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Welcome to University of Minnesota Extension's Nutrient Management Podcast. Each month we bring you the latest research in nutrient management for crops and how you can incorporate the latest tips and best management practices to your farm.
University of Minnesota Nutrient Management Podcast Episode:
“MANURE PODCAST 2024”
July 2024
Written transcripts are generated using a combination of speech recognition software and human transcribers, and may contain errors. Please check the corresponding audio before referencing content in print.
(Music)
Jack Wilcox:
Welcome back to University of Minnesota Extension’s Nutrient Management podcast. I'm your host, Jack Wilcox, communications generalist here at U of M Extension. Today we're going to talk about manure and manure application in 2024. We have four panelists here with us today. Can you each give us a quick introduction?
Melissa Wilson:
Hi, I'm Melissa Wilson. I'm an associate professor and extension specialist in manure management, manure nutrient management specifically at the University of Minnesota.
Chryseis Modderman:
And I'm Chryseis Modderman, also from University of Minnesota Extension. I focus on manure nutrient management as well. I'm officed out in West Central Minnesota in Morris.
Mary Keena:
I'm Mary Keena. I'm the Livestock Environmental Management Specialist with North Dakota State University Extension. I'm located at our Carrington Research Extension Center.
Amy Schmidt:
Hi, everyone. I'm Amy Schmidt, professor at the University of Nebraska Lincoln with extension and research responsibilities in engineering and manure nutrient management.
Jack Wilcox:
Amy, this question is for you. This year, fertilizer prices are still high as compared with 2018, 2019. What's the value of manure today?
Amy Schmidt:
I think the easiest way that we can put a dollar value on manure is looking at the actual nutrients that are in it. Then we need to account for what is available this season versus future seasons. Nitrogen is a nutrient that has to, the organic fraction of nitrogen in manure has to become available to the plant. That happens by microbial action in the soil, converting that to an available form for plants. We will typically look at a manure nutrient analysis, identify total nitrogen, phosphorus, sulfur, potassium, other micronutrients. Then we can assign a dollar value to those based on what current fertilizer prices are for those individual nutrients.
Then it's up to that farmer to negotiate if they're trying to sell that manure or if they're a person trying to buy it, based on which of those nutrients do they actually need on the crop land where they want to apply it because there's no real value to say potassium if the land receiving the manure is not in need of potassium. Then it's a negotiation of what nutrients are needed, how far does it need to be transported.
Then there's other benefits to using manure that we don't really have a way to monetize, so how will it affect soil health? We're trying to improve soil organic matter, aggregate stability, reduce runoff in erosion. There's benefits that manure offers, but we don't really have a good way to value those.
Melissa Wilson:
I think that's really important to think about those soil health aspects too. That's one of the reasons why we always are promoting to spread the wealth, so to speak, and try to get manure on as many acres as you can, even if you are applying maybe a lower rate and then coming back with nitrogen or phosphorus and applying with commercial fertilizers to meet the crop needs. But that value of manure is really in the nutrients, but also some of those soil health aspects too.
Chryseis Modderman:
A question I get quite a bit when looking at value of manure and folks looking to either sell their manure or buy it as a crop farmer is whether they need to have a written up contract, something that's in writing in person. Personally, I know my folks have a handshake agreement with a neighbor. That's what they do. But a lot of people like to have that written down in a contract form. If you're looking for templates on that, you can find those online or you can talk to a consultant. They often have some of those out there. I don't know what Amy, what you guys do in Nebraska, if there's a lot of the written-out contracts or if it's more handshake agreement type situations.
Amy Schmidt:
I think we have both here. We do have a handful of brokers, I guess you'd call it, manure brokers in the state who work with animal feeding operations to market the manure that they're producing. They probably have a more formal contract or written agreement, whereas individual farmers, I would imagine it's more of a handshake agreement, like you mentioned, Chryseis.
