Farm Food Facts

Research on perennial companions in soybeans

September 20, 2023 USFRA
Research on perennial companions in soybeans
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Farm Food Facts
Research on perennial companions in soybeans
Sep 20, 2023

Our leading expert Jenny Rees, an extension educator at the University of Nebraska-Lincoln, is a wealth of knowledge and expertise in the field is nothing short of impressive! We discuss the basic benefits of planting a perennial companion in soybeans, common perennial companion crops, on-farm research, challenges and if perennial companions will become more popular. If you're as interested in this topic as we are, then check out Jenny's blog at and stay connected to research items like this by following the Nebraska Soybean board at  

We appreciate the support of this topic from the United Soybean Board. You can stay connected with the future innovation of soybeans by following the United Soybean Board website at

Show Notes Transcript

Our leading expert Jenny Rees, an extension educator at the University of Nebraska-Lincoln, is a wealth of knowledge and expertise in the field is nothing short of impressive! We discuss the basic benefits of planting a perennial companion in soybeans, common perennial companion crops, on-farm research, challenges and if perennial companions will become more popular. If you're as interested in this topic as we are, then check out Jenny's blog at and stay connected to research items like this by following the Nebraska Soybean board at  

We appreciate the support of this topic from the United Soybean Board. You can stay connected with the future innovation of soybeans by following the United Soybean Board website at

Speaker 1 (00:38)
Welcome back to Farm Food Facts, brought to you by the US Farmers and Ranchers in Action. I'm your host, Joanna Guza. And today we are joined with Jenny Rees, an extension educator at the University of Nebraska Lincoln. She focuses on irrigated crop production and plant pathology. Today we're going to discuss the new research with perennial companions in soybeans. And before we dive into that research item, Jenny, can you just give the basic benefits of planting a perennial companion in soybeans?

Speaker 2 (01:19):
Yeah, well thank you for having me today. And I'd say before I go into benefits, maybe what's the big picture here as to why we have farmers interested in this And the reason is as farmers are looking at chemicals being perhaps limited in the future or hard to get as they look at fertilizer, also being hard to get, or maybe regulations coming down the road or even what is the consumer going to demand from the farmer? They're looking at what are the ways that they can reduce inputs in their system. And so the benefits from that can be cost savings. It can be on the environmental side too, not as many chemicals, not as much fertilizer used. And then another benefit can be from erosion control, having something anchoring that soil in the off season as well.

Speaker 1 (02:18):
And from your work and have you worked with a lot of farmers that are already doing these perennial companions or is this kind of a new idea?

Speaker 2 (02:27):
It's a pretty new, um, it's a, it's a newer thing. There's not as many farmers that are doing these kind of outside the box ideas yet. But the farmers that I'm working with on it, they just, they wanna figure things out before they're forced to figure things out.

Speaker 1 (02:44):
Right. And we know that a lot of these farmers are already feeling some of those challenges that you mentioned. What are the most common perennial companion crops that you've worked with?

Speaker 2 (02:54):
Yeah, and the ones that we've worked with, mostly our clovers. And so specifically we're using mammoth red clover, medium red clover, and then different white clovers like dutch white, everlasting. We also have some farmers looking at perennial grasses with the clovers. So looking at Kentucky blue grass and even buffalo grass.

Speaker 1 (03:18):
And does the type of species depend on where you are? I mean I know you're focused in on Nebraska, but what about a farm in Wisconsin or Indiana? What would they be considering or have they used it with perennial crops?

Speaker 2 (03:33):
You know, I would think that these types of perennials would be fairly similar across the Midwest and um, just because they are, they are species that are grown anyway in some ways. This is really old school. It's thinking about what our grandparents and great-grandparents did. And it wasn't that uncommon to use perennials like this with other crops too, before fertilizers and other chemicals were used more extensively.

