Field Crops Webinar Series - Drainage Management for Nutrient Retention

February 18, 2019

This webinar features Dr. Ehsan Ghane addressing issues related to drainage of crop fields and nutrient management.  When excess phosphorus from farmland reaches downstream water bodies, it causes eutrophication and harmful algal blooms like the ones in Lake Erie and Saginaw Bay. Much of this phosphorus is soluble and readily available for algae growth. Most of this phosphorus is transported by subsurface drains. In this presentation, two drainage conservation practices including controlled drainage and saturated buffers will be discussed.

Video Transcript

- Good evening everyone. Welcome to tonight's seminar. Again, my name is Eric Anderson, I'm a field crops educator with Michigan State University Extension. I just wanna right away apologize for those of you who just got emails in the last couple two, three hours, about tonight's webinar. That won't be the case every week. The plan moving forward is to get you folks a link beginning on the Friday. So starting this Friday you'll get one for next week if you have signed up for the whole series. But then also I'll be sending out one like on a Monday afternoon type of a thing, so just a little bit of a reminder. You're all on, so you have will gotten a link, but you just in case future emails get put into your spam, you may want to white list my email address. It's, and again, since you're on right now, you must have gotten that email, so you may just want to add me to your white list. That will be how I send out these links. So a couple of housekeeping things before we turn things over to Dr. Ghane. If you have not done one of these webinars, we use Zoom platform that we're using. All of the communication that we'll do tonight will be via the Q and A feature at the bottom. You probably also see something called chat. That's something for the most part will be just for panelists to use, but that's also how we'll get information out to you, as you can see, one of the bullets down here. They'll be a link to follow. We're trying a few different things new this year, for those of you who have joined us on the webinar in years past. One of the new things is the way that we'll view surveys and the application for the RUP credit. So I'll talk a little bit more about that towards the end, but if you have any questions for Dr. Ghane as the evening goes on, feel free to type those into the Q and A, and then he can address them. Actually Ehsan, would you like to address those as you go or would you rather wait until the end? That's up to you. - [Ehsan] We can address it as we go. - Okay, and I will monitor the Q and A as well in case you don't see one that pops up, so. And with that, I'm gonna go ahead and stop sharing my screen, and turn things over to Dr. Ghane. So Dr. Ghane, he's been with us now for a little over a year, somewhere between one or two years. He's with our ag and bioengineering group on campus, and tonight he's gonna be focusing on a part of what he does for research, and that is dealing with field drainage, but also with nutrient management. So Ehsan, I'll have you go ahead and share your screen, and you can take over. - [Ehsan] Welcome everybody to our field class webinar series. My name is Ehsan Ghane. I'm going to be talking about water management for nutrient retention. You likely heard the question of do you have a nutrient management plan for your farm. So in addition to that plan, the nutrient management plan, we also ask about do you have a water management plan for your farm? So that's related to the talk today, tonight, and I'll be talking about that plan and the conservation packet that relates to the plan. So to start off, I want to show you the map of Lower Peninsula Michigan, and you can see we got the counties here, and the color range is basically the percent of total county area with subsurface drainage. So it's zero to 3% for the white counties and the range continues to 48 to 59%, and these are our 2007 estimates. So we know that agriculture is an important part of Michigan, and based on the data we have for subsurface drainage, we know how, what impacts subsurface drainage has for crop production. We know this is a vital component of agriculture. So here you can see the density of drains of mainly two areas. This area in the thumb, and also southeast Michigan. So it will be next to Lake Erie and also the Saginaw Bay here. So let's zoom in to Saginaw Bay. I have an aerial image here from NASA Worldwide that shows from July 19th, last year, and shows the algae. You can see the green on this side and a bigger extent of it on the east side of the bay. So I'm going to keep going forward and you'll see a photo every month. So this is the July one, this is August. Again you see here, here, September again here and here. And this is the last one October, again algae. So the reason it's occurring on these two sides is because these are shallow areas and not so much this area or in this spot, because water is deeper, so it takes longer to warm up. And these areas are shallower, and temperature is one of the ingredients for the algae to grow. So we can see the algae on these two sides, and the reason the main nutrients that's causing this is phosphorus. So where is this phosphorus coming from? So let's look at some of the sources of the phosphorus. So now we're looking at Lake Erie. So the sources are general, so we can actually generalize from Lake Erie to Saginaw Bay. So if you look at this part, I'm mainly focusing on the western Lake Erie Basin. So this