Latest / The Illinois Nutrient Loss Reduction Podcast / Episode 25 | Uncovering the Benefits of Cover Crops
Transcript
- Episode 25 | Uncovering the Benefits of Cover Crops 00:00:06:03 - 00:00:29:12 Todd Gleason This is the Illinois Nutrient Loss Reduction Podcast, episode 25 Uncovering the Benefits of Cover Crops. I'm Illinois extensions Todd Gleason. Today, we'll explore the benefits and challenges of using cover crops in a conventional corn and soybean rotation with a researcher and the farmer. We'll start with Lowell Gentry. He works for the University of Illinois and now joins us. 00:00:29:12 - 00:00:35:12 Todd Gleason Thank you, Lowell, for taking the time. Can you tell me a little bit about yourself and your research? 00:00:35:14 - 00:00:57:07 Lowell Gentry I am a principal research specialist in agriculture in the Department of Natural Resources and Environmental Sciences. And, I've spent most of my career looking at the nitrogen cycle. So, I started out as, a trained agronomist in, soil fertility and plant nutrition. 00:00:57:09 - 00:01:30:24 Lowell Gentry And, we've been trying to tighten the nitrogen cycle, through all this research, trying to get the, the fertilizer to the intended crop with as little loss as possible. So my work had been about, improving fertilizer recovery, but, I entered into the water quality world, in the early 90s when we started doing constructing wetland projects to use wetlands at the end of tiles to remove nitrate. 00:01:30:24 - 00:01:53:15 Lowell Gentry And so I was thinking, man, this is great, but, we're just treating the symptom. And, why is all this nitrate coming out of the tile? So we started doing more research in the field, and, much of that was the timing of an application fall versus spring versus split applications. And now we've, tried cover crops as well. 00:01:53:21 - 00:01:56:00 Todd Gleason Where do you conduct all of this research? 00:01:56:03 - 00:02:17:02 Lowell Gentry Almost all of our research is on farm. So we're we're taking it to the real world. We're looking at, tile drainage from pattern drain fields. Some of these fields are as large as 50 to 75 acres. So our plot size is that large. It's hard to get replication in those situations. 00:02:17:02 - 00:02:29:26 Lowell Gentry But if you do the research long enough, you start seeing that, management of nitrogen and the rotation effect, all of those things certainly play into how much tile nitrate I see. 00:02:29:28 - 00:02:33:27 Todd Gleason On the rotation effect, what do you see from cover crops? 00:02:33:29 - 00:02:45:20 Lowell Gentry Well, the first time we tried cover crop, in our, in our replicated study and in Douglas County was, the winter of 2015 to 2016. 00:02:45:20 - 00:03:13:07 Lowell Gentry And we tried cereal rye after corn. I had a soybean, and it grew very well. It was a warm winter, and we reduced the tile nitrate load by more than 40%. And, so we were off to a really good start. Proof of concept that, cereal rye can act as a cover crop, act as a catch crop, and, soak up a lot of nitrogen that was, heading towards the title. 00:03:13:07 - 00:03:40:18 Lowell Gentry Possibly if we get enough rain. Nitrates, nitrate. It doesn't matter if it comes from fertilizer, if it comes from, mineralization of soil organic matter. Once nitrogen and nitrate form they can move with water to tiles. And cereal rye does a good job of, sucking it up and keeping it in the plant. And then hopefully that's released over time and gets into our intended crop. 00:03:40:20 - 00:03:46:20 Lowell Gentry And so we just minimize the amount of nitrate that's available for leaching when we have a cover crop. 00:03:46:22 - 00:03:56:29 Todd Gleason Is it a challenge to incorporate that into the same year rotation? Meaning I this is seeded in the fall and then has to be eliminated at some point in the spring? 00:03:57:01 - 00:04:03:25 Lowell Gentry That's right. And and I do believe that the overwintering type cover crops work best. 00:04:03:27 - 00:04:30:02 Lowell Gentry We try to oat and radish for a few years, and we just never got enough biomass and Nitrogen uptake to, impact the tile load. But we are generally drilling cereal rye in after corn, and so that's usually in October. This past year was November. November 10th is when we got our cereal rye planted, but, it's doing pretty well. 00:04:30:05 - 00:04:56:14 Lowell Gentry We, terminated, I had a soybean, but last year in one field we were unable to get in. Was too wet. Unable to get into spray. So we actually planted green, something I've never actually seen myself. We were planting into a three foot tall cereal rye that was heading out. But we still got a very good yield from that. 00:04:56:14 - 00:05:07:12 Lowell Gentry So we think that cereal rye after corn, ahead of soybean is the safest place to start. If you want to try introducing a cover crop into your operation. 