The Moos Room™

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Joe: Welcome to The Moos Room, everybody. We have a guest on today's poo-cast. That's what we're calling it today.
Emily: Oh, I see what you did there.
Joe: I know. It's just the kid is six months old now, the dad jokes are just coming in strong. They're coming in strong. The reason we're calling it a poo-cast today is we have Melissa Wilson here with us. She is on the manure management team.
Melissa Wilson: I'm an assistant professor and extension specialist in manure management and water quality.
Joe: I would've definitely missed the water quality piece. Melissa Wilson is here. She is going to help us talk through all of manure management today, and we might even get into water quality, but there's a lot to talk about. I'm really surprised that we hadn't talked about it yet, or hadn't come up, and it's something that every farmer probably thinks about every day in what to do with manure, how to move it, what storage is like, where it's going to go, all those different things. We're excited to have her today.
Emily: This is going to be a crappy episode. Ha, ha, ha.
Joe: Ha, ha ha, poor dad jokes.
Emily: I've been waiting.
Joe: I know.
Melissa: If we're talking about poor jokes, I can say that I have the number one extension program in number two.
Emily: Yes.
Bradley: Exactly.
Joe: I am all about dad jokes right now. I love it.
Emily: So many poop jokes.
Joe: I know. We'll try to keep them under control. Bradley will tell you there is a correct answer. There is.
Bradley: There is only one correct answer.
Joe: There's not actually [crosstalk]
Emily: They're lying to you. They are lying.
Joe: Let's go with dairy. What is your favorite dairy breed?
Melissa: I like the Jerseys, they're so adorable.
Bradley: Yes.
Joe: Yes, that is the correct answer on the dairy side. Absolutely. That is a great answer. We're going to update the count.
Bradley: Are we ahead now? Are we ahead?
Joe: No, we're still behind, but that's okay, we're catching up. That puts Holsteins at five, Jerseys at four, Brown Swiss at four, Dutch Belted at two, Normandy at one, and Montb�liarde at one. We're getting there, we're getting close. The correct answer was Jersey, and thank you for picking them.
Emily: No, the correct answer is anything.
Bradley: They all produce manure so they're all your favorite.
Joe: Yes, that all of the cows produce manure, and that's what we're here to talk about today. I think we need to start real big, real general. What is manure management? When you say that, what are you talking about?
Melissa: We know that everything that goes in must come out. In fact, 75% of what goes in comes out the back end, which means-- You know how much a cow eats, correct? All 75% of that is coming out the back end. People don't like to deal with it. It stinks on its way out, and sometimes it's runny and it's just not fun to have to figure out what to do with. That's one of my jobs is figuring out what are the best ways to manage it. Especially environmentally, there's a lot of concern about nutrients, especially escaping, or pathogens even. That's my job, figuring out how to land apply it in the environmental way, but maximizing our use of the nutrients so that way we can grow the crops to then feed the animals again.
Emily: It's all part of the sustainability cycle on the farms.
Melissa: It is. People always, how does a girl from Pennsylvania get into manure management? [chuckles] I think I've always been interested in how we grow our food, and I've always been interested in water. Grew up fishing, boating, all of those things, and always wanting to protect those resources. Working with livestock has been a lot of fun because it's just so integrated with everything I've ever learned throughout school, is how everything works together. I get to help recycle things, so that's always cool too.
Joe: We talk a lot about on this podcast that the forgotten nutrient is water when we're talking from a nutrition side for the animals. To me, the forgotten element when we're talking about building design fields, fertilizer, anything on that end, is manure. It has to be one of the biggest things you think about when you're designing a building and what you have to think about when you're putting animals in the location, no matter what you're doing. It can be handled really, really well, and manure can be very, very valuable.
Again, it somehow gets forgotten about sometimes. I think that's changing a little bit. It's probably because of people like Melissa out there teaching people how to use it correctly, but we're seeing more and more of deep pit barns and buildings that are being built specifically so that people have access, easy access to this manure. Tell me why manure is valuable. I guess that's the really long way to ask you why is manure valuable.
