Dealing with Early Season Weather Concerns for the 2024 Corn and Soybean Crops
And welcome to the University of Minnesota Cropcast. This is the University of Minnesota podcast from Minnesota Extension. My name is Dave Nicolai. I am a host here of Minnesota Cropcast along with my co host, doctor Seth Nave. He's a University of Minnesota Extension specialist in soybeans.
Speaker 1:We have as a special guest here today in the studio, doctor Jeff Coulter. Jeff is with the University of Minnesota Extension. He is the corn specialist here at the University of Minnesota. And we're back again, Seth, here. We've we were recently, featured on a, University of Minnesota field notes program, last week talking about crop growth and development.
Speaker 1:But since then, we've had some weather situations that have developed, in the last week or so, especially within the last, couple of days here, on Monday Tuesday across the state. We had some significant rainfall in some different areas. There's going to be some decisions that are gonna have to be made. Some crop scouting that should be done as well, with that with some of our early planted crops. And we wanted to have what I really call version 2 here.
Speaker 1:So some of you may have heard some of this information, but we wanna take some time here to update that since we're approaching the Memorial Day weekend. Looks like there's some forecast in terms of continued rain that may develop. So, with that, a couple of things to think about, with that. Not everybody's got their soybeans planted. A majority of them are, but there are some fields that have not been planted.
Speaker 1:Along with that, Seth, we also had some soybeans that are planted, very early, in terms of, what we normally plant back in the month of April. We have some concerns a little bit about seed treatments and how long that they can be viable, in terms of protecting the seeds. So some things to think about that. And then, Jeff, also, if we're gonna be needing to, perhaps replant some corn in some of these areas, thinking about relative maturity, in terms of hybrid selection. I know some of the seed companies are are involved with, making some recommendations already at this point in time because, as we record this, it's the 22nd May.
Speaker 1:So, a number of things, but it does involve going out and look. So, Seth, comments that you might have.
Speaker 2:I think you covered it. I think we can just end this right now. I think we covered the whole front. No. I I I do agree that it's good that we can be back on talking about this today.
Speaker 2:It does sound a little bit repetitive, but I think in light of this year, we've had some really kind of unusual weather patterns, I would say, where we had some real long periods where, you know, early on, we could get into the field, and then we were held out for a week or so. And then there was another period where we could get back in. And then since then, it just seems like we've just had these really short blocks where it's either raining every other day or or every 4 or 5 days. And so I know it's very variable out there. There's parts of and Dave alluded to this.
Speaker 2:There's parts of the state that, you know, that got planted early, and there's some farmers that probably had almost all of their corn and soybeans in in early April. And then there's other areas that, were held out quite significantly later. And so I guess, in light of these some of these rains that came through, we just need to need to get back and and and talk a little bit about the details here. So, I think we should we should hit on corn first. I think it's the most important topic for us.
Speaker 2:So I'd I'd like to bring in Jeff here, and we can talk about what folks need to do if they had some trouble with stands or if they've got some drowned out areas and what what their first steps are should be in thinking about those corn fields that maybe look a little bit tough.
Speaker 3:Yeah. Thanks, Seth. Yeah. So thinking about these areas where we got water standing, you know, typically, the corn can survive about 2 days under ponding conditions. And part of that depends, you know, how fast does that water reside.
Speaker 3:And then, you know, once once we're able to, like, go in there, we can kinda see, you know, what's our stand like, how many plants are left. If we need to be replanting in those areas, you know, we may wanna consider no tilling in there since they're just small areas typically. And if we have to wait for the soil to dry out enough to do, you know, tillage before the planting, that even can further delay things. So sometimes, just going in there and no tilling isn't a bad idea. Another thing to think about is the stands so, surprisingly for corn, it can yield quite well under, you know, 23,000 plants per acre, which seems low considering, you know, a lot of people are planting around 35,000 or more.
Speaker 3:But, it can do quite well, up until up until around 23,000 plants per acre. Once it starts to get lower than that, then we may wanna consider replanting. But we also need to be thinking about the calendar at this point and, you know, the calendars have been kind of moving along. And, you know, today is May 20 second, and if we planted today, we'd have, oh, probably a little over 90% of maximum yield potential. And that's based on research trials where we've done planting at different dates throughout the season at multiple locations over multiple years.