one, West Basin total. We can see the different sources or phosphorus. So there's nine percent of the phosphorus is from point sources. For example, industrial discharge, for example, whisper achievement plans. There's two percent atmospheric, coming from the atmospheric position, and there's a bigger part of the pie, 89%, is nonpoint source, phosphorous. So that can be urban storm water runoff, it can be stream bank erosion, and other things. One of the major parts of this nonpoint source is agriculture. Research has shown that it's mostly coming from agriculture landscape. So let's zoom in to a field scale. Let's see what happens if it is coming from agriculture, most of it's coming from agriculture. Let's take a look at the water balance at the field scale. Let's see what's happening here. So we have precipitation, rainfall coming down, infiltration, so the rainfall coming down infiltrates into the soil, and it goes up the waters here. Some of the water, may, depending on conditions, may storm off from the surface and that can cause surface runoff. And this component here is the drainage discharge, because these are the ladles right here, and the ladles are coming to a main that will be collecting the water, and the water will be discharging into the drainage ditch. So the pathways of nutrient loss will be there's a surface runoff component, which is this component right here. So water runs off the surface and that mainly erodes the surface to soil and carries with it a particulate phosphorus, which is the phosphorus attached to soil particles, and it can also take with it some soluble particles. In 1990s, after we realized how much soil was eroding, 1990s, early 2000s, up to now, there's been a lot of effort to reduce the surface runoff component. And it's being successful. We have reduced a lot of the sediment, a lot of the erosion occurring from fields, but many different practices. We've had (audio cuts out) and other practices (audio cuts out). We recently, the last decade, we have realized that algae is still occurring, and we've noticed that the drainage is just, right here, this component is actually carrying soluble nutrients including nitrate and also soluble phosphorus. So I mention again because water flows into fresh water bodies, phosphorus is that limiting nutrients for the algae. So this will be very important for us in Michigan. So let's take a look at some of the findings for soluble reactive phosphorus. So reactive means that it's readily available biological activity. Plants and biology. So the recent, recently a paper was published and they were looking at the soluble reactive phosphorus load, and they found that in the early 2000s, they found that the load going to Lake Erie increased, and they found that the majority, most of the SRP load increase was because of two factors. So the two reasons, the first reason was because of increase in soil phosphorus. Basically the soil tests phosphorus, and they were able to attribute that to practices that would build up phosphorus that could (audio cuts out). That would help support local phosphorus and soil, and also application of fertilizer when it was unnecessary, but the main reason that is in my area is in number two, is the rapid water transport. And over the years, we've seen more drainage installation, and also along with more drainage being more installed, 'cause there's more land and more land that farmers want to farm, so that's one of the more drainage point. Every year there's more drainage getting installed into the fields. And the other reason also is narrower drain spacing. We will hear that people go in into the drainage systems and they split the drains into half, and then they kind of operate the drainage system so they can remove water quicker. So that goes into reason number two, that rapid water transport is moving a lot of, the water a lot faster, and when water is moving, it can carry the soluble nutrients. That's the drainage such component that I showed you in the water balance. So that brings about this challenge of water quality. If this water is moving some nutrients with it, then we got to be able to do something about it. We have to do something about it because we're looking at both sides. We're looking at production with the drains, and also we want to look at some kind of conservation system, conservation drainage, so we can reduce some of the nutrients that leave the field, and retain them. So that takes us to the golden rule of drainage. So the golden rule of drainage says, drain only the amount of water that is necessary for crop production and not a drop more. So basically if you're in a non grain season and you know, it's basically non rain season and there's no crops, well you don't drainage during that time. So basically it says don't drain the field as a rule here, and whenever there is need for drainage, for crop production, yes, drain the field, remove the water, so we can have crop production. So that's kind of the golden rule of drainage, kind of the foundation of this conservation practice called controlled drainage. It's also known as drainage water management. So with controlled drainage, this is the field, this is the drainage ditch, these are the lateral drains, and that's the main pipe. That's connecting the water and it's flowing into the drainage. So this system, what is elevation with the wheel. So you can see the wheel here. So water has to go over the wheel and out, and I'm gonna quick transport into the drainage ditch. So with that, we can hold some of the water in the field for crop uptake and