2 - 2020 South Central Ag Lab Field Day
Mike Kamm
Author
12/04/2020
Added
11
Plays
Description
South Central Ag Lab Field Day
Searchable Transcript
Toggle between list and paragraph view.
- [00:00:04.680]Hi.
- [00:00:04.890]I'm Sabrina Ruis.
- [00:00:05.780]I'm a research assistant professor with the agronomy and horticulture department
- [00:00:08.930]at the University of Nebraska-Lincoln.
- [00:00:11.350]and I'm going to talk today a little bit about,
- [00:00:13.760]some corn residue removal study, that we have going out on out here.
- [00:00:19.430]And the study has been going on for about six years.
- [00:00:23.330]So I'm going to present both three-year and six year data.
- [00:00:26.780]And this topic is actually really important because we
- [00:00:31.460]kind of know the generally high rates of, crop residue removal,
- [00:00:36.140]can have negative impacts on soils. And,
- [00:00:40.190]but we really don't have a lot of long-term data,
- [00:00:43.580]particularly from the Great Plains region.
- [00:00:46.040]So what we did was we assessed the impacts of crop residue removal that are moveable after
- [00:00:50.030]three and six years on soil properties and crop yields.
- [00:00:55.010]So our experiment is located here at clay center.
- [00:00:59.690]We also have a sister site, just in, in the East that is rain fed gear,
- [00:01:04.340]it's irrigated, but I'm going to focus on the irrigated site itself.
- [00:01:09.500]And so we have treatments of zero 25,
- [00:01:12.920]50 75 and 100% residue removal.
- [00:01:17.120]and you'll see on the slide that it does talk about cover crops a little bit.
- [00:01:20.090]That is also part of the project.
- [00:01:21.620]What I'm going to focus on the residue removal apart.
- [00:01:25.370]I will be talking a little bit later about the cover crop portion.
- [00:01:29.960]And so we measured for this study,
- [00:01:32.360]corn grain yield and a variety of soil health parameters,
- [00:01:37.730]that will include lay bile or easy to degrade organic matter total organic
- [00:01:41.810]matter water erosion, potential or soil structural quality,
- [00:01:45.950]compaction, water, infiltration, water retention, and, heat transfer.
- [00:01:51.710]So first we're going to talk about particulate organic matter.
- [00:01:55.250]And in year three we saw no effect of crop residue removal.
- [00:02:01.040]And in year six,
- [00:02:03.110]we found that anything over 25% removal basically
- [00:02:07.520]reduced that particular organic matter or lay organic matter.
- [00:02:11.180]Now particulate organic matter is really important because that's what the
- [00:02:14.450]microbes are going to be feeding on.
- [00:02:16.400]As they feed on that particulate organic matter, they are,
- [00:02:21.260]are acting on that. They are,
- [00:02:24.350]decomposing that and they produce various glues and sticky substances that help
- [00:02:28.430]to form aggregates.
- [00:02:30.560]So when we reduced our particulate organic matter, we're reducing our,
- [00:02:35.330]food for the microbes and thereby probably our aggregation,
- [00:02:38.420]which I will get to momentarily,
- [00:02:40.970]for total organic matter or overall organic matter at this site,
- [00:02:44.750]we saw no effect after three years,
- [00:02:48.770]from residue removal,
- [00:02:49.790]but similar to the particular organic matter or lay bile,
- [00:02:54.110]the total organic matter did also decrease with crop has removal starting at
- [00:02:59.020]about 25% and higher.
- [00:03:03.010]What aggregate stability is, just are,
- [00:03:06.160]you can think of that as our water erosion potential
- [00:03:11.110]and on the slide I'm showing both the rain fed in the irrigated site.
- [00:03:14.410]I'm going to,
- [00:03:15.130]I'm just talking about the irrigated sections site that are circled.
- [00:03:19.330]And in year three we saw no effect of croppers
- [00:03:23.680]removal on what aggregate stability or aggregate size.
- [00:03:27.730]And you can see on the Y axis of the slide that it says, mean weight, diameter,
- [00:03:32.340]water, stable aggregates, just think of it as aggregate size.
- [00:03:36.580]in year six,
- [00:03:38.110]we saw that any residue removal rate greater than,
- [00:03:41.620]or equal to 50% reduced our aggregate size.
- [00:03:45.880]So treatments with 50 75 or a hundred percent removal,
- [00:03:50.170]they are more susceptible to lottery erosion.
- [00:03:53.080]And so let's say we get a heavy rain storm.
- [00:03:56.170]They're more likely to see runoff compared to our
- [00:04:01.000]zero and 25% because the aggregates are smaller.
- [00:04:04.330]They're more easily carried by water compaction and water
- [00:04:09.010]infiltration are the next two properties that we're going to talk about.
- [00:04:12.490]And we didn't measure either of these in year three,
- [00:04:15.130]just because they're a little bit slower to change with management.
- [00:04:18.790]after six years we saw no effect of crop residue removal rate on saw
- [00:04:23.620]compaction parameters. And we, we,
- [00:04:26.080]we looked at soil compaction from two different angles, woke density,
- [00:04:29.320]which is our massive,
- [00:04:31.270]soil over a set volume and then penetration resistance,
- [00:04:35.470]which is the,
- [00:04:37.360]you can kind of think of it as the soil is resistance to something moving
- [00:04:40.660]through it, like a root moving through the soil or an earthworm that's,
- [00:04:45.820]it's going to be what they are seeing as they move through the soil.
- [00:04:48.910]And with our, our site here,
- [00:04:51.670]we saw no effect of compaction or no effect of residue removal
- [00:04:56.620]on compaction, water infiltration.
