Improving Drip Irrigation Efficiency: Keeping Irrigation Water in the Root Zone
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EmailMarch 7, 2025
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This session focused on irrigation scheduling, uniformity testing and other management practices to increase drip irrigation efficiency. Blue dye testing assures irrigators drip irrigation water is wetting the root zone with minimal loss downward leading to better decisions on equipment and management.
The 2025 MI Ag Ideas to Grow With conference was held virtually, February 24 - March 7, 2024. This two-week program encompassed many aspects of the agricultural industry and offered a full array of educational sessions for farmers and homeowners interested in food production and other agricultural endeavors. More information can be found at: https://www.canr.msu.edu/miagideas/
Video Transcript
For those people that are joining us, this is today we're doing a program called Michigan Ag Ideas to Grow with, and this is the Water Day, the Irrigation Day, and we're talking about water applications to agricultural ground. Please welcome Brendan Kelly. He's an agricultural water use efficiency educator based in Mason County, and he's going to talk about keeping water in the root zone. So, Brendan, the floor is yours. Thanks, Angie. Yeah, keeping water in the root zone, there's a lot of factors that go into it and each of them is a little bit different how it plays and where the water ends up. To recap, I'm Brendan Kelly. I work as a team with a team from MSU extension on irrigation. You've heard most of these speakers talk already. Doctor Yung Suk Dog and Angie Gratis spoke earlier, I believe on field crop irrigation and Linda and I have this particular session. You're interested in hearing more topics from the MSU irrigation team, please sign up at the QR code for our mailing list linked here. As I mentioned before, there are a ton of factors that go into where your water ends up more than are listed here for all being honest. These all can be condensed into how big is the area we are really applying to, and that is based off of these are out of order, but plant and application size. How big is the plant we're irrigating, each individual plant, and then how big is the area that the water is going into within that plant ideally. The next is how much the water can the root zone actually receive? In this we're going to base off of the rooting depth of the crop and the soil characteristics. Then lastly, we have when should we be applying, which we're going to base off of irrigation scheduling. I'll briefly mention irrigation scheduling here. I think Linden is going to cover that more in depth. But there are two main approaches we'd like to use. We want to either replenish what has been removed by ET and the best methods to look at this with are the MSU irrigation scheduler or checkbook scheduling. I'm personally partial to the MSU irrigation scheduler as I like to stay in house. If you like to use somebody else's scheduling system, say in Nebraska or anywhere else, totally fine. I'm not going to be offended. We just really want to see you using something like this to manage when you're irrigating. Alternatively, we can look at maintaining soil moisture and we like to do this using soil moisture monitors and sensors. This is by far the most up to date real time data you're going to get from the root zone. So even though it does cost more in both time and money to install individual sensors and loggers, it can pay off to really have the best data available. We could also use estimation by feel. If you're like me, this is not a precise method of assessing soil moisture. If you can tell me the difference between 90% soil moisture and 80%, I'll give you props, but that's really not the ideal way to do it. You could also look at the crops condition. This is by far the worst option. By the time the crop is wilting, it's too late. If the crops wilting, it's like saying, I'm shutting down now, like the government in this case. Yeah, there's nothing you can do at that point except apply and accept the damage that's already been done. Ideally, you'd look a couple of days earlier using a scheduling approach or soil moisture monitoring and see that you're getting close to that point and apply before that happens. Lastly, you could estimate soil moisture by calculation. I put this in here because this is really what the irrigation scheduler does in the background. So it's really kind of the same coin. You're just looking at two different size, whether it's half empty or half full. Scheduling tells us when, but not necessarily how much. We could play around with the numbers and see how much we could apply, but how much we can apply should really be looked at a maximum in this case from a scheduler. There's other factors like your soil and where that application is actually being applied that determine how much it actually reaches the plant. Probably seen this slide earlier in doctor Dong's presentation. I hate to copy off of him, but it's a