Increasing Pasture Productivity and Quality to Support Grazing Livestock
This seminar will describe the structure and function of cool-season grass pastures in the Midwest including those dominated by perennials and seeded with annuals. Strategies and knowledge gaps to enhancing pasture productivity and quality through cultivar introductions, interseeding, and planting of simple to complex mixtures will be emphasized.
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[00:00:00.800]The following presentation is part
[00:00:02.710]of the Agronomy and Horticulture seminar series
[00:00:05.830]at the University of Nebraska-Lincoln.
[00:00:09.120]Good afternoon, everyone.
[00:00:10.760]Welcome to the Agronomy and Horticulture seminar series.
[00:00:14.190]It's my great honor
[00:00:15.240]to introduce today's speaker, Dr. John Guretzky.
[00:00:18.309]John is a associate professor
[00:00:20.690]at the Department of Agronomy and Horticulture.
[00:00:23.480]He received his Bachelor Degree
[00:00:24.910]in Natural Resources and Environmental Studies
[00:00:27.740]from the University of Nebraska-Lincoln.
[00:00:30.520]He received his PhD in Crop Production and Physiology
[00:00:33.700]from Iowa State University.
[00:00:35.860]John's area of focus is on grassland system ecology,
[00:00:39.160]and his research focuses on the impact of grazing systems
[00:00:42.500]on structure and function of grassland ecosystems.
[00:00:45.920]So without further ado, let's turn it to John.
[00:00:48.600]Thank you, Lucci.
[00:00:49.850]That's good about my biography a little bit,
[00:00:54.150]but I do want to just mention a little bit,
[00:00:55.930]kind of some of my philosophy,
[00:00:58.910]kind of some of my guiding principles
[00:01:00.760]and things I think about
[00:01:02.040]and particularly as they relate to this talk
[00:01:08.160]and my belief system, right?
[00:01:11.480]So particularly, I mean
[00:01:14.210]I think we should have more grasslands.
[00:01:16.710]To me, it should be expanded,
[00:01:18.919]and we should be increasing
[00:01:20.880]those pasture-based grazing livestock.
[00:01:26.297]And tied with that,
[00:01:28.484]I also think we should make living the good life, right?
[00:01:33.550]We're in Nebraska, the good life.
[00:01:36.030]Part of that is eating well.
[00:01:38.242]What goes well with good steak?
[00:01:41.704]A good wine, right?
[00:01:43.930]That's all part of that, right?
[00:01:45.390]We should be doing more.
[00:01:48.498]We should be gathering with friends and family
[00:01:50.520]and make that a priority because when we don't do that,
[00:01:54.730]it gets lonely, and we don't eat as well.
[00:01:57.550]If we're always on the run, we're not eating well.
[00:01:59.866]And that ties with to me, with ruminants
[00:02:05.220]in the rolling pastures
[00:02:07.120]and their ability to use those pastures.
[00:02:12.810]Back to our education system,
[00:02:14.760]and part of my job is, you know, I teach in my position.
[00:02:18.530]I teach undergrad courses in forages.
[00:02:21.548]And so thinking about educating new generations
[00:02:25.849]of students and thinking about how do we enhance grasslands?
[00:02:30.999]How do we enhance grazing?
[00:02:33.260]We need more grassland farmers.
[00:02:35.000]So that's in part what I do.
[00:02:39.737](indistinct) my colleagues
[00:02:42.620]that I most closely associate with
[00:02:44.528]and that's the range people
[00:02:46.730]and how much they love the non-native introduced grasses
[00:02:51.450]in Nebraska, but they're important from a forage standpoint.
[00:02:55.338]I tell them they should be appreciated,
[00:02:58.713]and hence, a lot of my talk
[00:03:00.550]is gonna cover those introduced grasses.
[00:03:04.688]And then lastly thinking about,
[00:03:08.220]kind of as it relates to management and pastures,
[00:03:11.458]and kind of as it ties to a lot of what I'm gonna talk about
[00:03:17.620]with research and maybe research directions
[00:03:22.000]is thinking about how do we enhance,
[00:03:24.047]and it goes back to role, our role.
[00:03:26.550]We're in an agronomy and horticulture department.
[00:03:29.450]And what are we trying to do?
[00:03:30.430]We're trying to enhance health.
[00:03:32.940]We want plants to do well.
[00:03:34.680]And thinking about in a pasture situation
[00:03:37.280]with perennial plants,
[00:03:38.420]I think about how do we make them so they're thriving?
[00:03:41.410]And then in part with that,
[00:03:43.901]thinking about landscape systems
[00:03:46.590]that pastures would be on is plant diversity's important
[00:03:51.300]because there's a lot of spatial variability in grasslands.
[00:03:55.730]And so that plant diversity and space
[00:03:58.680]as well as time is an important component to that.
[00:04:04.160]Okay, so grazing is a great way to go.
[00:04:07.790]And they're beautiful animals,
[00:04:10.140]not just beef cattle, but other ruminants as well.
[00:04:12.720]All right, so what I was going to talk
[00:04:15.380]to you today about is some of my research
[00:04:17.597]on the pasture side and a lot of what I've done is mostly
[00:04:22.501]in Eastern Nebraska.
[00:04:24.600]And I do a lot of that at Eastern Nebraska research
[00:04:27.160]and Extension Center at Mead,
[00:04:30.330]but some of that work has encompassed a couple
[00:04:32.105]of these three different areas
[00:04:33.820]and that's nitrogen fertilization.
[00:04:35.760]I've been involved with some studies on pastures
[00:04:38.756]and aspects related to that.
[00:04:42.120]Then also alternatives to nitrogen fertilization
[00:04:46.430]like interseeding legumes.
[00:04:48.690]And then lately the last few years I've been doing some work
[00:04:51.650]on how do we ramp up,
[00:04:53.478]can we increase productivity even greater
[00:04:56.616]than using simply perennials,
[00:04:59.730]but interseeding annual warm-season grasses
[00:05:03.920]in those pastures,
[00:05:07.030]and then I'll end with a couple,
[00:05:08.780]just a couple of thoughts
[00:05:10.340]on maybe some potential knowledge gaps.
[00:05:13.540]Okay, so the first one,
[00:05:15.116]I mean nitrogen fertilization,
[00:05:17.850]nitrogen fertilizer application pastures isn't new.
