Corn Residue Removal - A CropWatch Podcast
Michael Sindelar, Nebraska Extension Educator
Author
12/06/2018
Added
18
Plays
Description
Nebraska Extension Educator Michael Sindelar talks with Virginia Jim and Marty Schmer, researchers with the USDA Agricultural Research Service, about their long-term research on corn residue removal and its effects on crop production and soil quality, as well as how to manage the field after residue removal.
Searchable Transcript
Toggle between list and paragraph view.
- [00:00:00.153]Welcome to the CropWatch Podcast. I'm Michael Sindelar, the
- [00:00:03.044]crop assistant extension educator. For today's CropWatch
- [00:00:05.989]Podcast, we'll be talking about corn residue removal.
- [00:00:09.361]We'll be joined today by Virginia Gin and Marty Schmer.
- [00:00:12.774]Both are research scientists with the USDA ARS.
- [00:00:16.382]Yeah, my name is Marty Schmer, with USDA ARS, I'm a
- [00:00:19.577]research agronomist based out of Lincoln, Nebraska.
- [00:00:22.816]My name is Virginia Gin and I'm also with USDA ARS, and
- [00:00:27.064]I'm a research soil scientist.
- [00:00:29.952]Alright, well, I guess the first question people are
- [00:00:32.713]wondering is what do we do with corn residue after we
- [00:00:35.479]remove it.
- [00:00:38.994]Well, I think, historically, we've used it for
- [00:00:41.278]livestock feed or in some parts of the Corn Belt, we use it
- [00:00:46.767]for bedding for the dairy industry. I think in Nebraska
- [00:00:51.394]Historically, we've used it mostly as a livestock feed.
- [00:00:54.576]This has probably been going on for a number of decades,
- [00:00:57.655]probably particularly in the North Platte Valley in the
- [00:01:01.738]Panhandle.
- [00:01:03.417]They've been taking stover off for a while, and so there's
- [00:01:05.099]pockets of Nebraska where you see people take stover off,
- [00:01:08.752]particularly for livestock feed, but probably in the last
- [00:01:13.593]20 years, there was interest for cellulosic ethanol, so
- [00:01:19.801]that's where a lot of our research came from. But probably
- [00:01:22.692]most of it is going as a livestock feed.
- [00:01:26.923]Right, and we'd like to keep it on the soil
- [00:01:29.809]surface, just for purposes of soil conservation, but we
- [00:01:32.670]know just by looking out the window that you can see
- [00:01:36.178]producers are taking that material off, so a lot of our
- [00:01:40.670]research questions revolve around that.
- [00:01:44.384]Okay, so what are the effects? We'll start out with
- [00:01:47.651]probably the biggest one on maybe yield from removing
- [00:01:50.655]corn residue or corn stover?
- [00:01:54.438]I think based on the data that we've collected
- [00:01:58.160]with USDA, some of the work that's been done by University
- [00:02:01.913]of Nebraska and some other land-grant institutions is, generally
- [00:02:06.085]we don't see a yield hit, particularly in irrigated systems.
- [00:02:10.339]We sometimes see a slight yield bump. We think that's maybe
- [00:02:14.764]due, because there's less residue off, the soil gets a
- [00:02:18.185]little warmer, there's less nitrogen in mobilization, the
- [00:02:21.979]corn just grows a little faster. But there have been times
- [00:02:28.271]when we're in a drought period and under rain fad conditions
- [00:02:32.248]where we see a yield hit from taking stover off in the
- [00:02:35.199]previous year.
- [00:02:37.089]Okay, so continuing with that, what happens in the soil,
- [00:02:44.125]fertility first, when you remove residue? Has
- [00:02:47.948]there been reduction in any of the essential nutrients?
