Stu Duncan

(Jim) Good morning folks, welcome to That’s My Farm, I’m Jim Shroyer your host. And today we’re in the greenhouse because it’s a little too cold outside. But we have Stu Duncan with us and he’s gonna be talking to us about things we need to be thinking about prior to soybean planting. So folks, stay with us. We’ll be right back after these words.

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 today we’re in Manhattan, Kansas. We’re in the greenhouse because it’s a little too chilly outside, but it’s soybean planting time in a month or so. So, what we’re gonna do is we’re gonna talk with Stu Duncan today. And we have Dr. Stu Duncan with us and he is our northeast area Extension Agronomist and covers all crops. And so we’re gonna talk soybeans today Stu. What should farmers be thinking about at this point, prior to planting time? (Stu) Well Jim good question. I’m glad to be here and thank you… (Jim) Thank you. (Stu)…for having me here. The big things that a person needs to look forward to as he’s getting ready to plant, first he needs to have his machinery ready. But let’s get to the agronomic part of it. (Jim) OK. (Stu) That’s the real important thing. The… I think maturity group selection and planting date, especially planting date in Kansas can be quite important. If a guy’s growing beans on dryland acres, it’s gonna be a little bit different than if they’re irrigated. And that’s what we found the past few years. But at some of our soybean schools that we had the first week of February across the state we covered a wide range of the area. A lot of the folks will see in the popular press work from Nebraska, from the corn belt, further back east on planting dates and will see things like you lose a third to almost a half a bushel for every day they planted after May 1st, for everyday in Nebraska. Now, that was a two year study, and one thing to remember is when they did that in Nebraska they were on sandy, well-drained soils. So, they weren’t gonna retain moisture very well or they weren’t gonna get soggy like we can get in Kansas. (Jim) East central Kansas. (Stu) In heavier soils. So, those with higher water holding capacity use some judgement with that. Soybeans- we have seen decreases in planting the first of May in Kansas and over several years some of the different studies we’ve had around the state, we’ve also seen losses, if ya got ’em, that first week of May. But generally I don’t like to plant by the calendar but somewhere from Mother’s Day to Memorial Day there’s not much difference in our yields overall. (Jim) You get into June now we’re talking some serious yield losses. (Stu) Ya, so once you get past about the 10th of June you’ll really see some drop-off, unless you’re in that southeast corner of the state where traditionally they’ll plant in June with those Group 5. So, the bulk of the state plants a Group 3 or Group 4. (Jim) Right. (Stu) The indeterminate varieties and that was of course, a little further north, those guys tend to… or those beans will tend to function pretty close to the same, yes they’ll differ from year to year. One thing we used to see at Hesston when our experiment fields that the Group 3’s or the Group 4’s would either yield three to four bushels better than each other every year, but you didn’t know which one it was gonna be. (Jim) This year, yea. (Stu) When it rains is very key. Soil temperature will play a big key in that too. (Jim) What’s the soil temperature we should be looking for? (Stu) I don’t like to see beans put in the ground under 60 degrees. I know guys will push it up to 57 or 58 degrees. Those oil seeds can get shocked and they don’t recover when they get a chilling injury. They may grow all year, but they’re not gonna put on very many beans and they’re gonna be chronic looking. Just the issue with them has been, once they get that cold shock they just don’t perform very well. And so we like to be careful…that’s when we plant, earlier in May we plant we tend to catch fronts a little more often that can dump a cold rain on and it will stay cool for two or three days. (Jim) And the longer the beans stay in the ground the more chances of disease problems… (Stu) Absolutely. (Jim) …and emergence problems. Stu hang on. We gotta take a message here. Folks, 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 we have with us Dr. Stu Duncan and we’re inside in the greenhouse here on the campus of K-State because it’s just a little too cold outside, but we’re thinking about soybean planting. So, Stu we talked a little bit a second ago on planting dates and soil temperatures. You’ve done some work on seed treatments and associated with planting dates. And that’s… so talk to us a little bit about the seed treatment data that you’ve done. (Stu) OK. Yea, that’s a really important aspect, especially if a grower’s planting early. And by early I mean soil temperature at 60 degrees, or right in that 60 degree area which in a no till situation that’s going to run almost to Memorial Day. (Jim) Right. (Stu) Dependent of course upon the previous crop and what kind of residue cover he’s got there. On a conventionally tilled, clean tilled field, the fungicide treatments just
don’t… you can go without them a little sooner. Maybe a week or so quicker. We had a rule of thumb at one time if it was…if you were planting no till, Memorial Day was the… you better have the seed treated until Memorial Day if you were conventional tilling. After Mother’s Day or the 15th of May you were OK. Not necessarily always true but… (Jim) OK. I’ll give you a lob here, why, why the seed treatment, why the importance? (Stu) The seedling diseases. The longer the soybean sits in the soil, it’s got to pull a lot more moisture, just the total amount of moisture that seed… because of a side has to absorb before it will germinate and emerge is much greater than say a wheat seed or sorghum especially. But that seed…soybean seedlings are pretty subject to being attacked by phytophthora, epithelium, there’s some other fungi out there that can wreak havoc, not very often, but when you’ve got ’em, you’ve got problems and you’re replanting. (Jim) OK, so let’s talk about some skips in the stands. I’m thinking associated with poor stands and that sort of thing. We don’t like to see any skips, but it’s not probably as important as with corn. (Stu) Exactly, that’s been the findings of something that we’re putting the data accumulated our results that I had from some years back. In a 30 inch row, I don’t have as much on 15s or 7s or 10s. But it took about an 18 to 2 foot, 18 inch to 2 foot long gap, to really see much of a yield drop on the soybeans, because of their ability to branch and to throw on those extra seeds. (Jim) Fill the middles up. OK. Well Stu hang on. We’ve got to take a break here. And folks, now it’s time to go get that cup of coffee and we’ll be back after these words.

