Latest / The Illinois Nutrient Loss Reduction Podcast / Episode 13 | Managing Cover Crops as Part of Your Cropping System: Advice from Experts
Transcript
- Episode 13 | Managing Cover Crops as Part of Your Cropping System: Advice from Experts 00:00:05:18 - 00:00:29:28 Todd Gleason This is the Illinois Nutrient Loss Reduction Podcast. Episode 13 Managing cover crops as part of your cropping system. Advice from experts. I'm University of Illinois Extension's Todd Gleason. Today we'll hear from three different experts and their view of cover crops. We'll start with Barry Fisher. He's with the United States Department of Agriculture and a soil health specialist for Indiana. 00:00:30:02 - 00:00:37:13 Barry Fisher Basically laying out some foundational principles to improve soil health and to improve soil function. 00:00:37:15 - 00:00:52:15 Barry Fisher And then followed up with that is there's, basically management principles that that help help producers trying to improve soil health and soil function. From a management standpoint, what are some some baselines that they need to stop start from? 00:00:52:17 - 00:00:56:16 Todd Gleason So start with the foundational principles. What might they be? 00:00:56:18 - 00:01:15:25 Barry Fisher Well, from a soil health standpoint, if we look across all agriculture enterprises, we find that if we can reduce the soil disturbance, if we can keep the soil covered, if we can add some diversity of plant life, that that gives us diverse food sources for the organisms in the soil. 00:01:15:27 - 00:01:36:23 Barry Fisher And then if we can find a way of since we're feeding the organisms in the soil from the plants, then we need those plants growing. We need living roots longer than just our, our summertime, crops. So therein lies that's why our cover crops fit into to a lot of those four key principles. Cover crops play a good role. 00:01:36:26 - 00:02:05:12 Barry Fisher And so what kinds of things would they promote in the soil itself? Well, the cover crop, because it has the ability after the rest of our crops senesce and go into dormancy and get harvested. There's still a lot of days of sunlight left of free sunlight energy that that cover crop can grab, that sunlight. Energy grabs carbon out of the atmosphere, build sugars, build proteins, build, build food essentially. 00:02:05:12 - 00:02:28:10 Barry Fisher And those actually come out the roots. Those are come out as exudates into the root, into the soil. And that's the foodstuff for many of the really important organisms, the mycorrhizal fungi, the important bacteria that, you know, there's even beneficial nematodes. There's there's a lot of living things in the soil that really help us provide pore space and nutrient cycling in our soil. 00:02:28:10 - 00:02:46:09 Barry Fisher So if we can feed those organisms using that free sunlight energy that we otherwise are not capturing, in the late fall and into the early, earlier spring, before we plant those, we've got those two windows. That gives us a lot of extra feeding potential for the beneficial organisms in the soil. 00:02:46:12 - 00:02:51:18 Todd Gleason So the living Earth then gives back to the crop the next season? 00:02:51:20 - 00:03:11:08 Barry Fisher Sure, it's all part of nutrient cycling. It keeps all of our nutrients. That's what a lot of our conference is about. Keep the nutrients on the land. Keep them in play. If we can keep those nutrients when the crops aren't using it, if they can be assimilated into other living things that are going to cycle them back to the crop the next year, then that's a win for everybody. 00:03:11:14 - 00:03:34:20 Barry Fisher While those organisms are living and assimilating those nutrients, keeping those nutrients on the farm, they're also moving around in the soil. They're producing glues that aggregate the soil, that provide pore space, that allows better infiltration, that allows better water holding capacity of the soil, and more plant available water and more plant available nutrients for a longer period of time into the summer. 00:03:34:22 - 00:04:00:23 Barry Fisher So it's all about improving real soil function. You know, when we talk about soil health, it's not just something to make us feel good. We're talking about real improvements to soil functions that relate immediately back to productivity potential, resilience during tough weather times, and major, major economic, efficiencies in our agriculture system. 