Crop management considerations for soggy fields
I'm Ryan Miller, Crops Extension Educator. Earlier this morning, we recorded an episode of the Strategic Farming Field Notes program. Strategic Farming Field Notes is a weekly program addressing current crop production topics. A live webinar is hosted at 8 AM on Wednesdays throughout the cropping season. During the live webinar, participants can join in the discussion and get questions answered.
Ryan Miller:An audio recording of the live program is released following the webinar via podcast platforms. Thanks. And remember to tune in weekly for a discussion on current cropping and crop management topics.
Claire LaCanne:Welcome to today's strategic farming field notes session for from U of M Extension. And these sessions are brought to you by University of Minnesota Extension with generous part from farm families through the Minnesota Soybean Research and Promotion Council and the Corn Research and Promotion Council. So we're happy you've joined us for today's session for crop management considerations for soggy fields, and soggy may be an understatement at this point for some. My name is Claire LaCann. I'll be moderating today, and we have 3 guests joining us.
Claire LaCanne:We welcome Seth Naeve, who's our extension soybean agronomist, Jeff Vetsch, who's a researcher in our Southern Research and Outreach Center in Waseca, and Liz Stahl, who many of you know is an extension crops educator. And we know it's wet out there. There's some severe ponding and other complications. Several of us on the panel are in super wet parts of the state too. So we see those issues out and about, and we feel for you.
Claire LaCanne:We were just talking about all the road closures in our necks of the woods. And with that, I'll turn it over to Seth for his thoughts on how soybeans are doing and management considerations, especially in regard to the excess rainfall and flooding in many places?
Seth Naeve:Sure. Thanks very much, Claire. Yeah. I'd I I guess, I don't want to minimize the, you know, the major disruptions that this has caused to a lot of people's lives. But we're gonna really focus really specifically, today on those areas of fields, that need replanted or or have the potential to be replanted or need some nitrogen on those those corn areas.
Seth Naeve:So, you know, we're in some in some respects, we're we're working around the edges of some of these really, really bad spots, talking about some of those fields that are are marginal now and and, hopefully, this week, with some a little bit of a break in the weather. There's some now this week, with some a little bit of a break in the weather. There's some areas that are are starting to dry out just a little bit. So I'm getting some calls on either replanting or planting soybeans for the first time in some areas. And the most important questions are all about maturity group.
Seth Naeve:Lots and lots of questions about this. Our our old recommendations from way back when, said that to to keep a a soybean maturity until June 10. And then around June 21st or, closer to the end of of June, then we could switch out one full maturity group earlier than normal. We've done a bunch of modeling in my lab, and and this basically holds to be pretty true. I will say that, even those, even with those switches and maturities, those replanted or, late planted areas of fields are gonna mature just a little bit later than than the early planted fields at at a full maturity or portions of fields.
Seth Naeve:But I think it's important to to to, for most farmers wanna maintain as much yield potential as they can out there. That's those switches and maturities really allow you to avoid most of the risk of of early frost. I think there's always a potential in Minnesota for early frost and damage, but this keeps us out of the worst of it. I would say that farmers could plant near full maturity, even at a late planting date, But they're almost assured that those those soybeans will be frosted in the end, and they will be probably assured that there'll be some dockage at the elevator. And and various farmers have a whole range of different abilities to deal with, this kind of, soybean.
Seth Naeve:If it's just a few acres, they can, you know, they can, you know, put it in one truck and get it in early or blend it off. If their whole fields are very large portions of fields that are gonna dominate their crop, then they mean may may need to think a little bit differently. I do wanna mention just a couple other things that are questions have been coming up related to this, and and one is about row spacing and other is about population. Population's by far the the most common I get after maturity group for these late planted soybeans. There is some evidence that these late planted soybeans can can catch up just a little bit with some extra population.
