Manure laws and regulations in MN: Feedlots, storage, buffers & more
Hello, and welcome back to Advancing Nitrogen Smart, the special podcast series from University of Minnesota Extension. I'm Jack Wilcox in Extension Communications.
Jack Wilcox:Today, we're talking about laws and regulations surrounding manure application in Minnesota. Here with me are Brad Carlson, Extension educator, and Melissa Wilson, Extension manure nutrient management specialist.
Jack Wilcox:Brad and Melissa, we all know there are lots of rules pertaining to feedlots, but what are some of the rules that are specific to manure application?
Brad Carlson:Well, Jack, we don't spend a lot of time in Extension talking about laws and regulations, primarily because we are not an enforcement agency. So, you know, we're drawing our material from these podcasts from our Advanced Nitrogen Smart sessions and particularly the manure management one. And so there are some things in the laws that are very pertinent when it comes to doing land application and manure. So that's really what we're going to talk about today is some of that stuff, I guess. So that's kind of my disclaimer is don't look at or listen to this podcast as the be all end all related to feedlot rules, application rules, and so forth.
Brad Carlson:And in addition to that, as as we're talking here in 2025, it's important to know that the pollution control agency is currently in the process of looking at the possible revision of the state feedlot rules, and so also realize that this podcast could get dated at some point here in the future if these rules change. We were having a little conversation before we started recording about whether we think the things we're gonna talk about today are probably going to change. In general, we don't think they probably are, but they could. What we think is more likely to happen is there probably will be more regulations coming down the line in addition to this stuff. So again, you know, for now here, for for the time being, this is kind of where we're at with some of this stuff, and so we're gonna talk a little bit about it today.
Brad Carlson:The rules as they pertain to land application of manure come from our chapter seventy twenty of our pollution control laws. These were created the current version was created. I think it may have been modified here and there slightly since then, but basically in February, I personally was on the State of Mineral Management Advisory Committee that made up these rules way back then. So obviously, a long time ago, we're talking twenty five years ago when these things came around. I think a lot of folks who were around back then realized that there was a lot of controversy back then just related to some of the changes in the livestock industry, the sizes of operations, changes in housing and manure storage and practices, and so forth.
Brad Carlson:So these rules got incorporated into Chapter seventytwenty. They require setbacks to sensitive land features. There are a few differences in terms of the size of the operation and what is required of them. But I think there's a couple other things we need to also recognize is, A, very large operations that are classified as CAFOs come under federal rules, and we're not going to talk about that today. And in addition to that, counties did have the right to be more restrictive, and so there may be county rules additionally that have additional requirements.
Brad Carlson:We don't know what all those are as we go across all 87 counties in Minnesota, and so we're not gonna talk about that either. We're just gonna talk about the stuff that's in the state rules, and it's also important to realize that this pertains to sold or granted given manure, if you get manure from a neighbor, this also applies, no pun intended, but the rules do pertain to both the operation generating the manure and the operation that's doing the application to their cropland.
Melissa Wilson:One of the other things I wanna add is that for all sizes of farms, you cannot apply with manure or fertilizer or anything. Regarding that, if the manure is used, you cannot apply more nitrogen than the crop needs. So that's kind of another rule that applies to all sizes of farms as well.
Brad Carlson:Yeah. That's an important point, Melissa, because we'll frequently hear, you know, people discussing, well, you know, somebody did a manure application and then they also did a commercial nitrogen application, and while we don't regulate commercial nitrogen applications, at least at this point in time, it is important to realize that if manure has already been applied, that that does sort of get regulated as far as not doing an over application supplementing with the commercial stuff. And know, that can be a little bit difficult, and we'll be talking at some other point here with somebody not today, but with your information on establishing the nutrient value of manure and manure credits and so forth. And so that kinda comes into play there when we talk about supplementing commercial if if it turns out we didn't apply enough nitrogen for the crop. But that's that's a subject for another day, but, yes, that is that is also a part of the feedlot rules.
