2021 Nebraska Cover Crop and Soil Health Conference - Andrea Basche

Deloris Pittman Author

03/25/2021 Added

28 Plays

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Using Aerial Imagery to Determine Cover Crop Impacts on Cash Crop Growth and Development - Dr. Andrea Basche, Assistant Professor, Agronomy & Horticulture University of Nebraska-Lincoln

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[00:00:00.030][music].
[00:00:23.480]So, yeah,
[00:00:24.350]great presentations from Becca and Chad and some really good information
[00:00:27.260]about economics and herbicides and just some, some good numbers there.
[00:00:31.340]And I hope to give you some more information about, you know,
[00:00:35.690]kind of some preliminary work that we're doing to use imagery,
[00:00:39.200]to tell us more than just end of season impacts of cover crops on
[00:00:44.180]our cash crops. And so my name is Andrea Basche.
[00:00:46.330]I am an assistant professor in the department of agronomy and horticulture at
[00:00:50.000]UNL.
[00:00:50.600]I've been here for a little over three years and have been doing cover crop work
[00:00:55.460]for, I would say about 11 years now,
[00:00:58.730]between my experience in Iowa, which is where I want to start within,
[00:01:02.750]an image of, and, you know, I,
[00:01:04.260]I don't need to probably belabor the point about all the benefits that we can
[00:01:07.940]see from, from cover crops,
[00:01:09.890]but just as a reminder of what we're all talking about in this great,
[00:01:13.340]Thursday cold afternoon in the Midwest,
[00:01:15.560]about 300 of us here gathered to try to learn more about cover crop management,
[00:01:20.450]what are we really working on and, and trying to promote?
[00:01:24.110]So this is a photo I've used a lot. I took it from a field site,
[00:01:27.260]near Iowa state in April, 2013.
[00:01:30.110]I'm sure all of you can remember what happened in 2012.
[00:01:34.820]so we had a big drought across the corn belt,
[00:01:37.490]and then we had a really wet spring and, you know,
[00:01:41.660]this picture was taken right before we had some really heavy, rain and aims.
[00:01:45.860]And so, you know, when you drive around the landscape right now,
[00:01:47.840]what do you see? The landscape mostly looks like this on the right.
[00:01:50.420]It doesn't really look like, this on the left as we might want it to.
[00:01:53.660]And you know,
[00:01:53.930]now we're in this opposite water pattern where we have had a very wet
[00:01:58.370]2019, one of the wettest years on record.
[00:02:00.320]And now we're seeing drought conditions,
[00:02:02.720]especially in the Western Plains and kind of creeping, conditions.
[00:02:07.280]So we're in the opposite kind of weather,
[00:02:11.150]precipitation extreme. And so I just remind us that, you know,
[00:02:15.350]the conservation that we can get in the soil cover and the improved infiltration
[00:02:18.980]and water savings of growing that crop, preventing erosion,
[00:02:23.170]and all the benefits that we're talking about today are really important that we
[00:02:25.970]all continue to work towards.
[00:02:27.080]So I just like to show this because it's a reminder of, you know,
[00:02:29.900]the water challenges we face and, and the benefits that we can get from,
[00:02:33.900]from just continuing to work on how we can optimize
[00:02:38.870]use of cereal rye. I really liked the messages both from,
[00:02:41.820]from Becca and Chad on that front.
[00:02:44.090]So what I want to share with you today is a work that I've been doing along with
[00:02:48.140]Darren Redfern and many other people across Nebraska,
[00:02:51.350]work funded by the NRCS in our state to understand soil health
[00:02:56.120]management systems. And so we are working on some on-farm research. And,
[00:03:00.250]when I say we there's a lot of work being done by my graduate student,
[00:03:03.610]Fernanda crew Peck, who was on the first slide.
[00:03:06.520]and so we've written some crop watch articles. I'm gonna point you to that.
[00:03:09.730]and I can add them in the chat as well.
[00:03:11.080]I hope you will use the chat during my presentation.
[00:03:13.030]I know in the interest of time, we might not have time for Q and a,
[00:03:15.370]but I will certainly respond to all comments and questions,
[00:03:18.820]but we're working on with 17 different producers around the state.