Seth Naeve:If we if we increase the population just a little bit, we can reduce some of that yield loss just slightly. It's basically enough to pay for the extra seed. So I I just tell farmers that, whatever they can afford to put put down, they should they should bump up their seeding rate if if they feel comfortable. If they're only planting these soybeans as as, covers, they need to think a little bit differently about that system. If they're really just getting out there, to to get something on the ground, then they need to probably think differently than the economic model.
Seth Naeve:But I think overall, soybeans will, the yields will basically cover, any additional seed costs we have up, you know, up to 175 or 185 probably would be a reasonably high population. These will help those where those rows close just a little bit earlier. You have a little bit better weed control and then a little bit slightly greater yield potential on the backside. And lastly, row row spacing. You know, there was some early early recommendations from agronomists to plant with a drill stands out there across across some of these areas so that we can get earlier canopy closure.
Seth Naeve:And I would just recommend that farmers use whatever equipment works for them and the scale that works to replant or plant these areas. If they chose a planter to plant it, the first time, they should probably stick with that and and utilize that same thing. So I've used quite a bit of my time. I'd I think I'd rather take, you know, pass pass the mic and and let other folks talk a little bit, and then we can come back with specific questions at the end.
Claire LaCanne:Sounds good, Seth. I guess I was just wondering for people who have, you know, soybeans that are in ponded spots that are maybe completely underwater right now. What is the concern there? You know, soybeans are kinda sensitive to excessive moisture, but they can survive underwater for a while. Right?
Claire LaCanne:Like, under ideal conditions, maybe?
Seth Naeve:Yeah. I think, for sure, soybeans can can, you know, be underwater for a couple days. You know, as we increase temperatures the last couple days, that that number goes down. My general feeling is that what what's still underwater is dead. You know, there's a lot of questions out there regarding saturated soils.
Seth Naeve:I think that's these I think we're at a point now where the soils have been so saturated for so long. Even soybeans that have not been underwater or under significant stress, There's a lot of acres that look like that, that'll that are going to be a little bit challenged. But, honestly, there's nothing we can really do. We can't plant those at this time. Those are likely to, you know, to be really delayed if we especially if we get any more rain towards the end of this week.
Seth Naeve:So I'm not too concerned about those. Those are either either gonna live or die, and there isn't a lot that we can do with it. But, certainly, there I think farmers are going to have to scout more this year because we are gonna have more problems in some of those marginal areas than than we've had in in previous years for sure.
Claire LaCanne:Yeah. Yeah. So more scouting for diseases and yeah. That makes sense. Well, yeah, we can, hand it over to Jeff to talk about some nutrient management and, considerations there.
Claire LaCanne:So, Jeff, and and then we can come back to you, Seth, there as questions pop up. We can hand them over to you.
Jeff Vetsch:I'm gonna share my screen. Can everyone see that okay? Yes. Great. So I'm gonna just start a little bit with, some weather.
Jeff Vetsch:As everyone knows, we've had lots of issues with the, with the rainfall and the excessive rainfall. The good side is is our GDUs are running, ahead of schedule, which means that, you know, even for some of this little bit later planted corn, there's still a chance that this or there's still a good probability that this corn that looks good is going to have good yield potential. And not only we are ahead of normal, but I would also remind the listeners that, you know, 2 of the last 3 years we've at Waseca, we've accumulated almost 29 100 GDUs. Now are we gonna do that again this year? But we did that by having warmer than normal or or normal months and then later frost.
Jeff Vetsch:And that as Seth talked about some of these late planted crops, that later frost is certainly something that's gonna be important, if they replanted some of these wet holes and drowned out areas. There we go. This is the bad. The bad is, as you can see, we've had tremendous amounts of rain. And it started here at Waseca back in the 1st full week of May where we did not really get many planning opportunities then until the middle of May.
