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Hello, welcome to the WSU Wheat Beat podcast. We are two of your WSU regional Extension agronomists and podcast hosts. I am Rachel Wieme.
Morgan Menaker: And, I am Morgan Menaker. We want to thank you for joining us as we explore the world of small grains production and research at Washington State University.
Rachel Wieme: In each episode, we speak with researchers from WSU and the USDA-ARS to provide you with insights into the latest research on dryland crop production in the Inland Northwest.
Morgan Menaker: If you enjoy the WSU Wheat Beat Podcast, do us a favor and subscribe on iTunes or your favorite podcast app and leave us a review so others can find the show, too.
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Rachel Wieme: My guest today is Aaron Esser. Aaron is with WSU Extension in Lincoln and Adams Counties, where he has worked for 28 years. His Extension program is focused on integrated weed control and soil health. In addition to his role in the traditional Extension program, Aaron has served as chair of the WSU Wilke Farm Management Committee for the past 13 years. The WSU Wilke Research and Extension Farm, a 340-acre facility located on the eastern edge of Davenport, Washington is situated in the intermediate rainfall zone.
Thanks for joining me today, Aaron.
Aaron Esser: And, thank you, Rachel.
Rachel Wieme: Thanks for ushering us back into this relaunch of the Wheat Beat Podcast.
I see you are going to be presenting a session titled Making Cents Out of Crop Rotation at this year’s WSU Wheat Academy. Can you please give me an overview of this session?
Aaron Esser: Yeah. The term “Making Cents”–first of all, it’s spelled with a C, not an S–but it’s both the C and an S is what it should be, because you have to make common sense out of it, as well as economic cents. So, that’s where I spend a lot of my time–where I’ll be spending a lot of my time in the focus. I’m going to be summarizing a study we’ve had at the Wilke Farm since 2014. With some USDA NIFA funding, we implemented a long-term study where we are examining spring wheat and canola and chickpeas, and then we come back, we follow it with continuous-seeded winter wheat, spring wheat. And, then we put those treatments, spring wheat, canola, and chickpea back on those crops, and we’ve just had that thing rolling since 2014.
We’re going to review some of the critical takeaways that we’ve observed over this time. The study is unique as we follow the treatment crops, continuous winter wheat and then the spring cereals, coming back to the treatment crops. On the farm for that to happen, we have it in three locations, so that way each year we’re seeding the treatment crops. We have the winter wheat, and we have the spring wheat. So, it kind of minimizes some of that environmental [effect] that we may have with rainfall and yields.
To date, on two of the locations, we’ve run through four complete cycles, comparing the spring canola and chickpeas at those locations. The reason we don’t have three is we did shorten one of them up and change it. One of the things that became obvious—you know, spring wheat has looked good in this and it is competing economically quite well until you come back the second and third year. On that–at a quick glance, we just ended up with a tremendous amount of winter annual grassy weeds in that rotation that were quickly becoming limiting. So, we ended up making a change on that after it went through either two or three years of cycle and then we swapped the spring wheat out for spring peas. It was just prohibitive how much weeds we were having.
Over this time, as a side note, canola and chickpeas are pretty close over the life of the study in return over costs. The chickpeas have averaged $127 an acre and canola is averaging $136 an acre in their overall cost of production, which was kind of interesting to see how close those two are for cost. The return with those have also been very similar. So, when you start looking at that, the cost of production is similar, the returns have been similar–it really comes down to–the choice between canola and chickpeas comes down to the market price and then some other factors such as weed control.
Rachel Wieme: Alright, great. Any follow up questions on that, we’ll have to make sure we’re registered for Wheat Academy?
Aaron Esser: Absolutely. We’ll get the full story–the full agronomics story on it and some of the economics, as well.
Rachel Wieme: Great. Well, I know you’re also involved in the Pacific Northwest Herbicide Resistance Initiative project, and you present across the region on weed control. Can you tell me a little bit more about specific weed control aspects of this study?
Aaron Esser: When we started the study, a lot of it was focused on the cost of production of those crops and the gross and economic return over cost. When I talk cost, I’m talking the seed, the fertilizer, and the herbicide cost. And, we have a strong record on that.