also the nutrients in the water can be retained in the field. So let's look at the side view of a field. This is the drainage ditch, that's the corn, harvested corn. That's the main pipe. So think about the same graph that I showed you. So the laterals are perpendicular to the screen. They're carrying water. Under the conventional drainage system, rainfall water table rises and the nutrients that are in the water, the soluble nitrogen and the soluble phosphorus, because the water is flowing out, they end up into the drainage ditch. So under the controlled drainage management system, this scenario would be after harvest and fall field operations. So under this scenario, we throw in a structure, a box you could call it, and we throw in the wheel. And under this center, after harvest and fall operation, we put the elevation of the top about one foot below ground surface, near the edge of the field, right here, one. So under this scenario this time, when it rains, water table has to go over the wheel and out. So that's how we can, we change some of the water. And also the nutrients that were soluble in the water, only some of them, only some of the water that's going over the wheel end up in the drainage. So we, under this scenario, we can retain the nutrients longer in the field. Not also retain the water in the field for longer, but this would be after harvest and this would be the scenario that will go through wintertime as we speak right now. So along comes spring and it's time for planting. So before planting, approximately about 10 days before planting, so this water table's high because we were just going through winter time and then now we take out the wheel and we let that field drain faster because we need that field. We need to have trafficability and also we need to soak dry for planting. So we pull those out before planting to let the field drain. So the next scenario following that would be during the growing season. So for the corn state of V6, we know that the corn is well, has a better developed root system and we can actually raise the wheel. So we put the wheel in again, so here it is, the wheel's going in, and then during this period at V6 stage, we put the top of the wheel at approximately one and half feet below the ground surface, approximately. Now this scenario, when it rains, this water has to come up and go over the wheel and out. So in this case, when there is a rainfall during the growing season, we can actually retain that water in the field, and the nutrients with it too. So people ask, what happens if there is a two inch or three inch rainfall and followed by another big rainfall. So during those periods of time, this will require active management. So the wheels, you would have to take out some of the boards here to actually lower the water table, because it was an unusually intense rainfall. So this would require active management. So this scenario that I'm showing you is the ideal condition where you don't got really excessive flooding conditions. So some of the ways you can actually manage that. These are the means that can be done. So there's a structure made by Agri Drain Corporation. It looks like this. There's a structure by Haviland Drainage Products in Ohio, and you can see it's a round pipe. And there's another one, another manufacturer, ADS. And so these are the products out there to do this job and the wheels are made up of these boards or stop logs, or wheels that you can stack on top of each other. So there's a five inch and there's a seven inch. So five and seven inch, 12 inches. And this tool here comes with these. You can see the tool here is actually this steel tool right there that can actually pull this stop box up, so you can manage with the different elevation that you want to do. So I'll just briefly mention the word adaptive water management plan. So as you have your nutrient management plan, with this system, you're gonna need a water management plan. And with that system, you would have to develop the management plan. There are technical consultants that can do that for you. And following that would be the implementation of that water management plan, and also you would learn by raising and lowering those wheels, how the water table behind those wheels changes. How quickly that water table actually recedes. And following that, you would be able to fine tune the plan if needed. When I say fine tune, I don't mean really just completely do a totally different one. By fine tune meaning that if you have a water management plan, it's gonna tell you to lower down it, raise it during a certain period of time, so once you learn and implement this, then you'll get an idea of when during that range of time it's gonna be better to lower this or raise the elevation. It requires an active water management plan. So also let's take a look at some of the data. 