Corn Inter-seeding Trials: What We Learned About Row Spacing and Timing

0:04 So interceding cover crops into corn is a pretty hot topic amongst farmers these days because if we can make it work then it solves a lot of the labor issues, the timing issues at the end of harvest. And so we wanted to do some experiments, do some trials, some demonstrations to kind of see what we could learn, see what we could help other folks learn. There's been a lot of other work done, we're certainly not the first ones to do this, won't be the last, but we've learned some interesting things there. So Nathan, why don't you.

0:33 Tell us a little bit about how we set these demonstration plots up.

0:36 Absolutely, so what we did is we chose three row spacings. We have 60 inch corn, 30 inch skip rows which would be a 60 inch row, then a 30 inch row, then a 60 inch row, and then we have 30 inch rows. So we have three row spacings, and then we did six mixes across the row spacings to trial different species and different blends. But then we also did two planting timings, so we did a V2 V3 planting and then more of a V4 V5 planting, and so that's how we set up the trials.

1:06 It's definitely been interesting to observe the different cover crops, the different row spacings. Sunlight's a huge issue when you're talking about corn interceding, getting enough sunlight to get the cover going but not going too quickly. And so you can definitely see the different species thrive in the different amounts of sunlight they're getting, and then also the differences between the planting timing. The species that had an extra week and a half head start, all those mixes look really good.

1:32 And are in our quite a bit ahead of our of our later plantings.

1:36 Yeah so like Nathan mentioned sunlight is probably the biggest challenge, the biggest limiting factor and so by going to 60 inch corn like what we're standing in here it really eliminates that as an issue because there's plenty of sunlight coming in for the cover crop. Now the challenge then is going to be can we do that and not lose very much of our corn yield? So to do that it's important that you keep the same number of corn plants per acre you just move them into half as many rows so all of these plots have 32.

2:04 000 plants per acre as a seeding rate. They're just different densities within the row to get that same amount per acre. And so, you know, for the livestock guy who wants to grow corn, graze the stocks but also have some really nice cover crops to graze in the fall after harvest, I think the 60 inch corn is a viable option. If you don't have livestock, if you're not going to graze it, you're just a grain guy, you want to improve your soil, some soil health benefits, I don't know. You're probably going to have to take a harder closer look at it because we'll see what the yield does.

2:37 Practical Farmers of Iowa have done some really good experiments, some really good studies on 60 inch corn versus 30 inch corn, looking at yield differences. So I would encourage you to go to the PFI website, you can check those out and find out what those guys have learned. The guys that are doing it the best are losing very little yield by moving from 30 inch to 60 inch, but now weed control can become more of an issue. And so the herbicide selections can really affect what cover crops you have using.

3:06 Nathan, tell us a little bit about the herbicides used here. Yeah, so we did a

3:12 Very simple and simple program here. Essentially we did a burn down with Roundup right at corn planting and then we didn't do anything, and so the result of that was we did see higher weed pressure throughout the summer. We've had an issue with pigweeds and then kind of later in the season we had some barnyard grass come in and kind of compete with the covers that we had planted. But yeah, and so we've done some weeding here, so some of what you see if you were here for the tour or if you're watching this video, some of what you see has had some weeds pulled just so we

4:18 That could help as well. Sunlight number one issue, weed control is going to be number two, and then you also have to consider the crop insurance implications. You need to work with your crop insurance agent if you want to do this on anything other than just a plot size scale like what we're doing here, because you'll have to work with them to make sure it's not going to jeopardize your crop insurance coverage.

4:40 Takeaways from what we've seen here: in 60 inch rows you can make just about anything work because there's plenty of sunlight coming in when you get down to

4:48 Where we have the 30s versus the 60s, you'll notice there's a significant difference between how much cover crop is growing in the 60 inch gap versus the 30 inch gap. Kind of interesting to see how that works. And then all the way down to the 30 inch rows, the amount of growth is definitely compromised because of a lack of sunlight. And that's where the difference in the planting date shows up the most.

5:09 The one thing that's going to be interesting on the 30 inch rows where we went with heavy Brassica rates, thinking for that late season grazing after harvest, those brassicas.

5:19 They're held back because of lack of sunlight, but once we roll through with the combine, I think they're going to pop and we're going to see some really nice fall forage out of those later seasons, even though it is the 30 inch corn where we had less sunlight.

5:32 I think it's important to think about the goals of what you're trying to do with the mix. It's not just, you know, we don't want to intercede corn just to intercede corn. We want to have a goal and a plan that's going to get us there and making sure that we pick the species and the planting times and the.

5:45 Herbicides get the whole program put together to best achieve that success. And then the other thing we want to look at too is selecting different variety or different hybrids of corn that might work better. You know, because we definitely know if we'd have planted this at 24,000 instead of 32,000 more sunlight, better cover crops. So can we find a variety, a hybrid that would have a really good flex here that could yield almost as much as 32,000 at 24,000 because that ear can just get that much bigger. So we don't know, but those are some questions that we're continuing to ask ourselves and that we'll look at in future demonstration plots.