00:05:07:14 - 00:05:20:27 Todd Gleason You know, you somewhat boldly stated in a recent, report for the Illinois Nutrient Research Education Council that it takes about half a ton per acre of above ground biomass. 00:05:20:27 - 00:05:40:17 Todd Gleason You mentioned that, or at least biomass. And I'm wondering whether cereal rye has a significant impact on reducing tile nitrate concentrate loads and how you get to that much, that, that half ton an acre or a point 4 or 5 tons per acre? 00:05:40:20 - 00:05:57:22 Lowell Gentry Yes. I'm sort of, triangulating on that number, because when I see biomass accumulation above a half a ton per acre, I also see an effect on tile nitrate, meaning the concentration goes down. 00:05:57:24 - 00:06:26:28 Lowell Gentry Even a huge cereal rye crop doesn't take the tile nitrate all the way down to zero. But I've seen it below one part per million. When we have, closer to one and a half to two tons. That's a lot of biomass, and I do. I am concerned that that can interfere with the next crop. So we're trying to get just enough biomass to reduce the tile nitrate load, but not impact the next crop. 00:06:27:01 - 00:06:28:07 Lowell Gentry In any negative way. 00:06:28:14 - 00:06:35:04 Todd Gleason Does it have to do with tracking the number of degree days, growing degree days? 00:06:35:06 - 00:06:57:18 Lowell Gentry It does that we, we have a pretty good regression and relationship with, growing degree days when we drill, plant after harvest. And it seems like we need about 800 growing degree days to get about a half a ton of above ground biomass per acre. 00:06:57:21 - 00:07:21:11 Lowell Gentry And, we have tried flying it on, and, and that's hit and miss. It really matters if you get a rain right after you, apply or seed. But when you do that, that's often in September. And I've looked at the growing degrees when we plant that early compared to, say, middle of October, beginning in November. 00:07:21:14 - 00:07:54:12 Lowell Gentry And we might have 2000 growing degree days, yet we don't have any more biomass because the stand was thin and it's shaded for maybe a month as the crops drying down. So I don't have a good relationship yet. We're going degree days when we plant that early and have these other confounding factors, but when when we drill it and we have a really good stand, it looks like you don't really need any more than a, a half a ton per acre to have a significant impact on tile nitrate loads. 00:07:54:12 - 00:07:59:20 Todd Gleason So those 800 growing degree days pile up in the fall and not the springtime. 00:07:59:22 - 00:08:16:18 Lowell Gentry Yeah. That's right. So when we when we plant, we've planted, as early as the first week in September, we've, flown it on. We've also used a high clearance machine. And, the both of those are broadcast, and it depends on that rain. 00:08:16:20 - 00:08:41:15 Lowell Gentry And you don't know how long the seeds sat there not germinating. If we're not looking at all the time where the seed goes in the ground, it's got good soil seed contact, good moisture and germinates immediately. The seed made germinate, at sporadic times when, when it's broadcast. And it's just hard as a to get this relationship between growing degree days and biomass. 00:08:41:15 - 00:09:09:20 Lowell Gentry But but I'm pretty pleased so far that I, I can say that, for example, last year we got 0.6 tons per acre, on a farm in Piatt County that was cereal rye after corn. And, that was actually in continuous corn and that, that amount of biomass dropped that tile, from about, eight parts per million down to, almost one part per million. 00:09:09:23 - 00:09:43:28 Lowell Gentry So it was a really nice effect. But there is this tradeoff of how much biomass is, is enough to affect the tile but not negatively impact the next crop. Well, that's we don't have to worry about that as much in front of soybean, but in front of corn. So far, it's a real balancing act, and I'm not out there willing to say we should all be doing cereal rye in front of corn, but we do know that we lose substantial amounts of tile nitrate following soybean production. 