The one thing if I could take a little time machine and go back and start the study over, I would probably put more emphasis on the weeds. The weeds have probably been the most interesting story going on with the whole study. It was kind of surprising, and I really wished I had better data on that so I could say, “Oh, we have 42% less of this or 38% of that,” but I don’t. I do have pictures, and there are pictures that they say, well, a thousand words and I’m very confident in the photos and what my eyes are telling me in what we’re seeing.
I touched on the winter annual weed issue we had in the spring wheat cycle of that rotation, and it really became pretty crippling by the time we hit that third cycle. And, then we switched. The one thing as I look back at it, maybe I should have kept it going or wish I would have kept it going. As we ended up with new technology and tools coming along, the pyroxasulfone or the Anthem Flex or the Zidua, and that may have changed that grassy weed picture with spring wheat. However, with that, I sure would not like the selection pressure that it would have been putting those herbicides under. So, that was one of the things that really became interesting is watching that and how quickly that rotation fell apart.
I think overall, since we started looking at this, the return on costs with canola has been–always probably been the least. On average, it has the least return over cost. However, its real value that it brings to the table is the weed control. In this study, we’ve mostly used RoundUp Ready canola and we pair that with applications of clethodim, and these plots are spotless. We’re looking at A, A+ weed control. You know, I joke about we actually look like we know what we’re doing in these plots.
Peas, on the other hand, where we brought peas into it, they’re closer to a C to a B-. They’re not bad, which is interesting because they’re getting the same weed control options that we’re using for the chickpeas. Chickpeas are ugly. They’re F to a D- maybe, and then every year we have to desiccate our chickpeas, not just for harvest and getting the peas dried down, but for weed control. I really would like to find a way we could forego the desiccation. Peas, we desiccate once in a while, probably about 50% of the time, they’ve been desiccated, and all those factor into it when I talk about the economics.
Over the last couple of years, we’ve been using pyroxasulfone on the winter wheat because of rattail fescue infestations. And it’s interesting when you look at it, especially in the location we have in field two–heavy rattail infestations, but it’s only following the chickpeas. There’s no rattail fescue where we’ve had canola the previous years and very little where we’ve had peas. But you can walk through this spring–you didn’t need a plot map to figure out where I was going to be putting chickpeas in because all four of those plots were heavily infested with rattail fescue. And that’s interesting, and it’s our own fault. Maybe when we seeded the winter wheat in there, we didn’t use an Anthem Flex or a Zidua on the ground, which is fairly effective against rattail and now that’s one of our major go-tos is we got to keep that in there, but we’re putting it on mainly for the chickpeas, not for the canola ground.
Rachel Wieme: Uh huh. Alright. So, we’ve spent a lot of time talking about the above ground aspects of this rotation work, and I’m interested in this work from a soil science perspective. Have you looked at what’s happening within the soil regarding these rotations?
Aaron Esser: Should I be? Why would I be? It’s soil. [laughter] We’re really interested in the economics, aren’t we Rachel?
Rachel Wieme: Hey now. Of course.
Aaron Esser: Not the soil. [laughter]
Rachel Wieme: Over time, our soil can have an impact on those economics. [laughter]
Aaron Esser: Ok, if you say so.
I do joke about the Wilke Farm and our crop rotations and what we have going on. Our greatest loss of soil comes through a soil probe and these plots are no different. We joke about they’re about three inches less or lower since 2014 because we’ve removed so much soil via the probe. Every year before we seed our continuous winter wheat, after we have our treatment crops, we come in and we do an extensive soil nutrient analysis down to three feet and look at what’s there, what’s there for moisture, what’s there for nutrients and everything else. I’m in the process right now of compiling that, and I think it’s going to tell a pretty interesting story at the Wheat Academy this year and will really help explain some of it.