[00:03:22.360]You can see highlighted here, the different counties where farmers are located.
[00:03:26.980]And so farmer signed up either in 2016 or 2017 for an equip contract
[00:03:31.810]to look at different soil health management systems on their farm.
[00:03:35.920]And so I'm going to tell you a little bit more about what that means,
[00:03:38.830]and then we are doing some,
[00:03:40.390]some targeted data collection and study of these farms.
[00:03:43.150]So to participate in the project,
[00:03:45.370]these producers had to commit to five years of doing on-farm research
[00:03:50.770]and they are looking at different, again,
[00:03:53.260]soil health management systems with replicated strips across their field.
[00:03:57.790]And so,
[00:03:59.980]we are also coming in with data collection and we have on farm research reports,
[00:04:04.090]which I'll point you to at the end here of,
[00:04:07.900]agronomic information. So, some economics information,
[00:04:11.920]some herbicide information we're monitoring, cash crop yields.
[00:04:16.630]We are, along with the NRCS conducting some soil health assessments.
[00:04:21.580]and that's not really what I'm actually going to talk too much about today.
[00:04:24.100]I just wanted to mostly focus on some of the,
[00:04:27.790]monitoring that we're doing in season, but just to give you again,
[00:04:30.880]a snapshot of what some of the treatments are that farmers are looking at,
[00:04:34.330]they vary from field to field because farmers were able to select the different
[00:04:37.870]treatments that they were interested in looking at.
[00:04:40.420]So some farmers are looking at, monoculture fields,
[00:04:45.610]monoculture cover crops compared to mixed cover crop species,
[00:04:49.420]grazing cover crops versus no grazing of cover crops cover versus no cover.
[00:04:53.530]So you can see here, there's a range of different treatments.
[00:04:55.840]And as I walk you through some of the results that we're seeing,
[00:04:58.990]I just want you to keep that in mind that we have, you know,
[00:05:01.240]some different soil health management systems, again, with,
[00:05:04.570]different cover crop, management that's, that's ongoing. And so,
[00:05:09.070]so we're collecting all these things that you see on the right,
[00:05:10.990]but another really important element of our data collection is the use of
[00:05:14.800]imagery.
[00:05:15.250]And so we've selected a subset of those 17 farms based on the different designs
[00:05:20.170]that they have to have imagery on a
[00:05:25.360]sub monthly basis. So we don't always have weekly imagery, but we have,
[00:05:29.580]we're working the last two years with a,
[00:05:33.310]imagery provider that was providing multi-spectral imagery via an airplane.
[00:05:37.630]And so we had this for a number of fields.
[00:05:40.330]And so I'm going to be showing you some values for NDI.
[00:05:42.760]And I wanted to just really quickly show you kind of the science behind that
[00:05:46.480]imagery. If you're not familiar,
[00:05:47.740]I imagine that many people are starting to get more familiar with imagery as it
[00:05:51.160]becomes more available and, and all kinds of providers,
[00:05:55.750]collecting this information, how do we use it? Right? So the science of imagery,
[00:05:59.090]right? This requires us to think about solar radiation.
[00:06:02.000]And so as you probably are aware of the source of all energy on earth comes from
[00:06:05.180]the sun. So the sun emits energy at a range of different,
[00:06:09.830]wavelengths and frequencies.
[00:06:11.690]And so we can only visibly see the ones in that spectrum of visible light right
[00:06:16.190]in the middle.
[00:06:16.730]But the important thing to remember is that within all of that energy,
[00:06:20.300]that's admitted by the sun.
[00:06:22.780]we can.
[00:06:24.880]Then pick up what is happening from the soil surface and our plant
[00:06:29.620]canopy. And so, this image that I'm showing you here comes from,
[00:06:34.780]a great NAB guide about getting started with drones and agriculture,
[00:06:38.920]to some really good,
[00:06:39.610]basic information about imagery and about applications of imagery.
[00:06:43.660]And so what I'm going to show you that we are analyzing from these sites is the
[00:06:48.130]normalized difference vegetation index,
[00:06:50.290]which I'm showing you what this equation is here.