terribly good slide in this case. If you do decide to use soil moisture monitoring, pick a good area within the field, not the best, not the worst, probably something very representative of the average. As you can see, there's sensors at multiple depths here. We really want to make sure we get something below the root zone if we're going to use this method. This tells us when we're watering too much and is probably one of the easiest ways to assess that we're actually applying too much without calculation or estimations. Here's a really good example of what this looks like in the form of data received. As you can see the six inch depth and 12 inch depths vary as the season goes on, drying out as the crop uses it and as we apply it increases. The key here is we don't see that black line that's the 24 inch depth sensors report moving up and down a whole lot. That's indicating that our soil moisture that is resulting from our irrigation is staying up higher in the soil in the soil column. Up where the roots are. So if you had a corn plant that was 36 ", this probably wouldn't be a very good application just because it's fairly high up in that column. But if you had something like a soybean or maybe even a blueberry, this would be a perfect application because it's all in that top half of that root zone. I don't really have a magical number as far as how far the water should reach, but most of the activity within the root system happens in that top portion. Keeping the application high prevents us from pushing water too low and wasting it and also pushing out nutrients that are used by the plant. This leads us to the other question of how much can I apply? Can being the major word we need to focus on here. Just because the scheduler says you can put an inch on today doesn't mean that your soil can actually accept that 1 ". He prime example of that being if we're at 50% soil moisture, we don't want to apply more than 50%. In fact, that's probably more than we should be going even if you did apply exactly 50% actual soil moisture. So if you were to apply that, you'd be reaching 100%. If you went to 110, that is going to push the water out of the root zone where it can't be used. Another thing we need to look at is crop demands. If we're if it's a really hot summer day and we're using, say, two tenths of an inch, we're only applying a quarter inch a day, it's very easy to get behind. If you mess up one time and forget to water or something, you're going to be behind consequently every day after that until it rains, assuming you can keep up at that rate. As I mentioned before, reading depth is especially critical here and particularly, you need to look at the crop in your field and at your growth stage. Digging up the crop or just one sample even could really give you an excellent idea of where you are and where your water needs to be. Finally, I'll mention irrigation system output. Ideally, this is something you've worked out already and have the numbers on. I think Chris Lato will mention this later on and cover more in depth what he has to offer and solutions that match up best. But we really need to be making sure that the system that is in place matches up to the crop and it demands. In some cases, the water can actually run off. A lot of people think this is exclusively overhead irrigation applied, that it would have the chance to run off. But we have found in some cases that even with drip, if your soil is slightly hydrophobic because it hasn't had sufficient soil moisture, it may be running off. This is a great excuse to look under the hood, just pry up one of the grow covers, take a look at what's actually happening, make sure your mulch and everything is reacting in the way you predict that it should. Fairly basic concept, but I think the basics are probably some of the most important. So what is an inch of water when your neighbor says, oh, I put on an inch of water yesterday? Technically, 1 " of water is just 1 " of linear depth. So if I stuck a ruler in a five gallon pail or in the street, if that water is 1 " deep, it is 1 " of application or I received 1 " of rainfall. It doesn't have any specific area that is applied to. So obviously, 1 " in a five gallon pail may only be half a gallon, three quarters gallon, something like that. Fairly small amount. But 1 " applied to thousands of acres is hundreds of thousands of gallons, potentially, or more. So it's very particularly critical that we know how big of area we're applying to To give you a better idea of what a gallon looks like, if we were to put it in a 1 square foot area, 12 " by 12 ", that water would be 1.608 " deep. That's a pretty critical conversion factor that we're going to use for all the calculations related to this. I guess this is a great place for me to put a shameless plug for a extension article that's coming soon, gallons to inches. Hopefully, that'll be coming out any day now and it'll give you a little more on the calculations side of this. I mentioned system output. A lot of people think so this is just emitter spacing, emitter flow rate, number