Latest / The Illinois Nutrient Loss Reduction Podcast / Episode 16 | Getting the Dirt on Healthy Soil
Transcript
- Episode 16 | Getting the Dirt on Healthy Soil 00:00:06:07 - 00:00:28:00 Todd Gleason This is the Illinois Nutrient Loss Reduction Podcast. Episode 16: getting the dirt on Healthy Soil. I'm extensions Todd Gleason. We're now joined by Andrew Margenot. He's an assistant professor of soil science here on the Urbana-Champaign campus of the University of Illinois. Andrew, thank you for being with us. Can you first define for me soil health? 00:00:28:03 - 00:00:35:13 Andrew Margenot Soil health is a relatively new concept compared to other concepts in soil science. 00:00:35:16 - 00:01:07:26 Andrew Margenot You can think of soil health in terms of where it came from. So the origins of soil health perhaps were really from the Dust Bowl. People talked about soil tilth as a way to mitigate the dust Bowl erosion, loss of soil, and then that got taken care of. So then we see this resurgence in soil quality in the 1980s, and that's more of... building upon the concept of tilth is now quality in an effort to integrate chemical, physical and biological aspects of soils. 00:01:07:28 - 00:01:28:12 Andrew Margenot But that project was not really realized until the last decade or two with soil health. So the difference between soil quality versus soil health is a more explicit focus on the biology of soils. And we find this big emphasis on the microbes that make the cogs of the food chain work in soils. 00:01:28:13 - 00:01:32:17 Todd Gleason So how do you make your soil health soil tilth better? 00:01:32:20 - 00:02:02:23 Andrew Margenot That's a good question and one of ongoing scientific study. I think here we can learn a lot from what people know works. So what I mean by this is what is the objective metric of a healthy soil. And it seems sort of obvious. The term itself is intuitive. We know just like our bodies, what is, a state of being unhealthy, or maybe not so much. When it comes to actually parsing that out down to brass tacks, it gets a little bit more tricky. 00:02:02:25 - 00:02:26:22 Andrew Margenot And this is because a lot of the phenomena or properties that we know are important for soil function. They're tough to compare. So it's sort of apples to bananas. For example, what is a pH of a healthy soil. And how does that get weighed against a biological property like microbial biomass, carbon or a physical one like soil aggregates stability. 00:02:26:25 - 00:02:51:09 Andrew Margenot So these are qualitatively important. But integrating it can be tricky. That said, I think the utility of soil health is in that it makes people think about it keeping roots in the ground to drive the soil food web. And second, not disturbing that process to the greatest extent possible. So to answer your question, what can we do to make soils healthy? 00:02:51:11 - 00:03:06:04 Andrew Margenot Two things that we know definitely work, both scientifically and from what farmers are doing, is to minimize the disturbance of soils and to keep roots as long as possible. And that typically looks like in our part of the world, cover cropping. 00:03:06:04 - 00:03:09:23 Todd Gleason Can it do things to, for instance, reduce phosphorus loss? 00:03:09:23 - 00:03:15:23 Andrew Margenot Potentially. And my favorite answer that is ubiquitous in soil science is it depends. 00:03:15:26 - 00:03:48:29 Andrew Margenot I think there is a lot of work that might need to be done to quantify under what circumstances can cover crops give us a double win of mitigating both nitrogen and P losses. There's reason to think that for cover crops, phosphorus losses might be lessened or perhaps exacerbated. And there's a lot of work to be done here on the species of the cover crop, as well as the timing of when it gets terminated and when there might be a window of vulnerability for phosphorus losses to happen. 00:03:49:01 - 00:04:17:24 Andrew Margenot The reason for this is that there's lots of ortho phosphorus contained in plant cells. So following the termination of that cover crop, there might be a flush of DRP in the runoff. So there's sort of this double edged sword to consider about cover crops when it comes to phosphorus. On the whole though, I think there's reason to expect that cover crops will likely provide benefits to phosphorus losses, or rather, to mitigate those losses largely done by their reduction of erosion? 00:04:17:24 - 00:04:35:14 Todd Gleason Different subject matter, a little bit, when there are large gullies or erosion, as you mentioned in a field, are there things that producers can do and should do to create a better environment and to fix those problems? 00:04:35:17 - 00:04:42:08 Andrew Margenot Definitely. There's two ways to think about this. One is that you can treat the symptom and you can treat the problem. 