Manure Madness

In the spirit of March Madness, Dan Andersen and Jake Willsea spend this episode analyzing common livestock manures found in Iowa and discuss the benefits of each type.  

Transcript

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Dan Andersen  00:06

Hello and welcome to Talkin' Crap, a podcast by Iowa State 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/diversity/ext. 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 in areas of innovation. 

Dan Andersen  00:43

Hello, I'm Dan Anderson with Iowa State Extension Outreach, and this time we're talking March Madness of manure - a fertilizer face-off. As March rolls around basketball enthusiast across the USA gear up in that frenzy known as March Madness, and amid the hoop dreams and bracket busters lies another intriguing competition, maybe a bit less glamorous, but equally important. And that's the battle of manures. So we'll be talking today about solid, liquid, slurry manure, pig, dairy, beef, layer, turkey, what's the best some advantages and disadvantages and how you can work to use each of them as effectively as possible? So I'm joined this episode by Jake Willsea. He's here at Iowa State. And I'm gonna let Jake introduce himself.

Jake Willsea  01:28

Thank you. I'm Jake Willsea like he said, and I am a master's student here at Iowa State, mostly looking at manure management. And so I'm looking at how nitrogen application timing will affect your crop yield, and the economics of the system as a whole. 

Dan Andersen  01:43

Great. Thanks, Jake. And great to have you join us today as we talk through some of these manure questions. I know in all seriousness, it's a question I get quite frequently what's the best manure, and I generally try and differ and say all have pros and cons, but given the spirit of this season, I think it's worth us talking through. So before we get started, which one you go on with? What's your favorite manure? 

Jake Willsea  02:04

I think around Iowa, at least, it's got to be the deep pits one?

Dan Andersen  02:09

Well, that's definitely the most common and I'll give you that. So maybe we should start is what makes a manure good, what makes manure into or something you want, rather than something that you have to deal with? What do you think?

Jake Willsea  02:18

I think nutrient composition is definitely important. I think you want to have high levels of nitrogen. And phosphorus is also important, but you don't want it to be too high. Or else you can have excess phosphorus for the same amount of nitrogen. So I think that's really the main thing that you're looking for. 

Dan Andersen  02:36

That'sa great point, I think all manures start that way, right, the more we can get in a unit volume, the better off we are to haul it transported, apply it, fewer trips across our fields. So that's a great point. And then your second was sort of ratios, right? We want fertilizers that match crop need. And I like to say manure is a complete fertilizer, it has everything we need nitrogen, phosphorus, potassium, sulfur, a slew of micronutrients. But as you're getting at that balance isn't always right, we might end up with manures that have too much phosphorus, or maybe too little or too much potassium, or too little. So that definitely impacts how we can use it. Even if that would happen though, if you had a manure with more phosphorus relative to nitrogen than we needed for growing crops, there's a few things you can do. What's what's one that comes to your mind?

Jake Willsea  03:21

Well, I think just applying maybe every other year, and you could use a different type of fertilizer in between just to make sure that your phosphorus level is right where you need it. Absolutely.

Dan Andersen  03:31

And that's I think the easiest thing to do is manage to that right. So other fertilizers choices, think about crop rotations, especially adding a legume in there - alfalfa soybeans, something that will use some of that phosphorus but make its own nitrogen. On the other hand, if you have something like deep pit swine manure, which sometimes is looking a little phosphorus deficient these days, or has excess nitrogen relative to phosphorus, if you're in a corn soybean rotation, maybe that means doubling up on corn two years in a row to make sure we're back into balance and adding enough phosphorus to meet our cropping demand. So you mentioned a few different perspectives on why manure might be a resource or might be something that's a little more challenging to deal with. And I think that takes us to where we're going to want to start: solid, liquid, or slurry manure, right. And, and the choice that we use is extremely important. So how would you walk us through what's when you think of solid, liquid, and slurry manure? How do you distinguish between them? What do we really mean there?

Jake Willsea  04:25

Well, I think solids content is really the way that you can distinguish and really the way that you you handle it changes between those different types. So with solid your application method will be definitely different than what you would get with a liquid or slurry.

Dan Andersen  04:42

Awesome. And I think that's where we want to start. So let's really talk about solid manure. Can you give us some examples of different solid manures that we might see?

Jake Willsea  04:50

Probably, mostly we're looking at like a bedded pack system, or maybe poultry. So with your your turkeys and your broilers and layers, you've got bedding mixed in or just the consistency of that manure is higher solids, higher carbon content, that kind of thing that it's got more solids mixed in, especially if you have the bedding mixed in with that manure. 