Melissa: I joke that it's basically a nutrient source with a probiotic for your soil. Not only do you get the nutrients, but you also get the carbon that feeds the good soil microbiome as well as probably adds a little bit to the soil microbiome as well. It comes with multiple benefits compared to just fertilizer, which at least you can dial in and get the exact nutrients you need but it's not also feeding the soil.
Joe: I get that question a lot, why is manure more valuable than fertilizer? That's a great way to explain it. I think that's perfect.
Bradley: The question I have is manure is not really manure, it's not all the same, right?
Melissa: No, it definitely depends on, one, what are you feeding the animals. Your cattle that are on the high-protein diets because their milking is going to be way different than your dry calves and beef, et cetera, depending on what they're being fed. Then you have the ruminant animals with their four stomachs. They're going to digest the food way differently than hogs, horses, whatever it might be. All of it is really different. Then how you handle it. They say there's estimates of up to 40% to 70% of your nitrogen can be lost from the point it exits the animal to the point you apply it to the land based on just how you handle and store it. There's lots of different factors that can influence what kind of a nutrient source it is.
Joe: Wow.
Emily: I didn't realize you could have that much nitrogen loss.
Melissa: Yes, it's significant.
Emily: That's a lot.
Melissa: If you think about it, so animals eat plants, so they should be pooping out the exact nutrients that plants need, but because we lose so much nitrogen, what happens is you end up having to apply double the amount of nitrogen or double the amount of manure to get as much nitrogen as you need because you lost half of it, that not over applies all the other nutrients. There's this imbalance that happens, unfortunately.
Joe: That probably brings us to the importance of testing. Just like we talk about with testing forages on the front end, there's no way to know what you have until you test it, right?
Melissa: Exactly. That's one thing I wish people would do more of. We spend so much time making sure we're feeding the animals the exact right things. Don't we want to know exactly what we're feeding our plants that then feed our animals? It really varies. I asked a couple of the regional labs the semi-manure analysis data, so it ranges from 2012 up to 2018 or so. We ended up getting 66,000 samples from the region of manure data.
I would say beef and dairy, sometimes the nitrogen content will differ between 30 to 40 pounds between barns, and that's the average number, not the crazy barns that had manure analyses that don't make sense. I don't know, say you're applying 20 tons per acre and you think you have one set of nitrogen but you actually have 40 pounds less, when you multiply that by 20 tons, that ends up being pretty significantly different.
Joe: You're saying 30 to 40 pounds, that's on a per-ton basis?
Melissa: Yes. I guess my apologies, I was thinking of the swine because they can certainly have that big of a range. With beef and dairy, it's a little more dilute because there's usually more liquid or bedding associated with it. Even so, it's probably 30% to 40% rather than the actual pounds per ton.
Joe: We're talking a big, big difference between different barns or different systems depending on what's going on. What you feed, how much nitrogen you lose, all those different factors. You talked about already the complications of, I have to apply twice as much to get the same amount of nitrogen that I need, but that over-applies everything else. How do you fix that?
Melissa: There's a couple ways. One is think about the rotation. If you know how much phosphorus you need for the corn and the soybean, you can think about then you wouldn't apply phosphorus fertilizer for the soybean, then you would get to that phosphorous, hopefully, from the application that you did for the corn. Thinking about the rotation. There are people who are starting to apply at that lower rate to meet the phosphorus needs, and then adding nitrogen fertilizer to get it up to where it needs to be. Trying to balance nutrient needs with fertilizers is one way to do it.
Joe: What are the consequences of getting it wrong? Let's say I do over-apply, what does that do for me, or what does it do negatively?
Melissa: Over the long term, if you raise phosphorus, the one good thing is phosphorus isn't as leaky as nitrogen. Nitrogen just goes wherever it wants. With phosphorus, the soils can build up over time, and it does get to the point-- Soil is a sponge but it can get to the point where if you keep filling up the sponge, the water just starts pouring out of the bottom, and that's what happens with phosphorus. If you get these really high levels, it starts to become mobilized in the water, so you can lose it through your tile or down to the groundwater. The other thing is, and probably more importantly, is that regulations start to kick in about when and where you can apply manure if your soil phosphorus test levels get too high.
Joe: Obviously, we don't want that leaking into groundwater. That's the ultimate no-no, right?