Jeff Vetsch:And then at the end of May, it got very wet again. And then we went through another window of planting opportunities and field work opportunities at the end of May and early June. And then in early June, we had another, significant rainfall event that we had a nice window to try to finish up some spraying and other things and there were still some a lot of planting going on in our area especially for soybeans. We recorded a podcast, the Nutrient Management Group on nitrogen and whether we should supplemental or apply supplemental N or recommend supplemental N. We did that on June 14th.
Jeff Vetsch:And at the end of that podcast, I said, I'm more concerned about what happens in the next 10 days. And unfortunately, they were predicting excessive rainfall for the next week. That would have been last week, of course. And unfortunately, I was correct that what happened in the last week is really the most concerning issue and obviously not just from a crop standpoint, but from our neighbors and our communities too. But starting there, at Waseca on 14th, since then we've had almost 9 inches of rain.
Jeff Vetsch:There's places that are much more than that. There's places that are similar to that and maybe a little less. But what's interesting is how widespread this is. So here, this chart is from the DNRs. These are actual observer measurements, not radar measurements, and then they're they're smooth across the areas.
Jeff Vetsch:So you go back to May 29th to June 4th, and that was a wet area for much of the South Central or the Northern part of South Central. And it was okay here in Southeastern Minnesota, but it also touched up into West Central and the mid and the Central part of the state. Then you see that I've got a gap of a week here where I don't have a chart. And that generally, that period was generally dry through most of the state except for just a few areas that see it saw a normal rainfall, which normal rainfall for us here in South Central Minnesota is about an inch this time of year. Then when you get to the June 12th to 18th period, you see this very large area that covers a significant part of the corn, soybean and crop areas of the state, And also the twin cities that had anywhere from 3 inches plus in a week, which is 2 inches greater than normal.
Jeff Vetsch:And then this last period, which goes from the 19th to 25th, and you see another significant area that maybe kind of cuts off at the twin cities and south, but the significantly large area here. And now you're talking about areas that have not only seen 3 inches plus, but many areas that were 6 inches plus and with some reports near 10 in just a week. So obviously, what we talked about on June 14th changed again last week. So obviously, we know about the drowned out spots. Some of these areas have been drowned out once or twice, sometimes three times that we've replanted some of these areas more than once or we've replanted once and had them drowned out again.
Jeff Vetsch:And one of the things from a nutrient management standpoint is the lack of oxygen can mimic some nutrient management deficiencies. You get these very stunted plants, you get unevenness. One row will look bad, one row will look good. Is it nitrogen? Is it sulfur?
Jeff Vetsch:Is it just the lack of oxygen? It's sometimes difficult to tell. You see, someone mentioned this yesterday in the extension kind of update, this kind of crazy top and Bruce Potter mentioned that, and I've seen that on some plants where you have one leaf that looks fantastic and then another leaf or 2 that looks all twisted and very yellow. And that's probably due to just water sitting in the world excessive, through all this excessive rainfall. But people want to know about nitrogen loss and obviously denitrification has been the driving factor the last 10 days.
Jeff Vetsch:But we also had significant denitrification in those weeks before that in those other weekly periods where I showed significant rainfall. Back during the podcast, we talked about well, how much rain or how much end loss have we had from denitrification leaching, we thought maybe 30%. I would say now in most of these areas, you're looking at 50%. But when it comes to how much end to apply, if you're going to get supplemental on and on, still what we've done in our research over the many years I've been here is we rarely see more than 40, £50 necessary. Now this year may be the exception where maybe up to 60 or 70 might be required in some of these fields especially in corn on corn.
Jeff Vetsch:What sources of N were that were the first N applied that might be worse? I think obviously fall swine manure and fall manure is going to be the worst. Any fall applications of other nitrogen sources and hydrosammonia was applied early or late fall usually is better, but recognize that we've had plenty of time now for almost all and applied except for side dress and applied to nitrify and potentially be lost. So I don't think there's any one source that's safe even spring applications of ammonia probably still saw some significant loss. What types of supplemental and and how and what how to do that?