Brad Carlson:I think the first thing, you know, when it comes to the establishing what's actually in the manure is is the requirement for manure testing. It is a requirement for any new operation back when the rules were first passed, it was a requirement for every operation, no matter how old they were, that they establish a baseline of the nutrient analysis in the manure. And so what we require for any operation that has over 300 animal units is that they test for at least three straight years to establish that baseline, and then there also needs to be a test at least once every four years just to make sure there aren't changes. I guess it's kind of worth noting that we really recommend that all operations should be doing testing, and frankly, doing a test every year is just a good practice. It's not a requirement, but it is a good practice.
Melissa Wilson:Yeah, for us, some of the things that we see that might change from year to year, especially if you have outdoor storages, obviously, rainfall is gonna really influence things. Even with our indoor storages, we've seen pretty drastic changes just based on differences in feed from year to year, but also differences in, like, moving from traditional waterers to the wet dry feeders and hog barns. There is a farmer that came up and once told me that they were applying probably about six, seven thousand gallons thousand gallons per acre for their hog barn, and then they switched to those wet dry feeders, and the nutrient concentration came up so much because there was so much less dilution that they had to cut their rates down to, like, three, four thousand gallons per acre. So that could really make a difference if you make changes in your barns especially.
Brad Carlson:And on the flip side, I had a farmer tell me one time that they when they got their sample in for analysis, it was so diluted, they discovered a water leak that they didn't know they had. Yep. You know? And so so those things happen also. So it it is just simply worth keeping on top of it.
Brad Carlson:And and I think particular, if you look at changing your feeding program, if you're going to a different feed company, or you're gonna start supplementing in a way that you didn't before, I mean heck, even potentially if you start looking at differences in hog genetics, if there's a big departure from what you were doing before, say you suddenly want to go to some heritage genetics or something of that sort, you know, there's a chance that that stuff can be different. It's just simply worth keeping track of.
Melissa Wilson:Yeah. We say that what goes in must come out, so if you're drastically changing what goes in, then you can kind of expect what comes out to change as well.
Brad Carlson:Yeah. So so the rules say that the sample must be representative. That can mean a lot of different things. I guess when we're talking about hog barns, you know, particularly, I think the, you know, the obvious thing is is that that the manure should be agitated at the time that the sample is taken. Although I think folks do kinda recognize that a lot of the heavier solids, do kinda end up towards the end and towards the bottom of the pit, so that can be a little bit difficult.
Brad Carlson:It's probably not a bad idea to take multiple samples, you know, maybe one at the start, one at the middle, one at the end, and see how that's changing. And but but there's also the possibility of of putting a a pipe with a pull plug in it all the way through the column and just simply getting a sample from the column. Have have you worked with that, Melissa?
Melissa Wilson:Yeah. We've done a little bit of that. We still suggest maybe even getting it from a couple of different ports, again, for that to kinda see that variability across the barn. But we actually have one of our videos for how to sample a liquid storage pit is actually a swine barn using one of those things, so you can check that out online.
Brad Carlson:You know, and then from that standpoint, you know, it's it's it's probably best just obtained when you're loading the the manure applicator and all. A lot of people I've seen have, like, a sort of like a bucket on a pole that they can just kinda put underneath the downspout as as the loading is happening into the applicator, something of that sort.
Melissa Wilson:Even for something like turkey litter, sometimes getting a couple handfuls from every load can be helpful in mixing those up just, again, to make sure you're capturing some of the variability that you might see in that pile too.
Brad Carlson:And that's a good point for solid manure. Poultry is still solid. The amount of solid livestock manure is sort of variable. Dairy barns tend to be more towards the liquid side these days than than they were maybe at the start of my career. We had a lot of smaller operations that still had more solid.