Mary Keena:
Chryseis, something I actually share in my presentations that I do here in North Dakota is a quote that you wrote in a paper one time. It says, "The only real guideline is that both parties need to feel they're benefiting and getting some value out of this arrangement." I use that because we don't have manure brokers in North Dakota. We don't have formal agreements. A lot of it is based on a call to me from the crop producer and a call to me from the livestock or manure producer. Then both have conversations. I tell them the same thing and then they go back to each other and figure out what they're going to do from there. It's different for every
operation.
Jack Wilcox:
Expanding on the idea of value a bit further, Mary, you're conducting long-term research in North Dakota. Talk to us about what you see there.
Mary Keena:
Yeah, so we've been doing some research here since 1987 on the same piece of ground, the same plots. We call it our long-term cropping system. What happens there is we have, it's a four-year cycle. At the beginning of this four years, we put on 200 pounds of composted beef manure, 200 pounds of nitrogen goes on. That's one of the fertility treatments. The other ones then are zero, which is our control, 50, 100, and 150 pounds of nitrogen per acre.
Then we also have three tillage systems within that as well, conventional till, minimum tillage, and no tillage. Then on top of that, we have the cropping rotation. We are planting barley, corn, field peas, soybean, sunflowers, hard red spring wheats and hard red winter wheats. All of those different things have been in place since 1987. While a thing or two have changed, we've added a fertility. We've added the 150 in the last couple years. We've changed a little bit. When we started growing more soybean here in North Dakota, we added that into the rotation and took fallow out of the rotation soil health.
When we're looking at that stuff, consistently year after year, and so like I said, keep in mind we only apply manure one time in four years or the composted manure one time in four years, consistently the composted manure is either at or above yield for all of the crops every time. It doesn't matter. This is compared to the 0, 50, 100, 150. Once time every four years it is consistently for yield.
But then also we get into the soil health aspects of things. It's not just showing an improvement on the no-till, but specifically no-till with compost added into it we're seeing an increase in soil organic matter. That is where it becomes important. We can't necessarily put a number on that, but it does become very important when we're dealing with our soil health.
Melissa Wilson:
Would you say some of that is due to not only the soil health aspects, but probably the micronutrients and things like that too? I think a lot of times when fertilizer prices are high, the micronutrients are often overlooked, even the secondary nutrients, sulfur and things like that. But manure has that value as well that sometimes we're just not thinking about. Is there anyone looking at that in those plots, Mary, or is that just what y'all are thinking is happening?
Mary Keena:
We do take samples of the compost that we spread and we take a full analysis of all the, like you said, the lesser nutrients that are going on there as well. We do have record of that. We don't have anyone actively looking at that right now in a big way. We have the rest of the study. However, we have taken many other soil health measurements and again, consistently showing that. That is something else too.
When I'm visiting with producers, both the crop and the livestock producer, when they call and say, "What is the value of this," we talk about all the extra stuff besides the NPK, and sometimes S, that we're getting when we have manure, whether that's liquid or solid, as our fertilizer type. The other thing that we have a discussion about is it doesn't have to be the only tool in the box, but it is an active tool in the box.
Jack Wilcox:
What are some other best management practices for fall manure application season to get the best value out of manure? We talked a little bit about tillage and cover crops. Expand on that if you could.
Melissa Wilson:
I would say in Minnesota, because we have quite a bit of different climate shift as we go from south to north in the state, and I'm sure Amy and Mary both have different practices that are best management for their areas too just because they may be a little bit drier than us and then further north and further south. But one of the things that we particularly focus on is thinking about how to best preserve our nitrogen in the different manure types. Because a lot of manure goes on in the fall in Minnesota, we have to think about timing of that application because fall is when we're heading into winter. We don't really often have roots in the ground to capture any nitrogen. Timing becomes important because, as Amy mentioned, nitrogen moves through its cycle through microbial action in the soil.
When it's cooler, and we typically say about 50 degrees Fahrenheit, that the soil microbes really drastically slow down. They basically are, they're not stopping, but they're halting the conversion of the nitrogen into the nitrate form, which is easily lost through water movement to our groundwater.