[00:05:21.440]But when I first started here, about 10 years ago,
[00:05:25.470]they, my animal science colleagues had some,
[00:05:29.728]a lot of pastures at Mead are dominated
[00:05:33.870]by smooth bromegrass.
[00:05:35.800]And I would add that these are pretty intensively managed,
[00:05:40.180]and I'm going to demonstrate that with some of the data.
[00:05:44.060]So show how, I mean, that's an important part of it.
[00:05:47.400]So, but if you're not as familiar with smooth bromegrass,
[00:05:52.640]so it's perennial cool season grass, spreads by rhizomes,
[00:05:57.335]very high quality there during springtime.
[00:06:01.240]High crude protein, high digestibility when it's young
[00:06:05.914]and it's basically producing leaf.
[00:06:11.120]So that's probably that picture's probably taken
[00:06:13.830]about late April early May,
[00:06:16.874]but then after that, you know,
[00:06:19.430]eventually it's gonna go through vegetative to elongatative
[00:06:23.860]into reproductive stages.
[00:06:27.540]And we get a peak, big production peak,
[00:06:30.583]70% roughly of production there by the end of May
[00:06:35.310]or into June, about 70% of production.
[00:06:39.900]And then after that,
[00:06:41.260]you get a lot of drop-off of production.
[00:06:43.580]And even the performance of cattle grazing on pasture
[00:06:46.850]during summer starts to decline.
[00:06:52.120]But so was part of a study.
[00:06:56.610]I don't have,
[00:06:57.443]there was another treatment in that study.
[00:06:58.990]I don't wanna highlight that component,
[00:07:01.780]but just wanted to reference, just kind of pointing out,
[00:07:05.100]like going back to one of my talks
[00:07:07.670]about improving pasture productivity and quality
[00:07:10.245]and the importance
[00:07:12.010]of just emphasizing nitrogen fertilization.
[00:07:15.569]And so in these pastures, they were,
[00:07:18.790]we had unfertilized pasture
[00:07:20.692]being compared to fertilized pasture.
[00:07:24.950]And this is some of the background data on it.
[00:07:29.520]I'm showing these are put-and-take.
[00:07:31.683]So a lot of that, to keep up with all that growth,
[00:07:34.650]cattle get put on and then taken off
[00:07:37.680]just to maintain that overall pasture amount
[00:07:42.300]of forage there.
[00:07:44.551]But just pointing out so fertilization,
[00:07:48.010]you're gonna support more animals.
[00:07:49.630]And that's what that showing, is the stocking rates,
[00:07:52.091]animal unit months per hectare.
[00:07:54.860]You can see that there's more of that.
[00:07:56.870]Now these are intensively managed,
[00:07:58.880]and I'm pointing this out
[00:07:59.960]is utilization percentage here on an,
[00:08:04.180]that's the amount of annual forage
[00:08:05.900]that either gets trampled
[00:08:07.490]or the annual out of the annual production
[00:08:10.380]on that pasture,
[00:08:11.937]the amount of forest that either gets trampled
[00:08:14.290]or gets consumed, and it's close to 85, 90%.
[00:08:18.670]So it's, I call that's pretty intensive,
[00:08:22.350]and I'm illustrating this
[00:08:23.637]because this would be what looking,
[00:08:27.668]this would be for the same ecological site, the same soils,
[00:08:32.613]that'd be your NRCS guides
[00:08:36.820]for smooth bromegrass pasture.
[00:08:38.730]Now they, I think they underestimate the production
[00:08:42.550]a little bit there,
[00:08:44.010]and their recommended stocking rate is
[00:08:45.970]quite a bit less on those pastures,
[00:08:49.620]but that's smooth brome or tall fescue.
[00:08:51.870]That's just abbreviated there,
[00:08:53.270]smooth brome or tall fescue dominated range land.
[00:08:56.070]So that'd be range land.
[00:08:57.700]Range land wouldn't be fertilized.
[00:08:59.250]So but that would be that recommendation
[00:09:03.140]just for comparison,
[00:09:04.340]just point out this intensive management.
[00:09:07.240]So in, as it relates to that,
[00:09:11.020]you see that difference in stocking rate.
[00:09:13.100]Well, the goal there is
[00:09:14.670]to end up with the same amount of biomass
[00:09:16.770]at the same at the end of the year or the same amount
[00:09:20.500]of grass that's leftover.
[00:09:23.370]And so when we start thinking about pastures
[00:09:25.212]beyond production, you get in the ecosystem services
[00:09:30.720]like soil, soil components.
[00:09:34.472]Keep that in mind
[00:09:35.930]that we're utilizing all the grass
[00:09:39.140]and we're pushing it, so.
[00:09:42.040]Okay, but some of that data I wanna share from that study.
[00:09:47.840]So that was kind of a background in that study,
[00:09:51.950]but I want to show that that nitrogen fertilization,
[00:09:54.970]why as you would expect, right?
[00:09:56.350]It makes a big difference
[00:09:57.518]on that's amount of herbage that accumulates.
[00:10:00.910]And so I'm showing a chart here with either
[00:10:04.390]in that I said 70% by June.
[00:10:09.500]So and you can see, I get that in mega grams per hectare
[00:10:13.760]but 7.49 there by June,
[00:10:16.470]compared to unfertilized fertilization.
[00:10:19.200]So about 35% more forage by June,
[00:10:24.930]as I demonstrated with that picture, with that,
[00:10:27.291]it was around that time.
[00:10:29.420]After that, so new growth after that,
[00:10:32.020]there's still continue some growth,
[00:10:34.660]but you could see the drop-off in production
[00:10:37.270]across the summer period,
[00:10:38.716]and then measured there
[00:10:40.010]at the end of the growing season in October.
[00:10:42.880]Really no difference there between unfertilized
[00:10:45.480]and nitrogen fertilized.
[00:10:48.000]Again, that's at 90.
[00:10:49.010]Recommended rate for Eastern Nebraska
[00:10:52.290]is 90 kilograms per hectare.
[00:10:56.120]Again, I pointed out on the previous slide,
[00:10:58.200]the lower production values.
[00:10:59.840]They estimate there
[00:11:03.230]with that NRCS about 2.25,
[00:11:05.840]a little bit less than October as well.
[00:11:10.300]Okay, but why some of what we found in our research
[00:11:16.280]says really quite interesting
[00:11:19.550]that I find about these intensive management systems
[00:11:22.660]is without that fertilization, what we see,
[00:11:27.880]what we see at Mead and ENREC,
[00:11:30.140]you get a lot more weeds,
[00:11:31.720]and you get, particularly Foxtail is the big one,
[00:11:35.380]a lot of annual.