Brad Carlson:Not as much beef feedlot manure in Minnesota. Those tend to be smaller operations. However, getting representative samples, particularly if there's a lot of bedding, can be a little bit difficult. I know I've had farmers say, well, we bed with cornstalks. What am I supposed to do about that?
Brad Carlson:I can't grab a cornstalk and shove it in the sample jar. But, but I guess, really, you just gotta kinda try and do the best you can.
Melissa Wilson:Yeah. Absolutely. I mean, even in the lab, they can't grab a whole cornstalk and put it through the analyzer either.
Brad Carlson:Right.
Melissa Wilson:So they're they're trying to do the best they can, and we gotta try to do the best we can as well when sampling.
Brad Carlson:And and then the the last thing about the manure testing requirement is it does have to go through an approved laboratory. I don't think that's such a big deal anymore. I think back when we started requesting this or requiring this, there tended to be a there was at least originally a very long list of laboratories that would do analysis on manure, many of whom I had never heard of before at the time I saw the list and maybe never heard of since. It seems like most of those, the samples are going to just a couple of different labs in particular. We're not going to throw out names on this podcast, but I think most farmers who are doing mineral application know who those labs are.
Brad Carlson:The Minnesota Department of Agriculture does do is it the is it the the MDA or the MPCA that does the lab certification?
Melissa Wilson:Yeah. It's the MDA. They have the only lab certification program for the entire country, actually, which is pretty cool. But they basically their goal is to send around samples of really well mixed, well homogenized manure to different labs, and then the labs test it and send their results back. And they can detect then if a lab is really off compared to everyone else.
Melissa Wilson:They kinda flag it and help them get back under to where they're supposed to be. So it's basically helping to make sure that labs are fairly standardized in their practices so that we're getting fairly standardized results. I mean, you should know that any kind of manure sample is very not homogenous to begin with, so you can send the exact same sample to the exact same lab split several times, and you might get slightly different results back. Some of that's just from the variability in the manure, but some of it could also be the variability in the testing procedures as well.
Brad Carlson:Well, right, and they also do certification for cell testing labs in a very similar way. One the issues with cell testing labs, and I can imagine that it's potentially an issue with Moderna testing also, is just ensuring that the lab is using standard procedure. There tends to be lots of different ways you can analyze for different things, And so particularly if a lab were to choose to use a method that's maybe not standard or not approved, that can end up affecting the results. And so this is just kind of one way for the state to ensure some quality control and for farmers to feel comfortable with the numbers they're getting back. So something we already mentioned is that the rules do require that you have to account for all sources of nitrogen, and so that both includes the commercial nitrogen that may have been applied, but also your nitrogen credits.
Brad Carlson:If you have alfalfa in your rotation, if you have a manure credit, so particularly like if you're growing corn on corn and you did an manure application, you got a second year nitrogen credit from manure applications, and so forth, you are required to keep track of all of that stuff as part of your manure management plan. The state does allow for a little bit of an adjustment when conditions warrant, you know, that's kind of some of the stuff that we talk about with Nitrogen Smart is related to what those conditions are. And so I think particularly if the weather conditions have been a little strange, too wet, too dry, and so forth, we may see some variability, but I think also I think it's conceivable that the farmer could look at, as we just talked about having issues with taking a good sample, you know, if you got a dry manure or a pack manure that's very difficult to be consistent with, you know, it does allow you to make some adjustments there to ensure that you don't end up with spots in the field that were under fertilized. And they do allow for extra application if there are deficiency symptoms, however, I guess I would tend to caution that a lot of times those deficiency symptoms show up later in the year when it's getting a little bit too late to be making supplemental applications.