of drip lines. If we multiply all that together properly, all the math, you get an application rate. That application rate needs to be paired down to either a per emitter and you need to know how many emitters per plant or per plant application. That will allow you to know how many hours you need to run. Once again, that doesn't give you a depth, but that's where you need to start. This assumes two things. A, that your application is uniform along the whole drip line. If you have slopes or really long line, you may see drops in pressure which relate to decrease in application. That covers uniformity. The other thing we're assuming here is that all of the water makes it to the plant. So if we only have 90% making the plant, that means every time you put on any application, you need to reduce or cut out 10% to account for what you've lost. Depth and water holding capacity are another critical features that are dictate how far your water goes down. Once again, we need to know our maximum rooting depth, particularly of the variety of age of plant, all of those characteristics, and we need to know the soil that those roots are in. All of this is critical to know so that we don't push the water too deep. If we have different layers within the soil, that's going to dictate how wide the plume goes. I'll cover more of that in a minute. But the width of the application is going to dictate how deep that actually goes. Obviously, the coarser the soil, the lower the water holding capacity. Although that gives you better drainage, that also means the water is not going to expand as wide. That's the concept of the plume and the diameter of the irrigation we're achieving. So another critical factor to look at here, if we're going off of plant ET to get our inches of removal, that plant covers a certain area with its canopy. That area is only served by whatever you irrigate it with. So if you're only applying to a six inch area, you need to apply a lot more water within that 6 " to account for that whole crops water demand. This is going to drive the application even deeper regardless of what you have for soil. To complicate this further, the water holding capacity multiplies how far down it's going to go. Some good examples of this. If I had a sandy loam at 20% water holding capacity, so it can hold 20% water for whatever volume you're looking at. If I had a one square inch area, Regardless of depth at 20% of water holding capacity sandy loam, that application of 1 " would go 5 " deep. If I had a coarse sand instead of going 1 " or 5 " deep, within that 1 " area is going to go 20 " deep. Knowing your soils is critical to knowing the depth you're going to achieve. If you have different structures or soil horizons, hopefully you have some topsoil and you're not just irrigating beach sand. If you are, good luck. This is going to be especially important for you to know and monitor so that you don't push your water Q deep. But if you have a topsoil or something heavier, it's going to cause that irrigation to expand in width and hopefully retain more in the upper zones. If you run into some kind of clay barrier, that's your advantage. Hopefully, it's going to plume out, keep that more in the root zone as well. I hate to get all mathy with this, but math is the best way to estimate anything within science. There's two ways we can look at this. You can look at it per plant. We have a circular area where the plants going to root or the canopy, whichever you're looking at, depending if you're looking on ET or the application, and you have a square area figured irrigating per row, which would be just the row width and length. Depending what your setup is and the age of your plant, it may be better to go with one or the other. If you have a younger plant with a smaller root area, it's probably best to look at it per plant basis and use something with a circular diameter or radius. Calculation for the area of application. These are really all just based off of your application flow rate and excuse me. This is really just your application divided by how big of area you are applying it to. It doesn't really matter which one you choose as long as it aligns with the plants that you have and the condition that they are planted in. So an example I'd like to give for this is if you were to irrigate with 1 " of water to a plant that occupies a 1 square foot area with a quarter gallon per hour emitter. This is going to take just a little more than a half gallon of water, and it's going to take you about 2.5 hours to apply it. Seems pretty simple. The unfortunate fact is that not all of the water always reaches that. If everything was perfect, we'd have 100% efficiency and this would work fine, but there's some more complications. Approaching the numbers that would be achieved if we had 100% efficiency and a pure 17% sand in this case, if you were to irrigate 1 ", you would end up with 31 " of depth using that quarter gallon per hour emitter and that same example. The easy way to assume that I'm sorry, if you assume that your plant has a shallow rooting