00:04:42:11 - 00:05:05:20 Andrew Margenot So the symptom is that there's this yawning gap in your field. And so that of course has to be addressed. Or it should be, because the risk of gully erosion is that it feeds back on itself. So it's almost a feet forward process. To circumvent that, the best approach is to fill it in. And there's lots of resources by the USDA, NRCS on what kind of fill. Can you use 00:05:05:20 - 00:05:30:01 Andrew Margenot top soil? Can you use subsoil? The biggest thing would be to fill it, to try not to disturb it for that season. Now that can get tricky. If there's a gully cutting across one's site. So that's the immediate treating that problem, stopping the bleeding, so to speak. Then there's also, I think, some thought that should be given to why is there a gully erosion occurring on my field? 00:05:30:03 - 00:05:52:03 Andrew Margenot It could have been a very bad year. I'm very what you're like, what we're having right now. It could also be that perhaps the traffic is a little bit too much, or the tillage a bit too intense in that part of the field. Are there things that could be done literally upslope, of where that gully has emerged to mitigate the velocity in thus that erosional power of water going downslope? 00:05:52:06 - 00:06:10:18 Andrew Margenot So there might be some simple things like a grass strip, and that can then prevent future gully erosion from happening, because though one might fill it in, if the practices or the conditions that lead to that, well, that lead to that happening don't get addressed, it's likely for that gully to reopen the next season. 00:06:10:21 - 00:06:12:09 Todd Gleason What's your research about here? 00:06:12:11 - 00:06:39:04 Andrew Margenot Three main things. I'm a soil scientist, and I like to think that, well, soils provide a lot of services to human well-being. And the obvious one is we grow food, but we also grow fuel like ethanol. We also grow fiber. We also do things with soils like built homes, both on it and with it, like bricks. So what my lab does is we try to understand how soils function to provide those services. 00:06:39:07 - 00:07:03:01 Andrew Margenot More concretely, we work in three places or in three areas. One is how to manage phosphorus as the Goldilocks nutrient. So globally we tend to have these scenarios of a little bit too much phosphorus. And then in some cases a little bit too little. So on these twin aspects we work in the Midwest and in developing nations in the tropics, East Africa, South America. 00:07:03:04 - 00:07:25:25 Andrew Margenot A second pillar of what we do is looking at high value perennial tropical crops. So here, our favorite crops of coffee and cacao, you know, things that we like to eat. They're grown by smallholder farmers globally in the in the tropical belt. And there's not much knowledge known about how to close yield gaps but also quality gaps with these crops. 00:07:25:28 - 00:07:46:29 Andrew Margenot And finally, we work in more fundamental biochemistry of soils. This gets at, in our applications, for example looking at nutrient cycling. What makes those processes go forward. So we look at things like enzymes and microbes to understand the inner workings of soil function and soil health. 00:07:47:02 - 00:07:58:22 Todd Gleason So that's soil health, soil tilth from the scientists perspective. Andrew Margenots, he again is an assistant professor of soil science here on the Urbana-Champaign campus of the University of Illinois. 00:07:58:24 - 00:08:18:04 Todd Gleason Adam Braun is a Fayette County farmer and a participant in the tri state Advanced Soil Health Training, which was presented by University of Illinois Extension. I asked him to tell us a little bit about his view of soil health, starting with, of course, his operation. 00:08:18:07 - 00:08:34:25 Adam Braun So we're a mid-sized farm, and we farm a good mix of upland ground and river bottom ground, raising corn, soybeans and wheat and, we no till quite a bit and, try to increase our no till acres every year. 00:08:34:28 - 00:09:03:14 Adam Braun And I feel like, you know, maybe our soil diversity has given us a bit of an extra challenge in trying to implement that. As far as a one size fits all system. So while we're not 100% no till yet, we're we're striving for it. And we do no till and minimum till about 95% of our acres and, have a goal to be 100% never till sometime in the next 2 to 5 years. 00:09:03:17 - 00:09:27:22 Adam Braun So we're we're working on that. We've been cover cropping for about ten years, and we're just now to the point where we feel somewhat comfortable in cover cropping, you know, a more sizable portion of our acres. And we'd like to increase the cover crop acres in the futures. And to the point we're at was we started with, one species of, cover crops, you know, monocultures. 