'Cause one of the data, as I showed you in the side views, when that water table rises, it provides the water for the crop during the growing season. So the question is, is there a yield benefit to this water management plan? So this is part of the previous study that I had, and in this, we had, we had four years and also we had seven sites in northwest Ohio, and we looked at some of the yield response to controlled drainage. So this is our graph. So we have crop yield, bushes per acre, on the y axis, zero, 50, 100, 150, and 200. And then on this axis right here we have corn and soybeans. So the red is free drainage, blue is controlled. So let's take a look at corn first. So for corn, for free drainage on our site, we got about 170, a little bit shy of 170 bushels per acre. So for corn, this is what we got. So we got about 190 approximately, and we calculated about 6% increase which was statistically significant, and we found a 6% increase when we were looking at the crop in the water manage zone. So I should also mention that the water manage zone is an area of the field that can actually have water table raise, because as elevation increases in the field, there will be a limit where water would not be able to have an impact. So that's the water managed zone. So let's look at soybean. So it's kind of right on the line, so it's about 50 approximately, and this is the controlled drainage. It's not a whole lot different. It's only 4% yield increase. So we got to overall 6% increase for corn and 4% increase for soybean, and this was long term study, four years at 7th. So the important thing to remember is that this yield increase depends on the weather and also the management of the controlled drainage. So it will depend on the weather and if no rainfall falls during that growing season, as I showed you when the water table rises, then there won't be any impact. So some of the considerations for controlled drainage. This system performs best at nearly flat fields. So if you have a relatively flat field with a slope approximately, average slope of less than five tenths of a percent, then this would be really good. It doesn't mean that it doesn't work for fields with greater slopes, it's just that you need one control structure at approximately one and a half feet elevation rise. So if you have greater rise, you have three feet rising you're gonna need two of them. You have just one and a half, then you're gonna need one structure. This system, this part is very important. It works best when the laterals or drain tubes are on the contours. That's very important. That comes into play when the system, when you have a undrained field and you want to install drainage system. So that would really be useful if you have the field designed with the laterals on the contours. And then there's also NRCS EQIP. Environmental quality incentive program. So there is also some funds on the federal government that can help. So let me share with you some of the funding that I found from the latest amounts. So for the water management plan, because you're gonna need a technical consultant that will actually write your water management plan. So they provide this amount, about $2,500 approximately for a no drainage map. So if you don't have any drainage map, then this is the amount. If you do have a drainage map, then it's gonna be slightly less than this because it's less work for the technical consultant. There's for this structure, there's this set of money set aside for each structure. $1,748 for each structure. And then so the water managed area, or the water managed zone, whatever that area is, you would get $7.72 per acre of that water managed zone. And that would go for three years, from the start of that. So these are some of the equipped fundings that are available for controlled drainage. Now let's look at an example of this. We have here in the field, this areas now, these are the frontal lines in feet. This side is 800 feet, this side is 1,000 feet. So the area of this field is 18.4 acre, with a four tenths of a percent average slope. So under the conventional drainage system, we would lay out the main on the shortest length that would lead to the outlet. So this would be where the main would run. And then the laterals will go from east to west, as I showed you here. So under this condition, if I have a field that's already been designed like this, which is not the optimized in this way, because the laterals on not on the contour. In this scenario, I can throw on a structure and this would be my water managed, this is what I mean by water managed zone. So this is the area that the crop, the soybeans or other crop, will benefit from that raised water table. So this is the approximately year is 6.4 acres, which is under the water managed area. So by the way, so in the previous setting, it would be because of this layout that this field has, conventional layout, and it would be impossible to actually manage the water for the entire area of this field. So because the water, there is no main, there is no way to get the water into this corner because of the conventional design. So let's look at some of the numbers that I got. So looking at the cost, this is the cost that I got from ag region structure. So with a six inch box, for that drainage system, for that field, $674, $300 freight, $780. This is the price for the contractor, for labor and installation, and the EQIP, it came to approximately estimated $6 of cost. So let's take a look at the other incentives. So the water managed EQIP provides $7.72 per acre. So as I showed you, we had 6.4 acres of water managed area. So multiply that, $49 per year for the duration of three years. And also based on the data I got from Ohio, I averaged those incomes, and for the cost saving rotation, I was able to calculate, because we had three generation, we had controlled, so I was able to calculate the increased income for these crops when moving from free drainage to controlled drainage. And I was able to calculate about $30 increased income per acre, multiplying by the six acres that we had, that's $192 per year. So the conditions in Michigan, this dollar amount will depend on the location. The soils, location, the drainage system, so this is an estimated value based on the data that I had from Ohio. So we can