Irrigation and drainage updates after a wet summer
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.
Anthony Hanson:Welcome to Strategic Farming Field Notes, this program provided by University of Minnesota Extension and sessions are, brought to you by generous support by the Minnesota Soybean Research and Promotion Council as well as the Minnesota Corn Research and Promotion Council. And we're glad you could join us for today's session. Today, it's all about water. So we're gonna be talking about irrigation and also drainage, especially after the wet summer we've been having. I'm Anthony Hansen.
Anthony Hanson:I'm an educator in Integrated Pest Management based out in Morris, Minnesota, and we have 2 guests today. 1st will be doctor Vasudha Sharma. She is our irrigation specialist. And then, Lindsay Pease as well. She will be covering basically the drainage side of things.
Anthony Hanson:And, now really, in a year like this, I think this is gonna be a pretty timely episode just to cover what's going on, especially at the end of the year and maybe what people are thinking about how things went and what they could prep for next year potentially. So with that, I do wanna give a quick little IPM update because we've been getting a few questions coming in on that. Soybean aphid has been the hot topic and maybe a few other insects out there people looking for, but primarily soybean aphid. So just a reminder for that one, they'll still stick with the scouting thresholds. There's some fields that are at that 250 threshold.
Anthony Hanson:People have been out spraying. Just a reminder, that's not when plant damage is occurring. We're really trying to prevent getting closer to 600, almost 700 aphids per plant. And in that case, if you're at about a 100, 150 aphids, just keep going out and rescouting those fields. I know it's getting, to the end of the season.
Anthony Hanson:We're kinda getting a little tired of, different, scouting out there, basically, all the time that goes into that. But it is a point where, you know, you may be able to get away without having to spray those fields too. And those insurance applications to spring earlier, sometimes those can still backfire on us. So that's kind of the short short IPM update there. So with that, I think we're gonna go on to talking to Vasu about what's going on in the irrigation world.
Anthony Hanson:So, Vasudha, it's good to have you on here again. And now first off, you know, this is a very different year compared to when we usually talk to you. It's usually been droughts and obviously irrigation then. We're really focusing on that, at least folks that do have irrigation in their areas. So what's different for you in a year like this when it's wet?
Anthony Hanson:And obviously, there's still work to do on the irrigation side of things, but it obviously shifts a bit, doesn't it?
Vasudha Sharma:Yeah. So we are not as as tight as last 3 years. So 2021 to 2023, last 3 years were drought years. We we saw irrigators running throughout the season. This year, it's a little different, in terms of, I'm talking about just one site, but it's it's same for maybe all of Central Minnesota and throughout Minnesota.
Vasudha Sharma:So at Becker Station, we got around 9 inches of rain, from May since today, last year. And this year, it's around 20 inches. It's more than double that we got. So irrigation, we are still irrigating our crops because sandy soils need that irrigation in those dry spells. But, of course, from comparing to last 3 years, we are not even close.
Vasudha Sharma:So we irrigated around 2 times or 3 times our corn, at our locations in central central sands, unlike last year's where we have 8 or 9 irrigation events. You're muted, Anthony.
Anthony Hanson:Sorry about that. And you think I'd have that figured out by now. But, yeah, some of these rain events we've been having have been pretty heavy where, you know, a lot of times this time of year, it's almost a guarantee you would be irrigating. I know some areas people maybe turned on their pivot once so far this year. So that's one where, I don't I don't know if you get into kind of the general maintenance side of things a little bit too, but are there issues people should be looking out for, whether it's their gators themselves or just other things where they really haven't been using their pivots much this year?
Anthony Hanson:Are there things that could crop up potentially with that?
Vasudha Sharma:Yeah. I mean, in terms of maintenance, since irrigators are not running too much, I would say the regular maintenance that we do over winter, that's that's required. But, I just want to go back and talk about the heavy rain. So we got, just one example of one location where we got around 4 inches of rain, last week. And this week, the higher spots, which are more coarse textured sandy soils, are still looking stressed.
Vasudha Sharma:So it's not like you get 4 inches of rain and you don't need to irrigate for the next 3 weeks or 2 weeks. You know? You got to be looking out for those spots and looking out for the predominant soil type. If it is coarse textured, sandy soil, you might need to irrigate because in the sands, that water, even if it is 4 inches, that's going to go down really quickly, really fast. So we are going to irrigate that field again this week if it doesn't rain, today tonight.
