenever we want to change the size of them, it's not that complicated to plug it in, once you have the numbers calculated out and we can see the spatial difference between the different types and the different policies that might come to play.

Dan Andersen: 16:39

Yeah. And I think that's really what drives me on this. It's not, it sounds like a simple thing. We want to see generally where manure is going, but the implications from that really compound, right? They go into, should we change policy, or what's the economic cost if we say that you have to reduce your application rate to this, how much further does manure move, and what's that going to cost? And I think that opens us up to a world of possibility of really defining when do these laws make sense, and when do they do something that we're really not going to be feasibly able to do. So that circle that you mentioned is really the linking between manure resources that I generate, how much the crop needs. And I believe you got, have gotten pretty close to making a map of Iowa for a first estimate for circles.

Cain Bynum: 17:20

Yeah. So we've went through a few renditions, and we are at a point where we are going to have a new rendition soon with the storage types accurately put in for individual AFO information from Iowa DNR. And I think this will be the it'll give us a more, more effective view of the world of Iowa's manure, and how we look at it. And this latest, this latest addition, will be incredibly beneficial for us to look forward to the future, especially when it comes to the logistics of moving manure.

Dan Andersen: 17:54

Yeah, so I think we have estimates of what it costs to move manure around, and now that we'll have this sort of estimated for individual farms, you can start extrapolating that out and say, this is really what it's costing or really what we're doing in the state. So super excited about that. So when you think of the maps you've made so far, what are some of the things you've noticed? Are there big regional differences in manure relative to crop production? Are we pretty consistent across the state? What stands out to you?

Cain Bynum: 18:16

Definitely the Northwest sticks out more than anything. There's a concentration of manure there, where we have a lot of opportunity with it. And then if you look into like Washington County, keok I can't say it correctly, Keokuk, and you see these kind of like, these islands of manure where you can see that there's greater concentrations, but there is manure all over the state, not to say that there's only concentrations, but the concentrations stick out to you on a map more and more, because as the layers overlay each other, the depth of it becomes more and you can see that Iowa definitely does not have too much manure we I think that's what that really that's something I've had so many people tell Me, is we have too much manure. I'm like, Well, I mean, if we did, the map should be covered, and the map is not even close to covered.

Dan Andersen: 19:08

Yeah. And it still it comes down to making good manure decisions to make sure we're using it. But certainly there's capacity to responsibly use the manure that we're generating. And I think that's a good thing, and it changes out the perspective of how we do our job. One of the things you mentioned, there are places where two circles might overlap. How do what happens in that case? What are we going to do to fix our map?

Cain Bynum: 19:28

Well, we're going to use some the best way I can think to do it is we take the circles we can't double apply. So when you see a circle that overlaps another one, what we have to do is take that area, combine it together, and expand out the circle into kind of like a third circle, in a way, where we're basically seeing how this manure is actually going to be applied. Because once two circles overlap, that overlapped area has to go somewhere, because we're not double applying. So we take, for example, one of our fellow researchers is looking into using Python to help code that and basically take that area and apply it to an larger into an enlarged circle to show a more accurate understanding of where that manure is going. So, and we do have quite a bit of overlap in some areas, for example, the Northwest.

Dan Andersen: 20:17

Yeah, so I think essentially they aren't using the land twice if they share 10% of the area, each circle needs to get 10% bigger to sort of make up for that and expand. So it is going to take a little coding, but I think it goes a long way. And from just a practical standpoint, it might show us where farms are competing for those locations or resources of where they might put manure.

Cain Bynum: 20:37

Yeah. And it definitely helps to show that even though there is overlap, the manure is going somewhere and is being applied on the land for the nitrogen usage, and it still has a great value in no matter where it is, it still has something that is beneficial to the land, especially when a lot of these places are doing continuous corn in areas that may be higher concentrations of manure. Because it just makes sense. If I have plenty of manure and I want to use that nitrogen, why not do continuous corn?

Dan Andersen: 21:05

That's a great point. So we might be able to say, in areas where we see more of the continuous coverage, is there a difference in rotation? Are people making different cropping choices because there's more manure there? And how do those things relate?

Cain Bynum: 21:17

Yeah, and I mean, I think that comes down to the individual farmer will make that choice, but you can see a trend when you look at choice, because that's how economics generally works, is trend lines.

Dan Andersen: 21:27

So we're going to have this map, you'll be able to see it in our show notes about where we're at and what it's looking like. But I do want to talk a little bit about where do we go from here? What do we do once we generate these maps? How do we actually use them to make smarter manure decisions, or smarter policy decisions.

Cain Bynum: 21:42

The way I think of it is, what I'm trying to do for any for everybody, is to give them more resources to make the best decisions they can make. So when, for example, in governance and legislation, when they look at this, I would like for them to see this and say, Well, I can understand this map more so than I can understand maybe a big data table, and it may be, it'll give them more of an advantage when they're thinking about the best ways to responsibly use this, because this is, like you've said before, and I really like this. It's a circular system. This is something that we're trying to use the resources of Iowa, for Iowa, and that's, that's what it's all about at the end of the day, for agriculture, is trying to use our resources the best we can. And I think that giving people the most accurate data set that we can, showing people the best way we can is the is what we can do, is the academic side, is try to give them a way to effectively use tools that we provide and how they use that is on is for them to decide, but we can at least do our best to try to give them the most resources we can.

Dan Andersen: 22:50

So I know one of the things you and I have talked about is I have some survey data on what manure application costs, for different application rates, or for different transport distances. So you could really go to get go through your database and start saying, I have circles that tell me roughly where people are moving manure to what the application rate is on area in each of those circles, and say, what do we think manure application costs this state?