Dan Andersen  05:14

Yeah,absolutely. And I think you nailed it on the head. So in dairy and beef or pig systems, we're really talking about those bedded pack, maybe for dairy or beef, some open loot scrapings, and then with turkey and broilers, litter systems, and layer manure, at least something that we're getting dry enough to handle. And I think you hit one of the big points that we really want to talk about on the head when he talked about how much carbon is in the manure. And carbon in the manure is a blessing and a curse. We talk about soil health these days, and soil health is a lot about how much carbon is in your soil? How much carbon are we adding to feed that microbial system? So when you think about the choices, we had there, some bedded pack, manures and poultry litter, which ones come with the most carbon? 

Jake Willsea  05:51

Well, the ones that would have that bedding actually mixed in with them. And so it would be your layer systems have a lot of that bedding and a lot of organic matter mixed in there. 

Dan Andersen  06:02

Yeah, I think broilers and turkeys both. Using a litter system definitely comes with a fair amount of bedding. And especially those beef and dairy systems or pig systems where we're adding corn stover, or large amounts of it to soak up a lot of that material really have lots of carbon. And a good rule of thumb is that about 10 to 15% of the carbon we apply with manure will end up as soil organic carbon or soil organic matter. So that's really feeding those microbes helping to build soil health. And if you want to increase soil organic matter quickly, a solid manure is a good way to do that. With that said, if we're making a bedded pack and using corn stover, that means we're harvesting that corn stover from somewhere cycling it through our animal facility, using it as a bedding. Some of that bedding might get eaten, some of it might break down during storage, and then we're taking it back with manure to put on our field. And the point I wanted to make there is it's not a something for nothing sort of situation. It's a zero sum game, right? If we're going to use corn stover for bedding, well, I had to harvest that corn stover from somewhere, move it, and then reapply it. Maybe on the same field, maybe on a different field, maybe we won't put it on to every field every year, but in terms of thinking about building soil health and adding carbon to the soil, there really is a removal and then adding back sort of step. So if we're doing that maybe it's not as beneficial as as it would seem at first glance or first blush with how much carbon we're putting on. If you compare that with poultry systems where we might import the bedding, that's a pretty big, big difference, right? Where we're bringing something in and rice hauls might be an example of that. 

Jake Willsea  07:30

Yeah,definitely, I think that that's a good distinction to make is to whether you're bringing in your bedding from somewhere else, or if you're you're taking it from the crops that you're actually growing, there's a big difference in terms of the carbon buildup in your soils.

Dan Andersen  07:43

Yeah, especially in your soils. And still that carbon came from somewhere. But it didn't come from your field to your farm. And it really can be a net import. Another place that I had some experience growing up, we often use some marsh grass or prairie grass essentially for bedding for our cows. And I know there's places around the state now that are experimenting are exploring some bedding crops, miscanthus being one. And those are a little bit different just because they're perennials. So those perennials have lots of root biomass that we don't harvest and that biomass stays in the field that we're harvesting the residues from helping build soil health there. And since they're perennials, they have a fair amount of biomass. So even though we're removing it from that field, those soils tend to have pretty healthy soils to start with. So maybe that's the case where we can get some bedding material in and not impact our soil health as much. Even on the corn stover side, there are other things that come into play and one is tillage right. So if we aren't harvesting at corn stover, you might feel a need to be a little more aggressive with tillage, trying to bury some of it helps soils dry out or at least be black in the spring to warm up. And if we would harvest that residue and maybe be less aggressive with our tillage or remove a tillage pass, that can help with soil health too. So there's lots of things going on. One other aspects I wanted to hit on with that organic carbon in the field is related to nitrogen and carbon and nitrogen cycles often work together. So one of the things that we might talk about is carbon to nitrogen ratios, and how that ratio is relatively predictive of how nitrogen will be released from manure when it will become available. So one of the things we see with manures that have really high levels of bedding material or carbon added to them is they might have less available nitrogen in them, more of it's tied up in an organic form at the time of application. Andbedded packs are really a great example of that. Jake, do you have a rough? Guess for sure go to but what bedded pack manure might from a cattle facility might test at?

Jake Willsea  09:36

We might be looking at, I don't know, I think a lot of it can depend on how much of that bedding is actually mixed in there.