00:04:00:25 - 00:04:04:03 Todd Gleason What are the management practices that you talk about? 00:04:04:05 - 00:04:36:03 Barry Fisher Well, when we talk about management, we want to reduce tillage. Okay. If we can reduce the tillage either adopt some strip till or no till that takes a lot of the disturbance. The physical disturbance out of the soil. Okay. And then we look at nutrient management. We time it, we place nutrients less, you know, more of a spoon feeding process that actually takes some of the the chemical disturbance shock out of the system when we put a whole bunch of nutrients at one time, that's kind of a shock to the system. 00:04:36:03 - 00:04:58:13 Barry Fisher So that's a management practice. And it's actually beneficial if we if we spread that application out at a more timely fashion, it's actually beneficial to the organisms too and the soil function. But then we talk about adding the cover crops and managing that cover crop. And we may manage a different cover crop differently depending on what's the next crop in our crop rotation. 00:04:58:18 - 00:05:18:22 Barry Fisher So understanding of conservation crop rotation is also a practice I mean and so we talk about those those type things all bundling into a management system that those practices then are working synergistically toward an overall benefit to the soil function and soil health. 00:05:18:24 - 00:05:30:18 Todd Gleason When you talk about the nutrients that are applied, generally speaking, the source of N would be the primary, and the largest, applications that are made. 00:05:30:25 - 00:05:38:06 Todd Gleason Are you concerned about the other nutrients and how do you deal with N and spreading that out over a larger time frame? 00:05:38:09 - 00:06:03:27 Barry Fisher Well, certainly N, but but phosphorus is a big one to foresee. So as we look at this system, one thing that we do know is as we increase the ecosystem, it increase the biological populations in the soil, there's natural enzymes that are produced that actually release more, phosphorus from the soil, the mineral part of the soil, it detaches, it makes it more plant available. 00:06:03:29 - 00:06:44:28 Barry Fisher So we have to look at that and then decide, okay, should we alter our phosphorus management to this to match this system and the timing of its release. So you know, we start changing, you know, our nutrient management plan. We still focus on the four Rs. But those four Rs may change as we change the carbon cycle and change the, you know, some of those. Nitrogen the same way, if we can get a nitrogen management so that so that, when we're spoon feeding and we get those organisms in the soil, you know, bacteria is very high in nitrogen, you know, so we've got a good bacteria cycling and, and some of the organisms that 00:06:44:28 - 00:07:06:13 Barry Fisher are in there cycling, they're making them, a more stabilized source of nitrogen in the soil that actually gets released in the summertime during maximum uptake. So it provides kind of a, a good nutrient and nitrogen management tool. Just the biology itself does if we know how to manage that. 00:07:06:15 - 00:07:10:02 Todd Gleason One final question. The four Rs stand for what? 00:07:10:04 - 00:07:14:18 Barry Fisher Right rate, right time, right source and right place. 00:07:14:21 - 00:07:15:19 Todd Gleason Thanks so much, Barry. 00:07:15:21 - 00:07:16:16 Barry Fisher All right. Thanks. 00:07:16:24 - 00:07:33:22 Todd Gleason Barry Fisher is a soil health specialist with the United States Department of Agriculture. He's based in Indiana. Eileen Kladivko is also in Indiana, but at Purdue University, where she serves as an agronomist and looks into cover crops. I asked her about her experience with them. 00:07:33:29 - 00:07:39:14 Eileen Kladivko So cover crops generally are a very good tool for improving soil health. 00:07:39:17 - 00:07:57:23 Eileen Kladivko By improving aggregation of the soil or the tilth of the soil, friability of the soil, allowing water to infiltrate into the soil easier, for roots to grow better in the soil, for better aeration, water holding capacity, nutrient recycling. 