Melissa Wilson:One of the things I want to add is that for the nitrogen sources, one of the biggest errors we see with manure management plans, and this is here in Minnesota, but also during my time spent when I worked in Maryland, was that starter fertilizer, sometimes, like, people are thinking them as just a phosphorus starter fertilizer, but a lot of times they have ammonium or some other form of nitrogen in them too, and you do have to consider that when thinking about your sources of nitrogen. The other one is irrigation water. In some cases, you're putting on enough irrigation water, and if it has nitrate in the water, it could be a actual decent amount of nitrogen that you're adding over the growing season, so you have to account for that. And then the other thing I wanted to mention too is kind of like this more when there's deficiency symptoms, like, can apply more nitrogen if there's deficiency symptoms. These are always great things to run by your local county feedlot officer, someone who works at MPCA in the feedlot program just to make sure it's something they'll allow, kinda like Brad talked about earlier.
Melissa Wilson:We're not regulatory staff at all, so it's always good to get familiar with your local regulatory staff just to ask questions if you have them.
Brad Carlson:So the other thing, when we talk about all sources of nitrogen is, is MAP and DAP. So if you're using ammoniated phosphate, which the majority of the commercial phosphorus fertilizer is, you do have to add that into your total amount of nitrogen. Now a lot of cases, manure applicators are not needing to supplement with extra phosphorus, but that may be the case in some situations. And so that's something that's important to also include. When it comes to the rules, if you're over 300 animal units, you are required to keep track of your phosphorus in your fields to ensure that it's not building up to excessively high levels.
Brad Carlson:So that is a requirement that every four years you have a soil test where you're doing regular manure application to just to monitor phosphorus levels in the soil, and there is actually a trigger that if the soil test phosphorus gets too high, then there does need to be a switch over from nitrogen base rates to phosphorus base rates. And I would say in my experience, I have seen some fields, you know, particularly when we talk about some of these places where there was a long history of manure application, not so much in the last decade that we've been kind of paying a lot closer attention to this, but places that had larger production facilities, say, you know, maybe twenty or thirty years ago, and a lot of application was happening around the building site year end, you know, year after year after year, I've seen some pretty high phosphorus numbers. And, you know, in those particular situations, you know, it's probably best just to move the manure application to someplace else. And so there does need to be a plan if the phosphorus levels get really high to to on how you're going to address that.
Brad Carlson:And a lot of that is just simply the accounting for what the crop needs of the phosphorus are and how much you're doing for an application to ensure that they're not continuing to build up.
Melissa Wilson:Just for our listeners' sake, that trigger for soil phosphorus test levels is dependent on how close you are to water. So if you're within 300 feet of water, the trigger is 22 parts per million Bray or 17 parts per million Olsen, But if you're over 300 feet away from water, then the trigger's much higher. It's a 150 parts per million Bray or a 120 parts per million Olsen.
Brad Carlson:Which is pretty high.
Melissa Wilson:Mhmm.
Brad Carlson:You know, that that takes a lot to get those numbers that high, but when I said that I've seen some pretty high numbers, that means I've probably seen numbers that were higher than that. And so it does happen, you know, again, in some of these places where there was a history of MINR application every year. We don't see a lot of that happening anymore, but we did at one time. Really anyone that's over a 100 animal units in the state of Minnesota is required to have a manure management plan. It's not required to be submitted, I think, until you hit 300 animal units, but if you're over 100, you're at least required to have a plan and therefore it's required to be obtainable.
Brad Carlson:So for instance, if there was a problem related to some runoff or some complaint or something like that and the county feedlot officer came and asked, you should be able to hand over your management plan and say, here it is. And so you can't just say, Yeah, I got it up here in my head. That's not considered a legal manure management plan as far as the state's concerned. They do need to be updated annually, you know. I think part of the issue that I see in my experience has been is that plans are always just plans, and then you have some things happens.
Brad Carlson:We have bad weather that doesn't allow you to get to a field you wanted to get to. It turns out your test comes back different than it was in the past, and you need to modify your application practices and so forth. That's a good reason to be changing these things annually because, you know, what you plan to do when you made the plan and what you actually did could end up being different, and then it requires future adjustments. The other thing is for operations that are applying to frozen ground, which is not a lot of folks and primarily it's a lot of smaller operations, particularly some daily scrape and haul dairies. There does need to be a lot of extra information in those plans if you are applying on frozen ground relative to what the slope is, where you're doing the application, how close it is to surface water, and what you're doing to ensure that there's not runoff in those places.