Speaker 3:It shows that planting around today would yield around 90% maximum yield or maybe a little more. And if we wait for the soil to dry out, say, you know, 5 days from now or maybe a little more, then we're probably looking at a yield potential that's in the upper eighties. You know, 87%, give or take. So, you know, those are some things to consider. But the other thing to think about is that, you know, we talk a lot about planting date and yield but, really, the big drivers on corn yield are what are the weather conditions like the 10 days before the tassels come out and extending through the 3 weeks after the tassels come out.
Speaker 3:First off, what are the moisture conditions during that period? And then second of all, what is the temperature like during that period? Those are the 2 key drivers of corn yield. Another driver's planting date, but its influence is far less than those other two factors. So, you know, I we still have, you know, the whole growing season to go yet.
Speaker 3:And, the some of the weather outlooks you know, I looked at the Dawn site. It's a new site, developed by the University of Maryland in conjunction with the University of Minnesota, and they're projecting a warmer than average growing season this year. So, you know, that should help push things along and assuming that we don't run into moisture or drought stress later in the season, you know, we should have, hopefully, ample growing degree days to get the crops, to mature. But even saying that, I think we're at a point now where we need to be thinking about switching to earlier maturity hybrids. Based on our research, it it would be that between May 22nd May 28, we would want to plant hybrids that are 5 to 7 relative maturity units shorter than what is considered full season for your area.
Speaker 3:And when we get to May 29 to June 4, then during that period, we would want to switch to hybrids that are 8 to 15 relative maturity units shorter than what is full season. So those are some things to think about.
Speaker 2:Do you, do you think about those, the that change in hybrid maturity any differently if you're replanting a whole field or or just filling in a drown out spot? I I I know farmers are gonna wanna get in and harvest whole fields at the same time. So is it even more important to back off those, those maturities just a little bit? Or or is or do you just kind of, you know, look at this through the same lens as as just based on on drawing the that corn down eve evenly, whether it's a whole field or just a small spot.
Speaker 3:Yeah. Good comment. Yeah. I would say on a whole field basis, it's more important to be switching to an earlier maturity hybrid. If you just got a, you know, a few, an acre or 2 that's in a drowned out area that you need to replant, you know, ideally, it would be nice to switch maturities to something a little earlier so that it would mature at the same time as the rest of the field.
Speaker 3:But if the logistics just aren't there and it's too complicated, you could probably just take what you have, the earliest maturity that you got laying around, and, plant that in the that area and just maybe put that field on kind of the back burner for one of the later fields to harvest, and I think you would be okay, for the most part.
Speaker 2:Yeah. That's a that's that's a good comment. So I think in in the soybean side of I'll I'll jump in real quick on the soybean side on that maturity thing. I think I think it may be a little bit less important. Certainly, we don't recommend changing soybean varieties until mid June, mostly because the the soybeans maturity is driven in in big part by, by the environment.
Speaker 2:So shortening days, cooler nights, as we get into fall really drives maturity. And so we don't really need to pressure soybeans, in the same way. So I think planting the same varieties out there, for for quite a while, yeah, it's gonna be just fine. And thinking about yield potential, soybean is is probably still in above 90%, in correlation with what Jeff was talking about with corn. I mentioned in, the the our our, webcast a week ago that our recent data out of, when we've done a reanalysis of some data out of was of Lamberton, excuse me, with Bruce Potter, we found that soybeans drop about 1 and a half percentage points.
Speaker 2:I'm sorry. 0.7 percentage points, per no. 0.07. So less than 1 per less than 1 tenth of a percent per day over over the month of May. So takes 10 days, to get even a point, percentage point decrease, in in soybean yield across April so or across May.
Speaker 2:Sorry. Getting my numbers a little bit confused here. So we have a general decline in yield potential in soybean over a broad period of time, but we're really good until the end of May when things really drop off. The other thing about soybean is, as everybody knows with that have planted late soybeans, when we plant them late, they tend to come up in a few days. We have warm soils.
Speaker 2:They pop out, and they look they look really good and competitive with soybeans that are planted 2 3 weeks ahead of time. And that's that's part of the factor involved with why we see a a lower penalty, with those soybeans from being planted late.