[00:11:36.880]So that's annual warm season grasses
[00:11:39.820]just coming up from the seed bank.
[00:11:41.500]And we, I'm just showing this how we measure it
[00:11:44.920]is just different sampling frames
[00:11:47.310]where we use a visual observation
[00:11:50.060]and that's measured at a foot squared
[00:11:54.440]or 0.1 meter squared scale.
[00:11:58.677]So foxtail's the big one,
[00:12:01.560]but you get some forbs as well.
[00:12:03.150]Like Canadian horseweed is some of that forbs, but okay.
[00:12:10.550]But overall you can see in the red bars,
[00:12:13.530]all the weeding is total annuals compared to the fertilized
[00:12:17.740]quite a bit less.
[00:12:21.510]Okay, so other components.
[00:12:23.060]And in part what that,
[00:12:24.630]so we have more herbage accumulation.
[00:12:26.987]The graph I showed with herbage accumulation,
[00:12:29.530]that's measured in the absence of grazing.
[00:12:32.210]So what we have here is herbage mass.
[00:12:35.037]And so herbage mass would be what's available
[00:12:37.410]at any specific point in time.
[00:12:39.670]This would be the average herbage mass in the pasture.
[00:12:43.290]And again, you do,
[00:12:44.970]even though they're managing for similar target heights,
[00:12:49.170]you're getting more, on a general,
[00:12:51.180]you have more herbage here
[00:12:53.170]under that nitrogen fertilizer condition
[00:12:55.353]compared to the unfertilized.
[00:12:58.240]And then that also impacts,
[00:13:00.710]start to impact on the soil,
[00:13:03.620]see more litter
[00:13:04.520]because what happened leaves or dying,
[00:13:07.040]getting trampled on either (indistinct),
[00:13:10.110]they follow the soil.
[00:13:11.300]So you get more litter there in the fertilized
[00:13:15.170]compared to unfertilized.
[00:13:18.590]And that would contribute to where you see this weedyness
[00:13:21.650]that litter probably suppressed some of that,
[00:13:23.840]those annual weeds from coming up.
[00:13:25.420]So that would tie into that.
[00:13:27.920]And then just showing the last line,
[00:13:29.660]just some of the data we measured and showing that the rates
[00:13:35.044]that litters, that leaves are falling
[00:13:38.010]to the surface is greater under that fertilized.
[00:13:44.060]Other components below ground
[00:13:45.790]that starts when we start thinking about,
[00:13:48.885]I think about soil, soil ecosystem services.
[00:13:53.240]So need to look below ground,
[00:13:55.130]and what we've seen,
[00:13:56.640]one, the fertilized they're more productive,
[00:13:59.640]not just above ground, but below ground.
[00:14:02.070]This is measured at a zero to 15 centimeter depth.
[00:14:06.050]The total mass of roots and rhizomes
[00:14:11.610]in the pasture straighter under the fertilized,
[00:14:15.210]compared to the unfertilized.
[00:14:18.010]We also looked at a lot of sampling and some of the data.
[00:14:20.870]We published it
[00:14:22.490]over this few years back is particulate organic matter.
[00:14:27.340]We looked at carbon and nitrogen
[00:14:29.150]and these different fractions
[00:14:33.716]of those different pom fractions that course or fine.
[00:14:38.650]And then at different soil levels, but not to get,
[00:14:42.110]I didn't want to spend too much time on the table
[00:14:43.970]cause basically we didn't see any differences.
[00:14:46.870]No changes in the soil in the study
[00:14:53.900]due fertilization management.
[00:15:00.030]So that's a little bit emphasizing the importance
[00:15:01.047]of nitrogen fertilization.
[00:15:05.830]Other studies that I've been working on a lot is
[00:15:08.470]what we've addressed at Mead is how about legumes.
[00:15:13.040]So what about alternatives to fertilization?
[00:15:16.840]We would recommend interseeding legumes.
[00:15:21.290]And so some of those of you less familiar
[00:15:25.750]with those legumes.
[00:15:26.730]What are we talking about?
[00:15:27.860]We're talking about a lot of times,
[00:15:28.858]we're talking about alfalfa here
[00:15:30.630]in the upper upper left, red clover, other one.
[00:15:36.070]Also use a lot of birdsfoot trefoil in Eastern Nebraska.
[00:15:39.660]And we probably don't see any white clover,
[00:15:42.470]but generally a lot of times you'll find
[00:15:44.751]in permanent pastures, often see white clover
[00:15:48.020]as a common legume in pastures.
[00:15:53.633]But in some of our studies, a graduate student,
[00:15:56.360]Brad Chick, led this work.
[00:15:59.190]I didn't put all the citations up on all those studies,
[00:16:00.131]took some of that off,
[00:16:03.380]but he did a study where he looked at, well,
[00:16:06.670]we had ruminate,
[00:16:11.350]ruminately (indistinct) animals and we sampled,
[00:16:14.040]he sampled diets.
[00:16:15.150]And what's the diet and looked at dietary nutritive value
[00:16:18.230]of legume, interseeded,
[00:16:20.800]or legume mixed grass versus just nitrogen fertilizer grass.
[00:16:26.679]And so some of the data that he showed is,
[00:16:31.150]I got two different data points
[00:16:34.407]going on here, but in the blue bars,
[00:16:38.310]that's crude protein levels.
[00:16:40.500]So really there was no difference he saw in crude protein.
[00:16:42.392]These are diets samples.
[00:16:45.200]Samples of what they're eating and basically
[00:16:47.650]about that's on a concentration basis,
[00:16:50.360]but about 15, 16% crude protein,
[00:16:54.490]generally of diets of cattle grazing the legume-interseeded
[00:17:00.330]as well as nitrogen fertilized pasture.
[00:17:03.610]But what you see, particularly with legumes,
[00:17:07.490]the legume component is adding.
[00:17:11.660]What you see is shown here on the green line.
[00:17:14.430]This is neutral detergent fiber,
[00:17:16.710]and that's all shown on the secondary Y axis there.
[00:17:21.840]You saw what he found is you have an increase
[00:17:24.860]in amount of NDF
[00:17:26.040]that those animals are consuming.