Melissa: Yes, especially if it gets into lakes and freshwater systems. Phosphorus, again, is not like nitrogen. It doesn't turn into a gas. It just stays in the lake, and then it goes through this natural cycling system where it causes algal blooms and things like that.
Joe: Maybe I'm just disconnected, but we hear a ton about nitrogen. Nitrogen, nitrogen, nitrogen, nitrogen, but we don't hear a ton about phosphorus. Is that just because nitrogen is the current buzzword, or is it just because people want to ignore phosphorus?
Melissa: Coming from working with nutrient management planning and livestock farms in Maryland, and phosphorus was the big thing, but there they have issues where they have a lot, a lot, a lot of livestock concentrated in single areas. They were getting soil test phosphorus levels just completely through the roof, never going to come down in the next couple of decades or centuries even, so phosphorus was a huge issue there.
Here in Minnesota, nitrogen certainly is an issue because we continue to see groundwater levels rising, and that's problematic for health reasons when that gets into your drinking water. Another thing, we have a soil type in Minnesota, particularly in Western Minnesota, that has a lot of calcium in it, and it tends to bind phosphorus. It's harder to raise the soil test levels. You still have to worry about raising the levels, but it takes longer to do so, so I don't think people seem to be quite as aware of phosphorus being an issue.
Bradley: You have done research out at the research center in Morris, and we see that issue our phosphorus levels don't seem to be too much of an issue now. From the swine manure, you can feed phytase, which reduces the phosphorus load in there. We tend not to have much of a problem with phosphorus in our area just because of the factors that you said, Melissa.
Melissa: Yes.
Joe: One of the things that we've been coming back to a bunch, and this is something that we talked about with a couple different people on this podcast, is looking for the things that farmers can do that we consider low-hanging fruit or the biggest bang for your buck improvements or changes. I'm sure this is something you run into. What are those things that you continually run into that you wish people would do that they're not currently doing that would make the biggest change or the biggest improvement for them?
Melissa: I think one of the things is certainly, we already talked about it, testing your manure. Of those 66,000 or whatever samples I got, about 50,000 of them were swine, and then the rest were split out between dairy and beef, which suggests the swine producers are certainly getting their manure tested, whereas maybe dairy and beef producers could improve a little bit. The other things are definitely keep track of your manure plans and keep up on those soil testing levels.
Really, we like to see people thinking of manure as a resource rather than a waste. I know, you just want to get rid of it because it's not making you money, but trying to think of it in your nutrient management planning and how you can recycle those nutrients so that you don't have to buy more fertilizer is always helpful. Again, trying to balance those phosphorus and nitrogen needs can be important over the long run, especially when you don't want to be butting up against regulations.
Joe: I'm assuming that most farmers, at some point, they have to test soils. They have to know if they're going to apply manure. Is there a requirement to test the soil?
Melissa: It depends on the size of the operation. Obviously, the really large CAFOs are pretty heavy regulated, and they have to test their soils every four years. Then in Minnesota, we have permitted facilities which are 300 to 999 animal units, and they have certain rules that they have to follow. I believe they have to have soil tests every four years as well, at least for phosphorus, because you have to know when you start getting into those levels that become problematic. Under 300, I think it really depends on townships and what their rules are if they need permits and things like that.
Joe: Because I'm just trying to think of why would someone not test, obviously because they don't want to, that's part of it. Testing manure, it just seems like a natural fit to me. Why wouldn't you match the manure to the soil test that you had to take anyway by testing your manure? What's the big barrier to testing manure?
Melissa: One, it's a dirty job, especially if it's a solid manure, you really want to get a representative sample, and that can be hard when you have bedding mixed in because you get big clumps of bedding here versus a lot more feces over here, so it's a dirty job. It can be somewhat inconsistent just because of all of the literal crap that's in there, or lack of, depends on how much bedding you have. It's kind of a tough job, and it can be inconsistent, and I think sometimes people get frustrated with some of that.
Joe: I know, it's always baffled me. You're having to test the one anyway, why wouldn't you test the other? That does make sense if the testing loses value because it may or may not be representative, and it's hard to get a sample that's representative. That makes a lot of sense.