Speaker 1:I wanted to bring up a a a couple of things, and and one is I was visiting with our plant pathologist, doctor Dean Melvik. And, I guess he's really recommending that, don't always assume, without going out and looking that, the seed treatment perhaps, maybe whether it's in soybeans or, you know, on other crops, the viability is season long, in terms of that. You know, we have certain diseases, that, you know, we would we would work on in terms of soybeans if they're systemic. But otherwise, that protectants and, you know, Seth, you know, where there's a trend obviously to plant, you know, in the month of April. Here we are in towards the end of May, and under wet conditions and so forth.
Speaker 1:And so you you very well might be alright. But, you know, there is there is a length here to keep in mind or a half life, I should say, in terms of the longevity, on those. So it does really pay to come out and take a look. You might have to get out of that pickup, Seth, and and go and actually, do some scouting and so forth on the emergence on some of these earlier planted beans. Just make sure everything is is going okay because seed treatments oftentimes, if they're just a protectant, are not a a season long situation.
Speaker 2:Well, I'd I'll give you the agronomist view of of, of these seed treatments, fungicide, primarily if we're talking about about, this early planting, I think, on the fungicide side. I think there's a there's a notion among farmers that's been driven by the folks that are selling these products. It's kind of a plus minus deal. You put it on and you're protected. It's insurance.
Speaker 2:You know, it it it's this idea that you've either you got insurance or you don't. You have protection or you don't. But these things obviously are much more complicated than than that, and it's it's a nice way of selling these things. But the reality is these things don't work that way. There is, as Dave mentioned, there's a range of of how systemic these products are, but most of them are not very systemic.
Speaker 2:So mostly, they need to just behave in the in the soil profile. If we plant under dry relatively dry conditions or even ideal conditions where you lay a soybean down on top of the moisture and it imbibes moisture and it comes out a few days later, a lot of that seed treatment is actually dragged up to the top of the surface on the on the seed coat. It really doesn't do anything for the root. It's positionally it's it's out of it's out of location to help the soybean root develop. We need pretty good moisture.
Speaker 2:In fact, I think the seed treatments probably function the best when we have, you know, a half inch or an inch of rain after planting to kinda wash that wash that product off of the seed coat down into the soil profile where it can actually protect the root a little bit. I think that's part of the reason why there was a little bit of a push to doing some in furrow, fungicide treatments, in the past. But clearly, this the seed treatment ones are the most efficient to use and the most convenient for folks, and so those have really won out, in most cases. But I'm not trying to trying to, bash these things very to any great extent, but the reality is I think it's important for folks to know that sometimes they're gonna work for us and sometimes they don't. And the key is that most of the time, we don't know when they don't work because we didn't really need them in the first place.
Speaker 2:And so they're they're, really utilized broadly as as a protectant, but they're probably not protecting us most of the time. But when they do when they do work, they do work for us, and then they can pay.
Speaker 1:Well, certainly, we're we've had some significant rainfall in places. And even if where we haven't, we've had more moderate, but it does look like the forecast, Seth, is gonna continue with some more moisture again this coming weekend. So some of that ground's gonna stay saturated, limited oxygen environment and so forth. So there's gonna be some stress out there, in in terms of especially some low areas that some of those beans, if they recover in situation laying in saturated ground, they may not be that, well in terms of yielding by the fall if if it continues.
Speaker 2:Yeah. I think we, you know, we always talk about scouting, but it's the most important thing that farmers can do. And I think it's a really good use of the time when we're held out of the fields this time of year. Waiting, we need to get through these fields and see where we had some issues with with crusting early on and drown outs more recently, perhaps. It's, we don't know what we don't know until we get out there and see these fields.
Speaker 2:So and, you know, I think there's farmers have a good feel for each of their farms. They kinda know where they've got problems, and so they can target those areas that are most that that might cause us cause them the the largest, probability of having a problem. But it's really worth getting out those entire fields and and really seeing everything because we don't we don't know where some of this stuff happened. And there were some there were some weird things this year.
Speaker 1:You know what, Jeff? One of the things on on corn, obviously, that can happen, you know, whether you have carryover from a herbicide or injury or positional on a herbicide, sometimes you see see that and we have to go back and replant. But I was talking to a grower, this morning, farms down in in Southern Minnesota in a couple of years ago. You mentioned the fact that, you know, in some of those areas where they didn't replant, they ended up with weeds. And and so you gotta think about, you know, what are you gonna do for weed control if you if you leave them?