[00:17:28.280]So NDF refers to that component of that plant material
[00:17:35.860]that's not soluble in a neutral detergent solution,
[00:17:40.350]and it's related to,
[00:17:42.700]it affects intake.
[00:17:44.720]So it's related to the more NDF in an animal's diet,
[00:17:51.380]the less they can take in, the less they can eat.
[00:17:54.000]They get too full from more fiber.
[00:17:57.210]And that's basically,
[00:17:58.200]that's your cell wall components,
[00:18:00.240]cellulose and MI cellulose,
[00:18:02.370]and lignin is part of that.
[00:18:05.047]So animals can eat more so that what,
[00:18:12.040]okay, so that they can eat more and then gain better weight.
[00:18:18.290]But Brad also did a lot of studies on dung.
[00:18:21.460]And to tie, okay so,
[00:18:23.270]if they're eating well,
[00:18:24.610]you got better quality diets and under fertilized,
[00:18:28.940]or under the legume-interseeded pasture,
[00:18:31.040]does that relate back to nutrient cycling in the pasture
[00:18:34.410]and changes in soil?
[00:18:37.725]And Brad had a lot of data that publish on that.
[00:18:40.560]But he looked at, so he did a lot
[00:18:41.621]of sampling of fresh dung early morning.
[00:18:45.460]His sample was out in the pasture sampled early morning.
[00:18:50.010]Had big crews of students that helped contribute
[00:18:52.602]to this cause they had to sample a lot of dung,
[00:18:57.302]but what they found,
[00:18:59.150]just kind of highlighting some
[00:19:00.790]of the dung quality differences.
[00:19:04.370]And so in this study,
[00:19:05.900]they also sampled unfertilized pastures,
[00:19:10.340]but showing kind of the first column there, dry matter.
[00:19:13.921]And that's the amount of,
[00:19:14.754]so indicating about 14, 15% dry matter.
[00:19:18.640]So 80, 85% would be water right or moisture.
[00:19:25.960]But what you see legume-interseeded is that actually
[00:19:29.850]tying in with,
[00:19:31.730]is actually saw a little bit higher nitrogen levels of,
[00:19:39.027]and so this would be,
[00:19:40.600]I don't have the units be grams per kilogram, right?
[00:19:44.950]Yeah, that'd be grams per kilogram of nitrogen.
[00:19:49.850]So that'd be points 0.02% or so,
[00:19:53.940]was 0.02, three, 4%.
[00:19:57.660]So when you see greater nitrogen concentrations
[00:20:00.210]in that dung of legume-interseeded pastures
[00:20:03.410]compared to the fertilized or the unfertilized,
[00:20:08.380]and then you see a reduction
[00:20:09.710]in the carbon to nitrogen ratio.
[00:20:14.770]Okay so, and then from, from Brad's study,
[00:20:17.270]he did a lot of different,
[00:20:18.320]interesting things that looked at all the changes in soil.
[00:20:22.010]Basically carbon and nitrogen leaching from that dung
[00:20:26.450]or moving into soil also had some rings
[00:20:29.530]in the dung pats,
[00:20:31.140]placed a lot of dung pats to evaluate
[00:20:34.160]how the dung
[00:20:34.993]from those different diets
[00:20:36.630]translated back into facts on soil,
[00:20:39.940]in nitrogen cycling.
[00:20:41.810]And then also,
[00:20:42.980]the rings there measured CO2 respiration from those.
[00:20:47.590]I'm not going to share all that data,
[00:20:50.211]but just found that the legume-interseeded is speeding
[00:20:53.340]up nitrogen cycling, which in part,
[00:20:58.000]it relates to the ability of that forage to move
[00:21:01.530]through that animal as well.
[00:21:03.820]And so having, we would take that
[00:21:07.980]as having a positive effect on pasture,
[00:21:10.880]so improving, right.
[00:21:12.810]Increasing the production and quality of those pastures.
[00:21:18.713]So, and then ultimately having that mixed diverse system
[00:21:24.110]of grasses and legumes results
[00:21:27.010]in better animal gains on those pastures.
[00:21:37.193]So the last component I was going to talk about some
[00:21:38.367]of the newer research I've been working on and
[00:21:41.729]that's interseeding annual warm-season grasses
[00:21:48.920]And part of why this study came about is,
[00:21:52.810]is we've seen declines in well pasture acres.
[00:21:57.420]And so how do we, if there's declines in pasture acres,
[00:22:01.990]decreasing pastureland, increasing rental rates,
[00:22:05.120]increasing pastureal land values,
[00:22:08.380]the challenge is how do we get more?
[00:22:10.427]Can we get more production out of that?
[00:22:12.480]So we worked on a study.
[00:22:17.160]This is a multi location study.
[00:22:21.220]We had five locations in Nebraska
[00:22:23.600]or three locations in Nebraska
[00:22:25.650]and two locations in Kansas,
[00:22:28.322]part of a multi-state research project.
[00:22:31.610]We did it from 2015 through 2017.
[00:22:37.270]The perennial grasses,
[00:22:38.660]the base pasture and smooth bromegrass in Eastern Nebraska,
[00:22:42.080]as well as west central research
[00:22:45.520]and education center there at North Platte.
[00:22:49.940]Also smooth bromegrass at Sydney at the High Plains ag lab.
[00:22:56.500]They were the base pasture was crested wheat grass,
[00:23:02.824]and then at Hays, Kansas.
[00:23:04.140]We had Western wheat grass pasture,
[00:23:06.280]and in Southeastern Kansas and Mount Valley
[00:23:11.290]over near Parsons,
[00:23:12.298]they have a research center there.
[00:23:14.430]They had their base pastures tall fescue.
[00:23:18.790]Okay, in this study, in those studies.
[00:23:25.380]So I'm just showing a picture for me here
[00:23:26.721]and showing smooth brome grass.
[00:23:29.771]But in this study, we're looking at, okay,
[00:23:31.100]so how do you do this?
[00:23:32.000]How do you intercede more annual warm season grasses?
[00:23:34.940]How should we manage?
[00:23:36.186]How should we manage this?
[00:23:38.220]And so in these experiments,
[00:23:40.040]we waited until flowering of all the cool season grasses
[00:23:43.520]in the spring, and then we harvested them.
[00:23:46.650]So that gives you an idea of our study site.
[00:23:51.240]And then from there, we went in and drilled.
[00:23:53.800]We drilled seed into the stubble of that remaining grass.
