(Jim) Good morning folks, welcome to That’s My Farm. I’m Jim Shroyer your host and we’re in luck cause we’re on the agronomy farm here on the K-State campus. And we’re also in luck because we’re gonna be talking to Dr. DeAnn Presley our soil and water quality specialist. And DeAnn is gonna be talking to us in particular about soil management. And I know one thing she’s gonna be talking to us about is soil compaction. So, get your cup of coffee, hurry on back so we can start the show.
Closed Captioning Brought to you by the Kansas Soybean Commission. The Soybean Checkoff, Progress Powered by Kansas Farmers.
(Jim) Good morning folks, welcome to That’s My Farm. I’m Jim Shroyer your host, and we’re in luck because we’re on the agronomy farm, well actually several feet below the surface here of the agronomy farm. And also we’re in luck because we have Dr. DeAnn Presley with us. She is our soil management specialist and DeAnn, tell me what are we doing in this hole? What do you got here? (DeAnn) I’m checking out the soil profile. That’s what we call a vertical exposure of soil. It’s a soil profile. And I can look at a soil profile and I can tell a lot about the soil, how it got here, kind of its history. (Jim) How old it is? (DeAnn) How old it is. I can do that. I know because we’ve got some radio carbon dates from the soil. And also I can tell a lot by looking at the management. How this soil has been used, maybe abused, since the time that it was taken from the prairie and turned into crop land. So, that’s what I’m doing with the soil. (Jim) Well, keep on going. (DeAnn) Alright. So, every soil has a top soil. And in this case, when I pick down with my knife, gets to be from about here to here, that there’s a change. What I would call the top soil here and subsoil in this part. (Jim) Yea, I can see a color change right, just right in here. Right there where you put the knife. (DeAnn) And I agree. And I felt that also. I was feeling it with clay content change. So here in this part of the profile I was feeling it a little while ago, rubbing, making kind of a mud ball. We call that texture by feel. I can feel about 35 percent clay here and about 44 percent clay in this zone. And it’s interesting, that’s a natural process that took tens of thousands of years to happen, where rainwater has come into the soil, moved clay from this part and accumulated it right here. That’s called illuviation. But many, many, many, many soils in Kansas and throughout the Great Plains have that feature, where it’s a little bit lower clay content here and greater clay content here from the rainwater washing it down. Another thing I said, top soil. Top soil is the upper part that’s got lots of organic matter from the plants. So, if this was Tall Grass Prairie, in Tall Grass Prairie about 70 percent of the weight of a plant is below the ground. So, 70 percent is in the roots and maybe 30 percent of what that whole mass of the plant is, is above the ground. So, if you have 30,000 years or so of prairie grasses growing, living and dying, but the roots live and die down here. It accumulated vast amounts of organic matter. So, decomposed plant tissues and so this is… (Jim) And it’s also rich with microbes as well. (DeAnn) Oh definitely. (Jim) Especially active in this top foot. (DeAnn) Very, very active. Yes, if we had a little graph that showed how many microbes with respect to depth, many more microbes very active up here in the top part, and then they get considerably less numbers and less activity down here. (Jim) OK. (DeAnn) Plenty of oxygen from this part. (Jim) So, tell me why is this color difference here? (DeAnn) Ok, so here this black is from the organic matter and once we see colors that are a little bit more brown, that has to do with the main minerals in the soil. And so instead of having so much organic matter now probably most of this color is coming from things like feldspar and micas, some of the quartzes. (Jim) Closer to the parent material is that what you’re getting at? (DeAnn) Yes, exactly. The parent material. So for the parent material for this soil, most of this would have come from thousands and thousand of miles away, then blown in here and mantled the existing landscape. So here in Manhattan, we have the Flint Hills and then less was blown in from places like Colorado, Wyoming, places far away. Sources of dust and deposited as it would fall on the grasslands and accumulate over thousands and thousands of years. (Jim) DeAnn we gotta take a break right now, so stay with us. Don’t run away during this commercial break. And folks, stay with us. We’ll be right back after these words from our sponsors.