Speaker 1 (04:03):
Mm-hmm. <affirmative>. Well now what everyone's been waiting for, let's talk about some of this on-farm research that you've been a part of. Can you share some insight on that, on-farm research and and what you guys have seen with perennial companion crops in soybeans?

Speaker 2 (04:17):
Sure. So we actually got started with the perennial crops in soybeans and then also in corn as a result of our interceded on-farm research studies. So what I mean by that is we had farmers who had been interceding com or cover crops, mostly annuals, but we had clovers in there as well as a perennial. And they were basically when the corn and the soybeans were growing early on in the season, they would seed the cover crop then into the growing corn and soybeans and then they would grow together throughout the growing season. And what we learned from that is that the clovers survived really well and the farmers kept thinking, well first of all, um, the clovers survived very well but we didn't expect them to take off so well in the soybeans. And so that was something that we learned and we thought maybe this is something we need to explore further.

Speaker 2 (05:18):
And the farmers were very interested in having a perennial because of the fact that when you seed an annual every year, you've got that additional seeding cost and the seed cost. And so they were thinking if we could get something that's always living, then we don't have that cost. And so will that offset additional costs such as we, can we reduce our nutrients in a systems approach as we rotate between corn and soybeans? Can we reduce our chemicals in a systems approach as we rotate our crops? So those are the questions our farmers are looking at. Mm-hmm. <affirmative>. So then going back to your original question then about the, the soybean study with the clovers perennial crops in general, what we did there is our farmers dormant seeded the clover in this case. So what that means is they seeded the clover in March or April before the soybeans were ever grown. And the goal with that was to get the clover established, hopefully before weeds started coming because it changes then the herbicides that we can use and then we can hopefully reduce some of the herbicides that we're using once the clover is growing, once we then seed the soybeans into the clover in this case and then hopefully have an option for weeded control there. And um, it's been challenging. I'll say that <laugh>.

Speaker 1 (07:02):
Yeah. You wanna share some of the challenges that you've faced? I mean it sounds like it's been pretty positive. And, and actually before we jump into the, the challenges, I do have follow up questions. I was just waiting for you to kind of finish your answers.

Speaker 2 (07:13):
Uhhuh, <affirmative>,

Speaker 1 (07:13):
What was the application rate? So you said you planted in early March. Are you applying it a little bit heavier than if you were interceding it because you are planting before the soybean?

Speaker 2 (07:25):
Yeah, that's a great question. We've actually just stuck to a, basically a 10 pound rate when it comes to the red clover. So 10 pound per acre rate on the red clovers we've been doing. If we mix red and white clover together to create more diversity and also see how they work, which one maybe establishes better. We've been doing a five pound rate of each to equal a 10 pound per acre rate. Um, so that's pretty much what we've been doing. When the growers have done the clover plus the Kentucky Bluegrass or buffalo grass, we've been doing a five pound per acre rate of clover and a 15 pound per acre rate of the grasses.

Speaker 1 (08:11):
And then how tall was the clover by the time they were trying to plant the soybeans?

Speaker 2 (08:17):
Yeah, so not very tall. Not even in some, in the past two years. So our experience is mostly the past two years. It hasn't even been an inch tall by the time they're planting the soybeans.

Speaker 1 (08:32):
So then I'm assuming there's no issues then with the planter being able to get in to plant the soybeans because the clover's not very tall.

Speaker 2 (08:40):
Correct, yep. That hasn't been an issue at all with getting the soybeans planted.

Speaker 1 (08:44):
So with having that perennial companion, does that change the, the herbicides, the fertilizer that's being used? Can you walk through what some of those options are? And I'm assuming that's probably a little bit of a money saver for the farm?