Especially with our liquid manures, which have a high ammonia concentration, which can more rapidly convert to nitrate versus the organic form of the nitrogen, which has to go to ammonium before it gets to nitrate, we really recommend getting that on after that soil temperature reaches that 50 degrees. Even in some cases, if you have a really warm winter, like we had this year, there's still risk of losses. Trying to get the manure on as close to the time when you're going to be having growing crops back in the field is also a best management practice. But if you're doing it in the fall, waiting until later when the soil temperatures are cool is another practice to think about.
Chryseis Modderman:
Then, of course, always timing also when soils aren't saturated. We've had a bit of rainfall this year a little bit, just a little bit. Timing your application so that you're not applying onto a saturated field where there's nowhere for that manure to go into the soil to soak into the soil. If it's running off the surface, it's also being lost to the environment.
We were just talking about value a minute ago, and I think keeping your nutrients where you put them in the field and where they're applied is the best case for all parties involved. You want to keep your nutrients where you put them. That's how you get value out of them. It's as a fertilizer replacement, as a soil amendment and not lose them to the environment.
Melissa was talking about nitrogen quite a bit. We focus on nitrogen a lot, but I don't want to forget about the forgotten child phosphorus here. Phosphorus, we want to avoid building up phosphorus in our soils. Just thinking about application rate and knowing what your phosphorus content in your manure is, which means you're taking a manure sample. You're sampling your manure and you are sending it to a lab. You are sampling your soil so you know what you need. That way you're not over-applying phosphorus for long-term buildup because phosphorus is lost most often through erosion and runoff across the surface. We don't want that in our waterways either. We want to keep it right in the field where those plants can use it in coming spring.
Amy Schmidt:
In Nebraska, like Chryseis mentioned, we do have liquid manure handling systems and solid systems here. We're seeing confined beef operations, deep pit beef operations. We have a lot of swine here. Then we have our cattle feedlots and poultry systems. We get a fair mix of liquid and solid manure here. We try to avoid application of liquid manure when the ground is frozen, snow covered or saturated just for the reasons that Melissa and Chryseis already mentioned.
With solid manure, that's a little bit different in how we handle that. We typically are not placing it below the surface of the soil like we do with liquids that are injected or incorporated. Farmers have generally moved to no-till system so solid manure is applied to the soil surface and it's not incorporated. When that happens, it's only a matter of days before any of the ammonia nitrogen that was in that manure is probably lost via volatilization. Then we're looking at the organic nitrogen in the manure.
If we have a particularly cold winter where we've got a lot of frozen ground or we've got snow cover, it's not completely unreasonable to apply solid manure over a light covering of snow or on some frozen ground because there's not going to be that inorganic nitrogen available when the snow melts and things warm up and we're less likely to lose those nutrients to the environment.
But I will say that anytime we do surface application of manure, we want to see farmers following appropriate setback distances from sensitive water bodies using residue management, things that protect the soil surface and keep those nutrients where we've placed them, grassed waterways or vegetated areas around the field to separate it from streams. The way we apply it and when we apply it has to go hand in hand with the other conservation practices we use to keep those nutrients where we've placed them and not have them leave the field in runoff or erosion.
Mary Keena:
Yes to everything everybody's said. Amy, I would say that in North Dakota we follow very similar to what you said for Nebraska. A lot of our producers, especially central to western, have gone no-till. We do have some minimum till or full tillage in the eastern side of the states. We have a little bit of each. More so we have solid manure here, if we're using it. We do have some liquid operations. Most of them are taking care of that or handling that themselves. They're small enough that they handle themselves. They spread on their fields and there are not very many of them.
The biggest thing that I was thinking as you guys started talking was just the potential to pollute. What's our potential to pollute? That's what we talk about with our custom applicators, with our crop producers, with our livestock producers, what's your potential to pollute when you're going to be out spreading it, whatever season that is?