[00:06:53.500]And the only really important thing to remember is that we're just calculating
[00:06:56.770]an index of some of the different spectral bands that we're getting from
[00:07:01.660]the imagery, from these airplanes.
[00:07:03.280]And really what this DVI is telling us is some indicator of
[00:07:08.470]chlorophyll content, how much greenness is coming from the soil surface,
[00:07:13.030]or as an indicator of canopy density.
[00:07:16.180]So it can't necessarily tell us everything,
[00:07:17.980]but it can give us an indicator of greenness throughout the growing season.
[00:07:22.150]And so I'm going.
[00:07:22.630]To show you some.
[00:07:25.150]Of the imagery results from a number of our farms.
[00:07:27.910]And I'm going to show you first three farms where we have,
[00:07:31.990]where small grains were grown 2020. So this is all imagery from 2020,
[00:07:35.380]that I'm going to show you the results of,
[00:07:37.660]three that grew small grains last year, following a cover crop in 2019,
[00:07:41.770]and then three that had soybean two from 2021 from 2019.
[00:07:46.060]And so I'll show you the different cover crop mixes that they're using.
[00:07:48.280]And I would love to see some activity in the chat,
[00:07:50.800]just share with us your thoughts, because really this is preliminary.
[00:07:54.220]And I think the goal is to try to use.
[00:07:57.130]Who's in season data.
[00:08:00.460]To tell us what's happening potentially by the end of the season,
[00:08:03.520]because there's such a focus in our world about yield.
[00:08:06.820]But of course we all know that there's so much more that's happening to get us
[00:08:10.750]to that one point, to tell us about yield.
[00:08:13.450]So these are all locations where we're collecting imagery from,
[00:08:17.110]and I'm going to hone in on, like I said, just actually five of these farms,
[00:08:21.170]and show you a little bit more information about them. So the first farm,
[00:08:24.070]I want to show you some information from are the ones that grew small greens
[00:08:27.460]last year. Just again,
[00:08:28.570]to give us a sense of what is the impact of the cover crop during the cash crop
[00:08:32.050]growing season. And so the first County is kind of East.
[00:08:36.160]Central Nebraska, and.
[00:08:39.130]And I'm in Colfax County. So in 2020, their cash crop was wheat.
[00:08:44.320]And, um.
[00:08:46.810]Their cover crop,
[00:08:48.490]and their treatment mix that they were looking at was a cover versus no cover.
[00:08:52.150]And their cover crop was a multi-species mix.
[00:08:55.140]And so what I'm showing you here on the slide is just a little bit more
[00:08:57.840]management information about, the location.
[00:09:01.110]So this is a no till non irrigated site. And so what I'm showing you here,
[00:09:04.770]these first few and DVI values, you see the check and you see the cover crop.
[00:09:08.680]So I want to orient you to this cause I'm going to show you a few more graphs
[00:09:11.310]that look like this.
[00:09:12.500]the, these.
[00:09:15.590]values here for the month of June would all be during,
[00:09:20.180]the wheat growing season. And then this last one would be after wheat harvest.
[00:09:23.870]And so, these,
[00:09:25.490]these bars look pretty similar right between the two treatments.
[00:09:28.550]And so for this field, we did not see any differences in season for NDI.
[00:09:33.620]We did not see at the end of the season, any difference in wheat yield,
[00:09:37.850]and we don't actually have a biomass estimate. So where I have biomass values,
[00:09:41.240]I'm going to show you, those biomass values as well,
[00:09:44.240]just to try to give us a sense of what these,
[00:09:47.930]what this data might be telling us. So, so we didn't see any differences here,
[00:09:52.040]on the first field that I'm showing you in terms of NDI in season.
[00:09:55.940]Or, we yield at the end of the growing season.
[00:10:01.460]Okay. So then.
[00:10:01.920]Next farm that I want to show you is more central.
[00:10:04.850]Nebraska is from Howard County and their cash crop last year was cereal rye.
[00:10:09.680]so grown as a cash crop. And prior to that,
[00:10:13.580]the cover crop was a multi-species mix compared to no cover crop.