00:07:57:25 - 00:08:07:22 Todd Gleason If you don't have a problem with soil tilth and there will be a lot of soils in Illinois, maybe Indiana as well that don't have that kind of a problem, does it matter very much? 00:08:07:25 - 00:08:31:26 Eileen Kladivko I guess I would argue that that, although people think they don't have a problem, their soil actually isn't as good as it could be. We actually have a lot of crusting on soils, even though they might be higher organic matter, soil, and so improved aggregation and friability and rooting at the surface can then allow for better water infiltration and better aeration and better nutrient cycling, within that soil. 00:08:31:26 - 00:08:37:11 Eileen Kladivko So even though people might think they don't have a problem, it's not as good as it could be. 00:08:37:13 - 00:08:41:00 Todd Gleason How much of the soil profile are we talking about here? 00:08:41:03 - 00:08:49:29 Eileen Kladivko Cover crops will really affect the top couple of inches, but but their effects can actually go down a couple of feet because their roots are going to be growing that deep. 00:08:50:02 - 00:08:52:09 Todd Gleason And how quickly is the effect? 00:08:52:12 - 00:09:02:00 Eileen Kladivko For some effects you can see something already within the first year. The improvement in the friability and tilth of the surface happens with a good cover crop growth the first time you grow it. 00:09:02:02 - 00:09:05:29 Todd Gleason Can you give me a couple of definitions? First, for tilth? 00:09:06:01 - 00:09:18:14 Eileen Kladivko Yes, tilth. Tilth is that quality of the soil related to how it feels and how it breaks apart, and will roots be able to grow through it? 00:09:18:14 - 00:09:41:03 Eileen Kladivko And is it the kind of soil you would like in your garden that you could kind of crumble apart easily? So, organisms can get in and out of the soil. Earthworms can grow in the soil. Your roots can grow. And friability, give me that definition. Friability is how easy it is to break the soil apart, to crumble the soil in your hands. 00:09:41:06 - 00:09:46:22 Eileen Kladivko So soils in a moist condition and you can easily crumble it. That would be a friability. 00:09:46:28 - 00:09:50:25 Todd Gleason And why are these things good for crops? 00:09:50:27 - 00:10:02:27 Eileen Kladivko Those types of things help crops because it helps the crop roots, first of all, grow and secondly function and take nutrients up. So the plant is not going to grow very well if it can't extract nutrients from the soil. 00:10:02:27 - 00:10:05:10 Eileen Kladivko And improved friability helps with that. 00:10:05:12 - 00:10:11:10 Todd Gleason Turn your attention to water quality and the impact that a cover crop might have there. 00:10:11:12 - 00:10:30:12 Eileen Kladivko Cover crops are very effective in scavenging or trapping nutrients that are in the soil that would otherwise, be lost when we don't have a crop growing. So, for example, in much of Illinois, in Indiana, we have a lot of water that flows through the soil in the in the winter into tile drains. 00:10:30:14 - 00:10:47:23 Eileen Kladivko And they carry nutrients like nitrate, when there's no plant there to take them up. If you have a cover crop there to take it up, it will pick up that nitrate and keep it from getting into the tile drainage water and then recycle those nutrients in subsequent years for use by your cash crop. 00:10:47:25 - 00:10:49:24 Todd Gleason How efficiently? 00:10:49:27 - 00:10:52:27 Eileen Kladivko How efficiently do they work? 00:10:52:29 - 00:11:18:16 Eileen Kladivko They're very efficient. They'll cut the losses by about half quite often. Now, you don't get to use all those nutrients immediately. It's kind of like putting money into the bank, put in a CD, not into an account that you can extract right away. And that's part of our challenges, is talking about we're saving these nutrients. We're building our bank account, but we don't get to withdraw it all right away. 00:11:18:18 - 00:11:20:23 Todd Gleason Over what kind of timeframe are we talking? 