- [00:02:51.364]Well, I think what we tend to see in a lot
- [00:02:53.857]of our longer term studies is that in the surface soils,
- [00:02:56.728]we will tend to see a decrease in the organic matter
- [00:02:59.981]content, especially if you're being very aggressive with
- [00:03:03.370]the removal and doing this over a long period of time. So
- [00:03:06.661]a lot of producers may or may not choose to remove stover
- [00:03:11.098]every year, but for very aggressive removals that are
- [00:03:15.138]annual removals, then yeah, you might expect to see some
- [00:03:19.044]loss of soil organic matter in the surface. Some of the
- [00:03:24.057]nutrient export that goes along with the nutrients that
- [00:03:28.130]are in the stover itself. We have some really forgiving
- [00:03:31.416]soils though in Nebraska, so for the most part, we haven't
- [00:03:34.980]found that we needed to supplement nitrogen or any other
- [00:03:37.859]nutrient to replace what's been taken off, but again, that's
- [00:03:42.331]for a moderate rate of removal, not for super aggressive
- [00:03:47.555]rates. Then, especially if you see yield differences, you
- [00:03:52.712]would probably want to consider whether or not you need to
- [00:03:55.696]ameliorate that by adding back some nutrients.
- [00:03:59.693]Right, I think probably the biggest thing is, if you're
- [00:04:02.464]going to start, or if you have taken stover off in the
- [00:04:05.570]past is, you know, soil test your fields, get kind of a good
- [00:04:09.217]baseline, see where some of your nutrient concentrations are
- [00:04:14.025]at before you take stover off and then see if they have
- [00:04:16.598]changed dramatically. Usually you see you take some nitrogen
- [00:04:21.914]off, the second -- and then potassium is probably the highest
- [00:04:26.648]nutrient you take off. Phosphorous you take about four or
- [00:04:30.449]five pounds per ton you take off, and then sulfurs, you take
- [00:04:33.823]about three or so pounds per ton of stover removal, but we
- [00:04:39.905]haven't really seen anything in terms of needing to add
- [00:04:43.424]more nitrogen on some of our longer term sites. So I think
- [00:04:47.092]it goes back to Virginia's, you know, our soils are
- [00:04:49.891]fairly forgiving, it may take more than a decade or so
- [00:04:52.986]before you see some of those effects.
- [00:04:55.255]Well, I think it depends too on your rotation, so there's
- [00:04:58.293]a case in Iowa where they have a corn soybean rotation, and
- [00:05:02.500]the removal of corn stover actually had an impact on the
- [00:05:07.868]soybean yield because they needed more potassium, so in that
- [00:05:13.576]case, in that particular rotation, they did choose to
- [00:05:18.081]supplement with additional nutrients. But again, all of
- [00:05:21.508]those decisions on fertility depend on what your overall
- [00:05:24.669]management system is, and so doing the soil testing and
- [00:05:27.861]things like that is going to be important.
- [00:05:30.423]Alright. Now, I know that you mentioned loss of soil
- [00:05:33.729]organic matter. Does that loss of soil organic matter drive
- [00:05:36.544]any other changes in the soil that could be issues?
- [00:05:40.216]Yes, and what we find is that in systems that do stover
- [00:05:45.353]removal mechanically, the first thing that we notice is --
- [00:05:49.422]aside from potential losses in organic matter -- is there's
- [00:05:53.105]a lot of physical disturbance to the soil, because you just
- [00:05:56.737]have more machine traffic. And so, when you see things like
- [00:06:01.681]reduced soil stability, then you begin to worry a little
- [00:06:06.030]more about wind and water erosion, and any of the other
- [00:06:09.529]physical properties of the soil that go along with what
- [00:06:12.881]might be impacted by this increased machine traffic from the
- [00:06:17.850]stover removal. The organic matter content plays into soil
- [00:06:22.370]stability as well, so it's all interconnected in a lot of
- [00:06:26.630]different ways, but it's kind of intuitive to know if you've
- [00:06:31.038]got more passes because you have more intensive management
- [00:06:35.405]with mechanical removal, which could be more than two or
- [00:06:39.995]even three passes, depending on how you do it. Then yeah,
- [00:06:45.522]there are some physical soil property impacts of doing that.