00:09:44:00 - 00:10:16:19 Lowell Gentry And it seems like we're carbon limited after soybean, and that the nitrate that mineralizes after soybean harvest is a substantial contribution to the tile and therefore the river. So we do need to cover crop after soybean ahead of corn. But I'm not willing to say cereal rye for one, because I've seen yield hits with, more than a half a ton of biomass, the yield of the corn. 00:10:16:27 - 00:10:52:26 Lowell Gentry So this year we're trying winter wheat after sorghum. Because there's only two plants that I had out there that survived that winter vortex back in 2018. And, and it was cereal rye and winter wheat. Both of those survived -20. So we're going to try winter wheat as a cover crop. And, in fact, we just sprayed that, last Monday, at one of our farms, because the biomass, it was getting close to what we thought was, the right amount. 00:10:52:26 - 00:11:11:22 Lowell Gentry But we don't want to impact the corn yield. So it's a trade off. It's a balancing act, at least in front of corn. For soybean. It doesn't matter as much how much the, cereal rye grows. But in front of corn, you can have too much of a good thing. And it's not such a good thing. 00:11:11:29 - 00:11:14:29 Todd Gleason When you say the biomass was close to the right amount for you. 00:11:14:29 - 00:11:23:07 Todd Gleason Talking about half a ton. And, And what does the winter wheat crop look like? Is it. I don't know how tall it would be at that point. 00:11:23:09 - 00:11:44:21 Lowell Gentry It it's smaller. It definitely, so that's why we chose winter wheat in front of corn because, it doesn't take off in the spring as quickly as the cereal rye. And so it's, it visually looks like, quite a bit less biomass than cereal rye. 00:11:44:24 - 00:12:05:18 Lowell Gentry But it was a nice stand. And, we want to, you know, if all goes well, we'd like to plant here, plant the corn in late April. And so, you know, we've already chilled it. We were for cereal rye in front of corn. I think you need at least two weeks. Termination to be at least two weeks ahead of planting. 00:12:05:21 - 00:12:12:17 Lowell Gentry And so we're just sort of assuming that's the right thing to do in front of, of corn with winter wheat as well. 00:12:12:19 - 00:12:25:15 Todd Gleason And in this case, winter wheat would help control, I suppose, the, the winter annuals. And when you come back in, it's just your regular normal burndown, for wheat control, prior to planting. 00:12:25:18 - 00:12:26:20 Lowell Gentry That's right. 00:12:26:23 - 00:12:48:08 Lowell Gentry We also, put strips in in the fall. I forgot to mention that, we really like, strip till with, our cover crops, with the cereal rye or the winter wheat. If it's in front of corn where we're stripping and, that seems to work very, very well on, on our very flat soils that are pattern drain. 00:12:48:12 - 00:13:06:13 Todd Gleason Oh, wait. So you essentially have, the, the strip there and between the rows, then you have the cover crop. Yes. We plant the cover crop before we make the strip. So we do till some of the cover crop in the fall when we make our strips. You know, we can't always get our strips made in the fall. 00:13:06:13 - 00:13:30:15 Lowell Gentry Sometimes we make them in the spring. And I would never, recommend no tilling corn into cereal rye. Those strips make a big difference. You know, they create about a ten inch swath out of the 30 inch row that is disturbed and and that that makes a nice seed bed. And, it warms up more quickly. So that's why we're we're liking strip till with cover crops. 00:13:30:15 - 00:13:49:21 Lowell Gentry We are concerned with no till, but we are no tilling our soybean into cereal rye. Cereal rye, with the ability to fix its own N, it doesn't seem to be bothered much by cereal rye. And we get such good weed control with cereal rye ahead of soybean as well. 00:13:49:24 - 00:14:02:13 Todd Gleason So for those farmers who want to try this conventional tillage and strip till work okay in the soybean side and no till was a yes or no? 00:14:02:16 - 00:14:07:21 Lowell Gentry No till works very nicely with soybean into cereal rye. 00:14:07:23 - 00:14:31:03 Lowell Gentry So that's, that's something we're doing. We did try strips in front of soybean one time, but then we'd have to go back to 30 inch rows, and we're generally in 15 inch rows. But we thought with or 30 inch row, maybe that'll help us get our, our cover crop. Growing quicker. When we seed it into, standing, soybean. 