zone, as in most cases, say you have blueberries that are more likely at 18 or 24 ", this is far too deep. The easy way to correct this is either to break up the application or to apply to more area using more emitters or a tighter grip spacing. So if we divide this by two, we add one more emitter, say you just dropped another drip line on the other side of the row, you cut that number in half. Now you're only irrigating to about 15 " of depth. That's pretty appropriate in this case. If you do decide to go the route of increasing emitter spacing, there are some downsides. Every time you increase emitter spacing, you have more potential for off target applications. Obviously, if you have a continuously planted row and it is completely occupied by the root zone, that shouldn't be much of a problem. But if you have younger plants or smaller areas that are not occupied completely, it can really hurt your overall efficiency because you're applying to areas that have no plant or root occupying them. We also see another instance of this. Simply drip lines that are placed too far off to the side can have the same off target application. Although you're applying the right amount, it's not making it to the plant. You really need to make sure that those emitters line up with plants that are as close to the base as they need to be. They don't have to be touching the base of the plant or the stem, but they need to be close enough that they are well within the brood zone. To recap a little bit before I finish up, we need to aim to apply volume that reaches the target root zone. If you have a plant that is 18 " of rooting depth maximum, you probably shouldn't be aiming any more than 18. In fact, it's probably best to keep it a little above that in case your calculations off or you receive a bit of rain. Plan ahead so that you don't end up exceeding what capacity you do have. We're applying directly to the soil using drip lines, so it doesn't hurt to break up your application from one day to another. Instead of applying 1 ", maybe you do two half inch applications. The key here is if you do decide to go this route, ensure that you add whatever time or rather the ET that is incurring over that time period you're delaying. You're delaying one day for half of that application, you need to add that day's ET back in. You are reducing the total amount that you have in the root zone by delaying another day. If you can't keep up by delaying, you probably need to look at expanding how much you're applying. You can either add more emitters, so change your spacing out. That would remove one line that you have your old line and put in a new one, or you can simply add another line to the other side of the plant. Depending on what your situation is, it may be better to go one route or the other. Aging lines and whatnot, it would be a case where you need to crunch some numbers and see what makes the most sense for you. Yeah. By doing this, you increase the surface area you are applying to. Hopefully that keeps your total depth achieved a little bit higher and closer to where the roots are. If you want to go lower, all you have to do is irrigate a little longer and you will push that water deeper. Another great way to look at this is our infamous blue dye test. We simply inject a blue dye that stains everything horribly blue into the drip line and see where that water pushes that dye. It's a great visual example, shows you pretty much exactly where the water ends up. In this case, we had a pretty sandy beach sand down below and more of a loamy topsoil. I think this might have been at the Trevor Nichols research station, but I'm not exactly sure. We used half gallon per hour emitters in this case and did 20 minutes, 40 minutes, and 60 minutes of irrigation. As you can see, the depths achieved were not exactly linear as far as time applied versus depth achieved. But obviously, you want to stay towards the 20 or 40 minute area and away from the 60 minute duration if you were trying to irrigate to a 24 or maybe even 18 inch depth. If you're aiming for 18, 20 minutes is probably ideal. If you are going to 24, maybe you push it more towards 30 or 40 minutes. Just depends what your crop is at. Another example just to give you a different soil type. This is a little heavier. Really not sure what the location is that the sample was taken, but we used a little more than quarter gallon per hour emitters and 24 inch spacing pretty similar, just half the rate. And you can see that the water moved even less in terms of depth. 