- [00:06:51.632]Okay, so going on, are there other soil impacts that we
- [00:06:56.345]haven't discussed by removing corn stover?
- [00:07:01.618]There might be some biological impacts where soil health
- [00:07:07.839]is a really big and popular topic right now. And so, what the
- [00:07:13.909]idea is, is if you're changing your soil, the microbial
- [00:07:18.739]communities or your organismal communities because of
- [00:07:22.038]different management practices you're using, perhaps that
- [00:07:25.874]would affect the overall functioning of your soil. There's
- [00:07:28.974]not a lot of data yet that would really help make that link
- [00:07:34.231]between those biological properties and the functional
- [00:07:39.397]properties of the soil, but I think it's still something
- [00:07:43.658]where people want to maintain as healthy of soil as
- [00:07:46.817]Possible. And so, if there are ways to minimize the
- [00:07:50.958]impacts of the management that any producer chooses to use,
- [00:07:55.534]then biology may be one of those. But whether or not
- [00:08:00.121]that's going to be a major part of any decision,
- [00:08:04.058]particularly an economic decision, that's going to depend
- [00:08:07.531]on producer to producer.
- [00:08:09.815]And I think if a producer's long-term goal is improving
- [00:08:14.015]soil health, then taking residue off would --it just takes
- [00:08:22.038]a little longer for that -- for any of your goals to happen.
- [00:08:26.521]So generally it's not -- best management practices with
- [00:08:30.653]stover removal or any residue removal. Generally you can
- [00:08:34.717]maintain the soil -- some of the soil conditions, but if
- [00:08:37.452]you want to improve it, then generally you want to keep
- [00:08:40.659]as much of that residue, if not all of that residue on the
- [00:08:43.174]ground.
- [00:08:45.120]Okay, now you mentioned earlier different number of passes
- [00:08:50.801]with different equipment, what would be a recommended setup
- [00:08:55.008]and what equipment would people need if they were interested
- [00:08:58.225]in bailing residue?
- [00:09:00.685]Well one of the first ideas was that we would just maybe
- [00:09:05.542]send it through the combine, so that either you could have
- [00:09:09.475]it spread out -- you know, just have it dumped right under
- [00:09:12.720]instead of spreading it, you just have it dumping in
- [00:09:15.123]there. There's new equipment with the corn header that it
- [00:09:17.358]actually will make a windrow underneath the combine, so
- [00:09:20.309]it's not sending it through the combine. It's just
- [00:09:22.644]collecting it, cutting it, and then you can select how much
- [00:09:25.979]area or how much biomass you want to take from the windrow
- [00:09:31.735]off the corn header. A lot of times, farmers, I think have
- [00:09:36.704]more of an interest in having decoupled from the harvesting.
- [00:09:41.165]So what they want to do is, usually, they want to harvest
- [00:09:44.081]the corn first, and then go back in and harvest the residue,
- [00:09:48.015]and so what that usually involves is maybe something as
- [00:09:51.186]a rake, a hay rake that can make a windrow. A lot of times
- [00:09:56.446]people will also use the self-propelled disc mower, and
- [00:10:00.382]a lot of people use kind of a corn shredder, and then
- [00:10:04.059]usually that has an accumulator at the end where they can
- [00:10:07.899]mix it into a windrow, and then, either using a large
- [00:10:10.997]square baler or a round baler to collect the stover.