Speaker 1:He said he he had that problem. He left them for the season, and he had a lot of weed seed. And he said, you know, even a couple years later, he's still fighting those those areas where, the weeds went to seed and so forth. But so, you know, just planting or or spiking in, you gotta think about and the weed control or if you're if you're not gonna plant there, what, you know, weeds eat out. But, certainly, there's a lot of of factors, you know, sometimes whether it's carryover from a herbicide or or just your normal, pre emerge herbicide.
Speaker 1:Sometimes, you know, if if the corn is just coming up or peeking through and you've seen that too, you can get you can get some, situations where you can get, corn that's set back.
Speaker 3:Mhmm. Yeah. Something to watch for. And, like you said, it's good to get a crop or something at least planted in these drowned out areas to suppress the seed bank and to try to stay on top of those weeds to, you know, manage that seed bank.
Speaker 2:It wasn't too many years ago that we just talked about this from an economic standpoint that, you know, we talked about yield loss, you know, from the the or from poor stands relative to, you know, what the what the reap what the planting delay penalty would be on any particular day. And we basically put this down to the economics for farmers. But I think today, the reality is is that farmers are wanting to to to move or reduce their risk of having weed problems in these fields. So I think that really lends itself towards getting in and spiking, especially on the soybean side. If you've if a farmer has thin stands, there's relatively low risk of any damage, from from spiking in additional plants around those if they're low stands.
Speaker 2:I know we drive on a few soybeans and a few get trampled by some row units. But adding extra seed where things are thin really reduces our chances of having weed problems later. That can be costly in the current year. But then, as Dave mentioned, then they can be really problematic for the long term in terms of the weed seed bank. So I think these are years when we really just need to make sure every acre is covered with with a crop, and maybe even get in in a cornfield if if farmers aren't comfortable with planting, going back in corn.
Speaker 2:Maybe they've gotta put beans back in those those low areas if they're drown outs and and put some beans in there, at least having something covered, covering those up.
Speaker 1:So, Seth, I'll put you on the spot a little bit. If you're farming in Southern Minnesota, what kind of population keeps you up at night or makes you a little bit nervous about, it's a little too low here. I need to do something. And it again, I know it's it it varies and so forth, but or what are some generalities or or rules of thumb if we're if we're dropping that population down to, you know, a 100,000 or where where's your threshold of pain, so to speak?
Speaker 2:Well, we know that stands of a 100,000 if if farmers have an even stand of a 100,000, they're perfect. There's no problem there. And in fact, our research says that if we have good stands, even stands down to 70,000, we're right in there for for maximizing yields. The reason we're planting 125 or 145 or 155 is to make sure that we ensure that every acre has at least a 100,000 so that we're we're pretty bulletproof out there. But I would go back and, you know, you know, again, from repeat what I said earlier.
Speaker 2:If we had 70,000 out there, economically, there'd be no reason to to to go in and spike additional plants in. But my feeling is with with weed pressure and things like that, it's probably worth putting an extra 50,000 in the planter and going and driving around some of those areas if you've got 70,000 just just to reduce weed pressure from having a better, heavier canopy out there to reduce those weed pressures.
Speaker 1:Well, I think, Jeff, a lot of farmers have committed, you know, their their nitrogen or their fertilizer applications, in a lot of came with herbicides. So, you know, there's there's less room to, like, say, oh, well, I'm gonna rotate out of this crop into that crop or corn or beans or vice versa. So, it sounds like from your recommendations, you know, staying with it, you you really don't get nervous until, what, after June 1st for a lot of southern Minnesota in terms of a grain crop at that point?
Speaker 3:Yeah. Yeah. We can definitely plant quite a bit later. You know, for, like, southern Minnesota, basically, you know, we can plant all the way through about June 10 and still be okay as long as we're shortening our relative maturities. For Central and Northern Minnesota, June 5 is typically the cutoff for corn.
Speaker 2:So we got we've got plenty of time out there. I think we're, I think us academics are a little like farmers that we look out the window and we see all the rain and we get nervous and we put out podcasts and things. And farmers are trying to keep themselves busy, as well. So I think the good reminder is there's still time to get a good crop. We can still get corn planted, and there's, of course, there's a lot of time for soybeans.
Speaker 2:We still have near maximum yield potential in soybeans, and we're not anywhere near the time when we need to switch, switch maturities on our soybeans. So a lot of room to operate yet. Even with some rain in the forecast, I think there's a lot of room to be, optimistic about the crop.