(Jim) Welcome back to That’s My Farm and we’re in luck today because we have Stu Duncan with us, still with us. And Stu we’re talking about soybeans obviously. Let’s talk about row spacing. That always seems to be a hot topic no matter what or when. So what do we have on row spacings now? (Stu) Jim, that’s really a good question cause it has changed. Our thought processes over time because of some of the changes we’ve seen in equipment and in the adaptability and in our management of our soybeans. Still the yield level potential will determine what you… where we’ve got those high, going 45 bushel and above, you’re probably gonna see a, consistently see a not always a big yield response, but a consistent yield increase with a 15 or a 7 1/2-8 inch row even a 10 inch row. (Jim) Over the 30 inch? (Stu) Over the 30’s. You won’t see much of a difference between those really narrow ones and the 15 inches though, however. So, but you will see and that’s again in a high yield environment. When we get in an environment of 30 bushel or less potential, it doesn’t make much difference. And a 30 is depends on the equipment you’ve got. (Jim) So, tell me this, why is it that we have a yield advantage going from 30 inch rows down to 15?(Stu) Jim, what we see is sunlight is usually not our big limiting factor here in Kansas, it’s usually moisture. But by narrowing those rows up we can intercept more of the sunlight and get a quicker canopy closure. With the advent of some of our other issues we have like herbicide resistant weeds that canopy closure quicker is gonna be a big issue again. It was a big issue prior to the glyphosate and the Liberty soybeans being released. When we took all those out in the 30’s it wasn’t a big deal but we need to get… by getting those rows narrowed, we close that canopy quicker, we like to see it and I am stealing this from Jim Specht at Nebraska, green to the eye by the fourth of July. And to do that the planting date plays a role in that, but those narrower rows will canopy much quicker. (Jim) And you were talking 30-35 days as opposed to 45-60 days and 30 inch rows. (Jim) Absolutely and that’s gonna save on evaporation. You’re gonna be… your water loss is gonna be through transpiration, which is where we want it. (Jim) Right. (Stu) More T, less E. (Jim) So, basically light is not the problem here and further south you go. So, in the north tell me why we basically see consistent yield increases with the narrow row spacing in the corn belt or further north? (Stu) Jim, it’s a matter of growing season. And the ability to push that plant through its reproductive phase and get it to where we have some green. (Jim) So that’s why, like I said in Kansas and further south it’s a little bit inconsistent. Except in the higher yield environments. (Stu) Exactly. (Jim) Stu, we gotta take a break here. Stay with us, don’t run off. Folks, same goes for you. We’ll be right back with these words from our sponsors.