Anthony Hanson:Yeah. We might be, talking about similar areas too here in West Central Minnesota. I know, we had about yeah. Close to 4 inches too, and I definitely have seen some areas where they're drying out already.
Vasudha Sharma:Yeah.
Anthony Hanson:So that's kind of the question too. How is how how is the adoption for, say, variable rate irrigation and, you know, for everyone else out there who doesn't have that, how do they approach the last part of this, yeah, the last part of this growing season where, you know, we definitely wanna be getting water on, but it's gonna be really difficult to make decisions in some fields.
Vasudha Sharma:Yeah. I think that's a great question. So variable rate irrigation, for the audience, just giving a little bit of background. It's a precision irrigation technology where you can apply different amounts of water to different areas in the field. So this year, actually, it's, I think, more applicable than dry years because if you have a field that has lot of variation, you have sandy soils, you have maybe some heavier depressional soils.
Vasudha Sharma:If you have a VRI system, variable re irrigation system, you can actually manage efficiently because with these heavy rains, maybe those depressional soils or heavy, a heavy soil areas won't need irrigation, any irrigation. And the sandy soil, as I said, even with the 4 inches of rain, you got those stressed spots in the field, so you might need to irrigate just those. So VRI, I think, would be very applicable in years like like this, like we are experiencing or 2020, the last year. Last when we had so much rain. But during the dry years, it's it's hard to, economically explain the use of VRI in some parts of the state when you don't have that much variation in the field.
Vasudha Sharma:But, yeah, but I think it pays out if you have more of these kinds of years where you have lot of rain and lot of leaching. So you want to save on your nitrogen, your water, and apply water only at the locations or the other spots where you actually need it and not at the other other spots.
Anthony Hanson:So thinking about, now basically how the crops are gonna be developing the next month or so, when are you kinda considering the cutoff for when you don't need to worry about irrigation anymore? And this is assuming, you know, maybe we don't get as much rain in August. But, yeah, what what's your time of year you're generally looking at, for irrigation considerations?
Vasudha Sharma:So, usually, at this time of the year, we are in the reproductive stage, as for for corn, specifically talking about corn. We are still water is critical at this point, but not so much. We don't need that much of water as we would need in June, July, or mid the earlier part of August. Moving into August, I think we were if if it doesn't rain now, just starting from today, we might need couple of more irrigations for corn and, for similar crops. But, at the end of the season, maybe later August, September, crop is in the later stages of reproduction, so don't need that much of water to to grow.
Vasudha Sharma:So soil moisture that's there in the soil would be enough to suffice that. But if it is, like, really, really dry, like, I think there was 1 year when we went up to 1st week of September as well. But most of the time, if we get here and there 1 or 2 rains in August, I think this is kind of the last leg of irrigation. So I'm expecting maybe couple more irrigations, in the central sands if it doesn't rain.
Anthony Hanson:How about on the aquifer side of things? So this is the year we're, you know, expecting some recharge at least when we have this much rain coming in. But, yeah, for a lot of us, we don't hear about monitoring on that too much. So kinda what's kind of the, you know, 300,000 foot or 30000 foot view on, what you're seeing on that side of things?
Vasudha Sharma:Yeah. I'm I'm sure it would be really, really different than last 3 years. So last 3 years, we have been hearing about, you know, many complaints about well interference or aquifer, you know, decline. I don't think this year that we would have that problem with this much rain, and I'm assuming I don't have any data to talk about that, but I'm assuming that we have good recharge this year for sure.
Anthony Hanson:And kinda across the state, do you have a sense of, you know, because we've been getting different, rain events across the state, but also just irrigation is different across the state too. So, are there any kind of regional aspects you wanna focus in on how it might be different or, you know, areas to really keep an eye on?
Vasudha Sharma:Yeah. I think, not specifically about areas, but even in the central sands where we have a lot of irrigation with these, thunderstorms, it's very spotty. So sometimes you get, like, one location, you get 4 inches of rain, and other location, you just get 3 tens. So it depends on where you are located. It's very important to monitor how much.