00:14:31:05 - 00:14:45:15 Lowell Gentry But then again, that's in front of corn and, I'm not necessarily saying sure arrives the right one, but we're trying winter wheat and, have also been recommended that we try, winter barley, but, haven't tried that one yet. 00:14:45:17 - 00:14:49:01 Todd Gleason Any advice for producers who want to give this a try? 00:14:49:03 - 00:14:52:23 Lowell Gentry I believe trying cover crops for the first time 00:14:52:25 - 00:15:25:22 Lowell Gentry is safest ahead of soybeans. And cereal rye is such a hardy overwintering cover crop, and it's a simple place for us as researchers to start. And also farmers. It's not a mixture. It's not, it's not very expensive seed. And, it's, it's just very reliable. So we did, create a guidebook, with, Illinois Fertilizer and Chemical Association and, and, and NREC, Nutrient Research and Education Council. 00:15:25:27 - 00:15:52:25 Lowell Gentry We put out a sort of a guide book for beginner cover crops. And, and on this we've updated it and, it's called considering cover crop. And, it can be found on the NREC website. And, there's a host of authors and various, research that's shown in that document to, to back up what we're saying. 00:15:52:25 - 00:16:15:28 Lowell Gentry So I'm not sure I knew that, half a ton per acre at the time, but, that's still not as important ahead of soybean as it is ahead of corn. So I I'm just not ready yet to recommend cereal rye in front of corn. I know people are using it and they're having success, but you have to be really vigilant and really be on top of it. 00:16:15:28 - 00:16:26:19 Lowell Gentry And so I think it's just simpler. And, and easier to try cereal rye in front of soybean for, for your first foray into cover crop. 00:16:26:21 - 00:16:46:06 Todd Gleason Again, if you'd like to get a look at that cover crop guide, that's Cover Crop Guide 2.0. You can find it on the Illinois NREC website. That's an Illinois N R E C dot org, Illinois NREC.org. In the menu you'll look for resources and then technical information. 00:16:46:08 - 00:16:50:27 Todd Gleason Hey, Lowell Gentry from the University of Illinois, thank you so much for taking the time with us. 00:16:51:04 - 00:16:52:03 Lowell Gentry It's my pleasure. 00:16:52:05 - 00:17:05:29 Todd Gleason Brian Corkill is now here. He's from VA farms out of Galva, Illinois and has been doing some conservation practices. Brian, thanks for being with us. Can you tell me a little bit about, your farm and your operation? 00:17:06:02 - 00:17:34:21 Brian Corkill Sure, Todd. And I'm glad to participate. So I farm have raised corn and soybeans in, Henry and Stark counties in Illinois, I farm with my dad. Came back to the family farm in 1992 after I graduated from the University of Illinois. My family's always been conservation minded. So currently some of the things that we do at our farming operation were, 100% no till on soybeans. 00:17:34:23 - 00:18:03:00 Brian Corkill We strip till ahead of corn. And with that, we're expanding purpose of NP and K. So we put on dry fertilizer as well as, running a little bit of anhydrous in the fall if the fall cooperates. We also have implemented the use of cover crops about ten growing seasons ago. So we have probably have cover crops planted around 100% of our acres. 00:18:03:03 - 00:18:10:11 Todd Gleason And tell me about the acres themself. Do they roll? Why did you start to use cover crops? What was it? Was it erosion control? Was it something else? 00:18:10:13 - 00:18:24:25 Brian Corkill Yeah. So originally we started planning cover crops. I guess it was for some for erosion control. We farmed some really flat ground, but we had some pretty rolling ground as well. 00:18:24:27 - 00:18:41:13 Brian Corkill So. Yeah. So I think I was the first thing that drew it to us to cover crops was for erosion control and maybe some, compaction relief in areas of fields where maybe we loaded semis or drove the grain cart a lot, things like that. 00:18:41:15 - 00:18:45:18 Todd Gleason And have you noticed any changes in the soils of the crops since you implemented? 