10 ", 12 ", and 13 " represented the 2040 and 60 minutes applications. So the coarser the soil, deeper it goes, the heavier soil you can keep more up in that top zone. And with that, I think I'll turn it over to Linden to talk about scheduling for drip irrigation. I see one question came in from a doctor Anderson asking where will your article be posted? And I think she's referring to the one on inches. Yeah. That should end up on our irrigation web page, but it will be an extension article posted in MSU is it Book of extensions. News. Yeah. Yeah. So it will be a copy. You can also sign up to our mailing list. I sent the link to the chat so you can just be updated on all the articles, events, among others, so you can see it pretty quickly. Great. Before I get started, Brendan, can you go up like three slides on the blue dye testing? Right there. I think the important thing here is that the blue, everybody looks at the blue and it looks about the same in the pictures. But the one to the furthest to the left, the bottom of the blue is 14 " down, and the one at the right, it's down 26 ". And so that they're scaled differently. But this blue dye testing, I heard Brendan didn't like blue dye testing, and I think it's part of our future because it is the best way to demonstrate the challenge with drip irrigation, putting the water below the root system and causing leaching and inefficient water use. It's one of the challenges. We all think about drip irrigation being so much better because I'm not wetting the plant each time. I'm not increasing disease and I'm not losing water that tenth of an inch or so every time we overhead irrigate corn crops, we lose about a tenth of an inch to evaporation that never makes it to transpiration. Drip irrigation has that tremendous advantage, but the disadvantage is we can't see when we over irrigate how deep things are going. So just to take off of that. Did you want to say anything else, Brendan? No. I think that's a great recap. Probably should have highlighted a little more on the achieved depth, but great visual. You did great. You want to advance me up to the first slide. I think it had the team slide and basically teams there and that's how to get ahold of us. Notice I'm the only gray haired one here and we have people on there they've been on six months and I'm in the 30 some years working for MSU and Purdue extension. As irrigators, our goal is to meet the crop water need when rainfall falls short. I start a lot of the presentations with this graphic. Yeah, we use corn because that's the most irrigated crop in Indiana and Michigan, but rainfall is pretty much consistent. It has been going up 20 years ago. We were at 34 " and now we're at 38 " of annual rainfall. Unfortunately, the increases are happening this time of year in early in the spring and late in the fall. So we get a higher amount of recharge, but we have water available to meet that crop water need. And you as irrigators, what you're trying to do is that feed the crop that area of the f where the consumption is higher than the rainfall. So that's next slide. So when you do that, you don't get to inject directly inject the water into the plant. What you're doing here is you're putting the water into the soil, and then the plant pulls it up from the soil and puts it out and mainly for cooling It uses the highest amount of water is used for cooling and we call that transpiration. That's the water effectively going through the plant, and then we group that with something called evapotranspiration. That's the evaporation from the surfaces plus that transpiration. But it all starts in getting the water into the ground and not all of the soils that we deal with are equal as far as holding. They're not all as good a piggy bank. The nasty part about this is if you overfill the piggy bank, you lose it. And that's called leeching. And one of the problems that we have in potentially in irrigation is that we keep the profile wetter so it is possible If you really over irrigated, yes, you could overfill the piggy bank and leach water out at the bottom. But if you don't have enough room for the rainfalls, you potentially increase the chances even if it's not irrigation water, but rainfall water for moving through. From a nutrient standpoint, economic standpoint, and environmental standpoint, we don't want that water moving through the profile during the growing season because it may contain pesticides or nutrients that we paid for that we won't get used from, and that become potential contaminants to our aquifer below. Next slide, Brendan. So one of the challenges we have in Michigan, most of our irrigation is on what we call sandy loams like Ostimo sandy loam or sphinx sands or Spinx sandy loam. Those are to the left hand side. There's a fairly moderate soil that's fairly common called Brunson, and that's a sandy loam also. And then we get some Kalazo loams and Capex loams that we see some drip and trickle operations raising vegetables on. If you look at that and we say, okay, my vegetables are rooted to 6 ", There's a full doubling in the water holding capacity in that top 6 ". Spins on the sandy side is barely a half an inch of available water holding capacity where the loams get into that 1.2 ". If we think about a full grown tomato crop going down to 24 ", I have still again, double the amount of holding capacity in the loams that I do in the sands. We can help you with those find that information for your soil. I think that was in an earlier presentation today by doctor Dong. Next slide, Brendan. So I'm going to go into this. How do you figure out how much water