Jeff Vetsch:UAN dribbled or Y drops can be very effective. If you don't have access to wide drops, you can attach just rubber hoses on your nozzles if you have that ability and drank dangle them between the rows and drive down the field and kind of dribble it out of the hose, that works quite well. I did have a grower told me that some sprayers do not allow that based on how the nozzles work. He he's trying to talk to his retailer and see if he can get on their list, but he said it's a long list. They're right now about 2 weeks behind.
Jeff Vetsch:So timing wise, how late can we do this? I think if these rescue treatments, ideally you like to see supplemental and or side dress and beyond at V6 or V8, but these rescue treatments, if the weather turns around and these are definitely needed, they still can be beneficial easily up to v14. After we get to tasseling and later, then it starts to question whether the value of these treatments and whether you can get a return on investment. Other end sources and other possibilities to apply urea. If you do use urea, I would recommend, a urease inhibitor and BPT.
Jeff Vetsch:This can be done with a high clearance tractor and a spinner sprayer sprayer. I did talk to one of our local retailers and he said that the airplane will be here. This will be around in the next few days to apply some urea. One of the things though that when you look at these drowned out areas, there's no reason to keep applying nitrogen to these dead areas. So I don't know how effective the airplanes are at turning it on and off and not applying it in areas that are already dead and don't need more nitrogen.
Jeff Vetsch:You need to to monitor that or you're not going to get a good or you're less likely to get a good return on investment if you put it in places it's not needed and also you have the environmental consequences of that. Sulfur deficiency, I've seen a fair amount of that. These pale yellow stripings, If you applied a typical rate, which is 20 to £25, the sulfur maybe is AMS, I think you're probably still fine. These plants are just under stress now. They'll probably grow out of it as they get a little larger and and we get some oxygen in the soil.
Jeff Vetsch:If you want to add a little sulfur with your supplemental end, that's fine. But it doesn't take a whole another 20 or £25. Other issues with all the rainfall?
Claire LaCanne:Oh, Jeff, we had a we had a question about iron chlorosis this year. I think this is just a good time to talk about it because, we talked on our internal kind of extension call the other day that plants that maybe look like it's an iron chlorosis or an iron deficiency, might actually be more of a sulfur deficiency that that's more common. Do you have anything to add on that?
Jeff Vetsch:So iron chlorosis in soybeans, you can see some sulfur deficiency in soybeans, when they're small. But typically we don't fertilize soybeans with sulfur. So yeah, it can be an early season deficiency because of all the leaching of sulfur and the lack of oxygen. But if it's an area of the field that typically has IDC or iron chlorosis deficiency, I would assume it's still going to be related to that, but it could be triggered by just the lack of oxygen making the other symptoms, you know, complicating the factor or complicating the issue.
Liz Stahl:Okay.
Claire LaCanne:Yep. And that question was brought up during the soybeans, but then what about on the the corn side too as far as iron iron chlorosis.
Liz Stahl:Yeah. I
Claire LaCanne:some of the discussion yesterday was was some of that yellowing maybe iron, deficiency, or is it more likely to be sulfur?
Jeff Vetsch:Yeah. It's more likely to be sulfur or this crazy top which you see in this picture on the right. And it could possibly be zinc, but zinc is usually these long white strips. But I would say it's most likely sulfur.
Claire LaCanne:Thanks. Yep.
Jeff Vetsch:That's all I have. I just wanted to mention, obviously, we got some erosion. So when you're going across these fields with sprayers or supplemental and be careful and also the compaction. We took some soil samples earlier this week and it's amazing how this heavy rainfall can compact soils. Fields are very hard and that really hurts infiltration when we get more rain down the in days to come.
Jeff Vetsch:I will stop sharing, or maybe, Rick can do that.
Claire LaCanne:Thanks. And make sure to put your questions in the q and a, and we'll try to get to them. And I will probably have some time for questions at the end as well. But for right now, I'll hand it over to Liz who's now gonna talk about some of our options if we are in a prevented plant situation. So take it away, Liz.