[00:23:57.850]And so at the start of the experiment,
[00:24:02.150]we're concerned about competition.
[00:24:03.760]That's a big factor.
[00:24:05.513]You're seeding an annual into a perennial grass system.
[00:24:07.940]What about regrow of the cool season grass?
[00:24:11.020]Is that going to suppress?
[00:24:13.200]Is that gonna limit your establishment sorghum Sudan?
[00:24:15.910]So we'd cut the short,
[00:24:17.794]we'd cut it at one to two inch height, but in part we timed.
[00:24:24.560]So up to that point,
[00:24:26.090]none of that cool season grass was grazed or harvested.
[00:24:31.930]So we allowed,
[00:24:33.280]so that grass would get into flowering where it's elongated.
[00:24:36.890]So to reduce its amount of regrow that had produced.
[00:24:43.553]Okay, so giving you a little bit of an idea.
[00:24:44.770]And then we drilled the seed in the soil.
[00:24:47.110]Just kind of indicating right about there.
[00:24:49.960]The drill that we had was a great plains drill.
[00:24:53.910]It had about,
[00:24:54.743]In the upper right picture there,
[00:24:58.240]just indicating a seven and a half inch row spacing.
[00:25:02.370]And then we targeted to get that seed down
[00:25:07.333]into the soil.
[00:25:09.430]So we varied the seeding depth.
[00:25:11.670]We, depending on the species
[00:25:16.430]and it's recommended depth, seeding depths.
[00:25:20.750]And then again, I pointing out here that short,
[00:25:23.470]short stubble height of seeding into,
[00:25:30.260]but here's what we found.
[00:25:32.060]Some of our results just showing, tend to show more pictures
[00:25:35.600]than data here on some of these.
[00:25:37.050]But so we had six in this study not to go
[00:25:42.480]through all the treatments,
[00:25:43.960]but we had six different warm season grass types,
[00:25:47.150]including a non seeded control that you can make out,
[00:25:50.730]the non-seeded here right in that lower right picture.
[00:25:55.570]But we had sorghum Sudan grass.
[00:25:58.420]We had forage sorghum sudan grass.
[00:26:01.460]We even had corn in one of these.
[00:26:04.550]And then we had a pro millet was the other, so,
[00:26:08.010]and then we had two different harvest treatments
[00:26:10.060]where we harvested either both
[00:26:12.320]at 45 and 90 days after, after planting, or we had just,
[00:26:20.100]what if we allow that biomass to accumulate,
[00:26:22.570]we just harvest at 90 days.
[00:26:25.690]And so gives you some idea.
[00:26:28.640]Well, this was kind of an anomaly in one year
[00:26:32.420]shown in one of the pictures.
[00:26:33.990]We treated two years in a row
[00:26:35.710]on different areas within the same field,
[00:26:41.520]but it shows you the amount of the biomass that we're able
[00:26:44.450]to produce just in,
[00:26:46.020]this is just showing outside of the plot here,
[00:26:49.019]and it would be interesting.
[00:26:51.870]This looks like bromegrass regrow,
[00:26:53.920]but a lot of it's that Foxtail that I pointed out was
[00:26:57.580]particularly came in
[00:26:58.760]because how we managed the treatment was
[00:27:02.040]to get more success.
[00:27:03.253]We didn't fertilize in the spring to start with.
[00:27:07.690]So we fertilized after the annual warm season grass emerged,
[00:27:14.690]which is an interesting side note
[00:27:17.578]that I don't have the data to show you,
[00:27:19.370]but what we're observing then is that in other studies,
[00:27:24.500]we've since followed up
[00:27:25.840]that the timing of nitrogen fertilization
[00:27:28.250]doesn't affect the success of sorghum at all.
[00:27:32.860]Even though we're trying to apply it
[00:27:35.040]after sorghum has emerged in it.
[00:27:39.590]We find, okay,
[00:27:40.640]if we put in fertilization in summer,
[00:27:43.880]what do you think we don't want to enhance brome grass.
[00:27:46.910]We just enhance more Foxtail,
[00:27:48.910]which ties into some of that earlier pasture work
[00:27:51.930]I was sharing, but well,
[00:27:54.180]it gives you idea that we would harvest there at 45 days.
[00:27:58.510]Or if you wait,
[00:28:00.830]you don't harvest at 45 days and allow it to accumulate.
[00:28:03.960]At 90 days,
[00:28:05.440]we had a lot of productivity,
[00:28:07.678]and sorghum Sudan grass was particularly
[00:28:10.591]the most productive,
[00:28:12.990]but even purple millet did well,
[00:28:16.130]just highlighting a couple of the crew with some
[00:28:18.240]of the students there.
[00:28:19.770]Brad Schick was involved, Josiah Dolman,
[00:28:22.000]and then my brother was also up there and helped me
[00:28:24.140]out a lot on these experiments.
[00:28:29.530]But for this is growing this in a pasture right,
[00:28:33.187]you know, this not in a crop field,
[00:28:36.010]but growing within existing pasture.
[00:28:38.860]And so what we found and we published this data,
[00:28:44.620]it really increases the amount of forage
[00:28:46.700]that we produced during summer.
[00:28:49.583]These are the average yields across the five locations
[00:28:52.803]that we studied in those in Kansas, not all,
[00:28:56.070]not all were as productive as we,
[00:28:58.780]that was, that site basically
[00:29:02.250]where we found most success was
[00:29:04.050]at Mead with bromegrass.
[00:29:06.883]And we saw it also in interesting and Hays, Kansas.
[00:29:10.909]Colleague, Keith Harmony, there at Hays,
[00:29:14.510]Kansas has a lot of success doing this
[00:29:15.435]in Western wheat grass pasture,
[00:29:19.740]and then also saw success in Southeast Kansas
[00:29:23.100]and tall fescue.
[00:29:25.100]But here's the average data and showing the blue bars are
[00:29:28.780]if you just harvest it once 90 days after seeding.
[00:29:31.550]That's where you're going to really allow
[00:29:32.638]that the growing degree days and the heat units,
[00:29:36.957]and allow that sorghum to keep right on photosynthesizing
[00:29:42.050]and keep producing growth.
[00:29:43.630]And so that does best.
[00:29:45.650]And what you see forage sorghum, not a lot of differences,
[00:29:48.710]a little bit.