[00:10:17.000]This is an irrigated site. And so I'm showing you here,
[00:10:20.760]on the graph where the approximate rye harvest happened and what you see here in
[00:10:24.590]these three stars. and then those few stars once,
[00:10:29.240]the cover crops would have been planted after rye harvest,
[00:10:33.800]for the next year,
[00:10:35.660]these are actually places where we found statistically different,
[00:10:40.610]values for N DVI in the cover crop,
[00:10:45.140]in the rye following the cover crop, versus the no cover crop.
[00:10:49.350]So here actually we saw,
[00:10:51.680]a few data points where there were higher end DVI values in rye following cover
[00:10:56.420]crops, but that there was no difference in raw yield at the end of the season.
[00:11:00.560]So, so the first field, no effect on NDI,
[00:11:04.580]no effect on yield second field, higher end DVI,
[00:11:08.120]but no effect on rye yield. And then there was actually a pretty substantial,
[00:11:12.110]cover crop biomass the prior year.
[00:11:15.230]at this site.
[00:11:17.150]So there was, almost 3000 pounds per acre, but again,
[00:11:19.910]that didn't have any carry over effect on rye yield.
[00:11:23.180]even though it did have some impact.
[00:11:25.130]In season.
[00:11:28.130]The last field that I want to talk about is,
[00:11:30.460]is nearby also in central Nebraska in Greeley County,
[00:11:35.180]also had rye as a cash crop also had,
[00:11:38.270]the prior year a multi-species mix cover crop compared to no cover crop,
[00:11:42.290]also an irrigated site.
[00:11:44.480]And so you can see a few data points here before rye harvest,
[00:11:48.470]where the NDV values were actually slightly higher in the,
[00:11:53.410]strips that we're following, no cover compared to the cover crop,
[00:11:58.120]but again,
[00:11:58.630]no difference in rye yield and significantly smaller amount of
[00:12:03.280]biomass the year prior in that cover crop mix.
[00:12:07.560]So, so I'm just showing you three fields, um.
[00:12:12.700]Grew small grains in 2020 following.
[00:12:15.330]multi-species mixed cover crops with three different in season impacts,
[00:12:19.350]but no difference.
[00:12:20.130]This is in yield. So
[00:12:24.930]what can I do.
[00:12:25.410]DVI tell us there, it can tell us again how that cash crop is growing,
[00:12:29.190]but here we saw kind of some inconclusive mixed effects,
[00:12:32.610]but no effect in season, no effect on yield at the end.
[00:12:36.660]And I want to move on next to two sites that had soybean in,
[00:12:41.460]2020 and what we saw there, which is interesting. And again,
[00:12:45.150]I'd love to hear thoughts,
[00:12:47.670]either during or after my presentation that I can respond to in the chat about,
[00:12:51.720]you know, if this is similar to things that you have seen as well in.
[00:12:54.630]Season. So this location.
[00:12:57.270]Is in Stanton County. So more in Northeast Nebraska, again grew soybean in 2020,
[00:13:01.710]and this was a different, so a health system that they're evaluating.
[00:13:04.830]So they had a monoculture cereal rye cover crop versus a cover.
[00:13:09.090]Crop mix. And the mix.
[00:13:11.190]Here was also including cereal rye had winter barley, red Clover,
[00:13:15.800]rapeseed vet, and camelina. So the full suite of,
[00:13:19.260]of cover crop species in terms of legumes, brassicas, and,
[00:13:23.630]and grasses. And so what you see here is,
[00:13:26.940]an image that was taken when biomass samples were taken last spring.
[00:13:30.720]So the single species, the cereal rye had, slightly more biomass,
[00:13:35.520]85 pounds versus 15 pounds in the mix. So,
[00:13:38.550]and you can see the green coverage here that we've also have a measurement of as
[00:13:42.000]well, so pretty small amount of biomass, but more so in the single species mix.
[00:13:46.590]And what you see in our,
[00:13:48.690]end DVI values is that as the growing season went on,
[00:13:52.050]there was actually higher end DVI in,
[00:13:56.700]the multi-species or as I just go back again,
[00:13:59.190]the even smaller amount of biomass,
[00:14:02.130]the soybeans following that even smaller amount of biomass compared to.
[00:14:05.400]The single species. So.