Dan Andersen  09:43

That's a great point. Bedding management is variable from farm to farm. I normally think somewhere around 20-10-15 pounds of nitrogen,  P2O5, pounds of K2O, so phosphorus and potassium per ton. Okay, which isn't bad, but it's also not the most dense and I wanted to compare that with something that a lot of us are probably familiar with the the one that you pointed out as Iowa's maybe favorite or at least most typical. And that's a deep pits swine finishing manure. So if you think of swine finishing the newer, often times, since that's a slurry manure, we'll say 50 pounds of nitrogen per 1000 gallons, that works out to about 12 pounds of nitrogen per ton. So when we talk about these bedded pack manures on a mass basis, they actually start with about the same amount of total nitrogen, whether bed pack or slurry manure, right, we're just reporting it in different units. With that said, in that slurry manure, almost all that nitrogen will be first year available with our bedded pack manures. We only only are going to capture a fraction of it the first year, and some of its going to be more slowly released after that. And I think that's a pretty big contrast to some of the poultry litter. So while we're grouping them all together as a solid manure, with our poultry litters, Turkey litter or layer manure, we might talk somewhere in the neighborhood of 40 to 80 pounds of nitrogen per ton, you might be looking at 60 to 100 pounds of P2O5. per ton. So a lot more dense. And, and that means if we're gonna move that to a field, which one you picking and Jake?

Jake Willsea  11:07

I take the more nutrient dense one. That's right, fewer passes over the field, less compaction, I think that's a big benefit there.

Dan Andersen  11:14

Absolutely, especially distance plays a big role in that. I mean, we see really big layer facilities where we might want to move manure sizable distances, 10-15 miles. And when we start talking nutrient dense densities like that, it becomes a lot more feasible to do that. If you are using bed pack manure, you're probably pretty close to that facility. But you made some great points about all this application equipment is going to be heavy, we're gonna have to get through the field, a fair number of times and, and compactions, a function of both how much our equipment weighs, tire size, field conditions, but also just straight up the number of trips. So the fewer trips we have to make, the easier it can be. And then one big advantage of sort of solid manure compared to liquid manures that you might think about as storability. Especially if it's not something you do every day, if it's something that you've decided, just give manure a try, liquid manures we have to get applied instantly, the moment we take possession, or there's no good way to hold on to. Solid manures, we can use some stockpiling in our field, and maybe I'll land apply at a rate that works for us. 

Jake Willsea  12:13

Yeah,that's definitely a benefit, but also because you have to handle it that way. There's a lot less automation involved in the process compared to a liquid or a slurry.

Dan Andersen  12:23

Yeah, I think that's a great point. And I think that's one of the reasons that we've seen a lot of implementation of liquid and slurry manures is just an an easier system, maybe not to just mechanize, but to automate that mechanism, right? Because we're not out there with pitchforks, moving solid manure, but it is someone driving the tractor, the front end loader to load it up, haul it to a field, maybe make a stockpile, maybe land apply it, but if we stockpile it, we have to land apply it again. And that can make some work. One thing you mentioned earlier was that phosphorus to nitrogen ratio in manures. And then can you make a general statement about solid manures in that regard?

Jake Willsea  12:56

I would say that solid manures typically have more phosphorus for the same amount of nitrogen than when you're looking at a slurry or liquid. 

Dan Andersen  13:04

Yeah. So I think as you pointed out earlier, that means thinking about crop rotation trying to think about how do we balance that manure application schedule to with what we're removing to make sure we're taking full advantage of that. In order to get a benefit from our manure to be it have it be the greatest resource that can be, we have to take advantage of all the nutrients in it. We can't just say we need this one in that one, and not that one over there, we have to take advantage of them all. So planning ahead to do that is extremely important. All right, I think that takes us through most of our logic on some solid manures. They're definitely important. If you have any final comments for us anything anything you want to say.

Jake Willsea  13:41

I would say one last advantage, I would say for solid manure is the solubility of the nutrients. So when you're when you're looking at a solid manure, you have a lower solubility and so there's less risk of loss due to a rain event something like that. It wouldn't move through the water quite as easily as you would a slurry or liquid.

Dan Andersen  14:01

That's a really good point especially that initial runoff event is extremely important and having something that can help hold on to those nutrients if we don't get it worked in or don't get injected is really important to us. And in Iowa rules you often see that come through in our manure application guidelines for winter manure with solid manure it's still allowed, with liquid and slurry manures there's some some restrictions on when you can do that, essentially to help hold on to that. And I think that's that's a great point to make as you go from maybe some smaller farms, we had thought about solid manure before. Why do bigger farms have to be treated differently? And some of it's just the amount of manure they have, but the manure management system often switches with that and the implications it has for water quality. Great, great point. Okay, slurry manure.