We have super smartphones, almost all of us, all the time in our hands. When they're going to spread and it's going to rain five inches or one inch or they're like, "Well, I didn't know it was going to rain in 10 minutes." I'm like, "Come on, you guys. We have smartphones right here. We can literally tell almost to the minute when it's going to happen," and so those things.
Topography, we also spread on frozen and cold ground here. But again, what's our potential to pollute? What's the topography look like? Do we have any stubble out there? Is there any residues left? All of those things, I think wherever you're at, whatever state you're in become very important.
Chryseis Modderman:
I just wanted to jump in a little bit on the no-till conversation because we have pockets in Minnesota that are very heavily no-till, that are all about the no-till sort of situation. But I know folks that moldboard plow and are very much into tillage. I feel like this year I've talked a lot about converting from those heavier tillage systems to no-till systems and how to work manure in with that because here we're still recommending in a lot of cases incorporation, incorporating that manure into the soil to avoid losses through volatilization. That's always been on our BMP list.
But then folks are saying, "Soil health, what are we going to do? How do I reconcile those two things? I want to be no-till, but I want to use manure. What do I do there?" A lot of the meeting season this last winter I talked about no-till and manure and how to walk that fine line because it is a balancing act. I don't have a good solid answer for either side. You got to do what's best for your operation. Any amount of soil that you can get on top of the manure is going to help reduce that volatilization loss, but like both Amy and Mary mentioned, with the solid manures, a lot of it is just surface applied and not worked in.
Amy Schmidt:
We also see a big difference in Nebraska whether we're talking about beef feedlot manure or poultry litter. We've always had a lot of cattle in Nebraska. Beef feedlot manure is a common soil amendment we use here, but we've had a pretty significant expansion of our poultry industry in the last five years or so. More crop farmers are becoming familiar with poultry litter as a fertilizer source. I think they are going to be much more cognizant of when they apply it to be able to utilize all the nutrients in it.
Beef manure is pretty low in organic nitrogen to start with. They're used to not having that nitrogen to count on. They're used to just depending on the organic nitrogen becoming available.
But poultry litter is pretty darn valuable here. It's a good balance of nitrogen and phosphorus. It's applied at very low application rates. I think farmers who really appreciate the nitrogen value of that litter are probably not going to do a fall application, or they're going to maybe apply it where there's crop residue that maybe it sifts down through there and it's protected a little bit from volatilization, but I think the main thing they're going to do is try as hard as they can to conserve all the nitrogen that's in that poultry litter.
Chryseis Modderman:
Yeah, poultry's a big deal here in Minnesota too. We are the number one producer of turkeys in the country. It's probably our most bought and sold type of manure. I think it's because it's such a dry, transportable product, you're not transporting a lot of water with it. It's the most nutrient-dense manure that we have. It's like 10% nutrient by weight of all the nutrients, NPK micronutrients, et cetera. Circling back to that value conversation once again, everything today goes back to value, that the turkey manure presents a great value for Minnesota and Nebraska as well, it seems.
Amy Schmidt:
I think that's a really good point, Chryseis. As you were talking about that I was thinking if a beef feedlot operator knew what poultry producers get per ton for their poultry litter, they would probably fall over. But it's because of that difference in nutrient concentration. It's a drier material. It costs less to haul, but a lot of our beef producers may be lucky to even get paid for their feedlot manure. Whereas poultry producers may be getting $50 or $60 a ton and it may be higher where you are, but those are some of the numbers I've heard here. Again, that value all goes back to what's in there and what's needed by the person who's receiving that manure.
Jack Wilcox:
What's on the horizon for manure application?
Mary Keena:
Some of us just came back from the North American Manure Expo. There's an expo all about manure. It's really cool. We get to go see the new and emerging technology there every year. Then I come back to North Dakota and I'm talking with my applicators and for us here in North Dakota, what I would like to see, I don't know if this is coming, but this is what I would like to see come, at least for us here, I know other states are doing it, but I want to see scales on trucks. We have a lot of solid manure being spread, and yes, we can do a tarp method for calibration and see what we're spreading and hardly anyone's going to do that. But we have a lot of technology that goes into tractors, the crop producers side of things and I think something's I say is simple, though I'm not doing it myself, something simple that our applicators can do that's going to cost some money but is probably part of the future, is get some scales on those trucks so we know what you're spreading or calibrate them regularly.
