 The NRCS Rainfall Simulator, we actually purchased the Rainfall Simulator about five or six years ago. What we wanted to try to do with the Rainfall Simulator in South Dakota was look at the impacts of runoff and infiltration. In other words, those water relationships on various different landscapes associated in South Dakota, whether it be crop land situations and or range land sites. Some of the best situations that we could actually see in South Dakota would be some of those range type situations where reducing the amount of runoff and actually moving more of that water into the profile. We've got a various number of components that we put together over the last few years on the Rainfall Simulator. And as we start looking at the simulator itself, you can see that it's actually set up to demonstrate or look at different landscape positions within a confine of a few minutes as we look at the rainfall or runoff event in the demonstration. As we look at runoff events, you can see that we have a series of funnel type systems that are actually setting up to collect runoff into encashment jars. The trays that we actually use within the Rainfall Simulator to collect the samples in are perforated such that we can both look at the runoff and the infiltrated water associated either going through the sample or coming off the site itself. You can see that we've got a runoff component. In other words, that funnel that's actually moving that runoff into a catchment jar and or a catchment tray that's functionally underneath each one of the samples that actually is going to catch the runoff water and move that into the catchment jar. In either case, whether it's runoff water and or infiltrated water, we're going to actually look at two inches of water associated for our demonstration. And that gives us kind of a really good idea of the intensity of a rainfall event within South Dakota. The design of the Rainfall Simulator was actually by Dr. Paul Yasa, the University of Nebraska in 1992, so it's not a new demonstration. Site selection within the Rainfall Simulator really depends on what characteristics we really want to demonstrate. And of course, we're really looking for sites that have had a lot of intensive tillage in their history. They'll have low aggregate stability, reduced infiltration rate, something that we really want to see within the spectrum of the Rainfall Simulator. So we're going to be trying to select those sites that have limited as far as diverse rotations or their low residue amounts. And that's going to give us a conventionally tilled site that's going to be good from a selection standpoint for the Rainfall Simulator. The flip side from a crop line standpoint is really looking at a no-till site where we actually have developed good aggregate stability over time, have good macro pore development, and that infrastructure of the soil is intact. Typically, the no-till situations have good diversity within crop rotation. We'll still have something that has a really good aggregate stability, something that's very useful within the Rainfall Simulator. When we select sites on grassland, one of the first things we want to look at is the different kinds of plant communities that exist out there. When you're selecting different plant communities, you want to get something that has a strong native component, as well as some of the other types of plant communities that you'll see out there. Here we've got a good mix of forbs and native grasses, and that's what we want to look for when we're selecting a spot to put our pan. To contrast that, we want to look at sites that are dominated by some of the introduced grasses, such as Kentucky bluegrass. This is a good picture of Kentucky bluegrass that has a lot of duff, and that's going to probably show a lot of runoff. In addition, another one that contrasts pretty well is smooth brome. We want to pick sites that have native Kentucky bluegrass and smooth brome, especially in eastern South Dakota. What we'll see typically is Kentucky bluegrass is going to have the most amount of runoff, native will have the least amount, and smooth brome will be somewhere in the middle. Site selection, first of all, is based on the species that are there. The next thing that you want to look at is the management that's occurring out there. If you have a site that is very well managed overall, it's going to dampen the effect of the plant communities that are occurring out there. You may have these different plant communities, but if your management is really good, you won't see the effects of those changes in the plant communities as well. Where we have some pretty heavy grazing, you're going to see shorter grass typically, and where you have Kentucky bluegrass in those situations, you should see a good effective runoff there. As we move into the native plant communities, and those that are managed better with management, then you should see an effective more infiltration and less runoff. My name is Jeff Hemingway. I'm a soil quality specialist from NRCS. A rainfall simulator, I guess I'd really like to say it's really a soil quality demonstration. What I mean by that is that we're actually going to be looking at several different samples of fields. In this particular case, we've gone out here just last night to Jerry and myself and the other range cons. We went out and we collected some samples. We've got some samples here that we've taken out of the range. We've got a no-till soil here. We've got a conventional till soil. We put those on our rainfall simulator, and the idea is to put an inch and a half, two inches of rain on that and see what happens. The question that everybody has is, okay, so what? So we end up with runoff, but the rainfall simulator, this thing is actually set up to do a couple of things for us, is not only collect