00:09:27:22 - 00:09:31:21 Adam Braun And we're trying to move more into the direction of cover crop mixes. 00:09:31:23 - 00:09:33:17 Todd Gleason What do you do to improve your soil health? 00:09:33:23 - 00:09:59:03 Adam Braun I think no till and cover crops are both great steps towards improving soil health. You know, they're important practices to improve soil aggregation. And that's just a fancy term to say basically the the soil structure or the glue of the soil, which helps prevent the erosion and, and helps keep increasingly heavy farm equipment from making tracks and ruts through our fields. 00:09:59:06 - 00:10:25:10 Adam Braun It's, you know, it's important in allowing that water to enter the soil instead of running off down into the ditch, the soil should actually function as as a sponge and not a brick. And that's the point of soil aggregation. That extra water that the soil is soaked in during the spring rain events is a pretty big deal. When you get get farther along into the summer and you get into the to the dry season. 00:10:25:12 - 00:10:46:29 Adam Braun Another thing I firmly believe in a great starter system on our corn planter. So it's all about putting the nutrients where the corn plants can access them, and thereby improving our, nutrient use efficiency. And it's enhanced our corn yields, too, by the way. So how can you go wrong with that? I don't see a downside. 00:10:47:01 - 00:10:50:04 Todd Gleason So have you seen lesser erosion damage in your fields? 00:10:50:06 - 00:10:53:01 Todd Gleason Since adopting the conservation practice? 00:10:53:01 - 00:11:15:18 Adam Braun Yeah. And I'd say that goes without saying. Seeing is believing to me, which is really what one of my favorite things to do during an early spring rain event is to just drive around and look at the water that's running out of my fields, and you can tell by the color, of it, which is clear, by the way. 00:11:15:20 - 00:11:46:23 Adam Braun Now and then you can compare it to neighboring fields that are, you know, manage different a little bit differently. The difference is usually pretty stark. You know, when I, when I compare that clear water running out of my fields to neighboring fields that are kind of muddy and dirty and very brown at that point, I know for certain that we have reduced erosion, and I'll be the first one to admit that, you know, our water not used to not be so clear. 00:11:46:25 - 00:12:12:09 Adam Braun And, not only that, I've seen improvement in the areas in the fields that have had chronic washouts. So we used to have to take tillage equipment around into those areas that were washed out, fill in the ditches, and then we do a tillage pass across the field, you know, just to make everything uniform. And then that tillage pass would destroy our soil aggregation, and then it would wash away again during the next big rain event. 00:12:12:09 - 00:12:25:01 Adam Braun So there we were. We got caught in a vicious cycle. And the important thing is you have to identify that you are caught in that cycle and break it somehow. And that's what we did. And we're not going back. 00:12:25:03 - 00:12:35:16 Todd Gleason Hey, what advice do you have for farmers thinking about adopting practices? Like you have reduced tillage? No till cover crops, improve fertilizer management and the lot. 00:12:35:18 - 00:13:06:25 Adam Braun The most important thing you can do at the start is improve the small things and strive to increase uniformity across all your acres. When you focus on uniformity, improving uniformity, the solutions to the problems that you counter encounter along the way seem to pop out. So I'm talking about like simple things like making sure your combine straw chopper is distributing material evenly. 00:13:06:27 - 00:13:37:26 Adam Braun It's it's an important first step in no tilling the following year. So then find another small thing that improves uniformity and fix that. Pretty soon you'll have a farm uniform enough to be no tilled and cover cropped, but keep an open mind through that transition and enjoy the opportunity to be creative, because that's what you're really doing, is you're really creating a system that works on your farm, and that system that you create will be different than what your neighbors do. 00:13:37:28 - 00:13:55:13 Adam Braun And in fact, it's going to be very unique to your own farm. And that's the part that I really consider to be the fun part, because you get because and you get to enjoy the opportunity to differentiate your farm from the status quo and improve your bottom line along what along the way. 00:13:55:16 - 00:14:06:06 Todd Gleason Adam Braun is a farmer from Vandalia, Illinois and joined us on this Illinois Nutrient Loss Reduction podcast, episode number 16 getting the Dirt on Healthy Soil. 00:14:06:13 - 00:14:09:14 Todd Gleason I'm University of Illinois Extension's Todd Gleason.