00:18:45:20 - 00:19:14:12 Brian Corkill Actually, it's kind of hard to measure. We're we're actually, a field cooperator for soil health partnership, trying to learn a little bit more about how we are making changes to the soil from from a measurability standpoint. That being said, visually we've seen differences in the soils and we've actually sold it to Soil Health Partnership, but some of it on our own, we do see it. 00:19:14:12 - 00:19:42:08 Brian Corkill So typically it, yield improvement, especially in soybeans following a cover crop. And, and so as I said before we started for soil erosion. But now we're we're looking at more of looking at cover crops as, as a way to improve soil health more than anything. So, just trying to figure out how to measure that. And other than, you know, visuals and things like that. 00:19:42:10 - 00:19:46:11 Brian Corkill So that's part of why we joined up with Soil Health Partnership. 00:19:46:13 - 00:19:59:23 Todd Gleason Over the last decade, how have you changed the cover cropping system, meaning have you changed what cover crop you use? And what were the good things and the bad things that did and did not work? 00:19:59:25 - 00:20:10:16 Brian Corkill Yeah. So when we first started planning cover crop and growing seasons ago, we started out with using, annual rye grass. 00:20:10:19 - 00:20:39:17 Brian Corkill You know, it's great. It roots deep, does a good job of sequestering nutrients from the soil. The problem is, in our geography, pretty hard to get it established after harvest and have it survive the winter. And we even tried a couple of years of applying it on to the standing crop to try to get it started earlier, but we just had a lot of trouble getting it to overwinter, so we switched. 00:20:39:17 - 00:21:09:13 Brian Corkill After a few years we switched to using cereal rye and winter barley is just kind of what we used for the most part. We do have probably 40% of our acres. We'll use the more diverse mix. We'll throw in, several different types of oats, some radishes, turnip, rape seed, winter peas, just trying to get more diverse roots in the soil for different effects. 00:21:09:16 - 00:21:13:25 Brian Corkill All of the health that only a few soil health but sequester nutrient. 00:21:13:27 - 00:21:15:12 Todd Gleason How do you kill it in the spring? 00:21:15:15 - 00:21:30:23 Brian Corkill Typically we use glyphosate, that will terminate it ahead of corn, we like to do it about two weeks before we plant, or till we're sure that the cover crop dies. And so we have with the possibility of having allelopathy. 00:21:30:25 - 00:21:47:29 Brian Corkill So that's why that's why we try to terminate cover crop ahead of corn, you know, give it a couple of weeks to die down so there's less chance of allelopathy. Although last, last spring I planted in green into the cover crop. Well, that's that's the other thing you could do is you could plant green into it, but. 00:21:48:01 - 00:22:00:18 Brian Corkill So I'm not sure that I'm comfortable really doing that yet. Wouldn't feel like did it in last year. I was kind of forced into it because of weather, but that it worked out all right. That allelopathy can be an issue too. 00:22:00:18 - 00:22:07:01 Todd Gleason When when you say you terminated about two weeks ahead of time, is that essentially just doing a burn down? 00:22:07:03 - 00:22:32:23 Brian Corkill Yeah, yeah, that's we're doing a burn down. We'll, we'll put in our residual herbicide with that, with the glyphosate if the cover crop isn't too big. We put nitrogen on ahead of planting with our sprayers. So if the cover crops not too big we’ll throw 45 pounds of nitrogen. As 32% in with the chemicals. 00:22:32:25 - 00:22:57:20 Brian Corkill At that time, if the cover crop happens to be, I'd say, over 10 or 12in tall. I have terminated it or sprayed it to terminate it. And then a day or two later I'll go back in and I actually with the same sprayed on a stream nitrogen over the top of our strips, rather than broadcasting it just so we have less likelihood of a tie off in the current crop. 00:22:57:25 - 00:23:00:16 Todd Gleason Do you side dress the rest of the nitrogen in? 00:23:00:24 - 00:23:25:24 Brian Corkill Yes. So we we run a Higgins sprayer and we run wide drops of that. So I'll do my last pass of nitrogen typically around the 12 to 16 corn size. And at that time we also we throw in some potassium sulfate for a little bit of potassium and mainly for sulfur is what we're using it for. 00:23:26:01 - 00:23:27:06 Todd Gleason How do you handle soybeans? 00:23:27:06 - 00:23:55:17 Brian Corkill Those soybeans we have, gone to we plant soybeans green, so I'll either spray it to terminate it the day before I plant the field, or maybe 4 or 5 days after I plant it. And they will terminate at that time and whatever size it is, in 2017 I was planted in to cover crop that was six foot tall, it was soybeans. 