[00:14:07.530]There was a higher end DVI there,
[00:14:10.980]where there was very low biomass and it actually did have this field is the one
[00:14:15.690]that I'm going to show you that did have yield impact,
[00:14:17.910]that there was a seven bushel difference in the soybean following the
[00:14:22.620]cover crop mix, which again, had very, very low biomass.
[00:14:27.180]they both were lower biomass, but even lower in the multi-species.
[00:14:30.360]Mix here. So.
[00:14:32.220]Something happening there with NDI and soybeans.
[00:14:35.850]and then that's something similar we see here in Nemaha County. So more in, in,
[00:14:39.420]in, Southeast Nebraska. And so here again,
[00:14:43.590]soybeans grown in 2020 and the soil health system was a little different here,
[00:14:47.940]but some, some similar patterns that they were con they're comparing this site,
[00:14:52.160]a winter terminated cover crop mix compared to I'm a winter Hardy cover crop
[00:14:57.140]mix. And so you can see in the spring, when we took biomass samples,
[00:15:00.380]that there was about 800 pounds of biomass in the winter Hardy mix.
[00:15:05.720]And in the winter terminating mix,
[00:15:06.980]we didn't have a biomass estimate there for the spring.
[00:15:09.800]And so what you see here is that the winter
[00:15:14.060]terminated the soybean grown following the winter terminated cover crops,
[00:15:18.860]which again had,
[00:15:21.110]no biomass here in the spring show, again,
[00:15:25.940]a higher end DVI value than the winter Hardy cover crops. So similar pattern,
[00:15:30.830]their higher end DVI in the soybean following a winter terminated cover crop.
[00:15:34.400]But at this site,
[00:15:35.720]at least even with that in season impact that we could observe,
[00:15:39.200]there were no yield differences.
[00:15:43.130]And then the final site I want to come back to is Howard County.
[00:15:45.650]And the reason I'm coming back to this is, and we've actually written and I'll,
[00:15:48.350]I'll drop them in the chat. a couple of crop watch articles about this,
[00:15:52.310]as well as, a feature that we had on market journal.
[00:15:56.570]if anyone's familiar with that, outlet, about this site.
[00:16:01.130]And so, this is actually from 2019. So our graphs look a little different,
[00:16:04.760]but they had 20 nineteens at the Howard County site.
[00:16:09.590]so soybean in 2019,
[00:16:11.450]the cover crop mix was a multi-species mix compared to no cover
[00:16:16.340]crop. And so here, we also saw early in the growing season,
[00:16:20.780]there was a higher end DVI in the soybeans following no cover crops. And again,
[00:16:25.760]this was pretty good amount of cover crop biomass,
[00:16:28.700]but by the end of the growing season, there was higher end BVI.
[00:16:32.500]The trend had switched in the soybean following cover crops,
[00:16:36.470]but this did not lead to any difference in soybean yield.
[00:16:38.850]I want to actually show you what this looked like, in photos.
[00:16:43.040]And I remember when Fernanda came to my office that fall, she was so excited.
[00:16:46.130]She said, look what I found when she was looking at the imagery.
[00:16:49.280]and so she was determined to go out and see on the ground what was happening,
[00:16:53.390]this fall. So she went out right before,
[00:16:56.900]our producer collaborator harvested soybean,
[00:16:59.660]and you could see this huge difference.
[00:17:01.040]So here in the bottom is an image of the soybeans that were harvested in the,
[00:17:04.490]the control.
[00:17:07.190]and this is from September 25th and the image from the
[00:17:12.110]cover crop trips. So you can clearly see, and again,
[00:17:14.570]that NDI DVI tells us as well,
[00:17:16.640]that there was some kind of delay meant in development,
[00:17:20.540]such that the soybean following the,
[00:17:24.230]the control or the no cover crop, developed earlier,
[00:17:28.670]in the growing season and also Sonesta earlier compared to the soybean
[00:17:33.470]following the cover crop. But again, this did not lead to any yield differences.
[00:17:37.070]And Fernandez also looked at some indicators of grain quality and not seeing any
[00:17:41.240]differences there as well.
[00:17:42.470]So I'm going to wrap up here with just a few thoughts
[00:17:47.600]about all of these fields together.