Jake Willsea  14:45

I'd say the first thing is just the ease of handling in terms of automation. You can use more pumps and that kind of thing to automate the process a bit more easily. And also in storage, you have different types of storage We can work well with those pumps. 

Dan Andersen  15:02

Yeah, and I think that's been a huge change that we've seen in the livestock industry throughout Iowa. We have a lot of commercial manure applicators, they can use relatively big equipment, get the job done EXTREMELY fast and efficiently. And that automation of the system so that it's really mechanized, really pretty much controlled and out of our hands, goes a long way. And while we've moved a lot on maybe our solid manure applicators to get some weigh scales a little more precision the application, many of our liquid tanks have been using flow meters and controlling the rate that they've been putting the neuron for many years now, almost two decades. And that ability is extremely important. If we're going to say manure is a resource, that means getting the right amount, the right time, the right place. And that right amount is tough, especially for something where we don't always have the greatest precision on it. So the ability to get pumps that we can control flow rate, measure that flow rate and get some feedback was extremely important to hitting rate and getting the right amount and knowing how much nutrient we were putting out. Certainly our solid manures are going that way, but I know growing up when I was using bedded pack manure and putting it on a field, it was really set the manure spreader at this chain speed, put your tractor in this gear and drive and that's about the application rate we wanted to hit and and I couldn't have told you if it was five tons an acre or 25 tons an acre, right. And that makes it hard to take credit or take advantage of it. So the ability to really control it is extremely important for us. 

Jake Willsea  16:30

Yeah.

Dan Andersen  16:31

you mentioned that slurry manure seems to be Iowa's most popular. One of that was automation. What else do you think played into that? Or why did we go to those slurry systems?

Jake Willsea  16:41

Well, I guess the the style of barn we're all using, not all, but mainly using a deep pit style barn where the manure will drop directly below through the grates in the floor of the barn and into that deep pit storage.

Dan Andersen  16:55

Yeah, I think that's a great point. While, whatever system we pick really plays into what the characteristics are going to be like for land application, we often pick our manure system, because it works for us, right. It fits the animal production environment and handles some other challenges for us. And as you pointed out, Isaac Newton shows up to work every day on those deep pit barns and it just the manure falls through or works through the slats. Pigs stay pretty clean and it's sort of a set it and forget it system. You don't have to worry about manure accumulation too much, check and see how much is there occasionally. But chances of an overflow are pretty small, since we don't have rainwater coming in and diluting those nutrients. We don't have to worry about pumps going down and all those things are pretty nice. So I think you're absolutely right on that regard. The other thing I really wanted to point out is switching to slurry systems over a solid manure system will push a lot more of those nutrients available in any sort of pointed that out solid manures have less solubility, the customers often have really high solubility, but they also tend to have a lot less carbon. So we move more of that nitrogen to first year available that can help out our nitrogen to phosphorus ratios. So we're more in balance with what our crops need. But I think that at least plays a part of it. When you're trying to take advantage or use manure as a resource on your farm, knowing and being able to guess or predict how much nitrogen we're applying is extremely important to saying I'm going to get the most advantage for it. So getting that nitrogen up into the first year available, instead of saying, well, it'll come back in the second or the third year, just the certainty of that can help us understand how much to put on how much value we're going to get out and how to best use it. 

Jake Willsea  18:25

Yep. But also, when you have that first year available nitrogen, it's mostly in ammonium form, which again, is that gives you issues in terms of loss. So it can more easily convert into multiple forms, which can be in terms of either converting to nitrate or ammonia, and losing it either to the atmosphere or through the water column. 

Dan Andersen  18:48

Yeah,so it's more sensitive to timing of application than some of those solid manures. And do we have any techniques to help with ammonia volatilization, especially at the time of application?

Jake Willsea  18:57

I'm not sure I guess you would have to talk more about that one.