the runoff, and you can see that we've got a set of jars out front here, and those of you who've been looking at this thing, wondering what the heck is all the jars behind there, too, it's set up to actually not only collect the runoff that comes off each one of these flats that we have out here, it's also set up to collect all the infiltrated, in other words, the water that goes through the profile, in the bag jar. So the example here is in this range land site, we actually have collected water that's going to go through this in that jar behind there, and any runoff will be collected up front here, right? So the idea behind that is, okay, what's happening to our landscapes? What's happening to, what was it? The gentleman asked, why the waters come over the road? I think maybe we'll start to get a little bit of a better answer to why that's actually happening. You want to describe these rain sites a little bit more stand for us? Well, we have a, this just came from the pasture out here. This is more of a native standard grass. We've got a big blue stem. I think there was some little blue stem, some native forbs, what not. This one here was right next to the pasture, actually kind of on the section line road, I guess. But this is smooth roam dominated, and then this is right out of the pasture. It's where that Kentucky bluegrass dominated kind of plant community is. These are all plant communities that occur on the same basic soil and same ecological site, so it should be a good comparison. Okay, and in addition to that, as I mentioned before, we've got the no-till that has the residue on it, and then the conventionally tilled site, and what we're going to do is make it rain. Okay, as I mentioned, the rainfall simulator is actually going to put about an inch and a half to two inches of water on these flats in the next 15, 20 minutes. One of the things that I really like to point out, I think I really initially, is rim drop impact, runoff, infiltration, aggregate stability. These are all terms that you hear people talk about. Hopefully I'll be able to do a little bit better job of defining what exactly is the impact and how we actually are evaluating some of the activities that we do on our landscapes. One of the first things I always like to talk about is rain drop impact on the soil surface. For the most part, if you look at a rain drop when it hits the soil surface, there's a lot of kinetic energy when it hits the soil surface. This is just a diagram of that rain drop hitting the soil surface as many times blown up. It looks like a mini explosion. What happens when that rain drop hits the soil that's unprotected by residues, cropland duff by a canopy of some kind that intercepts that energy? What happens when it hits the soil surface? Well, it hits the soil surface, hits that soil particle, detaches that soil, it bounces up in the air, and at some point that soil goes into what we call transport. At that point, transport can be localized deposition or could be offsite deposition of that soil. That process is called water erosion. Within that detachment, you can actually say, well, gee, is that really occurring or not? You don't have to believe me. You can actually take a white 5-gallon bucket. I prefer white because it shows up really nice. Put a rock in it or fill it half full of soil or half full of water. Put it out on your conventionally tilled field. Next time you get a heavy rainstorm, go out and look at it after the fact. That soil, we bounce all the way up the side of that 5-gallon bucket, right? But if you don't want to do that, you can just look at this, too. See this white placard behind me right here? So what do I have going on here? As you can actually see over here, the soil that's bouncing up, see that? That rain drop is hitting the soil surface that's unprotected, right? And at some point over here where it is protected, then what? You don't really see that soil particle actually bouncing up on the soil surface. Now, the other thing that I want to point out is that what just happened as I was just talking? Where did the runoff actually start initiating first? So as we start looking at runoff associated on our larger landscapes and we start moving from grassland to cropland, could that start to answer some of those questions that we're talking about as far as water movement? The other thing that I wanted to point out is that we start looking at infiltrated water. Did you see that over here on this cropland side? Where is the infiltrated water at? The water that's going through the profile versus what's running off? Is that happening over here or over there? Hmm, that's kind of interesting. So what's happening with that soil that we actually have as far as soil structure? The thing that I didn't talk about yet is that when that rain drop hits that soil surface, it attaches that soil particle but it reorients that soil particles and what else does it do? Well, in a conventionally tillered or unprotected soil, it actually then starts to plug that soil. In other words, that plugging of the macro pores of the soil matrix actually does what? Increases runoff. We know that process. We don't normally go out in the rain and look at that. We know that process on conventionally tilled soils that have low aggregate stability. In other words, unstable aggregates as the after effects on our cropping systems and we normally call that crusting after it's dried up. And crusting normally affects what? Germination of our cropland fields. The second thing I guess I'd really like to talk about is when we started literally looking at soils, we talked about plant communities, we talked about duff, but the soils that we have that are typically developed within this area, we're talking typically that they have about half of that soil is mineral material and about the