Melissa Wilson:I think in most plans, it's probably good, even if you don't plan on or have usually have a need to apply manure in the winter, it's always good to have a plan in case there's an emergency. Maybe there's a pipe burst or something like that where you would need to apply it. You need to make sure you kinda know what fields it could safely go on so that it doesn't run off into waterways.
Brad Carlson:And and so as far as the application restrictions are concerned, I guess there's a couple of general things. One is you're not allowed to apply to a road ditch, and that means the road right of way. And I guess this is where beyond me being an extension educator, I don't know if I've ever thrown this out before on the podcast world, but I am a township clerk also. And so I get to routinely deal with some of the issues with our township roads and and say that the technically, the road ditch is where the road right of way ends Even if your township has allowed you to farm closer than they maybe would have preferred, the road right of way is actually where you're restricted from doing applications, and so that should not be happening. The other thing is the state rules do say that there cannot be any off-site runoff.
Brad Carlson:That does not mean there cannot be runoff within a field, that will happen from time to time depending on weather conditions and so forth. But what they mean is they don't want runoff coming from a field to another field or another location, a wetland, you know, your neighbor's field into the road ditch or so forth. And so running off-site is also not allowed based on what the state rules are.
Jack Wilcox:Brad, I know there's lots of interest in buffers and setbacks. Could you explain a bit about those?
Brad Carlson:A buffer strip, you know, I think in Minnesota, we're keenly aware of what a buffer strip is because of the rules that were put in place for buffers and drainage ditches and surface water and so forth, but these are areas of permanent vegetation. It's not the same thing as a setback. The setback is the distance from wherever that surface water is to where you do an application, and so that setback area does not have to be set back from the buffer strip. It still is also set back from the, you know, from the surface water. So if your buffer strip is only one rod, then there probably will be a little bit farther that's still a setback in some circumstances, but it's really important to recognize that setbacks are just simply going off of the distance from surface water.
Brad Carlson:They are not going in addition to the buffer strip.
Melissa Wilson:Typically, it's 25 feet from any surface waters where you can't apply manure. The only exceptions are wells and sinkholes that is 50 feet from those, and that's where you can never apply manure. You're not supposed to put it in grass waterways either because, like, that's where water is going to run, so you don't wanna put manure there for it to just be washed away. So that's a setback. And then there are additional requirements whether or not you're going to inject the manure.
Melissa Wilson:So another 300 feet, you cannot apply a manure unless you're going to incorporate it within twenty four hours or inject it. So if you're just going to surface, apply it, and then incorporate it over twenty hours later, you have to be at least three hundred feet away from the water body. This includes open tile intakes, ditches, sinkholes, etcetera. So that's another thing to remember as well. As long as you're going to incorporate it, though, you could come up and get as close as that 25 feet.
Brad Carlson:Yeah. And it's also important to recognize when we talk open tile intakes, you know, a lot of people, depending on where you are in the state, you just think of those as being in the low areas where the water ponds in the field. In that case, it does pertain to all the way around those intakes. However, in places where we have more terrain, we have these water control sediment basins that have open intakes in them and they collect the, you know, in essence the water gets to the berm and then gets run into a pipe underground instead of letting it run over the hillside. You know, in that case, the setback applies to the uphill side of that.
Brad Carlson:There's really no circumstance where the manure is going to come crawling up over the levee on the bottom side, and so in those cases, it is just strictly the setbacks are just for the uphill side, as well as for sinkholes in Southeastern Minnesota. Those can be a little bit more nebulous, I guess, from my observation than them. And frequently, there does tend to be land sloping into the sinkhole in all directions. In most cases, there may there are some places where they occur on a hillside where there is definitely an up upslope and a downslope, but the the setbacks from sinkholes and then from from wells is 50 feet, not 25 feet. And then now as as we've said, the the incorporation rule then is still 300 feet in those circumstances.