(Jim) Welcome back to That’s My Farm. I’m Jim Shroyer your host. And with us we have Dr. DeAnn Presley our soil management specialist and as you can see we’re still in a hole. DeAnn has more to tell us about this soil profile here. So DeAnn, tell us a little bit more, what we have here. (DeAnn) Sure. Well this is probably something most people don’t think about when they think about their soil, but how old is it? And it turns out you can do things like radio carbon date soils. (Jim) You mentioned that a second ago. (DeAnn) Yea. If we take a sample, I can send this in to a laboratory. In fact I’ve done this. And the soil, this part of the soil profile, usually dates to about 20,000 years ago. So, we know that it’s been forming and plants have been growing and living on this surface for about 20,000 years. And if I got down here deep in this profile… (Jim) Even deeper. (DeAnn) Yea, cause there’s actually more layers, we call soil layers horizons by the way, but down here there’s even more deeper layers and this soil is actually older. So old soils are called palevye, like paleontology right? (Jim) Right, the old. (DeAnn) Palevye soil. (Jim) Ancient. (DeAnn) Paleosols. And so paleosols, this paleosol dates to about 30,000 years. (Jim) Really. (DeAnn) So the fact that we do have different layers tells us that there’s been different episodes, different pulses of sediment that have come in, blown in and that’s very consistent with what’s happening with the rest of the continent in that time. So different times where the glaciers were active. Where there was lots of sediment and erosion and erosion someplace else leads to deposition here. (Jim) Right, right. (DeAnn) Really cool. Couple more things I can talk about with respect to layers in soil, is if anybody has a basement then… (Jim) Right. (DeAnn) These colors here can tell us a lot. So in this piece in my hand, I know it’s hard for other people to see, but in the piece in my hand I can see places that are a little browner, maybe a little redder. And other places that are a little grayer. And that means that this soil has a water table that fluctuates and might come up and go down, and come up and go down. And you ask me how often and that’s really impossible to know, unless you had a monitoring well or something here to check that water table. (Jim) But you alluded to basements. (DeAnn) Yes. (Jim) OK, continue that thought process. (DeAnn) Well, you know we’ve all been sleeping and have you ever heard a sump pump kick on in the middle of the night? (Jim) Exactly. (DeAnn) I’m so glad that kicked on. That’s what this soil…first of all it’s highly expansive. I dug this a couple days ago and it was really, really wet and you see all these cracks maybe starting to form now. That tells me that this soil is a clay soil and I can also feel that in my hand. But clay, shrinking, swelling, cracking clays is a really common feature in Kansas, but this color also tells me, yes a water table, it can come up and go down, and come up and go down. So, as far as a basement goes, I think we always want…basements are good things from storms, but also this means it’s gonna be a little tricky and we’re gonna have to deal with some cracked drywall every now and then with the cracking clay like this, is what I would call it. (Jim) Right, right, OK. Well DeAnn we gotta take another break here and maybe we’ll get out of the hole here and talk about some compaction and that sort of thing. So, stay with us. And folks, you stay with us as well. Now’s your time to get a cup of coffee and we’ll be right back after these words from our sponsors.