I really want, and if you are a crop producer who is paying for or receiving or getting manure from somebody or you're a livestock person who is getting rid of it or selling it, just know what you're selling. The best way to do that is to measure it. The best way to measure it is to have some kind of scale. Have a nutrient analysis done, like Chryseis talked about earlier. You're testing the manure. Then weigh it and know exactly what you're spreading out there because then that can help our agronomist go back and back calculate what we actually will need. It's another tool in the box.
These are not new technologies. These are just technologies that I would really like to see implemented here.
Amy Schmidt:
I think that's a really good point, Mary. We do talk a lot in our land application trainings in Nebraska about calibration of manure spreaders. Most of our custom applicators are pretty well-equipped with those things. I think the manure spreader calibration that you mentioned, whether it's the tarp method or using rain gauges with liquid manure, however, they are fairly low tech. But some of those farmers that are applying their own manure probably have fairly, they maybe haven't updated their equipment several years. Because they're not a huge operation that has a lot of manure to apply. We definitely do try to encourage them to, whatever method they need, but find a way to ensure that the amount they're putting on of manure is what they intended to put on so that they're not only so they aren't over applying nutrients, but so they're getting the most value themselves out of the nutrients that they have available.
The other thing I will mention, and it's not really a new technology necessarily, but maybe a new application of an existing technology, is a survey we conducted several years ago that we are still working on publishing. Melissa will probably smile because she's waiting on me to get that done. But one of the things we found is a common barrier to manure use is that uncertainty about nitrogen availability. When you put down an organic fertilizer, you assume 40% of your organic nitrogen will become available the first year.
Well, for crop farmers who are used to inorganic fertilizer application, they want to know for sure, am I getting 50 pounds of nitrogen per acre or am I getting 20 pounds of nitrogen per acre this season? While we don't really have a good way yet to make a better prediction on that, what we do encourage farmers to use and what I would love to see implemented in Nebraska and other states, is in-season nitrogen management where you put down that manure as a pre-plant fertilizer. You assume what you'll get out of it in nitrogen for that first season, but you measure the crop growth and color and use some of those in-season nitrogen tools to understand if the crop is deficient in nitrogen. Then you can come back and supplement either by side dressing or fertigation, however you might want to manage that. It takes away that risk associated with assuming what would be available from the manure you applied.
Just that in-season management I think is really critical as we try to manage our nitrogen use more efficiently.
Melissa Wilson:
I have two comments on the in-season management. I agree 100%. One thing that the research that we were just starting, so we finished one season and we're in the middle of the second season, we're looking at if you do pre-plant manure, can you use an in-season soil test to predict what amount of nitrogen you should put on?
In Minnesota a lot of our research for the pre-sidedress nitrate test is actually on non-manured fields when a lot of research from the East Coast has showed that it only really works on manured fields pretty regularly. We're just starting that research now down in Waseca, Minnesota with swine manure and dairy manure. Then we're also doing when soybean was the previous crop and when corn was the previous crop just to see if there's differences in that crop rotation. That's pending.
But the other thing that we're doing also is we're applying manure in-season. Instead of doing a pre-plant application, say it was a crazy wet fall, you didn't get it on, it was a crazy wet spring, you didn't get it on, which unfortunately we've seen more and more of these situations recently, you could potentially put on particularly liquid manures. You could side dress those in between the crop rows.
I've been doing some work on that in Minnesota, and we've been pretty successful with drag hose systems. Even though there's literally a hose dragging over the corn, as long as you get in before the corn has come to the V5 stage, which is the fifth leaf collar, the corn will just grow back even if it does get damaged with the drag hose.