will apply? One of the basics happened back in the 60s and the 70s and it was this work that our predecessors did and it was often done with weighing lisoeters. Now, this concept is fairly basic. For corn crops, it was a box the size of a semi truck box buried in the soil with the scales underneath it and you raised four rows of corn over the top of that scales. When it rained, The additional weight of the water would make the scale weight go up. And then when the rain stopped and the sun come out and the crop started using water, the water leaving through transpiration or evaporation ended up making the weight go down. So we put that on a time graph and we can actually find out how much water that plant in that much area used. If we take that and we say, well, let's add a little bit more water to it than it's using, so that there's always a little dripping out at the bottom, and I catch what's dripping and subtracted off of it. Now I have the maximum amount of water that that plant could use. If it has ample water, how much would that plant use? That's going to be the evapo transpiration for that plant. We pair that all up with a weather station and we have these in a number of locations. I think the last project we did was on AMP or Christmas trees, one of the two that was in this area. But we matched it up with weather stations, and then we can take that data and say if we had these weather parameters, mostly sunlight, moisture in the air, and then wind and those are the factors that have the biggest drive in the plant using more water. Next slide, please. Okay. If we do all that, we find out that almost all the plants, if they take in all the sunlight, come out to somewhere between two tenths and a quarter of an inch of water use per day at their peak. Peaks may be at different times of the year, but if you have a square foot of that plant using all the sunlight, you're going to require something more than a quarter of an inch or I'm sorry, something more than two tenths and less than a quarter of an inch. If you are in a row crop situation, that means that you're going to need 24 hours 247 to be able to pump during those non rain times something around five gallons per minute per acre. So 100 acre field would take 500 gallons a minute. In trickle irrigation, we don't have we're not watering areas that we are not um yielding or gathering the sunlight from. We're not watering the alleys and things. So this number is much smaller. But if you have an operation that's intercepting about 50% of the light, then we need 2.5 gallons per acre. And that's assuming 247. Most of our drip growers are interested in running 247 that pump so they're going to cut back. And of course, if you're only going to go 12 hours a day, you need double that number. Next slide, please. So before I forget it, and it's easy to forget, rainfall rainfall it's the cheapest way to get water is to take the credit for the rainfall that happens. Most of our crops in Michigan, two thirds of the water, if we can use rainfall, is going to come from rainfall and not our irrigation. We're a supplemental state. Not all of our configurations allow that. If you look at the, I think it's watermelons in the lower right hand picture, that's a solid plastic row cover. It's going to shed the water from rainfall almost totally until the roots get out from under that plastic. The they'll fill the row and they'll get out within two or three weeks. But for that two or three week time period, you have to supply all the water because of the rainfall is not going to get to those roots. On the other hand, if you see doctor Dong there working on the monitoring system on the fruit up to the upper right hand corner, all of that water can has a chance at evaporating towards the root system. Then there's covers in between. If you see doctor Dong there working on a project with tomatoes, Some of those covers have perforated plastic and as late in the season, we'll actually see the roots make it to the edge of the plastic, so we start getting some benefit there. There's different types of systems there and obviously in these pictures, doctor Dong is looking for other systems that help us take a look at those. But if you don't have a rain gauge out, to be able to tell you how much it rained, it's hard to make advantage of those. If the thing's partial, then you prorate it out. If you think half of the rainfall made it to the root zone, and you can detect that fairly quick with doing some digging, then you take half of the rainfall in the calculations. Next slide, please. So I'm going to tell you a couple of places that we can get these reference ETs. What they did is they said, look, we're not going to be able to give you a specific ET for every crop planted at different stages. So we're going to use a reference crop and they decided, everybody but Nebraska, decided that 6 " of grass would be the reference crop. On any given day, they're going to give you a reference number of six inch cut grass. How much water would it have used? Then we're going to use a multiplier, a crop