00:11:20:25 - 00:11:32:11 Eileen Kladivko Probably 5 to 10 years, which is the challenge that cover crops are, long term investment. And they're not generally going to pay a return, over the short term. 00:11:32:13 - 00:11:37:16 Todd Gleason Do we have that depth of research yet to understand what that return really looks like? 00:11:37:18 - 00:11:40:03 Eileen Kladivko There's a lot of research going on. 00:11:40:05 - 00:11:57:24 Eileen Kladivko But the timing of when it's released is very complicated. Of course. Based on what the weather is based on how much cover crop growth you have, based on exactly what your crop rotation is, what your soil type is. So there is a lot of work going on right now, but we can't provide people with a very definitive answer on your soil. 00:11:57:24 - 00:12:04:06 Eileen Kladivko You're going to start getting that back in four years or six years or seven years. We don't we don't know that yet. 00:12:04:08 - 00:12:10:00 Todd Gleason Are there best management practices for the use of a cover crop and are they regionalized? 00:12:10:02 - 00:12:20:10 Eileen Kladivko Yes there are best management practices for the use of a cover crop. They're somewhat regionalized in the sense of, where we have, different, different climate. 00:12:20:10 - 00:12:35:25 Eileen Kladivko We know that, you know, when you're further north, you're going to have different, different, concerns and different practices than when you're further south. So, yes, there's a lot of advice. There's a lot of good advice available from NRCS and extension in our in our different states. 00:12:35:27 - 00:12:38:13 Todd Gleason Can you give me some of those BMPs? 00:12:38:15 - 00:12:46:23 Eileen Kladivko Well, one would be to, to grow something like a cereal rye before soybeans, which fix their own nitrogen. 00:12:46:25 - 00:13:06:27 Eileen Kladivko And when you're first starting out, don't plant cereal rye before corn because there's the potential to tie up nitrogen. If you do plant cereal rye, then you want before corn, then you want to terminate it early and you want to use starter nitrogen so that the corn crop is not, hurting for nitrogen early in the season. 00:13:06:27 - 00:13:14:00 Eileen Kladivko You don't change your overall nitrogen rate. You just front end load the nitrogen a little bit earlier so that the corn crop can get at it. 00:13:14:03 - 00:13:28:16 Todd Gleason Corn is the problem in the rotation. That includes, a cover crop. However, I think that's related to how early it's put somewhat to how early it's planted with the earlier planting dates for soybeans. 00:13:28:19 - 00:13:32:28 Todd Gleason Do you anticipate that there will be a problem there at some point as well? 00:13:33:00 - 00:13:46:29 Eileen Kladivko No, because it's a it's a different problem. The main problem is the nitrogen tie up, that the cover crop has, before corn, before soybeans. You don't have that issue because soybeans fix their own nitrogen, of course. So even with earlier planting dates, I think we're fine 00:13:46:29 - 00:13:47:26 Eileen Kladivko with soybeans. 00:13:47:26 - 00:14:18:18 Todd Gleason Eileen Kladivko is a Purdue University agronomist. Lowell Gentry is a principal research specialist at the University of Illinois in the College of Agricultural, Consumer and Environmental Sciences. He's been studying the way nitrates move through the soil profile and into the river system for quite some time. I asked him about application rates and timing and how he gets farmers to think about those particular ideas as they relate to their management systems. 00:14:18:18 - 00:14:40:10 Lowell Gentry Yes, we've been looking at, timing of nitrogen applications. So we're looking at, fall nitrogen fertilization versus spring nitrogen fertilization. And what we've found over the last three years is that we're only losing 5% of what we put on, so we're losing about 8 pounds per acre more with fall in than spring in. And we're putting 160 on. 00:14:40:17 - 00:14:58:24 Lowell Gentry So that's 5% of the fertilizer that's being lost. But that is more than 30% of the tile load. And so, we might be losing, 24 pounds per acre, but eight of that came from fall. And so that's, that's where that 30% comes from. 00:14:58:26 - 00:15:04:20 Todd Gleason And so something for producers to keep in mind as they move forward into their growing seasons year after year. 00:15:04:27 - 00:15:19:29 Todd Gleason The other thing that they'll be interested in is your topic for the day here at the Cover Crops conference, and what kinds of things you've been able in your research to discover, as it's related to using these in a crop rotation for grain. 