Cain Bynum: 23:11

And when it comes to the logistics of manure, it's really interesting because we think of manure, we usually think of, well, if I want to move it, we don't want to move it very far. Liquid manure, especially has a one to two mile radius where you're kind of after that most farmers won't move it. And I think what's really interesting about becoming more efficient at knowing where it is now, it tells us what, where we could possibly move it later, and maybe like how these circles could change over time, just depending on how are we moving it, where are we going to put it, and how we use it most effectively.

Dan Andersen: 23:46

So I think, to my mind on that understanding what it's costing us now, but also saying, Well, if I did start hauling it to a field further away, how might that change cost? How might it change how long it takes me to apply manure, and just as importantly, how might it change the value I'm actually getting from that manure. If I go from a world where the phosphorus and the potassium maybe aren't offering me to value because my soil tests are already high, to a place where I really do need those nutrients and they replace a fertilizer.

Cain Bynum: 24:11

Yeah, and I mean that would be when they're in those kind of situations, the value of manure, the interesting thing to me, the most interesting thing to me about manure, what really kind of makes me interested in is kind of the economic side of it, because manure has a value. Manure is a currency, in a way this. It's something that when we it's not a waste, it is. This is a product that can help farmers and has helped them for 1000s of years. Farmers have always used manure for as far as we can go, I mean, and it has such a value that I think is kind of underplayed in some ways, because we tend to think of it as something we just have to get rid of. But I think manure has real value.

Dan Andersen: 24:50

Yeah, and I think that's a public perception that it's something we have to get rid of. And certainly farmers feel that pressure sometimes when storages are full, but we have been getting better. Farmers are doing a better job of taking credit for the nutrients in their manure. They understand the challenges and they want to address them, but we need to continue to develop and innovate tools that help them make those decisions.

Cain Bynum: 25:10

Yeah, of course. And I think that's really important here in Iowa.

Dan Andersen: 25:11

And then just as we're starting to get a little closer to finishing up, I wanted to talk a little bit about where does this fit with technologies, for instance, nutrient separation or anaerobic digestion. Does your analysis help figure out where we might use those or how we might use those pieces of technology?

Cain Bynum: 25:26

I would say it definitely can give you the more of like, maybe what I would think of as, like an opportunity zone, where, when you see higher concentrations of manure, you could say, well, if we were going to test out or if we were going to try an anaerobic digestion system, we would want to try it somewhere where there is the highest concentrations we can find. And the reason being, we can put more manure through it. That's how you make your money back. So when you see the this map and you see these higher concentration zones, you can think, well, that's an opportunity zone. It's not just a concentration.

Dan Andersen: 25:57

Or if you have those circles of where we're moving manure nutrients, we might think about nutrient separation technologies and say who's already moving manure greater distances. Are those the types of farms that maybe would be targeted, or are the best potential candidates for this machine that we might make to separate nitrogen, phosphorus, potassium?

Cain Bynum: 26:13

Yeah, certainly.

Dan Andersen: 26:14

Okay. So as we get to our closing questions here today, if someone listening farms or advises farmers or works in egg policy, why should they care about your work?

Cain Bynum: 26:26

Well, I would say that it shows them there's a spatial context matters when we're talking about manure, and that manure does have value. And I understand that there are constraints, like I remember having to shovel manure, and I understand it has difficulties. But to me, there's always a bright side on things. And I think the bright side of manure is that it does offer a nutrient value, and that's not going away. And if you any, if anything, the research shows that the nutrients of manure has increased over time, and I think that that's a benefit for us as not only as farmers, but as just people, because when we use this manure more effectively, it's better if they create that circular systems incredibly valuable when it comes to sustainable agriculture.

Dan Andersen: 27:08

Perfect. Yeah, and I couldn't agree more, I think we've used manure better. We've gotten better at water conservation to bring some of those nutrient concentrations up. Fertilizer prices have increased. So as long as we can think of technologies that help keep those handling costs as low as possible. It offers some opportunity for us, and anytime we're proposing new policy, I think it's important for us to explore both the spatial questions and then the types of farms that we're impacting. And I think your work really lets us

Cain Bynum: 27:34

Yes, certainly. And I think that it's an amazing go from kind of thinking of all farms are the same to zeroing in on what's the impact on different farms, and how is it different to you now. opportunity. And I've enjoyed being here. I think Iowa is amazing. I think Iowa agriculture is really it's, I mean, in the whole in the entire world, this is one of the places where agriculture has become, it's an incredibly efficient system, and I think that it's really amazing to be a part of it.

Dan Andersen: 28:03

Perfect. And thank you so much for joining us today. Cain, it's been great having you, and hopefully we can have you back as you move this along, and we start seeing maybe some of those economic results or analysis as we think about putting different nutrient application constraints on so really appreciate your time walking through what you're working on and sharing what you've learned so far.

Cain Bynum: 28:19

Thank you very much.

Dan Andersen: 28:21

All right, so signing off from a job that sometimes smells but never stinks. This is Dan Andersen. Keep on talking crap. Thank you for joining this installment of Talkin' Crap. Be sure to take a look at the show notes on our website for links and materials mentioned in the episode. For more information, or to get in touch, go to our website, www.extension.iastate.edu/immag/. If you found what you heard today useful or it made you think, we hope you subscribe to the show on your podcast app of choice, signing off from a job that sometimes smells but never stinks, keep on talking crap.