other half we don't normally think about that is air and or water. What we're trying to get to in a lot of these communities that we're talking about within in our soil matrix is that that biological activity associated is underestimated. We don't normally think about that and we need to think more about what is actually in that soil and what is actually cycling the systems that we actually have. In other words, is it fungal or bacterial? Is it really actively functioning within that system or is it not functioning? When I say functioning, is it infiltrating water? Is it processing that nitrogen cycle, the nutrients? Are they being released within that system? Are they being lost within that system? We start really talking about other characteristics that I guess one of the ones that we can measure is called aggregate stability. One of the products that we actually buy products that we actually know of primarily fungal development within in soils is a glycoprotein called glumelon. This happens to be stained green. It's typically brown within soils, but that's one of those products that actually holds soil together. I have a very simple demonstration I like to do. I have a no-till clod and you can see all the wormholes, et cetera. I just pulled out a conventional till. It's the soils that we actually have here. I like to put that in water and just see how water stable those aggregates really are. Again, the no-till one. You can kind of see that one of the first things, I don't know if you all can see that, is that first things that actually happen is that we actually have air that comes out of that clod and then my conventionally-tilled one. We put that in. Again, there's air escaping that water is moving very quickly into that soil clod and Stan, you're shaking, right? Actually, no, Stan's not shaking. He's fairly stable, but what happens very quickly is that you can actually see that within the conventionally-tilled clod that we end up with a lot of material actually starting to degrade or move off of that soil and why is that? Well, we have low aggregate stability. In other words, if we have a lot of those biological byproducts that are associated with actually buying soils together are not stable in water and why is that important? Well, if we're looking at moving water through soils, limiting the amount of runoff, trying to increase productivity by capturing water on our systems, well, frankly, increasing runoff is not what we want to try to do. So, we can let that sit here, Stan, and you don't have to hang on to that forever. Overall, on the grassland, we're getting a lot more infiltration than we are on runoff and it doesn't seem to matter here if it's the consecutive bluegrass or smooth bromo or the native. Normally, what we'll see in these situations is we'll see a lot more runoff from the consecutive bluegrass versus the native. And I'm guessing, and I can't say why exactly what I'm saying is much better. When you look into the native, there's actually a fair amount of consecutive bluegrass in there as well, but I don't know. But the good thing, I guess, overall is that we're getting a lot more infiltration than we are runoff across the board. And so, that's good. Every inch of water grows so much grass, whether it's 150, 200 pounds of grass, so if that water is staying on the ranch, then you're growing more grass than if it's running off. Normally, why would the consecutive bluegrass runoff? What happens is I talked about, if you dig a soil profile under Kentucky Blue versus a native, you actually see a change in the structure of the soil over time. The structure changes under introduced grasses and that soil just becomes almost massive under there and you get a buildup of that litter on the surface and so there's not as many pores in the soil and the water gets saturated and then the water just starts running off. The other thing too is we've had a pretty dry September, it may have been something to maybe pre-wet the soils and we might have had a little bit of difference after that. But it's pretty consistent in most of the times we run it. You get two or three times more runoff from the Kentucky Bluegrass season. Not today. Not today. Well, I am going to actually shut this thing down here. We've put on about two inches of water already and I guess I always find this very interesting to do. Mainly because people think that we set this up. Actually, we're always just kind of really interested in the results also as we come out and look at a piece of rangeland. What I think that we need to gather almost immediately is, conventionally till, what do we actually see? Very little infiltrated water, a lot of runoff. And what are we seeing with that runoff? Sedimentation, a lot of soil movement. What else goes with that soil movement? Pesticides, fertilizers, etc. apply to that field. So if you're looking at water quality within your community, certainly not an improvement. No till. That's kind of fascinating to me. Usually we end up with some kind of runoff associated with it, but not today. Color differences associated? That's even with the infiltrated water. On the bluegrass, very little runoff associated, all infiltrated. And I think you can see that on the other samples also. Very little runoff, most all water infiltrated through the sample. I always get a kick out of this. I tell people when water doesn't go in the soil and it runs off, it doesn't go in the soil. Pretty simple concept. But I always like to show people how that works. First of all, before we get too far along, I didn't say the truth. It was, what, an inch and 80-hundreds? So it's almost two inches of water that we put on. You can't see a difference. Every one of the grassland samples, the infiltration buckets are overflowing. Didn't quite make it until the top on the conventional