00:15:20:01 - 00:15:26:29 Lowell Gentry We've had really good luck with cereal rye after corn ahead of soybean and in a warm winter. 00:15:26:29 - 00:15:51:20 Lowell Gentry And we had two of them in 2016 and 2017, we had very good establishment and good growth of the cover crop. And, that reduced the tile nitrate load by 40%. And, there was even a beneficial carryover to the next drainage season. So, we were very pleased with, that kind of performance. And, it did not affect the soybean yields. 00:15:51:22 - 00:16:13:22 Lowell Gentry And so, we're we're pleased with that, but we're not sure what we should put in front of corn. Now, after soybean, we know there's quite a bit of nitrogen loss to a tile. Just from mineralization. Following soybean, you've got that low C to N ratio material, and, nitrate is nitrate, and it doesn't matter if it came from organic matter or from fertilizer. 00:16:13:22 - 00:16:37:15 Lowell Gentry It can leach. So, we need something in the rotation, I believe, after soybean. And so this year, we've tried annual ryegrass and radish ahead of corn, and, it doesn't look very good right now. As far as, these cold temperatures, it looks pretty dead. We're hoping it comes back where the cereal rye is hardy, and it looks better, but, we're worried about cereal rye in front of corn. 00:16:37:15 - 00:17:00:07 Lowell Gentry You have to kill it so early to make sure that there's, not a yield drag, and, we're killing it so early, then we don't get the benefit to the tile. So, we're we're also interested in trying wheat as a cover crop ahead of corn and, and killing it with roundup before we plant corn, just like we would any other cover crop. 00:17:00:13 - 00:17:04:09 Lowell Gentry And we might try that if if this annual ryegrass fails this year. 00:17:04:11 - 00:17:16:22 Todd Gleason So annual ryegrass at this point is what you think is the best option for producers who want to try this. What other kinds of things might they consider? And this of course will happen in the fall of 2019. 00:17:16:24 - 00:17:23:05 Lowell Gentry Right. I have not tried, as many different cover crops as I would, of course, like to. 00:17:23:05 - 00:17:55:01 Lowell Gentry We're limited by space in these studies. And I'm sure today at this conference we'll hear some other ideas. But I hear folks talk about triticale and also winter barley. But then I hear downsides, downside to both of them. That the triticale forms so much root mass, that, it might negatively impact corn and then, I heard recently that the, winter barley, may not overwinter very well, especially like this last year. 00:17:55:01 - 00:18:18:11 Lowell Gentry So we just we like cereal rye at this point because it's just so winter hardy. And we've tried oat and radish. So we've tried things that winter kill in front of corn and, we need that benefit of the spring growth. So the, the oat and radish that winter killed had no effect on the tile nitrate, you know, provided some cover, but it it it didn't, take up enough soil. 00:18:18:11 - 00:18:20:15 Lowell Gentry And to reduce the tile load. 00:18:20:17 - 00:18:25:24 Todd Gleason What are your best set of advice for putting this cereal rye in place in the fall? 00:18:25:26 - 00:18:52:18 Lowell Gentry We have tried both, seeding into standing corn and also waiting till corn is harvested so we can drill in. Clearly drilling is the most reliable. But if if you knew there was a rain coming and you had it set up and you could fly it on right before rain, then you can get good establishment, but it's all about, soil moisture if you're flying it on and it's been hit and miss and you hate to see a failure. 00:18:52:20 - 00:19:07:11 Lowell Gentry So, but when it did fail, when we flew it on and we drilled it. But that's added cost. But from an experiment standpoint, we wanted to cover crop, you see. So, I think drilling it after harvest is, is the most reliable way of doing it. 00:19:07:13 - 00:19:19:15 Todd Gleason That's Lowell Gentry from the University of Illinois. We also talked today on the Illinois Nutrient Loss Reduction podcast with Eileen Kladivko from Purdue University and Barry Fischer from USDA. 00:19:19:15 - 00:19:26:24 Todd Gleason He serves as a soil health specialist in Indiana. I'm University of Illinois Extension’s Todd Gleason.