- [00:10:14.702]I think the thing that we've noticed is that how you harvest
- [00:10:18.154]it also depends on how much stover is retained, or how much
- [00:10:21.163]biomass is retained, because some of this equipment
- [00:10:24.238]available, if you're too aggressive, it really chops up. It
- [00:10:28.114]makes the stover into small particles, and so even though
- [00:10:33.799]you can't collect everything, or you think you're collecting
- [00:10:37.333]a certain amount, or you're leaving a certain amount, a
- [00:10:40.356]portion of that will actually leave the field through
- [00:10:42.883]wind, particularly in central Nebraska, or it'll degrade
- [00:10:47.197]quicker and oxidize into the atmosphere quicker. So you
- [00:10:50.342]may not be getting all that full effect of maintaining the
- [00:10:55.021]cover that you want, so sometimes we say, generally
- [00:11:00.101]for stover, it's about 50% of your grain, so total biomass
- [00:11:04.449]of corn, of the harvest index, is about, we generally
- [00:11:08.091]approximate as 0.5, so you have half of it as grain, half
- [00:11:11.675]of it as biomass, so even if you take half of that biomass
- [00:11:15.090]off, depending on how you used the equipment, what equipment
- [00:11:19.398]you used, some of it may not be retained as much as you
- [00:11:23.712]would initially have thought, so that's one thing to
- [00:11:28.720]consider, what type of equipment you want to use. I don't
- [00:11:31.549]think there's one piece of equipment available right now
- [00:11:34.926]that's the dominant, I think most people either rake it or
- [00:11:38.351]use some type of shredder for that.
- [00:11:42.311]What would be the best economic decision for equipment
- [00:11:45.978]just to use?
- [00:11:47.973]Well, I think any management practices that reduce the
- [00:11:52.211]number of machine passes that you have on your field
- [00:11:54.871]is one that's going to have a big impact on your pocketbook,
- [00:11:58.403]simply because you're using a lot less fuel, and fuel
- [00:12:01.774]happens to be the category that takes up a lot of expense.
- [00:12:05.889]So if you have, say an option where you can mow and windrow
- [00:12:10.712]at the same time, or mow and swath at the same time, instead
- [00:12:13.873]of having to mow and then rake as a separate pass, that's
- [00:12:17.516]probably some place where you could have some savings.
- [00:12:21.839]Yeah, and I think it's just basically, you also have to
- [00:12:26.614]evaluate your labor, how much labor you have at a certain
- [00:12:30.113]time is another consideration to take into account.
- [00:12:34.039]Alright, so we kind of touched on it, what would be the
- [00:12:37.280]recommended practices for removing residue responsibly?
- [00:12:43.040]I think the bottom line that Virginia alluded to was the
- [00:12:46.659]potential loss in soil organic matter at the surface, so
- [00:12:50.716]what we recommend is if you're taking residue off, whether
- [00:12:54.382]it's just one time or a few times in a rotation,
- [00:12:59.850]you know, 50% of the time that you have corn or something
- [00:13:04.847]like that, that you have to reduce your tillage. So tillage
- [00:13:10.003]and removing stover or most crop residues is really not
- [00:13:14.444]compatible, so if you're going to take residue off or corn
- [00:13:18.488]stover off, you need to go, at the minimum, probably kind of
- [00:13:22.787]a split tillage, or a strip tillage type system, or what
- [00:13:26.399]we would probably recommend is no tillage. Convert over
- [00:13:30.221]to no-till, because what we've found from our long-term
- [00:13:34.399]research is that by going no-till, you tend to get a small
- [00:13:38.568]yield bump from taking the residue off, and so you tend to
- [00:13:43.381]get similar yields than if you have a disc tillage system.
- [00:13:47.076]So you tend -- the yields are exactly the same, but you
- [00:13:49.941]reduce the amount of potential soil impacts that you would
- [00:13:54.972]by having tillage coupled with residue removal.
- [00:14:00.314]Okay, and so we've heard some negative impacts to the
- [00:14:03.135]soil that can happen when we remove residue, what are some
- [00:14:06.900]options to remediate the soil itself?
- [00:14:11.260]Well cover crops are very popular right now, and it's not
- [00:14:16.473]just the popularity part of it, there's some real functional
- [00:14:19.474]aspects to having a cover crop and keeping soil cover.