We've had a little bit more trouble with tanker systems due to compaction, but we think there's probably tweaks we just need to make with those systems. Maybe the particular setup we had just wasn't injecting deep enough or whatever it was, but we think we can make some tweaks to bring those yields similar to what a commercial fertilizer would be. Lots of in-season stuff happening, whether it's a pre-plant application of manure or an actual in-season application of manure.
Jack Wilcox:
Was there any new technology at the North American Manure Expo that caught your attention?
Melissa Wilson
I think Glen Arnold from Ohio State mentioned it. It's an irrigation system, but it's like a manure irrigation system where it pumps from your pit and slowly applies manure over a week period for one 40-acre field. It just slowly bands manure along the side of the corn throughout the growing season. It just spoon-feeds the nitrogen to the corn. I think, I don't know if it was at Manure Expo this year, but I know I've seen it around, so that's an up and coming thing that we might see more use of.
But as far as things at the expo, I think we definitely saw a lot of interesting manure solid liquid separation systems. They had some cool demos showing those systems side by side, and I thought that was pretty neat.
Jack Wilcox:
ManureDB went live about a year ago. Talk to us about the ways this tool has benefited MN growers and producers.
One of the things we keep talking about is the value of manure here. That's hard to know what the value is without knowing what the manure test looks like. One of the things that maybe a new barn, someone who doesn't have a recent manure analysis might wonder is what should the manure look like or what should I plan for? We have some old what are called book values. These are standards from the American Society of Ag Engineers. They might be from the Midwest Planner Service. But we realized looking at these, all of these numbers were developed in the early 2000s, maybe even the late 1990s. Things have changed since then. Our production systems are different. Our manure handling systems are different.
One of the things we recently did is started working with labs nationally that analyze manure. They are donating or sending all of that data to us, and we're creating ManureDB, which is the manure database. The DB stands for database. Feel free to check it out. It's at http://manuredb.umn.edu. Do be careful it is http, not https. If you put on the S, you might not access the website. We're working on that, but that's something to know.
You can actually look up all of our manure samples. We have well over 400,000 manure samples in there from all over the country. You can pick what state you're in. You can pick a region, so like the Midwest, for instance. You can pick what species you want to look at. It shows you median or the middle of the pack, so to speak, for nitrogen, phosphorus, potassium, sulfur, et cetera.
You can also see what the spread looks like. One of the things that we noticed is that spread the nitrogen value, the phosphorus value is very high, even within the own state for turkey operations, for instance. It really emphasizes that you do need to get your own samples done and taken for your farm, but this is a resource to help you benchmark where you're at or if you're a new operation, give you an idea of what you can expect.
Jack Wilcox:
Thank you very much. Any last words from the group?
Melissa Wilson:
I think one of the things is start planning now. If you're hopefully taking a little bit break from some of your field operations, but get out there, check your equipment now. This is the time to make sure everything's in order rather than trying to rush and get manure out and then finding out your pump isn't working or your tires are flat or something like that. But definitely be checking all of your equipment now because safety is also really important when thinking about manure handling.
Amy Schmidt:
Yeah, that was my first thought, Melissa, was I've done some webinars on safe manure handling and unfortunately a lot of accidents come down to being rushed or not wanting to wait for someone to come help you. Particularly if you are working in a confined space, like a pit where you store manure or your manure tank, don't enter those areas without appropriate gear, personal protective equipment because things can go wrong in a matter of seconds. I would just say don't ever put saving time above saving your own life.
If you're an employee on a farm, a lot of times I think employees may not feel comfortable asking questions because they know their job is just to get this done, get the manure application done. But again, asking those questions could really make a big difference in safety of that individual and others on the farm. Just being careful around that equipment and manure storage I think is really important.
Jack Wilcox:
Before we go, if you have a question or comment for one of our guests or a topic you'd like addressed in a future episode, please email us at nutmgmt@umn.edu. Thank you. We look forward to hearing from you.
That about does it for this episode of the Nutrient Management Podcast. We'd like to thank the Agricultural Fertilizer Research and Education Council, or AFREC for supporting the podcast. Thanks for listening.
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