see, say here you may probably need (audio cuts out), because (audio cuts out). So that, this price point increased slightly, but overall, the reason I'm sharing this, I want to know that there is good incentive out there to install one of these controlled drainage systems, because you got water managed, EQIP coming in, you got, potential for yield increase coming in and the cost of that also is relatively low. So let's look at another center. Again, we have the same field, but this time I'm gonna design this. So imagine I go and I have the field like this, and I ask my drainage contractor, rather than installing it for a conventional system, I want him to install for controlled drainage. So let's take a look at this. So in this scenario, the main is gonna run right there, so it's gonna go on this side of the field and then on the north side of the field. So in this scenario, we're gonna have the laterals on the contours, so this is what the laterals are gonna look like, 'cause they have to go on the laterals, on the contours. So now we throw in one of those control structures and then we can manage the water, and this is the water manage zone, and then we will put in another one so you can see every one and a half feet I'm putting in a control. So I'm gonna put another one, and with that, I can manage the field. (audio cuts out). It was impossible to actually have water management system in this area of the field. I could only have it in these areas. So by having the system designed for this scenario, the controlled drainage, I can actually manage the water. So if you have a field that's undrained, please consider design for controlled. You may not immediately install control structures, immediately, to manage this, you could install it and that could be something for the future that you may actually go back, and also it could be valuable practice to have for the next generations, when you pass on the farm to your kids, so that would be really, in my opinion, very important to consider at least. So basically for doing controlled drainage, it would be cost effective for controlled drainage. So let's look at this field. This is the suitable 18.4 acre field. I'm not gonna put all of the components. I calculated about $18. I have, the water managed is a little bit greater here because it's the entire field, $142 per year. I got about an increased income of about $550 based on the Ohio data. So these are the incentives that, the first two, or actually the middle one would be incentive and this would be the Ohio data that comes from this. So quickly summarizing this, why controlled drainage? Because it's an edge of the field practice. It does not take land out of production. It's low maintenance. Once you install the structure, you are required to manage the altitude of the elevation. So you would raise that elevation, lower the elevation based on the water management plan. And with research has shown that this system is effective for reducing nitrate loss, and it's been effective because (audio cuts out), so it can reduce nitrate loss as well. And also we speculate, we have seen some data that shows that it could be effective for phosphorus. But in terms of phosphorus, there's less data available because many of the Midwest states, they focused on nitrate because they are the northern border of Mexico. Here in Michigan and Ohio, we are concerned about the phosphorus so there's not much data available for the use in result reactive phosphorus. That's why we're trying to focus some research here in Michigan to look at the dissolve reacted phosphorus. And also there's potential for crop yield increase when there is proper management and timely rainfall. So proper management I mean that you would actually manage the stop box, because if the stop box are just left outside the structure and in poor management, making an investment and having a structure is not gonna do anything. And also timely rainfall. So if you have a structure up like this, yeah I'm ensuring there is rainfall. So imagine have that elevation raised is during the growing season and it's dry and it does not rain, so there's not gonna be any difference between the wheel up high or wheel down at main level. Because there's no rainfall, there's no water to hold back, so that's what I mean timely rainfall. So there is, so we can't say every single year there's gonna be yield increase because it's water dependent. It's gonna depend on the rainfall, the tiny rainfall that comes at the time the crop needs it most. And water we can hold it here, retain the nutrients and the water for a longer period of time. So the take home messages for controlled drainage. We know that we have numbers, we know it reduces drainage discharge. With that, we know that it reduces nutrient loss. We know we're confident about the nitrate part of it, that it reduces nitrogen loss, and we have gotten some preliminary data, but we're still investigating the phosphorus section of this, the dissolved react phosphorus part. But we can speculate that because of that water, drainage water reduction, we can expect to have generally nutrient reduction loss. There's potential crop yield benefit when there is proper management and timely rainfall. And basically the message here is that controlled drainage is not the silver bullet. This practice needs to be used with other practices. So this controlling is an edge of field conservation practice. Other in field practices like force nutrient management, those are important that have to be used with, coupled with controlled drainage to reduction and