- [00:14:23.385]When you're removing residue, even though with the improving
- [00:14:28.000]amounts of biomass and yield we get, that means we have a
- [00:14:30.612]lot more residue on the soil surface. Using a cover crop to
- [00:14:35.811]replace some of the biomass that you're taking off as stover
- [00:14:40.869]is a good idea for helping to restore some of the organic
- [00:14:44.853]matter in that system, as well as some stability to the
- [00:14:47.654]physical soil property because the roots of the plants are
- [00:14:50.716]there. So that's one option, and another option is in
- [00:14:55.871]bringing back, again the organic matter that you're losing
- [00:15:00.062]with stover removal, is to use things like animal manure
- [00:15:04.663]or other kinds of green manures and incorporating that into
- [00:15:08.903]your system. We have both of those types of treatments in a
- [00:15:13.395]Long-term experiment that's at the South Central Ag
- [00:15:17.323]Laboratory here in Clay Center. And it's been using those
- [00:15:21.584]two practices to compare against where we've removed the
- [00:15:25.398]stover, has shown to have some benefit for our crop yields
- [00:15:29.205]and some of our soil properties. Now it takes a long time
- [00:15:34.876]for the management benefits to show up, just because
- [00:15:39.975]the soils are, again, very fertile here and they're very
- [00:15:42.687]forgiving, but I think it's that long-term perspective in
- [00:15:46.026]maintaining the soil health and sustainability where if that
- [00:15:51.091]could be one of the things that helps people make decisions
- [00:15:55.596]on management, then that's where we would push folks to
- [00:15:59.913]consider it.
- [00:16:02.290]And I think some general guidelines I would recommend for
- [00:16:05.972]producers is that probably for fields that are above 180
- [00:16:10.771]bushel is probably the minimum threshold for taking stover
- [00:16:15.896]removal, so anything below 180 bushel, you need to probably
- [00:16:21.475]leave the stover on. Fields that are averaging over 180
- [00:16:26.464]bushel, you could probably consider taking stover off, and
- [00:16:31.676]probably, right now our recommendation is take no more than
- [00:16:36.000]two tons per acre of stover off, that generally means that
- [00:16:41.297]the minimum amount of stover that's retained will ensure
- [00:16:47.835]that we meet the guidelines for minimizing soil erosion
- [00:16:49.957]from wind or water, and also maintaining our soil organic
- [00:16:54.294]matter concentrations in our soils. Another thing to consider
- [00:16:58.170]is if you have sloping soils, I highly recommend not
- [00:17:02.748]harvesting stover off of slopes and fields that are greater
- [00:17:08.838]than 4% or 5%, and if you're in a corn soybean rotation,
- [00:17:13.887]we'd recommend that you don't take the stover off every
- [00:17:17.891]year, probably do it once every four years. In a continuous
- [00:17:21.884]corn system, we'd probably recommend you don't take stover off
- [00:17:25.893]every year, maybe at minimum probably no more than once
- [00:17:31.740]every two years or so 50% of the time.
- [00:17:35.397]Alright, so do either of you have any online web resources
- [00:17:40.287]that you would recommend for anybody interested in removing
- [00:17:43.174]residue?
- [00:17:45.739]Well, clearly the NebGuides that are provided by UNL
- [00:17:49.398]Extension are an easy resource to use and refer to. There
- [00:17:53.762]are some resources available through extension in Iowa where
- [00:17:57.652]they do some residue removal as well, but probably not as
- [00:18:02.184]much as what we do in this state.
- [00:18:06.393]And the CropWatch guidelines online are excellent
- [00:18:10.240]Resources. They're updated continuously by the University of
- [00:18:14.201]Nebraska. They're a great resource for producers.
- [00:18:20.538]Thank you for your time, Virginia and Marty.
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="height: 5.62em; max-width: 56.12rem; 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/10307?format=iframe&autoplay=0" title="Audio Player: Corn Residue Removal - A CropWatch Podcast" allowfullscreen ></iframe> </div>
Comments
0 Comments