till, but it's still one. But if you've got a no-till cropland field, you can kind of see that it's kind of wet to the bottom. You can still see the soil structure. And by the way, as we start looking at any of the rain sites, this soil structure would be certainly more evident and better than if it was in a cropland situation. But under conventional till, we put on two inches of water with a two-inch flat. Now, think about this, is that most of our soils have capacity to hold about two inches of water per foot, right? Two inches of water per foot, I put on two inches, right? On a two-inch flat and still get dry spots on the bottom of it. So as we start breaking up this range land and put it in the crop land and start doing more tillage, what are we doing? We're increasing runoff, right? And as soon as you do that on fairly large landscapes, guess what happens to the water in spring? It runs over the road. Very good. It makes the culverts out. It makes your wife really upset when she wants to go to town. It makes the neighbors upset. Yeah, the neighbors upset too. I think those are some really interesting concepts that we need to keep in mind. And I think that in the past, we've been taught this whole idea that tillage is something that we need to do to increase intake and infiltration of water. And that's just completely the opposite of what really is the fact. We need to increase aggregate stability, macro pore development, so that we're moving water through that soil profile. How do you do that? Some of the best examples of that is grassland situations, period. It just really is. Questions? I always get a kick out of this, is that when you start really talking about canopies and residues, et cetera, having a canopy out there, having that surface residue and or duff layer is extremely important. And how can I demonstrate that is maybe we'll do this on that. We're going to run this again today, too, later and tape some more because we have the cameras out here. But I typically do this in addition to another flat, just take the residue completely off, like in this no-till soil. If I did that, it increases, dramatically increases the runoff almost to the point of this conventional till stuff. So you'd say, well, does that have an impact of having canopy and or a duff layer or residue? Absolutely. Other questions? I've always really just enjoyed doing this. It's always interesting from my standpoint to really start looking at some of these relationships and thinking about what we're actually doing. So with that, I'm about done. I think we're about ready to go on to our next presentation. I'm Stan Bolz. I'm the state range management specialist with the USDA Natural Resources Conservation Service out of Huron, South Dakota. We're going to demonstrate the rainfall simulator today and basically look at five different management scenarios on rangelands. The five scenarios we have picked out today, these are all on essentially the same ecological site, the clay ecological site. It's in the same MLRA. So we have a, essentially this is a prairie dog town that we got this from. This is a blue gram of sod. It's received pretty heavy grazing for a long period of time. And so we've got that characteristic blue gram of sod. This is a Kentucky bluegrass sod right here. There is a few native species in here, but mainly Kentucky bluegrass. This here was kind of right across the fence on the on the section line road. That's a smooth brome dominated. So this is a kind of a long term, no non use situation. And then at the, at the end here, we have our more native dominated grass here. We've got some big blue stem and some side of its grandma. And there is still some Kentucky bluegrass in there. But so we're going to run this simulator now and basically see how these things come out. So we're going to put a couple of inches of water on this. These buckets in front are going to let us see how much runoff we have from each management type. And the jars in back will show us what the infiltration is down through those soil plots. Another thing to kind of watch for is this backboard right here. Should start to see the impact of rain drops on the soil surface where you have very little vegetation. And you'll start to see what happens as those rain drops impact the soil surface and start to transport that soil. One of the things you can see here on the prairie dot town is water is ponding on the surface. And we'd probably be seeing more runoff actually than what we're seeing except it's just coming off the sides as well. But you can see the water ponding on the surface. And that thing you can see on the splash board here is the rain, rain drops are detaching soil particles and lifting them off and actually hitting that board on the back there. The runoff on the blue grama is cleaner than the prairie dot town. Our runoff on the blue grass is going somewhere else apparently because we're not getting any on it. We're seeing infiltration pretty much what I expect. The native is by far the most infiltration. We're at, what are we at now, a little over an inch of rain and it's almost filled up that jar. Infiltration on the smooth brome and the blue grass is almost half of that. For some reason we're not seeing the runoff. There should be a lot more runoff since there's not as much infiltration. We must have a hole in the side of our pan or it's just going off to the edge somewhere. We're not catching it down here but you can definitely see it in the infiltration. That jar back there is just about ready to go over the top now. These two are just halfway. Blue grama, again a lot of the runoff on this pan here is kind of heading over the edge as well. But you can see the runoff from the blue grama side is a little bit cleaner than that prairie dot town. But they're both pretty high in sediment. Infiltration