Speaker 2 (08:59):
Well, probably not in year one. Um, but that's what we're looking at is the whole system. So everything we do in agriculture is a system. If we're only looking one year at a time, we're not thinking about the whole system. So in year one, we had the cost of the seeding and, and the seed cost as well. But walking through the growing season, what these growers did is they planted their clover into usually dryer, a wheat cover crop. 'cause that's just something that we have growers doing anyway for weed control. So they planted their clover dormant, seeded into the dryer, the wheat then um, they planted their soybeans usually in late April into, and they plant it green into the fryer. The wheat, the clover was already starting to emerge or it was emerging still? It depends. We've been dealing with drought, so that's been a challenge.

But it was either just starting to merge or it was getting up to about an inch tall. Then what we did is once that clover had at least two to three tri foliates, we used a product in the group 15 chemistry. So what that is, farmers are familiar with products that provide residual, and these are products like warrant, dual outlook, ua, those products. What they do is once that seedling is emerged, it doesn't kill that seedling. So it's safe on the clover at that point, but it also provides residual control for any weeds that haven't come up yet. 'cause this is in that establishment process. We're trying to avoid weeds, we're trying to get the clover started, and then we used 10 ounces of CLE to kill the rye or the wheat in that case.

Speaker 1 (10:59):
Hmm. Now let's, let's jump to the end of the year. So we, we got everything planted. The clover went good, we got timely rains, right? We're <laugh>, we're living a good world. Um, and we get it's harvest season. So we harvest the soybeans. What happens next with the clover?

Speaker 2 (11:16):
Okay, so in the case of, we had two studies that actually made it to harvest. One was in corn, one was in soybeans in the soybean study that made it to harvest. That producer wanted tall clover and so it was mammoth red clover. The clover was as tall as the soybeans. It looked really scary, it would scare a lot of farmers, but he's, he's like, let's give it a try. So harvest time came, the clover's still green, the soybeans are brown, you know, they're ready to be harvested. He had the combine settings really well where combine threw it, it didn't chug down too much as he was harvesting those beans smelled beautiful out there, like fresh cut alfalfa. And it just had this after harvest, it had this really beautiful green stand of clover out there that was remaining on the soil surface the first year.

Speaker 2 (12:13):
Um, this is last year in 2022, the yield was less where the clover was seated. So it was 68 bushels an acre versus 78 bushels an acre. I'm sorry, 74 bushels an acre. So it was 74 bushels an acre for the check 68 bushels an acre for where the clover was seated. So basically, um, there was a little bit of a yield loss, six bushels an acre where the clover was, but he had that cover thereafterwards. And the goal is looking at the economics over three years. So right now there's corn planted in those same strips, great weeded control and the clover's growing and that clover provided 30 pounds of nitrogen for this corn crop after the first year of clover. And we figured that out by biomass samples, basically clipping the clover, sending it in for a nutrient analysis to find out how much nutrients were in that clover that was clipped so that that farmer then can credit that amount of nitrogen for his corn.

Speaker 1 (13:23):
And after they harvested those soybeans and then were, you talked about the next cropping year with adding the corn, they probably had to no-till that corn into the, the clover.

Speaker 2 (13:33):
Yep. So they can either no-till or they, in this case this farmer strip tilled into the clover. So we created a strips last fall. But yeah, they can do either way, um, no-till or strip-till. So in this case, what I'm sharing with you, this is year two and that clover in year two is looks very different than year one where we're just trying to get it established. Year two, it was kind of a mat on the ground and covered the ground. It looked, it, I don't know, I think it looks pretty cool. It's very different, but it, it's, it's really cool.

Speaker 1 (14:08):
Right. It sounds like some really exciting research and I know we're still in the, the beginning stages of it, but you know, even with a little bit of uh, lower yields, it sounds like, like you said, over those three years, hopefully that farm is gonna see some really good results from it. We always know that when we're doing these research projects, it comes challenges. Can you share some of the challenges that the farm and the field face and, and how they overcame those challenges?