coefficient, K C, we call it, to convert that consumption by grass to the consumption of your crop. You need that reference number. This Michigan enviroal weather is an excellent source for that next slide. It will generate a table like this for any one of those dots on the original map and it will tell you how much the evapo transpiration was in the previous days and what they estimated from their weather predictions in the future. Those will come out and here we go anywhere from 1400s of an inch to 20/200 of an inch and then down all depending on what they forecast for the day. Next slide, please. Some of you are going to say, Well, boy, I don't want to have to go to that weather station. If you sign up early in the spring on this website, they will text you the reference ETs for the past four days and the next forecasted five days. I get these for four stations in my area where we're doing projects. They come in about 5:55 or 530 in the morning and my texts will go bing, and I'll have a list that looks very much like the one on your screen. No cost to me, you just have to sign up. You got to sign up each spring because they clear the rolls. Next slide, please. So summary, you're going to say, well, I'm not in an area. I see some people from other states here. I need a source of information for this reference ET that's different than Michigan. National Weather Service has put up in the last few years this reference ETET. You can get it into a weekly ET or a daily ET. Right now, I've got this one set as a weekly ET. The links to the sites are up on the top. And on that map, of course, the more you blow up the map, the more detail it gets, but they will give you a reference ET number. Notice that in this one right here, I've got the box around 1.65. If I go down right there, it looks like near maybe South Haven or Holland. It was only 1.2 or 1.19, and then it goes back up. We had some lake effect there. But it gives you a number for your site. Then as I said before, that's the reference ET number in the red box. I'm going to take that times the crop coefficient. I've got the corn one up here we used for sweet corn in and seed corn and commercial corn, we take that KS C times the reference ET and I get, in this case, the weekly recommendation. 0.76 through three quarters of an inch. I'm going to subtract the rainfall that we talked about a few minutes ago from that. If I get a quarter of an inch of rain, all I need to do is add an additional half an inch. Now, how we add that half an inch, that's where we're going next. Next slide, please. Yeah. I need to remember, you don't care about the cord coefficient unless you're growing sweet corn. You would probably like the coefficient for some other crop and there was a number of different references out there. This has been well researched almost worldwide. We can find it for hemp and almost all even chestnuts and things. We found something that was very close to them to give you a reference ET. All of them start out fairly low because our crops are smaller and not filling the area like the six inch grass. And so they don't use near as much. They go up to a peak season, which is their highest level, sometimes 110% of six inch grass. And then as the crop matures, they drop off and we sens down to a lower number, sometimes half of what grass uses. Next slide, please. Brendan was talking about using the Michigan Irrigation Scheduler program and the new app that's coming out in the background behind those and you can find in the setup, they have over 40 different crops. Now notice that cucumbers are listed four times on there. It's different that F 12 means 12 inch rooting capacity cucumbers, F 18 would be 18 inch rooting capacity cucumbers and it's broken down by 10% increments and creates that same curve we've seen in the last slide. Next slide, please. So in a perfect world, I take that application. We say, okay, half an inch application, I may do that in two or three or four applications over the wet week through my drip irrigation. In a perfect world, I would get that moisture so that it was covering about three quarters of the root depth. So we don't want to go to the bottom of the root depth, but we want a little bit of a cushion there. Okay. And we would actually meet the wetted circles would actually meet within the row, but we'd never overfill the row. Now, you're going to say in those of you who have dealt with drip much, if you water by mid season, the plant has concentrated its roots where the water is, especially tomato plants, we've seen that where they're really concentrated right where the emitters are. But if you don't wet out further, you're not getting use of the nutrients that were stored in those soils and you're getting a smaller piggy bank of water holding capacity, and it becomes more and more hydroponic, just daily feeding and pushing nutrients to it. Next slide, please. So there's a couple ways of doing that. I see my one drip is actually coming out of the top of the soil. That's not correct. But when we overhead irrigate, we apply the water from the