Melissa: It can also be expensive. I think probably the cheapest place I found to run it for just basics N, P, and K is $25 a sample, $27 a sample, and then it can go up drastically from there if you want micronutrients tested and things like that, up to probably $70 or $80.
Joe: That's certainly not cheap if you're going to running more than one sample. Something that I've been curious about, and I think actually we may have talked about this before, I'm asking about it because I'm thinking that maybe this is one of your pet peeves and I haven't asked you about it. What's the difference between composting and piling manure?
Melissa: That's a great question. I guess I should have mentioned that. If you have a solid manure system, composting is pretty beneficial. Stockpiling is what we call a pile of manure that is just sitting there. The thing is, it can get pretty anaerobic, so there's not much air mixed in, especially in the center of those piles so, it's not degrading as well as a compost pile is. Compost is when you're actively going out and mixing that pile pretty regularly.
That gets that oxygen back in so the microbes can degrade that a lot faster. It's like our soils. No-till keeps the soil, the dark black topsoil staying there, versus tillage tends to burn up that organic matter more quickly, and that's just because you're mixing in that oxygen. The nice thing about compost is it tends to reduce your pile size by 50%, so with composting, you don't have to haul as much. You do have to actively manage it, but you don't have to haul as much, which is nice.
Joe: I see that a lot, and I've always wondered, a lot of people tell me that they're composting manure, but when you look at the pile, they're stockpiling manure. They're not composting it, so I've always wondered the big difference there. Then I see this on the dairy side as well, that composting is really valuable. You want to compost because of space, and especially with our dairy side of things, as expansions go and we get consolidated, you get manure system storage systems that are out of date for how many animals are on a farm. I think composting is a viable option if you have the equipment and the land space to do it, but yes, definitely different than just piling manure.
Melissa: The one nice thing is it stabilizes some of the nutrients. It does burn off some of the nitrogen, because like I said, nitrogen just wants to do whatever it wants to do but it does stabilize what's left into more of a slow-release fertilizer so, again, building that soil health when it's being applied.
Joe: In these pit barns, how do you handle nitrogen? Does that help or decrease the nitrogen loss by having it piled in a semi-liquid form like that and having a cap and all that?
Melissa: When you have a deep pit barn, they're depositing the manure straight down. It's not really being mixed until it's annually agitated. The nitrogen tends to be in different forms than it is if there's bedding for instance. If you're using a bedded system a lot more, the nitrogen tends to be in the organic form, which means it needs microbes to break it down to get it into plant-available form.
I've been working with a bedded beef pack for two years now. It actually tied up nitrogen in our crop fields the first two years, which is not what you want to do when you're producing corn. The bedding can dilute nutrients and even cause further complications, versus the deep pits. A lot of the nitrogen, it's about 50/50 in the deep pits. Even in dairy liquid storage systems, we see about 50% plant available and 50% is in organic, so usually our liquid manures tend to have that plant-available nitrogen ready a little more quickly.
Bradley: What kind of bedding was that? Was that straw, or with the beef, was it wood chips or--
Melissa: No. One year it was corn stalks, in another year, it was some sort of hay. I can't remember what straw it was, it was oats or something.
Bradley: I think the bedding choices are pretty important because that certainly can tie up nitrogen. Like you saw, we have had that issue. That's why we stop up with our compost barn in using wood shavings and wood chips because wood does not break down very well in manure, and it ties up nitrogen for the corn the next year. Wood is bad, from a manure management perspective.
Melissa: I guess it depends on which way you're looking at it.
Bradley: It's wonderful bedding for cattle, but it really affects things down the line that we tend not to think of.
Joe: Along those same lines, we see a lot of dairies with sand. Sand bedding. How does sand impact that manure value? I know it's hard on equipment, so that's a big piece of it.
Melissa: That's basically what I was going to say. It's an inert material because sand doesn't have nutrients, so it does make it a little more difficult because it's pretty hard on the equipment.
Joe: Other than that, it's not really affecting a ton, other than just the equipment breakdown.