- [00:04:59.110]We looked at initial water infiltration and we saw again,
- [00:05:01.900]no effect of crop residue removal on,
- [00:05:06.220]water infiltration, water retention. We,
- [00:05:09.520]we measure a number of parameters. When we look at water retention,
- [00:05:13.510]we have what's called field capacity,
- [00:05:15.790]permanent wilting point or PWP and plant available water or paw
- [00:05:21.730]field capacity is so let's say you have a saturated soil,
- [00:05:25.810]and then you let that drain and a silt loam or silty clay loam
- [00:05:30.760]for 24 hour 48 hours ish,
- [00:05:34.720]depending on the soil.
- [00:05:36.790]And then all everything that's gravity drained out of that what's left is our
- [00:05:41.710]water content at field capacity,
- [00:05:44.380]permanent melting point it's anything that's left after it's anything that's
- [00:05:49.270]really stuck to the soil particles.
- [00:05:51.280]It's not going to be available to the plants. So field capacity,
- [00:05:56.140]we, observed that anything,
- [00:06:00.590]any residue removal rate greater than 25% reduced plan available water outfield
- [00:06:05.540]capacity now permanent wilting point or PWP.
- [00:06:10.010]And we saw no effect of residue removal,
- [00:06:12.500]but when we look at the plant available water,
- [00:06:14.810]that was actually higher with no removal than with 25% and
- [00:06:19.550]greater. Now you're probably wondering, well,
- [00:06:21.890]why did we see these reductions in plant available water when we are
- [00:06:26.810]removing residents? Well, if you remember back a few slides,
- [00:06:29.720]we talked about particulate organic matter and organic matter being lower.
- [00:06:34.670]That means that because those guys are those two things are really
- [00:06:39.380]important for holding onto water, as well as our,
- [00:06:44.120]aggregate structure.
- [00:06:45.380]field capacity is more driven by organic matter and by aggregations.
- [00:06:49.720]So because both of those were reduced with crop residue removal.
- [00:06:53.960]That's why we're seeing those reductions. Now, thermal properties,
- [00:06:58.460]we're looking at three different components here.
- [00:07:00.560]We're going to focus on the first two thermal conductivity,
- [00:07:03.950]which is the ability of the soil to conduct heat.
- [00:07:07.820]so it warms up on the surface.
- [00:07:09.530]We want that heat to transfer down a little bit lower,
- [00:07:12.650]to warm up where a seed is placed, specific key capacity,
- [00:07:17.930]which is the second column of data. That's the,
- [00:07:23.210]amount of heat that it or energy that it takes to raise the temperature
- [00:07:28.370]of a unit of soil. So in both cases,
- [00:07:33.050]we saw no effect of residue removal,
- [00:07:34.700]and I'll let Michael talk a little bit more later about that. Cause he's,
- [00:07:39.080]he's got some contrasting data based on some of his research,
- [00:07:44.510]and now we're going to talk about crop yields.
- [00:07:48.170]And so we've got six years of crop yield data out here. And in only one year,
- [00:07:53.030]did we see an effect of residue,
- [00:07:54.440]removal and residue removal actually increased crop yields?
- [00:07:59.550]And the top line was 0% removal.
- [00:08:02.510]You can see it's 14.8 megawatts per hectare,
- [00:08:05.150]and then versus a hundred percent removal at 16.2.
- [00:08:10.370]So what did we find? And in summary here,
- [00:08:14.270]particulate organic matter after three years, no effect. After six years,
- [00:08:18.920]I rates of residue removal reduced and by high rates,
- [00:08:21.620]I'm meaning at least 50% overall, total organic matter,
- [00:08:26.390]no effect in year three, greater than or equal to 25% reduced in year six.
- [00:08:32.090]what aggregate stability or soil structure no effect in year three,
- [00:08:36.260]but after six years greater than or equal to 50% reduced initial water
- [00:08:41.180]infiltration and compaction plan available water and thermal properties were not
- [00:08:44.510]measured in year three. initial water,
- [00:08:48.440]infiltration and compaction. We saw no effect.
- [00:08:52.130]We saw no effect of thermal properties, but,
- [00:08:55.200]residue removal rates greater than or equal to 25% reduced plan available water.
- [00:08:59.820]And after three years we saw that,
- [00:09:03.060]resident removal kind of generally increased,
- [00:09:07.170]grain yields in one out of three years.
- [00:09:09.840]But then when we look at the second set of three years,
- [00:09:11.910]we saw no effect of residue removal. So what is our big takeaway? Well,
- [00:09:18.270]similar to other studies and other regions,
- [00:09:21.600]we saw no effect of crop residue or we're
- [00:09:26.370]seeing mixed effects of crop residue removal. And it's going to depend on,
- [00:09:31.410]on the residue removal, right? In general,
- [00:09:33.720]high rates of residue removal will have negative impacts on soil properties,
- [00:09:39.240]but overall, we're not seeing a lot of effects on crop yields.
The screen size you are trying to search captions on is too small!
You can always jump over to MediaHub and check it out there.
Log in to post comments
Embed
Copy the following code into your page
HTML
<div style="padding-top: 56.25%; overflow: hidden; position:relative; -webkit-box-flex: 1; flex-grow: 1;"> <iframe style="bottom: 0; left: 0; position: absolute; right: 0; top: 0; border: 0; height: 100%; width: 100%;" src="https://mediahub.unl.edu/media/15119?format=iframe&autoplay=0" title="Video Player: 2 - 2020 South Central Ag Lab Field Day" allowfullscreen ></iframe> </div>
Comments
0 Comments