(Jim) With us we have Dr. DeAnn Presley and we’re standing in a no till soybean field. Corn was last year, this past year. DeAnn you’ve got a funny little machine right here in front of you that I know what it is. But I want to talk about compaction, cause I think that we lose lots of bushels in all our crops from compaction. So, talk to us a little bit about compaction, maybe what soils are a little more prone to it and what this funny apparatus is. (DeAnn) Sure, so I would agree with you, what you said about compaction being…it’s kind of a sneaky yield thief. And that is compaction is always…it shows up really bad in wet years. So if the soil were holding up if there was compaction, which compaction is pretty straight forward in that it’s where we take a soil that normally has a bunch of pores in it and squash out all the air from those pores. So it’s just denser than it should be. In a really, really wet year if this soil was compacted it would pond water. And I can tell you that this soil must not be that compact because yesterday…a couple days ago we had an inch and a half of rain and it’s all soaked in quite nicely. (Jim) Well, that’s what it’s supposed to do in a no till soil. (DeAnn) It is. Yea, this has actually been no till since 1999. So, going on its 16th year of no till. And that of course means without any tillage any more. So the seeds are directly planted into the ground. And over time no till soils actually build up better structure. I have a nice paper I sometimes reference, but it shows the difference between a conventionally tilled soil and a no till soil. You can traffic across this field much more than you could a conventionally tilled field. You’d cause less compaction and be able to do it wetter, all things being equal. (Jim) Well, obviously you don’t want to drive across wet fields, whether it’s no till or conventional. (DeAnn) No. (Jim) But you’re saying you could abuse this a little bit more. (DeAnn) We would say it’s more resilient to compaction. (Jim) OK, that’s a better term. (DeAnn) Soils have resilience, right, that’s a nice way of putting it. So, not that you would, but it’s just that you could. So it resists compaction better because we’ve got more structure. Instead of a bunch of construction materials laying willy nilly, versus construction materials nailed together, right? They’s structure. So, organic matter has taken sand, silt and clay particles and really built it into… (Jim) Well, we saw that a little bit ago, when we were in the pit. That top soil had some structure to it. When we smashed it and before we rolled it into a ball or a ribbon, you could see those, that structure there. (DeAnn) Yep and you could break it open and see pores through it. So, it’s really important. Soils must breathe. They have to get oxygen, needs to get in and carbon dioxide needs to get out. So, that structure and process is very important. (Jim) And also structure is important so the water can penetrate. You know we’ve had a lot of rainfall… (DeAnn) Very wet May. (Jim) …this spring and early summer. And I’m thinking that with soils that won’t hold water, it will help the bacteria for soybeans so we don’t have saturated soils. (DeAnn) Yes, saturated soils, no good for most of our crops in Kansas. (Jim) OK. DeAnn hang on here a second, we gotta take a break. Folks, stay with us. Get a cup of coffee and see us back after these commercials.
(Jim) Welcome back to That’s My Farm. I’m Jim Shroyer. DeAnn Presley is with us, our soil management specialist. And we didn’t get to talk about this apparatus that you had here in the last segment. So, tell us what it is, and what you use it for? (DeAnn) OK. Well, I use this for research. Now it can be used by a farmer or a crop scout or something. But what I use it for is to push on the soil. So, it’s got… (Jim) It’s on now. (DeAnn) Yea, it’s on now. It’s got a little scale in it, just like a bathroom scale, but I’m pushing down on it instead. (Jim) OK. (DeAnn) And so, what I’m looking for…it’s feeling, it’s recording how many pounds per square inches of pressure I’m putting on it at every given depth. And so what you can do is look for these dense layers with it. (Jim) Right. (DeAnn) Now I like it and I don’t like it. Because when I do that I can’t see what the plant roots are seeing. So, the best thing I can do is I can take a measurement or I could use my five dollar spade and dig a hole. (Jim) OK, we’ll get to that five dollar spade here in a second. But what kind of a, what kind of a number do you get? And what does that number really say? (DeAnn) OK, so it gives me a number. Zero pounds per square inch is obviously no pressure. You and I with our feet we’re probably exerting somewhere in the 25ish pounds per square inch, something like that. So this is, simply if I push start, is measuring how much pressure. So, it’s in pounds per square inches. (Jim) OK, let’s do it. (DeAnn) Push this…is the unit. Have to push start. Let’s see…and so I’m getting a reading of about 200 pounds per square inches, maybe a little higher. Maybe 250, 249 right there. (Jim) There you go. (DeAnn) And it’s…so what’s considered root limiting is 300 pounds per square inch. And actually at 300 pounds per square inche is where plant roots aren’t seeing anything. There not going anywhere. (Jim) It’s just too compact, no pore space and they can’t penetrate. (DeAnn) Just, yea, they’re just not strong enough to get through. So either they’ll turn and go a different way, or sideways or whatever they can do. But if you’ve ever seen a plant root growing down and you see it kind of flattened and smashed, if a plant root can’t access the soil, it can’t get at any water or any nutrients stored in that area. (Jim) And you know what I’ve seen over time is a lot of nutrient problems. Deficiencies show up because of the roots… (DeAnn) Yep. (Jim) …not being able to explore their environment. (DeAnn) Exactly. (Jim) OK. Talk to us about that five dollar spade. (DeAnn) Yea, so this thing is pretty expensive and I don’t like it cause I can’t see anything, so if I go get my five dollar or ten dollar spade, my fancy one…(Jim) I was gonna say where’d you get one for five dollars, I wanna go there? (DeAnn) I don’t know. (Jim) OK, well go ahead. (DeAnn) Well, it’s a fancy spade. But if I were to dig this up, the best thing I could do is use a spade to dig up the soybean roots and ask them, how are you feeling today? Look, are they twisted and deformed or are they white and fleshy and healthy, many, many root hairs. And look and see if…do I see big blocks of soil, or do I see more of a crumbly, small blocks of soil hanging off the roots. So, this is OK. But I more use this in a research context and if I’m talking to a farmer or talking to a homeowner, I would be using my spade to get a better look at this. (Jim) And again, you can see the horizons and you can see that compaction zone and you can see the roots going horizontal as opposed to putting down like they’re supposed to. (DeAnn) Yea. (Jim) DeAnn, hang on a second. We’ve got one more segment to do. You folks at home, stay with us we’ll be right back after these words from our sponsors.