[00:29:49.543]Forage sorghum sudan grass or sorghum sudan grass types.
[00:29:54.790]Generally we use sorghum Sudan a lot and in further studies,
[00:29:59.885]but you could see the unseeded control
[00:30:02.442]limited growth in summer.
[00:30:05.890]And then you also see it if you harvest it twice.
[00:30:09.620]So if you don't get as much forage accumulation there,
[00:30:13.310]but improves the nutrient value or the quality of say,
[00:30:16.278]if you're going to utilize it,
[00:30:17.625]maybe under a grazing system.
[00:30:21.760]Also saw those also differ from that unseeded.
[00:30:29.380]Okay so from following up on that, we were wondering
[00:30:32.270]okay so that was a plot study.
[00:30:34.170]So what about, can we do this while we got cattle present?
[00:30:37.920]Can we do this in an actual pasture?
[00:30:39.900]So that's where we've been trying to work on it, but okay.
[00:30:45.710]So following, I'd say,
[00:30:47.990]but before I introduced that, but so how do we do that?
[00:30:51.417]And so we did this, we have pastures
[00:30:54.470]that meet, and we have 12 pastures.
[00:30:58.324]And then in each, each of those 12,
[00:31:02.890]they consist of six paddocks that are rotationally stocked.
[00:31:06.630]So animals aren't just camped out on the full pasture.
[00:31:11.030]They're segmented into six different groups
[00:31:14.980]or six different blocks that they rotate through,
[00:31:17.990]which we call paddocks.
[00:31:20.860]But within those, we had seeded in unseeded halves.
[00:31:26.290]Now we didn't see the whole,
[00:31:30.157]all six paddocks don't get seeded.
[00:31:32.100]So every other year we rotate
[00:31:34.890]at which we've seeded two each year.
[00:31:37.117]And so after three years, all six would've been interseeded.
[00:31:40.890]We had all six of those paddocks
[00:31:44.070]would have been interseeded.
[00:31:45.510]And then for comparison wise,
[00:31:47.840]we had unseeded, the unseeded half.
[00:31:50.290]So if we didn't seed,
[00:31:53.560]and then we had,
[00:31:54.533]so if you had to interseeded and unseeded halves,
[00:31:58.190]you had four of them.
[00:31:59.330]We didn't take vegetation data on,
[00:32:01.690]but they're part of a grazing and part of the rotation.
[00:32:06.770]And then they're rotationally stocked
[00:32:08.820]or rotationally grazed.
[00:32:10.920]So the cattle go back on these five times a year,
[00:32:14.860]roughly four to six, depending on weather conditions.
[00:32:17.300]But generally we get five cycles of grazing each year.
[00:32:22.187]How do we do that?
[00:32:23.020]So I showed the plot study where we were harvesting
[00:32:25.850]the grass at a one to two inch height.
[00:32:28.210]Well, that's hard to do when you have animals
[00:32:32.800]within the system.
[00:32:33.670]We're probably not big enough.
[00:32:34.630]Maybe you could do it from a hay equipment
[00:32:36.900]that would approve it if you basically essentially,
[00:32:39.740]hay, but we tried to do this with just grazing.
[00:32:41.960]Can we heavily graze in the first two cycles of the year?
[00:32:46.900]So when animals first go on the pastures in late April,
[00:32:51.100]and then they rotate through all six paddocks and then come
[00:32:54.260]back 30 days later and camp animals on there again,
[00:32:59.230]and graze it tight.
[00:33:01.313]So that gives you an idea though.
[00:33:02.560]It looks a little different than that field plot study.
[00:33:05.710]And then after that second cycle, we're interseeding in,
[00:33:09.160]we'd use sorghum sudan grass, but you can,
[00:33:12.770]you can kind of make it out, right.
[00:33:14.640]Doesn't look near as good as the plot study.
[00:33:17.360]So in terms of our effectiveness ability
[00:33:21.770]to get that sorghum established
[00:33:23.640]has been a bit more of a challenge,
[00:33:27.020]but then within the context of that grazing system,
[00:33:30.619]we are allowing it to grow, right?
[00:33:32.820]Just like the plot study,
[00:33:33.980]we're allowing it to grow at least 45 days.
[00:33:36.780]So here cattle would be
[00:33:38.550]in those four non experimental paddocks.
[00:33:41.930]They'd be grazing there,
[00:33:43.277]and we're allowing the two experimental paddocks
[00:33:46.790]to rest and allow that sorghum here,
[00:33:49.890]you can make out little, little bits of it here to grow up.
[00:33:56.258]And then by cycles four and five, we get mass.
[00:34:00.760]We have sorghum sudan grass coming up.
[00:34:03.790]Cattle come in during that time.
[00:34:05.849]We graze it.
[00:34:07.965]So not to get deep into the data, but what, what we saw.
[00:34:13.860]So we have three years of data here that varied quite a bit
[00:34:16.900]from year to year,
[00:34:18.180]weather conditions had some effects.
[00:34:21.020]There's 2017, 2018 was our best year,
[00:34:24.197]and 2019 was poor.
[00:34:26.820]But basically we saw significant effect though,
[00:34:33.030]of well, particularly the cycle.
[00:34:34.910]So after cycle two, there's none.
[00:34:36.660]Cause that's when we're seeding it.
[00:34:38.020]But you see a cycle times,
[00:34:40.710]year by cycle interaction here,
[00:34:43.560]by cycle foue when they first come on,
[00:34:46.255]there's not a lot yet,
[00:34:48.110]but by cycle five that keeps growing.
[00:34:50.160]So that sorghum sorghum keeps going,
[00:34:53.940]but it's still a little bit limited
[00:34:55.251]on production, a thousand.
[00:34:57.303]I mean, at best,
[00:34:59.160]we're up here 500 to a thousand kilograms
[00:35:02.326]per hectare of mass.
[00:35:05.064]So, that leads us to where are we going
[00:35:10.030]and where a lot of our follow-up studies,
[00:35:12.109]I mentioned the nitrogen rate,
[00:35:13.896]we're wondering about, okay, how's nitrogen rate and timing?
[00:35:17.530]How is that affecting sorghum sudangrass success?
[00:35:21.490]So we've explored a little bit that
[00:35:23.903]in some of our more recent research,
[00:35:28.420]but really focused on how do we improve
[00:35:30.300]the establishment of this.
[00:35:33.560]And then, I mean, just what we see.