(Jim) Welcome back to That’s My Farm. We’re at the greenhouse at K-State and we have Stu Duncan with us. And there’s one question I want to ask to follow up on the row spacing thing. Why is it under drought or low yielding environments that narrow rows don’t work? (Stu) Good question Jim and that’s one that we used to see all the time in central Kansas because of the… just the architecture of the planting pattern. In a narrow row the plants are a little further apart or more evenly spaced, which is good, except their root structure develops the same way. It tends to be a little more shallow and explores sideways. Where as in a 30 inch row they tend to force each other down. (Jim) Down, right. (Stu) Yea, they tend to force each other deeper. (Jim) So when times are tough the narrow rows are actually going to get hurt worse? (Stu) Oftentimes they usually… in severe drought we’ve seen, they’ll die first. The 30 inch rows will hang on a little bit longer. (Jim) A bit longer. (Stu) Yep. (Jim) OK. Let’s talk about plant populations. I know we used to talk about 156,000 seeds per acre. So, what are we talking about now? (Stu) Jim, another good question. And we’ve tried pushing ’em way up, we’ve dropped ’em way back. Right now K-State’s recommendations are somewhere between the… drop 125,000 to 140,000 and we are really pushed hard to find a difference between 105,000 final plant stands up to 120,000 plant stands just seems to be just as good as that 150,000 to 160,000. If we’re in a really high yielding environment like 60 a bushel and above, a few more thousand plants per acre may be appropriate. But we can raise a pretty decent stand, soybean crop with 100,000 to 105,000 plants out there per acre. (Jim) I know some of the yield contest winners over the past have been in that 90 to 110,000 seeds per acre, or plants per acre out there. (Stu) Soybeans are an amazing plant. Their ability to compensate and to hang on, of course there are dryland soybean contests. If they can hang onto those rains in August and get a couple of good rains, they will set pods on those sites as long as they’ve got plenty of nodes and they’ll flower, they’ll pod and they’ll fill. (Jim) Yea, one thing bad about low populations though is that branching issue and then cutting. (Stu) Absolutely. They will branch lower and if those side branches are heavily loaded a lot of them may stay on the ground. And even if they don’t, you’ve got a lot of pods set very low. So, you’ve got to be able to go low to get ’em, if you can. (Jim) OK. Stu, we gotta take a break here. So hang on. We’ll be right back and folks we’ll be right back after these words from our sponsors.

(Jim) Welcome back to That’s My Farm. I’m Jim Shroyer. Stu Duncan is with us and we’re gonna wrap up in this section on rotation. We talk about rotations all the time and what’s the scoop on rotations as far as beans go and talk about corn as well. So, what’s the importance? (Stu) Well Jim you could cover that with any of our crops that we have. But with soybeans, I really like a good rotation of at least every other… no closer than every other year with soybeans on a field. Or with any other crop for that matter. Beans, the second year or if we go into beans two years in a row, we’re probably gonna see anywhere from a 10 to 15 percent yield reduction. Now that will fluctuate with environmental conditions, but whether it’s at Parsons, Kansas, or Madison, Wisconsin, every place we’ve done those rotations or seen those rotations, studies done over a number of years, if you go soybeans five or six years, you keep knocking that yield down every year by doing that. (Jim) And then the disease populations come in. (Stu) Absolutely There’s just something about switching that host crop up that tends to lead to a reduction. You know with beans a simple rotation you’ll see a 10 to 15 yield bump versus continuous soybeans. You see the same thing and that would be rotating with sorghum or with corn. Now Eric AD over at the Kansas River Valley Experiment Field was in Illinois for several years and they had winter wheat in that rotation too and actually kicked those bean yields up even a little more by having that third crop in there. Now, depending on where you’re at in the state wheat may or may not be a feasible rotation crop in there. But getting something else in there just does so much for that host plant versus what its environment is. The soil environment where the seedlings gonna start off at. That’s just a really big key. (Jim) Yea. And it’s good to you know, mix it up as far as herbicides go and the soil till and you know it’s pretty easy to plant corn in the soybean stubble and not too bad going the other direction as well. (Stu) Absolutely. Yea, we get that decay, that composition and you know we’re planting soybeans later as a general rule than we do with our corn. I guess the big thing I would be on the look out for there is not getting my beans in when the soil is too damp, we’ve just seen… (Jim) And cold. (Stu) And cold. I’ve seen more potash deficiencies the last four years and it’s usually been in a no till situation. A guy’s got so many acres to cover, he has to get it in there, and we get a little bit of sidewalk compaction that has seemed to last all season long, we have potash deficiencies showing up when we don’t have a potash deficient soil test. (Jim) Basically because those roots don’t have the zone to explore because they’re confined by that sidewalk. (Stu) Absolutely. And it will look fine. When it gets dry you’ll see it in about two weeks, especially when beans go into that reproductive stage, especially R2, R3. When they start filling pods and they’re pulling so much moisture that’s when it shows up. (Jim) Stu I want to thank you for being on the show with us this morning. I know you’re a busy man. (Stu) Thanks Jim. (Jim) And folks, thank you for being with us on this issue of That’s My Farm and don’t forget, next Friday, same time, same place. Be here for another issue of That’s My Farm.

Closed Captioning Brought to you by the Kansas Soybean Commission. The Soybean Checkoff, Progress Powered by Kansas Farmers.

No Comments Yet.

Leave a reply

You must be logged in to post a comment.