Liz Stahl:Sure. Thanks, Claire. And and again, you know, being in southwestern Minnesota, yeah, there's just been some really devastating impacts. You know, you don't really have any idea how bad it's gonna be when they talk about the rain like you were talking, Jeff. And, yeah, it's just been been incredible.
Liz Stahl:So, again, hearts go out to everybody who's dealing with property damage and, you know, not being able to get anywhere because they're all isolated, roads closed all over. But crops, yes, the crop areas certainly have been impacted. We do have a lot of fields that were not able to be planted. I shouldn't say a lot, but there's fields here and there that were not able to be planted in the first place. So we have prevent plant.
Liz Stahl:Then, of course, we have fields that were planted and now, you know, are completely underwater. And, yeah, they're just when you look at the calendar and when we're ever expecting those fields to dry out, not really realistic to put any corner soybeans in those in those areas. So then that's where another option would be. Okay. Let's look at cover crops.
Liz Stahl:And you know, the reason to look at that. Well, again, whenever you have these drawn out spots or prevent plant area, you've got different options. You know, one would be okay. You could you could do nothing. But, you know, if you do nothing, yep, that's just a great spot for waterhemp, for example, and our late emerging weeds.
Liz Stahl:And you think about that if you're not controlling those weeds, you're gonna build up a tremendous, resupply to that weed seed bank, and you'll deal with those issues for years to come. I'm sure we've all seen those spots, you know, that had been drowned out and then the weeds just go to town. So that's that's a big concern if if we don't do anything. Plus you have issues with potential for erosion, and so forth. You know, wind erosion, more soil erosion if we continue to get more rain.
Liz Stahl:So again but that is, you know, that's an option. Otherwise, you could do tillage to control the weeds. And, again, your ability to do that to do anything is is how accessible are these drawn out spots to be able to get in. Because hopefully, you do have crop, around these spots, you know, because you have to be thinking, okay. Can I get to this area?
Liz Stahl:You know, you're gonna be driving over crop to get there. All these things you gotta weigh out, you know, on on whether what you can do. But again, if it's something you could do tillage that is an option as well. But there again, you know, now we're not having anything growing in that, area of the field. We do have concerns about fallow syndrome.
Liz Stahl:And if you're not familiar with that, you know, there's good fungi. I'm sure Jeff could give you a more scientific explanation, but I'll just say, you know, there's good fungi in the soil, that help with nutrient uptake of the plants. They need to have living roots to survive. If we don't have growing plants out there, they they just their populations really drop, and that then can affect your crop yield the next year. So, again, it's good to have something growing out in that area too.
Liz Stahl:And, also, you know, if you're in a situation you have livestock, if you, you know, again, can plant a, cover crop, you could use that cover crop for forage, potentially too. That is one thing that has changed, from our last time that we've dealt with or last times we've dealt with prevent plant. Again, always check with your crop insurance person for sure. But, the latest information that I have as well is, you know, if you plant a cover crop, you can harvest that for forage. You cannot harvest that for seed, but you could harvest that for forage.
Liz Stahl:So so that is a potential. So just again, some things to think. Well, we've looked at, I worked with Axel Garcia Garcia at the Southwest Research and Outreach Center at Lamberton for I think we did this trial for 4 years just looking at different, cover crop options that you could plant, you know, around the middle of July. Again, looking at this prevent plant or drown out spots. And it's been pretty interesting, what we found, you know, you do have some different options.
Liz Stahl:Of course, when you look at cover crops, you've got your general families, you've got your brassicas, you got your legumes, you've got your grasses. We've planted, you know, a different suite of, cover crops out there. Hands down and above, you know, we've looked at sorghum sudangrass, for example. Tremendous biomass producer. Know, if you're planting that in the middle of July, if you're looking for forage that has just knocked it out of the park.