Melissa: Yes. That's what we've seen so far. A new thing coming in is that we're starting to see more of the liquid-solid separation from dairy barns. That's interesting because it takes out some of the solid materials, which takes some of the nutrients with it too. We did some studies trying to see if that released nutrients any faster than non-separated, just raw liquid dairy manure, and we haven't seen too much. In one year at one site it did, but then at the other years it was pretty similar to that. A lot of people had concerns about that.
Would that behave differently than just raw dairy manure? I'd say right now we're not thinking that it does, but it does. It has interesting implications on the cycling of the nutrients that stay in the barn, because some of these places are doing the liquid-solid separation and then taking the solids and putting them back in the barn for bedding. We don't know what's going to happen over the long term with the carbon in the manure. Will that slowly break down? How does that all work? That's an interesting thing that's going on.
Joe: It's becoming more and more popular, these recycling systems and using manure as bedding. What else are you working on? We should get into that. What's the big projects you've got going right now?
Melissa: We got a couple cool big projects. One is integrating cover crops in manure in the fall. That's one of the things we're doing up at the research center in Morris. We also have some stuff down at the research center in Waseca. Just looking at can we get cover crops established before we apply manure? Then if we apply manure, will we just completely destroy the cover crops, or can we do it in such a way that the cover crops will actually benefit from manure application? Then can the manure help hold some of the nutrients from fall into when we're getting our plants or crops actually planted.
That's been going cool so far. One thing we thought was if we could get a cover crop really nice and growing, could we apply manure earlier in the fall? Because we don't actually recommend that because we've seen just significant nutrient losses when the soil temperatures are warm because of those microbes just cycling through things pretty quickly. We thought if we had cover crops that would hold up the nutrients, keep the nutrients away from the microbes, maybe we could get away with early fall application.
We're in the middle of our second year, but for the yield that we got this year where cover crops and manure were planted two falls ago, it did not work out well. The late manure still outperformed the earlier manure by far. The late manure outperformed the spring fertilizer too in fact, which was interesting. The spring fertilizer outperformed the early fall application. We definitely saw a lot of nutrient losses from that early fall application. By early fall, I'm talking like September.
Joe: We hear about cover crops all the time, that this is a responsible thing to do and there's all sorts of reasons to do it. Specifically with manure, you just said that applying earlier, it doesn't really help if you have cover crops or not. You still want to apply late fall. What is the value in cover crops when we're talking about manure?
Melissa: In that case, the one thing that we're looking at is are there�s synergies between manure and cover crops for soil health aspects? I have a grad student working on this. He's going to look at soil respiration, which is an indicator of your microbes in the soil. We're looking at bulk density to see if that changes with the different practices. I don't think we're going to get to look at soil aggregation because we don't have one of those. They have these fun contraptions that look at how the soils hold together and all the kinds of stuff. We're not that technologically advanced in my lab, but we're just trying to see if there's these synergies that can help when you get the probiotic nature of the manure plus all the cool root exudates that cover crops put into your soil.
Joe: You pointed out early in the episode, we have to address it. We say the word "manure" very differently.
Melissa: We do.
Joe: Very differently. Emily, can you say it once.
Emily: Manure
Joe: Bradley.
Bradley: Manure.
Joe: Manure. Go ahead, Melissa.
Melissa: Manure.
Joe: You've got an O in there. Is that an East Coast thing?
Melissa: I don't know. When I go home, my family are not farmers, so they don't ever say the word, "manure", so I don't know where I picked it up from. I noticed it when I moved back here and was out talking to people. We had a little survey. I was like, I'm saying it differently than all of you are, but none of you say it the third way, which is manure.
Joe: Yes, we don't say manure.
Emily: I feel like I sometimes say manure if I'm with somebody who says it and they say it that way, then I'll just start saying it that way too. [laughs]
Joe: We need to call John David. I bet you he says manure.
Emily: Oh, I bet
Joe: There's no way he doesn't it.
Bradley: He probably doesn't say manure. It's probably other words.
[chuckling]
Joe: Maybe that's true.
Emily: Hey, but while we're on that topic, Bradley, how do you say antibiotics?
Bradley: Antibiotics.
Emily: [laughs] Antibotic. It's always funny.
Joe: Oh yes, I forgot about that. That's a good deal. Another T-shirt idea.
Bradley: Always making fun of the tenured professor, I guess. So be it.