Dan Andersen  19:00

All right. Well, I was hoping you you give me injection there, right. We know that most soils carry a negative charge, ammonium carries a positive charge. So if we can get that manure in contact with the soil, we can really help limit some of that volatilization. And the good news about liquid systems is we can run them through some of our injection injector systems, get that manure down into the ground in contact with the soil to help limit some of that ammonia loss at volatilization. With solid manure, we don't have that option. The good news, when we sort of talked about those is many of those manures especially the bedded packs don't have that much ammonia, most of the nitrogen is in the organic form. With some of our poultry litters that can get a little bit more challenging, we can hold some of that nitrogen in the ammonium form. And there's no really good way to get that nitrogen incorporated in the soil right during that application pass that normally is a second pass where we have to come back and do it. But certainly on the liquid manure side injection, we've see some vertical till sort of immediate incorporation tools that that can really help with that ammonium side. So I think while that can be a challenge, it's also something where because it was a challenge, people have developed some pretty good techniques to work with it. And then the last one I wanted to talk about was liquid manure. And that sort of tailors with what you're working on for your project, liquid manure, one of the big things is, if you're going to have a liquid, we've probably added some dilution water to it, and maybe we had rainfall going into it. And that takes us to maybe an irrigation system fits for us. And, and that might be a reason why we think about a liquid manure. When you think about what you saw, maybe last year, when you started your research, is there any advantages to liquid that that you can think of?

Jake Willsea  20:32

Well, I would say, like you said, the ability to irrigate, as well as apply that fertilizer is important. You also being able to apply that in-season will probably cut down on some of your methane emissions that you're getting, that are coming from the storage actually. So being able to empty that storage while it's while the temperatures high outside, you can limit some of those methane emissions coming from your storage.

Dan Andersen  20:59

That makes sense and is especially on the liquid side. There's some challenges, right, it gives us more material to handle generally. But if you put yourself in a situation where that water can be an asset, it's not so bad. Certainly I don't want to be hauling liquid manure very far, we're going to end up with some high application rates. And we've talked a little bit about the logistics of that earlier, it can be a challenge. But sometimes water has a value, we've had a couple of dry years in Iowa the last couple, if you have a liquid manure system, that probably means you have water laying around to use it. I know that we've often seen farms do a lot better job of minimizing water leaks, water loss, trying to be most efficient with their water. And that's led to some increasing nutrient concentrations and manure. In general, Iowa is a pretty rainy state. And we don't need that liquid, but certainly in other parts of the US, and even in the last couple years here, that added water can be a real benefit. And then the last thing I wanted to say is, in all these systems, there's sort of an aspect of the manure alchemist dream, right. Turning the manure into gold, or sometimes liquid gold. And just because we might say that farm has a slurry system to start with, for instance, maybe a dairy that scraping into a reception pit, it starts out as a slurry, they might want to do something to that manure, solid liquid separation, so they end up with both a liquid and a slurry manure. And you can do that for various reasons. There's various levels of sophistication, you can use sort of that screw press separator, all the way to ultra filtration membranes to try and separate more or less and end up with different nutrient streams of different contents. And they can be complicated, they can be costly to run, they can sometimes be simple. And what we're choosing there is impacted by lots of factors, oftentimes by how much ground do we own nearby? Where are the crop fields? What nutrients do they need? And where do we have to think about getting those nutrients transported to? So trying to make some different properties. But it is something that plays a role in almost every system, you might say, well, I don't have any of that on my farm, I don't have to think about it. If you have an outdoor open storage system, there's probably some settling going on. That settling, we might come back and agitate and work some of those solids back into solution so that they get land applied, but some of it still stays settled out and will have to dredge occasionally, and you end up with a foul solid product there. And all those things matter and a lot of systems sometimes more than others, but they all play a role in both where we are right now for our manure systems and potentially where we might want to get to. That seems like a lot. How are you doing, Jake?

Jake Willsea  23:25

I'm good. Well, I had a question about that liquid manure. 

Dan Andersen  23:28

Okay. 

Jake Willsea  23:29

Do you think the ability to apply with that irrigation equipment could also cut down on soil compaction? 

Dan Andersen  23:36

It can, yeah. I think there's a couple of balancing factors there, right. So we know that spring has a tough time in Iowa, because it's generally pretty wet. But in summer, when soils dry out, you can get onto the field a lot more easily. And really, when we talked about compaction, soil conditions are probably one of the most important factors. I know there's been a fair amount of research work done at Iowa State to try and to understand compaction. When did it occur? Why does it occur? And we can say some of its related to axle load, tire pressure, all those things. But in truth, the weather conditions are probably the biggest factor. If the soil is moist, but not wet, tt's sort of lubricated, and the particles slide next to each other. And that's when we get probably our worst ruts, worse compaction. If it's really dry, it's hard to move many of those those particles around and you don't tend to see as much compaction. So yeah, one of the advantages of liquid system is you can sort of move when that application event would occur and that could reduce compaction. But it is it's hit and miss right because some years are wet, some aren't.