Vasudha Sharma:So rain gauges in each of the fields are really important to know how much actually you got. And then one other resource that growers can use is soil moisture sensors that will tell you the real condition of of your soil. So I would recommend everybody who is irrigating not just to depend on weather websites or, you know, look at, like, oh, like, 1 10 miles apart, the weather station shows me 2 inches, and that's what I got. This is like the rainfall is very spotty, so you might not get that much or you might got too much of water what your weather station is showing. So it's really important to look at your in field data, your rain gauge, and soil moisture you know, for some of us, if our closest one
Anthony Hanson:is 30 miles away, you know, for some of us, if our closest one is 30 miles away Yeah. Then, you know, it might be a little more obvious. But even for ones that are pretty close, sometimes wind speed, rainfall, it's vastly different, especially within your field too. And I think we've seen that play out a lot of times in some examples out there. So Yep.
Anthony Hanson:A good reminder for folks.
Vasudha Sharma:And then other other thing that I want to mention is crop is another factor. So for corn, as I said, we irrigated 2 or 3 times at Becker. But for our potatoes, which are very high demand demanding, water water demanding crops, so we have been irrigating, but not too much. Our frequency is higher than our corn irrigation, but the amounts are really small because these crops some of the crops needs that water frequently, rather than taking that stress for very, very long time. So less less, drought tolerant crops would need frequent irrigation even in wet years like this year.
Anthony Hanson:Kind of one, you know, broad question here for you to kinda wrap things up a little bit. What are you looking at for the future in irrigation in Minnesota? Is there anything on the horizon that's, you know, really, piquing your interest? We talk about variable rate irrigation a bit, but, now what are some other areas that might be something interesting for growers to at least keep an eye on in the future, if not considered for future work?
Vasudha Sharma:Yeah. I think precision irrigation management, we have been working a lot on looking at how we can use these remote sensing tools for in season water stress diagnosis and try to find a solution for in season management of water rather than just depending on weather stations as I mentioned, which might be 30 miles away. So if you have your in field, in season measured data using remote sensing, how we can make use of. So that's something that we are exploring research side. So we have some plots at Becker where we are collecting UAV remote sensing images and trying to build some relationships of water stress and remote sensing.
Vasudha Sharma:And then VRI, of course, this is this is the future. We, are collaborating with MDA here who got funding, RCPP funding 3 years ago, for cost sharing, VRI systems for our growers. It was very successful program. From last 3 years, we are applying again. So if we get the funding, then we have more money to help our growers to, to see the benefits of VRI technology in the state.
Vasudha Sharma:So what I'm seeing from last few years that we are progressing, very well on this path of precision irrigation and and, efficient irrigation management. And that's what I see in the future.
Anthony Hanson:Thanks, Vasu. Oh, we do have one question that came in here. They're asked about limited irrigation affecting or has limited irrigation affected fertigation? Would that be an option would non fertigation application be an option? And that's an example of, like, there's no irrigation at corn height of 6 to 12 inches.
Anthony Hanson:So that's a very specific question there, but, yeah, they fertigation. If you wanna just comment on how that's been set up.
Vasudha Sharma:I, yeah, I'm not sure if I understand the question, correctly, but I what I'm assuming is how limited irrigation are this year. Like, we irrigated very less. How would that affect nitrogen uptake or fertigation? I would say we have water in the system. So plants need water to uptake nitrogen.
Vasudha Sharma:Right? It doesn't matter if it comes from irrigation or it comes from rain. But if it comes from rain and it's, like, 4 inches of rain, all that nitrogen that you have applied is going to go away. So that's where if we have if we have if we are managing irrigation, we can manage nitrogen as well along with it because we know how much we are applying and how much it is it is required such that crop uptakes it rather than leach it. But with rain, it's hard to tell, like, where it is going, you know, if how much is is the crop uptaking it and how much is going below the root zone.
Anthony Hanson:Alright. Thank you, Fazu. One last thing. I think you have an event going on tomorrow if you wanna, mention that a little bit to folks.