Joe: It's part of that title. If you become tenured, you get made fun of on The Moos Room. It's just a rule.
Melissa: I won't join next year then. No, I'm just kidding. I don't know when I'm going to get tenured, but--
[laughter]
Joe: Don't do it. I think we've covered some of the basics. There's so much more. Go ahead.
Melissa: Can I cover up-and-coming issue that we are seeing in Minnesota?
Joe: Absolutely.
Melissa: There is an invasive weed called palmer amaranth. It is not fully established in Minnesota yet. We found it in a couple places. It is like they are so afraid of it getting into Minnesota that if anyone finds it, MDA shows up and burns down the plant so that it doesn't spread its seeds. This thing can spread hundreds of thousands of seeds for one plant. They're very concerned about it getting into the state. Anyone who is importing feed from down South or Nebraska, or wherever this seed might have already become infested, you need to really make sure that they are aware that this is a problem and that they don't potentially have contamination issues.
I know they had an issue, I think it was up in North Dakota where someone had brought-- Even in Minnesota, some of the spreading issues had been when sunflower screenings or other screenings brought in from out of state. It can become a big problem real fast. Even the animals that eat it, I think 90% tends to get killed in the gut, but when we're talking about one plant, that they only need one seed that survives that can then cause problems. That's something to keep in mind that that's an issue that we're worried about.
Joe: It's a big issue. Like you said, it's screenings from down South. I think I had seen cotton seed shipments had been an issue as well. The big issue is that it's really hard to identify this plant. It looks a lot like other plants in the area, like--
Melissa: Water hemp.
Joe: That's right.
Melissa: Pigweed.
Joe: What are people supposed to do? If they think they see a plant that looks like palmer amaranth, what do they do?
Melissa: I believe there is a hotline that you can call. I would just do Palmer Amaranth Minnesota. You'll find that on whatever search engine, I think it'll come up pretty easily.
Joe: Perfect. I'll try to put it in the show notes so that everyone can see who you're supposed to call and someone who knows what they're looking at can come out and look at it. Don't just start burning down plants without having someone have a peek at it and look at it. That's important to know.
Bradley: Have you seen it out in the field, Melissa?
Melissa: I have not, but there have been reports in the state. Because usually they burn it down before many people can see it. I think a bunch of it came in with some conservation plantings at first, but there's been at least two cases, I think, now where it came in with contaminated feed and got into cattle manure. In fact, one of my research projects is figuring out how to sort these tiny, tiny little seeds out of manure, which is a fun project. That way in the future, if it's expected to be in the feed, we could potentially sift through the manure and send the seed for genetic identification.
Joe: This is a bad plant. I'm starting to remember pieces of [unintelligible 00:30:10] presentation about this. It will completely take over a field, completely crowd out soybeans. I'm talking 50%, 60%, 70% gone because of this plant. [crosstalk]is--
Melissa: Then it could be 7 to 8 feet tall too. Even corn, it survives in.
Joe: We'll look for that in the show notes. I'll put the hotline number, I'll find it and put it in there. If you do see something that looks like that, make sure you give that a call. We do not want that in the state. I think with that, we've recorded long enough. It's time for happy hour. We're going to get out of here. We appreciate you listening today to our poo-cast. If you have comments, questions, scathing rebuttals, please send them to themoosroom@umn.edu.
Emily: That's T-H-E-M-O-O-S-R-O-O-M@umn.edu.
Joe: Please check us out on Facebook at UMN Dairy and at UMN Beef. Check out the website, extension.umn.edu. Melissa, give us your plug for nutrient management.
Melissa: We're at manure.umn.edu for our website. You can follow me on Twitter, I'm @manureprof.
Joe: With all those spellings of manure, you use a U, spell it correctly. Don't use an O based on how Melissa is saying it. Check us out on Twitter as well, @UMNmoosroom. No more plugs. Thank you, everybody. Catch you next week.
Emily: Bye.
Bradley: Bye.
Melissa: Bye.
[music]
Joe: Emily, can you say it once?
Emily: Manure.
Joe: Bradley.
Bradley: Manure.
Joe: Manure. Go ahead, Melissa.
Melissa: Manure.
[music]

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