00:23:55:17 - 00:24:17:00 Brian Corkill And that worked out great. And actually that year we were able to, curtail some of our post herbicide applications and soybeans because we had a good growth of cover crop, and we had to mat of residue on the soil surface, we didn't really have to do or we didn't have to spray all or acres post to keep the weeds down. 00:24:17:00 - 00:24:21:14 Brian Corkill And we didn't have any leadership skills. That was kind of an added benefit. 00:24:21:17 - 00:24:31:27 Todd Gleason Do you have no till acres that you don't use cover crops on, and what are the differences between the soil condition between the cover crop and and non cover crop no till? 00:24:32:03 - 00:24:43:09 Brian Corkill Yeah. So a lot of years we built. But once in a while if we don't get over acres covers because of weather or maybe we did purchase enough seed ahead of time or something like that. 00:24:43:09 - 00:25:10:03 Brian Corkill We'd have had to split fields. In a wet year, I like planting soybeans into a green cover crop because it tends to dry the soil out faster. So it is it uses up a tremendous amount of moisture, especially as it gets closer to pollination time for the cereal, rye and the barley. So that helps dry the soil out. And soil conditions are actually better than than where we just have to spare no tilled ground. 00:25:10:05 - 00:25:24:14 Brian Corkill And conversely, I mean, if you if you were terminated at the wrong time, then that that should be an adverse effect to having a cover crop, because that the days before you get into plant it it and it becomes more ground safe, that takes longer for it to dry out. 00:25:24:14 - 00:25:27:29 Brian Corkill Do you run any special equipment on your planter? 00:25:28:01 - 00:25:52:21 Brian Corkill No, not really. I guess the one thing I will say is, and I know a lot of guys run, but not everybody does. We run vision planting, clean sweep. We can put down pressure on our residue managers. And, that does a pretty good job of making, a strip, per se, when you run through the field with when you're planning. 00:25:52:21 - 00:26:12:02 Brian Corkill So then the beans have about a ten inch wide strip where they're not really competing with the cover crop to try to get up and get going. But other than that, you know, we just run. Well, we have all the precision placed, we have downforce and, you know, stuff like that. But you know, nothing really special. 00:26:12:05 - 00:26:15:14 Todd Gleason Any advice for farmers who want to try cover crops for the first time? 00:26:16:24 - 00:26:53:27 Brian Corkill I guess, if you start now my recommendation would be to maybe start out with a species of winter field, they're a little easier to manage some of you don't have to worry about the spraying and and things like that. You can still get some benefit out of it. Gauge if you wanna skip that, skip that route and go right into things like cereal rye and barley and things that that overwinter, just have hope in conversations with your, you know, your retailer in your if you work with a consultant or independent agronomist or something like that and, and have a plan going in the spring and how you how you 00:26:53:27 - 00:27:18:20 Brian Corkill want to terminate it, how you want to handle it, you may have some, disasters in the spring if you're not not prepared to manage it in the spring. So, you know, make sure you get it terminated a lot of times ahead of corn, a lot of times if you have a cover crop, you should probably put on some some nitrogen right around planting time because there could be some extra nitrogen tied up to break down residues. 00:27:18:22 - 00:27:26:23 Brian Corkill You I have seen that happen and it could be kind of disappointing. So, I guess those are the main things. 00:27:26:26 - 00:27:42:18 Todd Gleason That was Brian Corkill from VA Farms in Galva, Illinois, he and Lowell Gentry, a principal researcher in the College of Agricultural, Consumer and Environmental Sciences, joined us for our episode 25 of the Illinois Nutrient Loss Reduction Podcast. 00:27:42:20 - 00:28:04:24 Todd Gleason The program was produced in conjunction with Illinois Extension watershed Outreach Associates Jennifer Woodyard and Haley Haverback Gruber. As described in the State of Illinois Nutrient Loss Reduction Strategy, Woodyard works in phosphorus priority watersheds and Haverback Gruber's work is with nitrogen priority watersheds. I'm Illinois Extension's Todd Gleason.