Jake Willsea  24:34

Yeah. And I guess I should say one more advantage to that liquid system. It gives you the ability to apply in the season. So if you wanted to do split applications, you also have that freedom where a solid manure it's a lot more difficult to get out there especially during side dress to if you wanted to apply that while the corn is growing or whatever crop you have. 

Dan Andersen  24:55

Absolutely, that's a great point, especially as we think about precision management, precision control, understanding where the growing seasons going, how it's been going so that we can tailor our rate to more what we think the crop needs probably is a way of the future and what a systems look like, and how do we have to think about systems to make that a reality? All right, now that the fun part, we talked about solid, liquid, slurry, certainly we pointed out some big advantages. If you're further away from the livestock facility and looking to buy manure, it's probably going to be that solid manure and just because it's more easy to transport, it's more economical to transport and probably something that you can get your hands on. If you are sort of in a mid-distance where you know someone who has slurry manure, that might be an option for us. And really, liquid manure is probably used in our own farm or it doesn't go very far. I want to talk at least a little bit about some species characteristics. You ready for that?

Jake Willsea  25:46

Yeah, let's go. 

Dan Andersen  25:47

All right. So we have pig, dairy, beef, layer, broiler, turkey, horse, goat, sheep, duck, pretty much endless options, some some more available than others. Should we start with pig manure?  

Jake Willsea  26:00

Sure, we can start with pig manure. We're in Iowa, so it seems fitting,

Dan Andersen  26:04

What's the most common system? Walk us through it.

Jake Willsea  26:06

Well, a deep pit system is typically what we're going to see in Iowa, you might see more of a shallow pit in other parts of the country. But since we're Iowa State, and we can look at Iowa. Typically, in a grow finish farm, or a barn you would have the slats in the floor where the manure will drop in, and then you can pump out and apply that typically once or twice a year. 

Dan Andersen  26:30

Absolutely. And I think there's a few things that we've tended to see occurring in many of our systems. We've gotten a lot better, especially at finishing barns at water management, often switching to wet dry feeders, so we end up with a little less manure than we used to get at these specific facilities. But that manure is more nutrient concentrated. They're feeding generally, higher levels of distillers, higher levels of phytase, and that's led to less amounts of phosphorus in the manure. We still have pretty good amounts of potassium. If I start thinking about what are typical application rates for this manure, I certainly would recommend sampling, tailoring to your crop needs. But some general rates, you're probably in that 2000 to 5000 gallons an acre if you're using deep pit finishing manure as your fertilizer source, hoping to get most or all of your nitrogen from that manure source. And if you're a gestation farrowing farm, you might be in that somewhere around 8,000 to 12,000 gallons an acre. Again, depending sort of on water management and other things. Overall, we feed swine, some pretty highly concentrated diets, that's resulted in pigs that grow really well, really quickly. But it tends to lead to a fair amount of nutrients in the manure, often a lot of nitrogen, highly plant available nitrogen, that we're pretty good at predicting its availability, especially at some of these lower application rates, almost regardless of what injection system you might be using. Or if you're even surface plying, we can get that manure into the ground pretty quick, because it's not that much water that we're adding. If you are surface, applying odor can be a little bit of a challenge, but getting that manure injected tends to help with that. So I mean, you pointed out that it's an Iowa tradition that looks like to be a pretty good Iowa favorite. And given all the characteristics pretty easy automation, really high fertilizer value, it's a pretty good contender for one of the best manures that you can get your hands on.

Jake Willsea  28:12

Yeah, I would definitely agree. It's relatively easy to handle, we've got good experience with it here. And it's high in nutrient content. So I'd say it's definitely a good contender for first place.

Dan Andersen  28:23

Then we have layer manure, and if you are looking to buy manure, this is this is probably a nice one for you, I will say, not all manure is created equal. We have some old high rise facilities sort of chickens up top, manure falls through to underneath the chickens, where a lot of fans are nested. And we're trying to blow a lot of air out of the barn and move air down across that manure to help dry it. Even with that said, that manure tends to be a little bit wetter, oftentimes a little bit lower in nutrient concentration than some of our newer layer barns where they might have a belt system. And then periodically, sometimes daily, sometimes a couple times a week, run that belt move manure out to a stacking shed where it tends to end up a little bit drier, a little bit more nutrient dense. And if you're doing that, that is a pretty good way to control some of that odor from the manure. If we keep it dry, it tends to have low biological activity hold on to those nutrients really well. And because it is so dry, you can get some pretty high nutrient concentrations in that manure. So in this case, you might only be looking at two to three tons an acre, depending on your cropping rotation.