Back in 2019, I got some additional funding from the Washington Oilseed Commission that was pretty cool. It allowed me to take a deeper dive into what’s going on with the physical and the chemical aspects of the soil, so a deeper dive into what’s going on with the nutrients and a little bit on the physical characteristics, soil compaction. You always hear a lot about soil compaction and how magical is that canola root with breaking up hard pans and everything else. So, we took a strong look at that and bulk density. The long story or the short story is bulk density, we really didn’t see a difference between all three treatments, the canola, the chickpeas, and the wheat. The Haney soil samples, we saw some pretty cool trends. Most of them were very favorable for canola, as far as the CO2 burst, overall soil health and stuff–but in the end, it wasn’t significant, but the trends were very, very positive. On the nutrients, we looked at the boron and the zinc and everything else and nitrogen, and the thing that was interesting is you always hear about canola takes a lot of sulfur. You know, you have to have maybe a little bit higher nitrogen to sulfur ratio with canola compared to wheat. The interesting thing is, when you come back in soil sample following canola, you always have more sulfur left than you do after wheat or you do after chickpeas. And, that was very consistent over each of those three years, so that really makes me question or ponder why that is. So, that was one of the interesting things.
Of course, with moisture, we did see differences in moisture. We have more moisture following chickpeas, which is to be expected. Most of that is in the third foot. Canola and chickpeas would draw about the same amount of moisture in that first and second foot, but chickpeas leave a lot of moisture in that third foot. I don’t think that’s a newsflash [or] shocking, but it did show up.
The other thing I thought was interesting going back and looking at soil pH—and, you know, these crops respond differently and everything else, and that’s not really what we’re looking at. But we came in and we also did a pretty extensive soil sampling on this ground, looking at soil pH at the 0-3, 3-6, 6-12 inch, and we also looked at the extractable aluminum. Similar to what we saw with some of the trends in the Haney soil sample, we also saw some very favorable trends for soil pH with canola where on average at 0-3 and 3-6 [inches], we have a trend for a higher soil pH. It wasn’t significant though. However, when we started looking at extractable aluminum, we had significantly less extractable aluminum, where we had canola on the ground versus the chickpeas or the wheat. And, there wasn’t a lot of difference between chickpeas and wheat, which is interesting from my standpoint because when we put the canola in the ground, it gets fertilized. When we put the chickpeas in the ground, it only gets a starter fertilizer, it gets no bulk nitrogen. So, you would think, there would be a lower soil pH following the canola and more aluminum. That’s not the case. And I’m really looking forward to–I’m trying to get some additional funding to do some follow up on that and what’s really going on with the soils. I’m hoping to bring some more of the biological into it as well as we try to wrap these studies up.
Rachel Wieme: Yeah, that’s a lot of very interesting findings that I have some follow up questions on, but maybe we’ll save those for another time.
Aaron Esser: Oh, we have lots of time. Let’s go. [laughter]
Rachel Wieme: Like you said, with soil it takes a little more–there’s a lot of things to look at. It’s complicated, and there can be a lot of surprising and sometimes interrelated trends going on. So, that’s really interesting.
Aaron Esser: I touched on the soil compaction story, but I didn’t actually talk to you on what we saw. We looked at soil compaction and how magical that canola root can be. We didn’t see a tremendous amount of difference between the crops in soil compaction down to 18 inches, but we do have significantly less soil compaction following canola at about 4-8 inches down. There’s significantly less soil compaction with canola.
Rachel Wieme: Yeah, so, it is living up to that reputation.
Aaron Esser: Living up to it, but it’s not as like Hercules as people want to make it out to be.
Rachel Wieme: But maybe based on your other findings, you know, also doing some of that scavenging for nutrients and things that people also mention with canola.
Aaron Esser: I think that’s very much telling a piece of the story and why we’re seeing what we’re seeing with the sulfur and stuff.
Rachel Wieme: Exactly. Yeah. With all of that, that’s quite a bit. What will be two or three key takeaways for the participants who get to attend your session at Wheat Academy?