Speaker 2 (14:34):
Right. Yeah, definitely always challenges. So for us, we've had two years of drought and so dry springs, when we've had non-ed fields, it's been hard to get the clover di in Germany or so that was this year, hard to get the clover to germinate at all. Last year it germinated, but then we got no rain and so it can't keep growing. So that was the difficulty with that. So drought is definitely a challenge. We also had a massive hailstorm that hit several counties last year. So then the fields that we actually had that were irrigated, that had clover established, then the hail came and it took out the crops and then the farmers had to start over with something. And so in that case, um, the clover was terminated in those situations too. And then the biggest challenge honestly is weeded control. So trying to figure out, okay, the timing of getting the clover emerged and then being able to control, control the weeds as well. So that's been a challenge. This year we lost several studies again due to drought weeded control. And then, um, we just had another hailstorm last, uh, last couple weeks, so

Speaker 1 (15:59):

Speaker 2 (15:59):
So there's always challenges how we overcome 'em. Our goal this year is for everyone that lost their fields in this year so far, the goal is we're gonna try and plant clover in the fall instead. So we focused on this dormant seeding and early spring seeding because that's what all the resources we're recommending. But our farmers are like, let's just try it, let's just try it in the fall. We've been starting to get some rains here, so maybe it'll be a benefit to us. And the biggest factor for us is the weeded control. If we can get the clover established in a, in a timeframe where we're not dealing so much with weeds, maybe we have a better chance for that clover than surviving being ahead of the game going into next year's growing season.

Speaker 1 (16:48):
Right. And I, I know I'm not a scientist, but then even having like that clover established, that probably will help with the moisture and some of those droughts that we might see in future years. So it almost sounds like that could be the game changers planting in the fall.

Speaker 2 (17:02):
It could really help a lot. I mean, cover crops do take moisture too. Our, our research, we've, we've put your like moisture sensors in the soil and trying to document moisture in the soil as well. And what we found is when we have several species of cover crops together with that corn crop, we haven't done it as much in soybeans, but I've got 'em in soybeans this year. It doesn't take more moisture than the check treatment with no cover crop. And so it's like something's happening with the roots that they're all sharing or doing something different.

Speaker 1 (17:40):
Right. Really exciting research. We've been talking with Jenny Rees, she's an extension educator at the University of Nebraska Lincoln. And last question for you, Jenny. Will perennial companions become more common than other crops? Or will more farms be implementing them, uh, as a companion crop with, with what they've already have established?

Speaker 2 (18:02):
That's a great question. I think it will probably be easier for farmers to incorporate 'em into corn first, or maybe even wheat first, like grass crops first. But then because we work in a systems approach, they will be in soybeans as well. So just thinking about that whole system, it's very much on the innovative side for the farmers that are doing this. So knowing how much it will be adopted in the future, I don't know. But our goal is figuring out how to make this work, working out the kinks so that if more farmers in the future decide to try it, hopefully we have a path forward for them.

Speaker 1 (18:43):
Right. And I feel like with some of the other conservation practices that farms have been trying in the Midwest, I mean they feel that burn and that hurt a little bit in the beginning, but you know, now that they've been doing no-till or strip-till or cover cropping, you know, for so many years, they, they're starting to see those benefits. Um, but they're not gonna see them in the first year. So it's making sure that we're staying optimistic.

Speaker 2 (19:05):
Yeah. Keep, keep working through things. And I'm so blessed to work with these growers who are willing to try things and willing, I mean, 'cause honestly there's a lot of failure with it, but failure creates learning and then opportunities to keep growing and moving forward. So.

Speaker 1 (19:21):
Well said. Well, it's great to have experts like Jenny covering this topic so farmers can better care for their land. If this topic interests you, I recommend that you check out Jenny's blog at I'll make sure we drop a link in the description 'cause it's kind of a fun play on words. You can also stay connected to research items like this by following the Nebraska Soybean board at and check out the research tab. Well, we appreciate you spending time with us and if there's a topic you'd like covered on Farm Food Facts, just send me an email at I'm Joanna Guza for Farm Food Facts.