Jake Willsea  29:25

Yeah, that's a big advantage to only have to take a few trips out, compared to maybe a less nutrient dense manure, you would have to do multiple trips, which is more money out of your pocket, basically.

Dan Andersen  29:37

Absolutely. And especially if you're going to move at any distance, that's probably the winner in my mind just because it is so nutrient dense. With that said, I really liked turkey litter and broiler litter too. We talked a little bit earlier about building organic matter and sort of the first two choices there, we said high in nutrients, but because they're so high in nutrients you don't end up getting nearly as much carbon moved with the manure as you do in some other cases and maybe turkey litter and broiler litter are the compromises that. Still pretty high nutrient concentrations, we might be looking at 40 pounds of nitrogen per ton, but you also get a sizable amount of carbon coming with it. So if you're looking to build soil health, I think that's a pretty nice advantage. When we talk about Turkey litters, I'm often looking at application rates in that two to five tons per acre range. You sort of pointed out earlier that some of these salad manures can be really high in phosphorus, I often think 100-120 pounds of P2O5 per ton. That means that we probably don't want to be putting it down every year, so that we can take full advantage of that.

Jake Willsea  30:33

Yeah. And we also one advantage of that turkey or broiler litter would be actually the the bedding that's mixed in there. And it gives you the ability to get into some composting if you want to do that with it. 

Dan Andersen  30:47

Absolutely. I know as a home gardener, if I can get my hands on turkey litter and do little composting before I get it on, love it. It makes my plants look beautiful, all growing season long. And I've seen some of those water holding benefits where the rainfalls we do get seem to soak in pretty good, and then despite the fact that it's been super dry and hot, the last few summers, I still don't have to water my garden too much. And that works out pretty well for someone cheap like me who doesn't want to pay a city water bill.

Jake Willsea  31:14

I think one other advantage of that is the ability to stack and stockpile it pretty easily in your in your fields or wherever you need it.

Dan Andersen  31:22

Absolutely. That bedding material makes it more likely that the stockpile will stay in pretty good condition still have the nutrients that we started within it. So huge advantages. Dairy manure, dairies have so much variation. And I'm from Wisconsin originally, and I love dairy farms, I love the way dairy cows look, by talking about their manure systems, it's a little bit of this a little bit of that hard to find a lot of consistency, which is fun, right? It makes the job interesting, but lots of stuff going on. So you could see anywhere from a solid bedded pack manure, all the way to a slurry of manure, right on up to some liquid systems where they're using multistage lagoon or, or have some solid separation that goes with it. So just a lot of things going on there. And that makes it hard to say this is the typical system, but they are certainly interesting. One comment I wanted to have with dairies is bedding choice for the cows is important, right. And we don't pick the bedding that we're using because it has certain characteristics for the manure. But it matters a lot to how we might think about use it. One of the most common beddings we see is sand. Nothing against sand, cows love it, it is great for cow comfort. But from a manure standpoint, it's pretty heavy. It's pretty abrasive. And it can be hard on equipment. Not the end of the world necessarily, but something you have to think about when you're designing or developing your manure system.

Jake Willsea  32:40

You might want to look into something, like a sand separation unit, to get some of that sand out there when you're actually handling the manure.

Dan Andersen  32:48

Absolutely. And even though those were pretty well, you might get 99% recovery efficiency, 1% slipping through every day still does tend to add up. But definitely run some sand recovery on that, and it can still be a nice benefit. It's just something that you have to think about, are we getting the liquid topping? Are we getting stuff that has high amounts of sand? And maybe even do we want that sand in certain fields? And can we tailor where it's going. If you're using a liquid dairy system, or a slurry dairy system, your typical application rates might be somewhere between 8,000 and 15,000 gallons an acre, in some cases pushing up to 20,000 gallons an acre depending on what it's testing at. And then maybe some crop needs. If you're using a solid manure system that bedded pack for heifer rearing or even for cows, you might be more in that 5 to 20 tons an acre range. And I know that's a huge rang, but we like to say it depends, because lots can go on. You mentioned betting management earlier. In some cases, you can get some solid separated material off something like a screw press separator or a centrifuge that that dairy farmers are running. And that can give you manures with different characteristics. This has more the phosphorus oftentimes in the solids, and that liquid tends to follow the water the liquid manure around. 