Vasudha Sharma:Yeah. So every year, in collab in collaboration with Pope, SWCD in Westport, Minnesota, we organize a field day, where we talk about irrigation, nitrogen management kind of research. We have our plots up there at Farm. So that field day is tomorrow, August 15th, from 9 to 12. So if you are in the area, feel free to stop by and, listen to what we are doing and maybe look at our plots.
Anthony Hanson:Yeah. And we'll both be there tomorrow too. So, yeah, if anyone wants to chat us up on that, that'd be your opportunity. So, again, thank you, Vasu. We're gonna move over to Lindsey now.
Anthony Hanson:So, Lindsay, my question for you is, you know, I don't think we've had you on the show before. So do you wanna give a little introduction on what you do and where you are?
Lindsay Pease:Yeah. Hi, everybody. I'm Lindsay Pease, and I'm a nutrient and water management specialist, in Northwest Minnesota. I am based out of the Northwest Research and Outreach Center in Crookston. But my work focuses pretty broadly on on both drainage, but then also some nutrient management questions.
Lindsay Pease:And of course, you know, being up in the Red River Valley, we have some different we have a little bit of different, you know, soils and and weather than Southern Minnesota, but kind of a lot of the strategy that are a lot of what I'm thinking about here is, you know, if you can make it work in Northwest Minnesota, you could probably make it work anywhere in Minnesota. That's, that's maybe a challenge I would put, out there for many of you.
Anthony Hanson:Yeah. So working with drainage a lot, obviously, you know, a lot of folks know it's wet this year, and we're needing drainage in a lot of areas. But what have kind of been the things come I should say floating to the top, not pun not intended there, but what's really the, you know, things on the radar for you this year that have been issues or, you know, good things people seem to have been working out for them?
Lindsay Pease:Yeah. You know, I think I think that's something that this is the type of year where having a subsurface drainage system can really show the advantages. You know, obviously, it was we were going into this season pretty, you know, pretty scarce on the water side. As Vasu mentioned, we went from that really 3 year really dry cycle to then all of a sudden having way more water, than we can deal with. And, you know, the scenarios, like, we dealt with this year and we're are still dealing with in many cases where that amount of water that you're seeing is preventing your equipment from getting out in the field and preventing timely planting, and also timely harvest, whether that's wheat or alfalfa or corn and soybeans.
Lindsay Pease:You know, anything that's really preventing you from those timely operations is a signal that maybe a subsurface drainage system. If you don't have one would be something to consider because, you know, a lot of the time, that's that's what can help with that traffic ability. You release just a little bit of that water a little quicker, and then that helps you get your equipment out, in a timely manner.
Anthony Hanson:Yeah. So thinking about, you know, what what basically areas would people be looking at for maybe improvements in the future or especially this year? It sounds like we've been talking about even before, we started on the webinar here that during case of prevented plants, some people are thinking, oh, maybe I can get some drainage tile in now or maybe they're working with their ditch assessments and, you know, things that might be going there. So is this this is basically the year to think about what's going on for the future. So anything that really would stand out for specifics that, growers might really be looking at if that is their situation this year right now where they don't have a crop out there and they can get out in the field and at least get the drainage side of things taken care of?
Lindsay Pease:Yeah. Definitely. There are some considerations that I would really encourage people to look into. You know, one of them being about how often you feel like your fields are wet versus they're dry, you know, because that's something that specifically in northwest Minnesota, we're we're looking at here at the research center because, you know, obviously, we've had about 1 every 4 years, since I've been here in in northwest Minnesota been wet versus been dry. So you think about that return on investment.
Lindsay Pease:A drainage system is very likely not gonna pay off in year 1. You do wanna think of it as a long term investment, for your farm and for your land. So, of course, then thinking also about, you know, future plans for that land, whether it'll be staying in the family or if you're renting, you know, those conversations can be kind of difficult sometimes. If you're thinking about, yeah, I think I think that's kind of one of those big questions you have to ask if you're gonna be doing an install. An extra thing beyond just the subsurface drainage infrastructure itself would also be whether you wanna add, some control drainage management into your system as well.
Lindsay Pease:That's something that we've done a lot of research on, and and it's really good at, at reducing excess drainage during times of the year when you don't need it. You know, if we have 3 years of drought and you have a controlled drainage system, you can actually make use of the rainfall that you're getting. You're not gonna over drain. You're really not gonna over drain the soil anyway, but if you do get, you know, some rains, you can make use of that. That's something we've seen.