Melissa Wilson:One of the things I wanna point out too is we mentioned the winter application. It's not happening as much, but if you are thinking about an emergency spot to put manure, remember that the ground is frozen in the winter, so there's no way to incorporate it, so you would have to have automatically have that 300 foot setback on any field that you're thinking about applying to, so just something consider.
Brad Carlson:Yeah. I know there's a neighbor that I a field that I drive by that has a dairy farm that does do some winter application, and I've seen situations where they've done the winter application and done a really good job of staying keeping that setback away, and you can just see the, you know, the application and then the white snow underneath. And I thought that would make a good photograph, but then I've also thought they probably didn't want me stopping on the road and taking a picture of it either. So so I've never actually done that. But, yes, that's that's a very important point, Melissa, that, you know, there is no incorporation when the ground is frozen.
Brad Carlson:So, you know, that's it's a nuance you need to think about. Kind of a few last points here, you know, as we're kind of wrapping this thing up is part of your manure management plan does have to have a statement or some sort of a plan on how you intend to prevent phosphorus from building up, and so if the phosphorus level in the manure greatly exceeds the crop need and you're doing manure application every other year, it is probable in those cases that the soil test phosphorus level will continue to go up over the years, and in that case, what is your plan? Your plan may be to just keep testing the soil, and if it gets to the high point, you're gonna stop doing application. Your plan may be you're going to only apply every four years instead of every two, but there does need to be some acknowledgment if the phosphorus level in the manure is higher than crop need, that the soil test phosphorus level will continue to build up. There's also a requirement that you follow soil nitrate testing as per university recommendations, and so particularly in cases of manure application where you've got corn on corn, we do recommend doing a soil nitrate test in those situations with long term manure history, but also in when there's been a drought is particularly the place where we would also look at that.
Brad Carlson:I guess it's worth noting that there's kind of a difference between what we recommend and what you can do. I mean, we'll talk a lot about doing, for instance, you know, pre side dress nitrate test. That's a test we offer assistance from interpretation, for interpretation, but we aren't really recommending that you go do it and so forth, so there's no requirement that you have to go do a pre side dress nitrate test so forth. However, if you are, you're supposed to be following our recommendations. And then the last note here is, as we said earlier, that if you purchase manure, you need to review all these requirements annually as part of your application practices, and that needs to get incorporated into the manure management plan that is both yours and the feedlot owners jointly because that's part of what's happening in the feedlot.
Melissa Wilson:Yeah. You do need to keep land application records too, and that's required for any feedlot with a 100 or more animal units or anyone that receives manure from a feedlot with a 100 or more animal units, and you have to keep those for three years, actually. I think with the exception of manure that comes from an NPDES permitted facility, then that is a six year requirement. So just a reminder to keep records for where it was applied, at what rate, that sort of thing.
Brad Carlson:So that kinda wraps it up. I guess I'm just gonna end here by restating what we said at the front, and that was that the state is in the process of revising the feedlot rules, and this stuff may change. We don't think that any of this is going to go away by any means, but there may be some additional requirements coming up here in the future that we didn't cover in the podcast today.
Jack Wilcox:Brad Carlson and Melissa Wilson, thank you both very much. We appreciate it.
Brad Carlson:Thanks, Jack.
Melissa Wilson:Thanks.
Jack Wilcox:Do you have a question about something on your farm? Just send us an email here at nutmgmt@umn.edu. Thanks a lot for listening and we look forward to seeing you next time.
Jack Wilcox:Advancing Nitrogen Smart is proud to be supported by the farm families of Minnesota and their corn checkoff investment through Minnesota Corn.