Liz Stahl:We've looked at, some of our data, it's over £6,000 per acre biomass we produce, you know, by the end of the season with sorghumston and grass. Your millets come in, very close to that too, like pro millet, Japanese millet, we've looked at. And those also did very well again for biomass production. We've had tillage radish out there, as well too. And some years that didn't do so well.
Liz Stahl:The last couple of years we did the study, it really, took off. So that's another one you could get some really nice, biomass production. There's also options you could look at, like, you know, oats or cereal rye. Again, those are cooler season grasses, so they don't do as well, you know, when you're planting them in the heat of the summer. But they did still produce some respectable biomass.
Liz Stahl:We had by, you know, the end of October, they were up to about over £3,000 per acre. So it took it took a while, though, for those to take off too. So that's something to look at. If it's slower to get going, you're gonna have more issues with weed control. So you wanna have it's nice to have something that really takes off.
Liz Stahl:And the legumes, yeah, I I know people really like to look at those, you know, for nitrogen benefit. We had a challenge, you know, really, they've been slower to take off. They have not liked being planted. At that time, in our trials, we've had more challenges getting those, to take up, but those are an option too. We have had them, like crimson clover we've looked at.
Liz Stahl:We've planted that in a mix as well. But, again, there's there's a number of different options, but, you know, things to look at. You know, what's your availability of seed? What's the cost? You know, how big of an area are you looking at?
Liz Stahl:So, you know, and a number of of things. Do you want something to overwinter or not too, or do you want it to winter kill? Like the circumstance, it's gonna winter kill. Pearl millets, you know, in the millets, those will winter kill. Cereal rye planted that time, probably, you know, shouldn't winter kill, but it might because, again, it doesn't get as well of established.
Liz Stahl:But a lot of different things to think about. We do have a lot of resources online, and I think those will get posted, on this webinar. We'll also have those with the recording here too of of to look at for different types of options. I don't know if you have any questions or or other comments, but but, yeah, it's it's a tough situation. And I think availability of seed and the cost and your ability to get out to these areas is really gonna be a big factor in in determining what you can do.
Claire LaCanne:Yeah. Thanks, Liz. And I know you have some resources that you'll share for kinda cover crop considerations, in our resource list. But there's also the Midwest cover crop council has a selector tool so that can maybe help people, you know, kind of they can put in when their planting date would be for that cover crop and get some options there as
Liz Stahl:well as it considers frost dates for the county. And and that's And
Claire LaCanne:I can't believe a herbicide down beforehand too? So, you know, because, again,
Liz Stahl:your herbicide can control that cover crop too. So, again, you gotta know, because, again, your herbicide can control that cover crop too. So, again, you gotta look at that history. But, again, we have some nice resources that kinda go through that whole decision process.
Claire LaCanne:And we do have a question that popped up. Do we have some do nots that we should be aware of? I think that's in relation to cover crops, Liz.
Liz Stahl:That's a that's a great question. Well, one one caution we always have is something like buckwheat or, you know, something that can bolt and produce seed fast. That can be a challenge. You know? Again, can grow very fast.
Liz Stahl:You can get a lot of ground cover, but then it can produce seed pretty fast too. So you have to keep your eye on that. And if you don't wanna have buckwheat next year in that area, you know, try to control that before you would get seed production. So that would, that would be one of those. Yeah.
Liz Stahl:Maybe not a do not, but have a little asterisk. Proceed with caution.
Claire LaCanne:Yeah. Good point. I will just say that we know that, these weather conditions can be really stressful, especially when things aren't under, you know, our control. And so we do have a resource in our resource document that'll be shared with you about taking care of yourself under stress. So just wanted to say we feel for you, and we know it's stressful, and take care of yourselves.
Claire LaCanne:So as we part here, I just wanna thank you again for joining us and thank our sponsors, the Minnesota, Corn Research and Promotion Council and the Minnesota Soybean Research and Promotion Council.