Lindsay Pease:You know, Jeff Strach in Southwest Minnesota has done a lot of research on that and has found good results from. And, of course, if you have a lift station in Northwest Minnesota, that's you can just literally turn those flip the switch on and off as you need it, and that's something a tool that I would really encourage growers to think about that, we don't use enough of.
Anthony Hanson:And that's kind of a good segue to a question I had actually was, I I asked Vasu this too, but also on the drainage side, what varies across the state? And I know, yeah, we hear more about lift stations, in your neck of the woods out here in West Central Minnesota. It's more just your drainage stitches. And, yeah, you have some control over your drainage tile maybe going into those ditches. But, yeah, how does it look across the state in terms of what infrastructure we have for folks who maybe aren't as familiar with it?
Lindsay Pease:Yeah. I definitely think, you know, the lift stations are something that are way more common and are very, very flat topography in the Red River Basin. But, also, I mean, could be used anywhere. Basically, the the places in the landscape where you would put a lift station are where you don't have one of those really deep road side ditches that you can outlet your system into, which those can happen anywhere on the landscape. But, of course, in northwest Minnesota, we took a little bit longer to develop, you know, going back into the 1800.
Lindsay Pease:So so there was nobody around to dig those deep, roadside ditches like you may be familiar with in southeast or southwest Minnesota, even west central. So that really makes sense, for those locations. I think that's one of the big geographic differences, of of drainage, but also how how new or how old those drainage systems are. I think we've seen, you know, in especially in the southern part of Minnesota, drainage systems have been around for a long time. Whereas up here, the latest survey from, from from, the Census of Agriculture, they only estimate about, you know, as you get into Wilkin County of only about 15% of the land has subsurface drainage, and that reduces as you go further and further north towards the Canadian border.
Lindsay Pease:So there's a lot less drainage up here than people, I think, realize, even though there seems like there's a lot going in right now.
Anthony Hanson:Alright. We do have a couple questions coming in that, you may be able to tackle a little bit. And this, partly covers just the water and the soil, basically nutrient side of things, but also getting to cover crops a little bit too. So it's kind of the connection here was basically our kinda high water urine related to nutrients. So, kind of the first one, I'll kinda rope 2 together here.
Anthony Hanson:Basically, potential nitrogen credits. How does that work in terms of cover crops, especially a wet year like this? And do you think, is that showing a trend with fertilizer sales or anything along those lines too?
Lindsay Pease:Yeah. This is a it's a really good question, and I think this is one of those questions that, you know, as a research as, you know, a research
Anthony Hanson:team here at the university, we're
Lindsay Pease:still kind of trying to figure out exactly how much crediting versus, you know, crediting you could get from a cover crop in terms of that fertilizer sales. One thing that I would say, in terms of if you're planning for fertilizer for next year, and you're doing a cover crop, usually what we're seeing is that the cover crops are tying up nutrients, of course, during the winter, which is when you want them to be tying them up, and during the early spring, but they may not release those until a little bit later in the season, basically until any of that vegetative material has broken down, or any if there's any straw like residue, the microbial activity in the soil is gonna tie up that nitrogen, which, of course, is what we want in many cases, for in terms of water quality. But in terms of planning for your next crop, that is going to be something that, may be detrimental. So I would really encourage maybe switching some of that, maybe thinking about, like a starter application of fertilizer with your crop maybe instead of a pre plant application just so you can get those targeted nutrients closer to the seed, so that it's less likely to be immobilized early.
Lindsay Pease:Of course, later on, those nutrients would become available. And so doing things like maybe taking a soil test before you do a side dress application, I know that's something that Brad Carlson really, rallies for everybody be to be doing, but, you know, in cover crop situations, that would be a really good situation to do it so you know what you have and what you might need on top of that. Hopefully, that answers that question, Anthony.
Anthony Hanson:Yeah. And this might be our wrap up question here, but kinda turning on the nutrient side of things. So this year, obviously, I think almost everyone has seen fields where you have some low spots, just even little areas within fields, sometimes wider ones, where either there's flooding, it was wet, and corn especially just did not do well. You could see it was stunted. Nitrogen deficiency or nitrogen leaching going on, we expect.