[00:35:35.692]I mean, just to point under that pasture system,
[00:35:40.650]you have a lot of production
[00:35:43.383]from that brome grass grew up in summer.
[00:35:46.700]So that rotational grazing seems to favor that brome grass.
[00:35:50.270]And so you get good regrow from it.
[00:35:56.410]But some of our newer studies.
[00:35:58.848]This is led by Heidi Hillhouse and Presana.
[00:36:04.330]They're been leading this work
[00:36:08.690]out at, and reckon,
[00:36:09.930]so valuating different herbicide
[00:36:12.660]or herbicide rate really essentially,
[00:36:15.747]what if we spray this first?
[00:36:17.260]What if we spray to suppress that brome grass?
[00:36:20.750]And we've, where they're finding positive,
[00:36:23.710]as we'd hypothesized, suppressing bromegrass,
[00:36:29.845]and the more rate more herbicide you use,
[00:36:32.680]generally get good responses of sorghum.
[00:36:36.880]And of course,
[00:36:38.295]it's all just stocked there because that cattle hit it.
[00:36:42.090]They ate it up, so highly digestible forage, so okay.
[00:36:53.720]So looking at that, the problem with using an herbicde,
[00:36:58.870]we're not trying to convert this
[00:37:02.980]to an annual system, but using an herbicide
[00:37:08.240]or do we kill the bromegrass?
[00:37:10.707]We want the brown grass to come back.
[00:37:11.610]And so in our plot studies where just by harvesting
[00:37:12.778]and growing sorghum sudan grass,
[00:37:19.720]we harvest by September.
[00:37:21.400]We got a good amount of days left of growing
[00:37:24.030]for bromegrass to recover.
[00:37:25.860]And then the next year we're not seeding the same field.
[00:37:28.630]Again, that's the next year's growth on brome grass.
[00:37:32.250]So we fertilize, again,
[00:37:34.100]back in spring at the recommended rate,
[00:37:36.070]you kind of make out the plots here,
[00:37:38.870]solid stand a smooth brome grass.
[00:37:40.810]So we're not seeing any lasting effects of doing that
[00:37:43.780]on the brome from the pasture.
[00:37:49.681]So what, are we finding?
[00:37:55.510]Just to summarize up those studies and kind of
[00:37:57.730]what we're thinking,
[00:37:58.610]what we see and what I would recommend.
[00:38:01.379]So nitrogen-fertilized pastures.
[00:38:03.470]I mean, they're going to support greater litter,
[00:38:06.886]greater herbage, litter.
[00:38:07.940]And then that live below ground mass
[00:38:10.620]than unfertilized pastures.
[00:38:13.500]Unfertilized pastures contain more annual weeds,
[00:38:18.280]but interseeding legumes,
[00:38:19.760]that's an alternative to fertilization,
[00:38:22.900]enhances nutritive value,
[00:38:25.000]nitrogen cycling and animal weight gains.
[00:38:31.760]But we've to really, to try to enhance that further,
[00:38:35.740]we see that in, we're seeing positive effects
[00:38:39.055]of any warm season grasses in Nebraska,
[00:38:43.200]particularly sorghum sudangrass can be a strategy
[00:38:46.601]to increase that summer forage, but we're limited.
[00:38:52.820]We need better methods to get better establishment.
[00:38:57.660]So generally I would end by just saying
[00:39:01.490]these intensively managed brome grass pastures
[00:39:05.170]are best managed either as nitrogen fertilizer
[00:39:07.670]legume grass pastures
[00:39:09.570]without the interseeding at this time.
[00:39:14.830]So my last little bit here,
[00:39:16.330]just point out a couple of things,
[00:39:17.800]just kind of going tying back to them a little bit
[00:39:20.240]about my philosophy.
[00:39:21.890]I always wonder, right?
[00:39:23.070]These are intensively managed systems in part, right.
[00:39:27.030]Producers have to pay the rent or the taxes on the value.
[00:39:32.690]Rob Mitchell talked about that earlier this week,
[00:39:35.230]and that's something that takes away, right.
[00:39:36.980]It's gotta be productive for, I mean,
[00:39:40.770]the producers have to pay that.
[00:39:42.790]So the land value or the taxes or the rent,
[00:39:46.410]but I wonder, thinking beyond just production, right.
[00:39:52.070]You know, what if we reduce, can we reduce,
[00:39:56.460]can we reduce that stocking rate?
[00:39:57.910]Do we have to utilize them quite as intense?
[00:40:02.090]And I wonder about that.
[00:40:03.170]What if we left, right?
[00:40:04.190]Instead of going down to 10 centimeters,
[00:40:06.370]can we leave a little bit more, more mass?
[00:40:09.925]One thing that we find in those animals gain studies,
[00:40:13.990]they don't do great during summer.
[00:40:15.750]Most of their weight gains are during spring, spring time.
[00:40:20.710]So could we reduce that a little bit in summer and then,
[00:40:25.660]but what are the trade offs?
[00:40:26.980]I mean, how are they going to affect cattle weight gains,
[00:40:30.750]the plant composition,
[00:40:32.910]as well as some thinking about going back to soil, right?
[00:40:38.090]And tying it to some of the bigger,
[00:40:40.160]bigger issues and ecosystem services,
[00:40:42.817]maybe relating that to climate change
[00:40:43.650]is building soil carbon and nitrogen.
[00:40:48.480]Can, could we all,
[00:40:50.170]what are the trade-offs with that?
[00:40:51.620]So to me,
[00:40:52.560]that's kind of an important question.
[00:40:55.400]And then the other tied into maybe some of the research.
[00:41:00.210]Now I'm starting to work on,
[00:41:01.043]what about even on annual grass pastures
[00:41:05.260]and thinking about annual systems,
[00:41:07.290]thinking about crops, you know,
[00:41:09.930]how does having more perennials where I recommend, right?
[00:41:14.900]I want to see more perennial grasslands be expanded,
[00:41:18.100]but what do they do to things like ecosystem services?
[00:41:23.840]You know, if we're putting perennial grass on the landscape,
[00:41:27.830]how that, and even interacting
[00:41:30.930]or changing management intensity, how does that,
[00:41:34.410]how does it affect these components?
[00:41:39.040]Okay, so last,
[00:41:40.100]I just want to acknowledge we get a lot of funding support.
[00:41:43.280]That's support from the Nebraska
[00:41:44.980]agricultural experiment station.