Speaker 1:And and really with that rain, you, you know, we were kind of closing off here. We recommend that, growers can still go online. We you both have good, pages on the extension on the website for, corn growth, Jeff and on soybeans for, for Seth. People can look up more information about that. I know that, Dean Melbic also wanted to be mentioned.
Speaker 1:I know it's kind of an academic exercise, but we do have a plant disease clinic, here at the University of Minnesota, and that can serve as a basis for, if you are concerned about a specific, disease in terms of identification, whether it's a, or phytophthora, whatever. Some of these choices might help you in the future, if not so much this year, but in, you know, future planning. So, take advantage of that. We have a a crop doc, online too. So a couple of different things to help in identification of of those diseases if that is a concern to you or if that does, occur with that.
Speaker 1:So, any last comments from, either of you as, we conclude with this, version of, crop cast?
Speaker 2:This is a little bit tangential, but I do we've been pretty negative about all these, these rains that have come. But I do want to remind folks that there was quite a bit of corn out there and some soybeans that were struggling because of crusting, and they planted in, kinda marginal conditions a week or 10 days ago. And, some of those some of those fields really needed a rain in order to loosen things up for them to pop out. So in some ways, we had a we had a 1,000,000 or $1,000,000,000 rain out of this thing in order to help some of those earlier crops. So, I think we're focusing on some of the narrow bit of soy corn and soybeans that haven't been planted and some drowned out areas.
Speaker 2:But I think largely, we probably we got a big winner out of some of these latest rainfalls that came through.
Speaker 1:Oh, yeah. That certainly negated some of the needs for rotary hoe in a lot of these places, after that, in in terms of that. You know, depending on your soil type may really made a difference. So that has certainly been helpful as well. Jeff, anything else at this point?
Speaker 3:No. I think that's pretty much most of it. The other thing that we didn't really talk about much is nitrogen loss. So, you know, some of these low areas that have experienced ponding, you know, there could be significant denitrification that has occurred in nitrogen loss. So keep an eye on those areas.
Speaker 3:You know, if they're shot showing signs of nitrogen deficiency, they may need a supplemental sidedress amount applied, you know, later in the season. You know, v 6 to v 8 would be a great time to apply it. You know, one could take a soil sample, a pre sidedress nitrate test soil sample, and determine how much to apply that way. Kind of a general guideline is for corn that is showing nitrogen deficiency symptoms, from these type of events, typically, like, 30 to £40 of nitro nitrogen per acre for corn following soybeans is a good side dress rate. For corn following corn, more like 40 to £70 of N per acre.
Speaker 3:So, this should be visible. Should be able to see those symptoms if there if there was a significant nitrogen loss in those areas.
Speaker 2:And the good news is farmers are really geared up to do this now, and I think these split applications that farmers have been doing and changes in in the the form of nitrogen that they've had access to has really forced farmers to diversify their equipment a little bit. And I've you know, a lot of farmers are really well positioned to put on nitrogen at about any time or any place within these fields. And so I think it's it's it's a lot different than the old days when we were just dependent a 100% on on, ammonium in the fall. So, I think this is, it's it I think I think farmers just need to continue to scout and get out there and look and see what their fields look like.
Speaker 1:Well, good. I like to just put a shout out every week on Wednesday mornings. We do University of Minnesota field notes program. We're I guess coming up here on alfalfa, probably on weed science, is is hopeful for, this next week. So that'll be every, Wednesday morning, in terms of 8 to 8:30, and it's through Strategic Farming and University of Minnesota field notes.
Speaker 1:If you have an opportunity, you can go ahead and sign up and and take that, program in as well. So I'd like to conclude this program and and thank, both, Jeff and Seth for stopping in here and talk in terms of talking a little bit about where we are with field crops, corn, and soybeans, in Minnesota here given the current weather systems, with that. So thank you again, gentlemen, for stopping by, and visiting with us here, today. So this has been Dave Nicolai with the University of Minnesota Extension. I'm a agronomist in terms of field crops, working with the University of Minnesota Extension podcast, Minnesota Cropcast.
Speaker 1:And thanks again to our, cohost, doctor Seth Nave. And we'll see you again, next time on another episode of Minnesota Cropcast.