Anthony Hanson:And what's that gonna mean for next year, especially, if we continue seeing wet weather like this? Can I any general advice for what to expect on the nutrient side of things with these conditions we're having going forward?
Lindsay Pease:Yeah. I think definitely, where you have had a crop underperform, and this goes for drought years too, you probably have over applied nutrients in that particular spot. So that again is a place where I think your best friend is getting a soil test out there to see what you have left. I think, you know, it's not uncommon after a drought year after many drought years, especially to see nitrogen flush out of the soil because you finally have water moving down through the profile. So we may have had a lot of nutrient movement early out of the field.
Lindsay Pease:And then on top of that, if you have a crop underperforming, you know, you may have a lot of variability based on the patchiness of of your crops. So those would be some things, that I would really take forward, especially into this fall as you can get out into the field. Yeah. I think soil testing is really your best friend.
Anthony Hanson:Yeah. No. That's one this year I think I've heard many times is basically once people get out in the field, they're curious about what's going on. And, yeah, that's one where I I don't think there's been as much field work going on in the wet areas right now just because, you know, whether we're talking about, any pesticide applications or just field testing, that's been tough. But, yeah, I think that's on the radar for a lot of people going forward here.
Anthony Hanson:I have one question that came in here, about bioreactors and yeah. For filter out fertilizer.
Lindsay Pease:Yes. So, great timely question, from Kathy, because actually we are working on some we have some active areas of bioreactor research around the state. We just started we just started our, most northern bioreactor, about 30 minutes from Crookston yesterday, so very timely. I think, you know, those edge of field structures can be really useful in scenarios where you maybe have a sandier soil that is losing a lot of nutrients, something then you have that that filter on the edge of the soil to help catch, you know, your you can be doing your best possible in the field, but sometimes the scenario, of what your soil, you know, sometimes you're doing your best, but the soil still wants to leak out a lot of nitrogen. And, of course, we know that, you know, in sandier soils, it's it's an issue.
Lindsay Pease:So those types of places can be a really good option for a wood chip bioreactor that can be used to just use the biology to be filtering out nitrogen from the water. I really like these practices. I think, you know, I think the cost, we've probably we probably spent about $15,000, which is on the higher end of a wood chip bioreactor, but that's also because we, we are sort of we're sort of trying to do it in a rush last winter, last fall before things got cold. So if you can plan ahead, you can probably cut that cost. But, you know, that would be certainly an option, for reducing those edge of field losses out of the tile drainage system.
Lindsay Pease:And happy to talk more. I know we're at the end of our time, but, people can reach out to me, if they have specific questions.
Anthony Hanson:And speak of which, I have one last question I wanna try to get, and then, yeah, we'll have to cut it off there. But I had a question about a drainage ditch. Basically, downstream, they drain into this ditch, but it's plugged with trees downstream. They're asking, is a lift station a possible answer? What other options would they be looking at there?
Lindsay Pease:Yeah. It it depends a little bit on the topography. If the if the lift station could let you kind of jump that blockage in the in the stream, that could help a little bit. You may end up in a situation though if that outlet is just not able to hold more water, then, then that water you'd be pumping it out and it's just underground gonna be coming back towards your field. We run into that scenario a lot up here during, you know, extreme flooding conditions.
Lindsay Pease:You know, if there isn't an outlet, unfortunately, I don't know that that lift station is gonna help very much. What probably you would need to do is figure out a way to to clear those trees out of the ditch. The hopefully, the yeah. And again, depending on where you are, I may or may not be able to give some targeted help, to that to that person. So, feel free to reach out to me with with that type of question, and and maybe we can help brainstorm some ideas.
Anthony Hanson:Alright. Thank you, Lindsey. And thank you again everyone for attending our, University of Minnesota Extension field notes program today. Again, reminder, we have one more episode next week, that we'll be covering basically end of season harvest wrap up. We'll have doctors Jeff Coulter and Seth Navan.
Anthony Hanson:Again, thank you to our sponsors, Minnesota Soybean Research Promotion Council as well as Minnesota Corn Research and Promotion Council.