Jake Willsea  33:56

Right. And I think as hard as it is to make generalizations about dairy systems, I think one that you can make is that the diets of these cows are typically high fiber diets. And so you'll have a lot of that organic material coming out in the manure, more than you would expect in a typical slurry or liquid situation.

Dan Andersen  34:16

Absolutely. And probably in that same regard, we tend to end up feeding a fair amount of phosphorus to dairy cattle. So it's another manure where even in the liquid form, it's a pretty good contender that it has more phosphorus than than nitrogen relative to what plants need. So thinking about what that means for management in the long term really important. 

Jake Willsea  34:34

Yep.

Dan Andersen  34:35

Okay. I think that takes us to beef. 

Jake Willsea  34:37

All right. 

Dan Andersen  34:38

All right. I think we have three options for beef cattle, which one do you want to talk about?

Jake Willsea  34:41

I guess we can start with the open feedlots. That's a pretty good system there. 

Dan Andersen  34:47

Yeah. So open feedlots. That's probably the most common system in Iowa. We do see both concrete and earthen lots. You're trying to manage most of the manure as a solid material that you scrape up and stockpile and then land apply. You will get some liquid from that system, you have to have some rainfall that falls directly on it lose some runoff and you do have to manage that. It tends to be pretty low in nutrient concentration. So really thinking about that irrigation system. But if you're running an open lot facility, you're probably thinking about beef manure management as a solid manure. And that's, that's really what we have the most of. It can work really well, you're probably looking at that 5 to 15 tons per acre application rate. And again, often times really high in phosphorus relative to nitrogen, that manure was sitting exposed on the lot tends to lose a little nitrogen before we get it collected. So it really is a phosphorus potassium fertilizer and more than a nitrogen fertilizer. But make sure you're taking credit for some nitrogen, there'll be some nitrogen moving around, probably about five to 10 pounds of available nitrogen per ton. 

Jake Willsea  35:43

Yep. 

Dan Andersen  35:44

The other two systems that we tend to see deep pits and bedded pack, they're both becoming much more common on the finishing side, a lot of new facilities are taking advantage of those. And I think a lot of that comes to what we've seen on some of the other ones, when I look at deep pit beef barns, they're probably emulating a little bit of what we've seen with deep pit swine barns and saying, man, that slurry manure automation has some real advantages to it, we see why they're moving that direction. Of course, beef cattle, like you mentioned with dairy tend to be eating a little bit more fiber, it leads to a little bit different manure characteristics and some challenges for for handling those solids. But there are ways through them sometimes adding a little dilution water, sometimes just making sure that we're tanking or not having to pump this far to make that workout. With the bedded pack manures, similar that we talked about on the other facilities that bedding management gets to be really important. And the characteristics, again, are really good manure. I love them if you're trying to to build soil health, but not probably something that we want to haul as far just because that nutrient concentration, when we compare it to maybe broiler litter or turkey litter or even that layer manure. If you do in beef manure with deep pit system, you're probably looking at 6000 to 8000 gallons an acre. If you're using those solid manures anywhere in that 5 to 20 tons an acre range is probably about what we're thinking about and working with. 

Jake Willsea  36:59

Yeah, and one advantage you do see with these deep pit beef barns is the nitrogen form. You have a higher nitrogen availability than you might see with the other other styles of a beef barn.

Dan Andersen  37:12

That's a great point. I think as we move forward and want to be more circular, at least get better at predicting what our what we're going to get from the manure that earlier availability sure is a nice benefit to have. 

Dan Andersen  37:24

 All right. With that, thanks for talking manure with me today, Jake. We'd really appreciate it. Hopefully you all loved tuning in. Again, in the spirit of March Madness, the competition between manure types has a great intensity, and each one brings their own strengths to the field. Careful management, good fundamental nutrient management decisions can make them all work great as a fertilizer source. Some of them can help build soil health a little bit more quickly than others, but all of them have their place. With that, I'm Dan Anderson from Iowa State Extension and Outreach. I've been chatting with Jake Willsea today and enjoying the March Madness of Manure. 

Jake Willsea  37:24

Yep.

Dan Andersen  38:03

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, Iowa Manure Management Action Group, which you can find at www.extension.iastate.edu/immag. If you found what you heard today useful or made you think, we hope you'll subscribe to the show on your podcast app of choice. Signing off from a job that sometimes smells but never stinks, keep on talkin' crap.