(Jim) Welcome back to That’s My Farm. I’m Jim Shroyer and with us we have DeAnn Presley, soil management specialist. And DeAnn in this last section here I want to talk about tillage a little bit. We’ve got a good example of no till here and we…this field right across the terrace here had been in no till, just like this one had been. But it got tilled here a couple weeks ago. So, tell us after 16 years, what’s gonna happen to that and what loss? What did we lose there? (DeAnn) OK. So, when in no till one of the things we do is we build up the physical properties and the organic matter, quite often. So, I’m sure we’ve probably built up the organic matter possibly went from maybe about two percent, maybe to two point four, two point five percent, some where in there. So, I don’t expect that to be wiped out or changed too much over night. Although tillage does increase the oxidation so microbes will get in there. It’s been fluffed up, the microbes will get in there and start working on breaking down that organic matter. So, that will happen a little bit. Also, what I don’t like about it is that now it’s opened up to the possibility of erosion again. Although there are terraces on this farm. Terraces are designed to capture water as it runs. Well, whenever we lose soil from one place and move it to another, it’s lost. It truly is lost. So, we have a lot of our best soil in the world in the Gulf of Mexico forming the Delta, the Mississippi River Delta, right? So, I don’t like to see soil moved so that’s what I don’t like about tillage is it opens us back up for lots of erosion. And so, I don’t think that the organic matter levels have been dropped overnight. But it’s gonna take time again for all the physical pore spaces, for all that to be rebuilt. And that process takes a while. It might take three, four, five, six, seven years, to built that back up again. So, before it starts to really take water as good as this does, I bet that’s gonna take you know, more than a handful of years, probably to build it back up. (Jim) Well, it will be fun and interesting to watch it come back to no till. And they used a disc on that. (DeAnn) They did. And a field cultivator. (Jim) And a field cultivator. (DeAnn) Three passes. (Jim) So, tell us a little bit about that naughty farm implement of the disc. (DeAnn) OK, so a disc is kind of interesting, I was always taught in college it is the implement of compaction. (Jim) Exactly. (DeAnn) So, it’s shaped as a disc. It’s concave. It cups soil and lifts it. And for every action there’s equal and opposite reaction. There’s a great amount of pressure being exerted into the soil. Probably 200-300 pounds somewhere in there. Does that sound familiar? Two to three hundred pounds would be exerted off of the backside. And that then becomes root limiting. And so many times in a tilled soil you’ll find a level of compaction zone that is somewhere in that four to six, four to eight inch kind of zone. (Jim) Right. (DeAnn) So a disc is the number one implement of compaction, no doubt about it. (Jim) OK. Well DeAnn, I really appreciate you taking time this morning to talk to us. Always good to see ya. (DeAnn) Good to see you. (Jim) We talked about cover crops in an earlier episode and so thank you for being with us. (DeAnn) Thank you. (Jim) Folks thank you for being with us as well. And don’t forget next Friday about this same time, we’re gonna have another show on That’s My Farm.
Closed Captioning Brought to you by the Kansas Soybean Commission. The Soybean Checkoff, Progress Powered by Kansas Farmers.