[00:41:47.410]And then multi-state fronting from two projects,
[00:41:50.570]NC1181 and 80 NC1182 in the USDA.
[00:41:58.300]Now do you have any questions?
[00:42:03.350]John this is really fascinating work.
[00:42:05.990]And as I said before,
[00:42:07.750]you started kind of way back in pasture management,
[00:42:14.481]but some of your conclusions,
[00:42:18.660]especially relating to perennials
[00:42:21.160]and perhaps expanding perennial systems,
[00:42:26.752]seems like that's back to nature, so to speak.
[00:42:32.040]Would you think that it would be feasible in the future
[00:42:36.380]to expand perennial grasslands
[00:42:39.880]and stock with bison as opposed to cattle?
[00:42:46.700]I know that's off target, but.
[00:42:49.290]Yeah, I'm not sure, okay,
[00:42:52.590]if I'm supposed to repeat the question,
[00:42:54.400]but should, can we expand perennial grass and use bison?
[00:42:59.270]I suppose I would say there's marginal areas for,
[00:43:07.120]it's kind of a two-part question.
[00:43:08.440]There's marginal areas of crop land
[00:43:10.680]that could be particularly
[00:43:12.950]where perennial grass could be expanded.
[00:43:17.980]There's people growing bison
[00:43:19.630]in the Sandhills and rains lands.
[00:43:22.140]So I just figure probably a bigger management challenge,
[00:43:26.840]and then you have to have a market for it too.
[00:43:31.460]So that's the important aspect.
[00:43:33.580]So, but I don't see why there's, it can't be done.
[00:43:39.070]So I think (indistinct) are great.
[00:43:42.207]Bison, cattle, goats, sheep.
[00:43:45.460]I didn't want to throw in a slide
[00:43:46.535]for every pretty animal there.
[00:43:48.500]So, but I was thinking that right, eat well, right.
[00:43:52.610]Or dairy cattle are tied in and not even eating meat,
[00:43:57.370]but dairy are ruminants.
[00:44:00.170]I think that's my philosophy.
[00:44:03.130]I liked your philosophical statements.
[00:44:19.010]Thank you, John, for a great seminar.
[00:44:24.930]My question relates to your fertilized pasture, right?
[00:44:31.030]And there's a lot of discussion around water quality
[00:44:34.670]and nitrogen below the root zone.
[00:44:38.550]Have you considered or looked at nitrogen budget
[00:44:45.350]in the legume versus fertilize system?
[00:44:49.640]It seems like the legume interseeding could be robust.
[00:44:56.690]That's a good question, Martha, about nitrogen budget.
[00:45:00.784]We documented that like about the inputs
[00:45:04.940]in the fertilized versus the nitrogen
[00:45:08.090]in that first part of that first study,
[00:45:10.590]I talked about some of the, when I,
[00:45:16.310]I joined and when I came on at UNL,
[00:45:18.480]we had some graduate students,
[00:45:20.300]and they published a little bit of work on that
[00:45:23.337]with the nitrogen versus the unfertilized,
[00:45:26.220]and then they had another treatment
[00:45:27.910]where they're supplementing with distillers grains.
[00:45:30.660]I left that out from the study,
[00:45:32.750]but now we haven't done that with the legume question.
[00:45:41.020]I mean, we're not adding any in.
[00:45:43.190]Now, I don't know about leaching.
[00:45:45.760]We, you know, what we hear is that in those soils,
[00:45:49.890]you're not getting leaching
[00:45:51.740]from pasture environment.
[00:45:53.530]On thinking about water quality from that standpoint.
[00:46:02.080]But I mean, right, Martha,
[00:46:03.750]you were part of the dung study.
[00:46:05.360]And so, you know, that that data
[00:46:08.490]from the movement of nitrate from say dung patties there,
[00:46:14.257]what would have been, there was more movement
[00:46:18.216]from that dung, with the higher quality dung
[00:46:21.808]than the nitrogen fertilized dung.
[00:46:24.330]So, but there's more,
[00:46:28.910]there's probably more research questions.
[00:46:31.100]These are long-term studies that I would think
[00:46:36.100]that there's a lot of unknowns that,
[00:46:39.307]and you go beyond my head.
[00:46:41.370]I mean, where people with soil expertise
[00:46:44.390]could add to some of this research.
[00:46:51.643]I have a question online
[00:46:52.730]from Tom Hoganmeyer, and he asked,
[00:46:55.990]there are lots of brome pastures on Bluffs
[00:46:56.823]and other steeply sloping sites in Eastern Nebraska.
[00:47:02.400]Do you have suggestions on how to revegetate
[00:47:05.360]with perennial native grasses?
[00:47:15.830]So how do I,
[00:47:16.710]how do we change that from an annual brome system?
[00:47:21.610]Well one you'd have to reduce the,
[00:47:24.800]you'd have to reduce the grazing intensity first.
[00:47:28.210]You could use fire.
[00:47:35.393]That's another component you could use,
[00:47:36.610]the burning cool season grass in spring.
[00:47:39.870]If you have a buildup of plant matter,
[00:47:43.690]that can be a challenge.
[00:47:47.100]The other is,
[00:47:48.870]but you'd have to seed it unless they're present,
[00:47:51.450]unless you would have to seed it.
[00:47:52.990]You'd have to seed
[00:47:53.823]into those cool seasons to enhance warm season grasses.
[00:48:01.180]Graze them intensively during spring.
[00:48:03.600]That's how you reduce cool season grasses,
[00:48:05.750]graze them intensively in spring.
[00:48:07.710]Then rest during summer.
[00:48:09.040]Don't graze during summer
[00:48:09.873]because you're going to need, you have a warm, perennial,
[00:48:12.530]warm season component.
[00:48:13.600]You need time to allow it to grow without being bit off
[00:48:17.680]every little bit.
[00:48:18.550]So that's how you need to shift that competition.
[00:48:22.700]So shift that competition.
[00:48:25.220]Change your grazing.
[00:48:26.230]So avoid grazing during summer,
[00:48:27.900]that's probably the best thing you can do
[00:48:28.842]to enhance perennial warm season grass.
[00:48:31.760]So I hope that answers part of it.
[00:48:38.920]Good question outside of my talk.
[00:48:42.470]Okay, if there's no further question,
[00:48:45.030]thank you everybody for joining today's seminar,
[00:48:47.440]and thank you, John, for a great presentation.
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