also reduce the loss of these nutrients. And this is the take home message, and I put this on a separate slide because this is very important. So if you're got a new field and considering installing a drainage system, please consider the drainage design that's compatible with controlled drainage. You may not immediately use that controlled drainage (audio cuts out), but that maybe something that you may want to revisit in the future or the next generations, they want to be hopefully doing some conservation drainage with this practice. And if the other conventional system is designed, it's most likely not gonna be helpful, like the example that I gave you. It's not gonna provide the most cost effective controlled drainage system because some of that water is not gonna be managed in some parts of the field. Only parts of the field can be managed if the conventional system is designed. If this is considered when this system's designed, then there's a possibility for controlled drainage, which is very important point. So this is my oops. So Eric, how much time do you have? - [Eric] You got about 10 more minutes or so. I don't have any questions in yet. Just a reminder to everyone, if you do have any questions for Ehsan, go ahead and type those into the Q and A box. But yeah, we've got 10 minutes. - [Ehsan] Okay, so since we have some time, let me talk with you about another conservation practice we're looking at in Michigan. This is a fairly new one. Controlled drainage has been around a long time, but this saturated buffer is a fairly new practice. And in this practice, I have here the lateral ones, that's the main pipe coming in to another structure. So in a saturated buffer, when water comes from the field it reaches the edge of the field, it arrives at the structure. The structure redirects the water into perforated rain tube, that runs underground, so this is a pipe that's underground. They run underground and along the length of the ditch. So as water moves out of these perforations, it builds up head and water seeps in, seeps through the soil and it reaches the ditch eventually. So that's the whole idea. Water comes in, it gets redirected, and the additional flow water has to go over the wheel and out, so there is a bypass mechanism in place. So let's quickly look at the scenario of this. This is again a side view. And we're looking at a field that has greater than 2% slope. So this could be, greater than one percent, excuse me. So this could be one and a half percent or two percent slope. So we're at the edge of the field, this is the main, the black circle is that perforated distribution pipe where the water is really reacted into the buffer. So under this scenario when it rains, water level builds up and this water here actually makes this, here, and under this condition, the bacteria in this soil helps convert nitrate that's in the water into mostly nitrogen gas, that leaves through the system. So here in Michigan, we are concerned, because we're concerned with phosphorus, we're looking at other ways we can take the phosphorus out of the system, so we're looking at. So again going back to this, this is the bypass flow so where the water goes out. So for the phosphorus, we're looking at plant taking phosphorus, because of the dynamics of phosphorus, we have to look at some way of taking out the phosphorus from the system, because the soil here is gonna build up phosphorus as it absorbs the phosphorus in the water. So it's gonna reach saturation, it's gonna slowly release phosphorus at some point. So we think that we can have a strategy of taking up some of the phosphorus with the vegetation, the grass here, and harvest the grass and recycle the phosphorus in the (audio cuts out). So let's go back. So this is a scenario where you got a sloping field, slope greater than one percent. Now here I got a scenario with a slope of about less than five tenths of a percent. So it's got slope, but it's less than the previous scenario. So under this scenario, we have the same field, drainage ditch, this is the main, the black circle is the distribution pipe. For this, if you notice, we have three chambers here. The reason for that is when it rains, water table actually rises. So then I can actually do controlled drainage with this first chamber of this structure that allows me to do this. So I can have controlled drainage. And that would give me additional benefits. So I can have crop yield benefit from certain parts of the field, and also retain some of the nutrients. And when water goes over that wheel, it builds up into the middle chamber that causes this water path to be generated, and that's the water that will take out the nitrate through denitrofication. So from the middle chamber, if there is excess water, that is just gonna go over the wheel again. (audio cuts out) So this scenario gives us, so we have the best of our knowledge, we have one saturated buffer in Michigan, and that saturated buffer we have a three chamber structure, so we can actually manage the first chamber to give us controlled drainage and the we have the structure to give us additional reduction benefits. So this is helping of the tool conservation drainage practices. That's all I have. I typed in my email right here. - [Eric] So folks feel free to jot that down, and again, as Dr. Ghane mentioned, feel free to either contact him or if you had any questions, you can always for any of the speakers, I may or may not be on each week. Other folks will be hosting, but you can always send me an email and I can get in touch with our speakers as well, so.