is lowest on the prairie dot town out of all of them. So you can see that obviously one of the aspects here is a lack of vegetation and lack of intercept of those raindrops is causing disturbance of that soil surface which is increasing runoff. When you alter the plant community you change the soil structure and the aggregate stability in that soil below the surface and that's what's really affecting the infiltration. And so it's a combination of factors. The degraded plant community as well with the blue grass causes reduced infiltration because your soil porosity goes down, your bulk density goes up and your soil structure just becomes a lot less natural. So you can see on the native grass we're well over topped on our infiltration jar. It's been running over for a while now. Out of the more vegetated samples the smooth brum has the most runoff. The Kentucky bluegrass I'm sure would have had more runoff here but it must be running off the side somewhere on that pan. I think we can probably shut her down. So you can see that like I said the infiltration is the highest on the native. Kind of intermediate on these two over here. The smooth brum actually in this case was the least amount of the more vegetated. And then with the blue grandma and the prairie dog town they've got by far the least infiltration in the most runoff. But I do believe that the sediment yield is higher on the prairie dog town than the blue grandma side. One of the things that I was always told was yeah if you have overgrays and you have a blue grandma side you might get a lot of runoff but it'll be clean runoff. But in these infiltration runoff runs that we've been doing we've seen that the runoff isn't as clean as what I formerly thought it would be. It is quite dirty compared to the runoff over here with more grass. So I'll take this off and flip one of these over just to see. So we've ran about two inches of water on this and that's a two inch pan. And the water hasn't even, I mean that soil is still dry down here really dry. Most of it's dry actually. So there's been very little infiltration through that prairie dog town soil. See what the blue grandma looks like. And there again still dry for most of that area down. I mean that water only soaked in maybe a half inch in there when you look at the side view there. So that's not soaking in very fast in there. That's evidenced by the amount of runoff that we have. I suspect if we compare that to the native we'll see a lot different. That one is wet all the way through. And that just shows how much more infiltration, how much more water we're getting in the profile in those situations that are a little better. And of course every inch of water that you put into the soil versus running off is going to grow more grass. And I've heard anywhere from 150 to 200 more pounds per inch of water that gets into the soil. Just out of curiosity since we're doing this. The smooth brome looks like it's even dry in parts of it. So the smooth brome has already lost some of its structure down below and where it's got the smooth brome on it. And the water is just not getting in. Well that might as well do the last one. Oh that one's wet. When you have management that leads to either typically the Kentucky bluegrass or the bluegramma sod. You know you can get by in the wet years because there's enough rain at the surface that gets into the soil that grows some grass for that year. But if you get into a drought situation you're going to be impacted much more drastically in those drought years. The people that have managed better and gotten that water throughout their profile they can carry themselves through a drought and get a lot more grass production even in the drought years. Normally though when I run the simulator I'll just take these samples all from the same area but they're all managed with cattle grazing. The Kentucky bluegrass usually runs off three or four times as much today for some reason. It's probably your management. You made it not work for us. But usually the Kentucky bluegrass even in the same pasture a lot of times. I'll take the bluegrass right out of the same pasture in the native right by it and you'll see a difference there. And we did on the brome. You know the brome was still dry below there so we did see it there but not on the Kentucky bluegrass today. But normally yeah it's your native grass has by far the highest infiltration. Smooth brome is usually in between and then Kentucky bluegrass is the worst normally. In collecting the samples we really look at the pan depth is a little more than two inches. When we're collecting samples on sod range pasture typically those samples will be as consistent as possible. Segmenting a sample in different pieces is really not the idea of a good collection. What we'd really like to do is have a consistent sample that is in one piece as much as possible to try to avoid preferential flow around the edge of the pan. As you can see here we're cutting that sample such that we can actually come up with a uniform depth associated with that sample. And something that's one piece to again avoid that preferential flow around the side. Uniform depth we're trying to get about a two inch depth. We want that sample depth to be as uniform as possible but at the same height as the top of the pan. In other words that that duff layer etc. to be at that height of the pan itself so that we get good flow and try to get most of it to either come directly off as runoff or go through the pan as infiltrated water. As we put that sample together try to cut it as uniformly as possible around the pan itself to get a nice fit within the pan. Eventually you'll be able to come up with something that's nice and uniform, fits into the pan really nicely and gives you some really good results in the rainfall simulator.