[00:17:49.440]And so what we see in the first three that I'm showing you in
[00:17:54.360]terms of small grain, that there was no yield impact.
[00:17:57.270]I'm showing you a little bit here about the soil trends.
[00:17:59.340]It's also our soil health conference that we are seeing kind of across the
[00:18:03.390]board,
[00:18:05.730]improvements in soil health in some specific indicators,
[00:18:08.850]infiltration increasing in time or compared to cover no cover. But again,
[00:18:13.750]as I've already described that there's not the same setup on each of the farms,
[00:18:18.180]but we are seeing these trends either in time or,
[00:18:22.020]comparison and treatments with, more intensified soil,
[00:18:25.980]health cover crop management. And so,
[00:18:28.950]no impacts really in season or,
[00:18:32.380]on yield in the small grains fall in cover crops. But we do see this pattern,
[00:18:35.940]interestingly,
[00:18:36.780]where the NDV values in season were higher following either no cover crop or
[00:18:41.340]smaller amounts of cover crop biomass.
[00:18:45.000]so some kind of potential delay in development that could be occurring.
[00:18:48.720]And so just to, to summarize this, you know,
[00:18:51.090]I think the important point here is, again,
[00:18:52.950]our results are a little bit inconclusive,
[00:18:54.570]but hopefully this gives you some ideas of how we are using imagery to look at
[00:18:59.040]what might be happening during the growing season. Because as we know,
[00:19:01.950]yield is just the culmination of all these decisions that we make,
[00:19:04.950]but it really doesn't tell us what's happening in season that could eventually
[00:19:09.060]help us make different management decisions with our cover crop. And so,
[00:19:14.730]yeah, in some years we don't see any impact in other years,
[00:19:18.240]especially with soybeans, we do see some kind of impact,
[00:19:21.420]but it doesn't always lead to yield effects. So again,
[00:19:24.210]I'm showing you that we're not totally sure why this happening.
[00:19:26.790]We'd love to hear any thoughts.
[00:19:27.720]I see some things in the chat that I'll address here as I wrap up and,
[00:19:30.820]and after, you know,
[00:19:32.760]even with some of these differences that we are seeing on these fields that,
[00:19:36.000]that trend of increasing soil properties and soil health with time or relative
[00:19:40.740]to the different treatments.
[00:19:42.330]And so I'd love to hear any thoughts that folks have, you know,
[00:19:44.670]why might this be occurring? you know,
[00:19:47.100]the cover crop impact potentially on moisture temperature is this impacting,
[00:19:51.780]stand count,
[00:19:52.710]is it delaying germination development for some ways that some interaction with
[00:19:57.000]weeds? So I am going to in the interest of time, just look into the chat and,
[00:20:01.260]appreciate your attention and, feedback here. As we,
[00:20:06.020]we try to think through, you know,
[00:20:07.530]how we can use the new technology that we have to make,
[00:20:11.910]improved decisions about, cover crop management.
[00:20:14.730]And so I'm just showing you our team of folks who are involved with this
[00:20:17.370]project. This is a great collaboration that we have with all of the farmers,
[00:20:21.090]with extension, with our on-farm research network, with the NRCS,
[00:20:24.870]as Aaron heard our soil health, specialists in the state,
[00:20:28.020]right in the middle of our photo from the on-farm research network meeting,
[00:20:31.230]when we used to meet in person, this was February of last year,
[00:20:35.040]and then I'm going to drop in the chat.
[00:20:36.750]some of our crop watch articles that we've put together.
[00:20:39.090]This is specific to Howard County in 2019 and soybeans that we saw and just
[00:20:43.410]interesting pattern.
[00:20:45.690]and then our website crop cropwatch@unl.edu/soilhealth.
[00:20:49.240]And we've had some market journal features, as well.
[00:20:53.140]And we've got the on-farm research, reports there as well.
[00:20:56.230]So thank you again all for your good attention and the opportunity and for,
[00:21:01.240]you know,
[00:21:01.510]having this great community of several hundred people interested in talking
[00:21:05.140]about cover crops here in this cold February day. So thanks.

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2021 Nebraska Cover Crop and Soil Health Conference - Andrea Basche

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