Aaron Esser: Hmm, interesting. The three or a couple takeaways. The first takeaway that participants are going to have is they’re going to have a better idea on the market price structure needed to choose between canola, chickpeas, and peas. Each and every farmer has that number in their head up to a point, but sometimes, “Oh, my neighbor’s putting in canola. Maybe I will put in some canola.” Or, “ Geez, I saw they were putting in chickpeas and they had success with chickpeas, maybe I should look at doing chickpeas.” Sometimes those crop rotation decisions are made like that. Or I saw better wheat following that than that. I’m going to touch on it–I’m going to talk a lot about it at the Wheat Academy on the wheat thing and the rotation. Yes, you have better wheat following chickpeas than you do following canola. That’s no surprise. But when you come back on with spring wheat the following year, the spring wheat will usually be better following the ground that had the lowest amount of winter wheat yield, which happened to be canola. The lowest spring wheat yield is going to be where you had the highest winter wheat yields, which is chickpeas. You lose a little bit of that [wheat].
My dataset brings all that together. What happens with the treatment crops? What happens with the subsequent winter wheat crops and the spring wheat crops–brings it together–and, the piece of data I want out of this is if the current market price of canola is $0.23, what type of chickpea contract do you have to have to be equal to or significantly better or worse than to make it work? And, I like making those decisions based on data. So that’s the big takeaway, and that’s the piece I really wanted out of this. All this work we initiated in 2014 was a better way to make decisions based on long-term data, not just one year or anything else, but over the cycle.
I think the second thing participants will walk away with is a better understanding of the weed control and how it plays a major role in deciding between crop selection. Right now, farmers are making the decision with RoundUp Ready canola because that’s about the only thing that will control Italian ryegrass, but that also has implications. So, we’ll bring some of that into it. Weed control is critical, but as farmers, you must understand how much it’s going to cost and how much it’s going to benefit using these crops.
The final takeaway that participants are going to have when they walk away from this presentation is looking at what we were just talking about a little bit ago on the soil and what’s going on below the ground in regards to the soil, the physical and the chemical changes based on long-term rotations. And we’ll get a better glimpse into what’s going on there as well and trying to figure out a way to tie it all together between the economics, the weed control, and the soil, so farmers can make a better decision long term for their farm. That’s what I hope each and every participant walks away with. It’s just a better way to make decisions.
Rachel Wieme: Excellent. We’ll look forward to that. And, just in case, though, not everybody listening will be able to make to Wheat Academy. Is there anywhere else that folks can follow up to review some of this data and conclusions you have from this rotation study at Wilke Farm?
Aaron Esser: Great question, and yes, I will be talking about the presentation, Making Cents Out of Crop Rotation–I think I’m scheduled to talk about this one at the Spokane Ag Show and in my own meetings, and I have a couple of different places I know I’m scheduled. They’re escaping me where else I’m going to be talking about it. I know I have three or four of them on the books where I will be talking about it. And, I don’t hide my phone number. If anyone’s interested in calling and discussing and everything else–me sitting up in front of someone just throwing data at them or charts, that’s not where the difference is often made and the decisions are made. It’s through conversation and that’s the part I really enjoy is: What are the holes in the data? What is it showing? What could it be showing if we would have done it a different way? I really like those interactions and stuff. So, I’m not shy about talking about what we have going on. I don’t like doing the work to keep it in a bubble.
Rachel Wieme: For sure, and we’ll have that contact information in our show notes.
Aaron Esser: Great.
Rachel Wieme: Thanks again for joining us today, Aaron.
Aaron Esser: Thank you, Rachel, and I really appreciate you guys, you for stepping up and taking on this role. It’s great.
Rachel Wieme: Thank you.
Aaron Esser: Thank you.
Morgan Menaker: Thanks for joining us in listening to the WSU Wheat Beat podcast. If you like what you hear, don’t forget to subscribe and leave review on iTunes or your favorite podcast app. If you have questions or topics you’d like to hear on future episodes, please email us at small.grains@wsu.edu.
Rachel Wieme: You can find us online at smallgrains.wsu.edu and on Facebook and X (@WSU Small Grains). The WSU Wheat Beat Podcast is a production of CAHNRS Communications and the College of Agricultural, Human, and Natural Resource Sciences at Washington State University.
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The views, thoughts and opinions expressed by guests of this podcast are their own and does not imply Washington State University’s endorsement.