top and we pretty much go from the top down. As we drip irrigate, we apply at the soil surface or just below the plastic and we form this teardrop shape and sandy soils. Gravity is a little better than conduction sideways, and so our teardrop is more long and downward pointing in heavier clays, it becomes more flattened across. In some cases, we're going to have to look at using two drip tapes to be able to get that work done. As we get sandier, the more need for multiple emitter points for that plant to draw from because then we have a bigger pool of wetted soil to work with. Next slide, please. Yeah. The strategies here, if we look at emitters, as we look at fine textured soils like clays and loams, were more likely to spread out. If we're looking at sands on the right, you're more likely to go down with it, it becomes a greater challenge. We use smaller applications, more emitters on sands, you can use larger emitters and small applications on clays. Next slide, please. I goofed that up. I did exactly what I was hoping for. This is a study many years ago. I think a gentleman from doctor Hellmuth from Florida came up and helped us with this and discussed this. But notice the different applications that are there all about the same amount of water, but the difference is the spacings and how much soil is being contacted with the amount of water being applied. A good example here is in the tomatoes in the upper right there, the tubing is going down through and if you notice there's white roots. The hair roots of the tomato plant extend just about to the same point as the water distribution. The only reason it's not blue is that we flush the dye to the outer edge of the wetted zone. Next slide, please. Yeah. So there's some neat charts out there. Brendan is working on one, I think, too, but right now, we've been using this one from Penn State. It has a number of different emitters that are fairly common drip tape systems that are fairly common to get through there. And if you notice, it's just a reference of how long or how many hours it would take to get a 1 " application over that area. So this type of calculation. What I see most growers doing is once you've worked on this, they build their own chart for their system, and that's where we're going. Next slide, please. So here's a couple of the basic irrigation designs. Somebody's got this plot out here that is roughly a half an acre if we went right up to the edge, and they've put drip signs on there to raise looks like small vegetables. Next slide, please. Did we go two or one? Yeah. So if you take a look here, the gentleman puts together, it has a 20 gallon per minute well out there. It's pressurizes the line at about the main feed line at about ten pounds of pressure, meets the requirement. His drip spacings are 12 " and it can provide just a little less than a half a gallon per minute in 100 feet. Okay. When we do the math on that, we find out that he can feed that well, will feed 23 lines. So let's say his well didn't produce 20 gallons a minute and only produced ten gallons a minute, he'd have to divide this in half and do a morning irrigation and an afternoon irrigation, the north half and the south half or every other line. And a lot of times in the smaller truck crop farms, they'll put valves on the main line on all of them so that they can rotate between the crops so that you don't have to water the crops that are not needing water at any one time that have already sensed. So next slide, please. Yeah. So same description there. We worked out that if he needs to we're going to base it on a 1 " application. You never make a 1 " application. We're going to divide that by the number of applications that you're going to do that week. And then we convert it all over and we say, okay, if he has a sunlight interception area of 30 " or 2.5 feet, that he needs 300 gallons per line to get a 1 " application. In that week, if they said that the application needs to be a 1 " application, he needs to get 300 gallons per line to feed that 2.5 foot roll that's there. If we look at that and he divides that by his capacities, we actually come down to minutes and that ends up being about 34 minutes for every tenth of an inch that he runs. Now, this varies a little because when we start out, we have very narrow rows and we grow to a bigger and bigger bad row width. That chart below with the blue and gray actually converts that number. You can see the 2.5 there at 34 minutes per tenth. But you notice when he starts out, it's only 7 minutes to get it and his tenth of an inch and if he gets all the way to three foot widths, it's going to take 41 minutes. Things like watermelons and those types of things in the production, it's pretty important to have a chart to help you recognize how much more you need to water each day as things spread out. Next slide, please. Yeah. I think we already talked, I think Brendan did a good idea of talking about how you can convert that number to a per plant. If you could say, okay, I've got trees here and roughly those trees each need to get 27 gallons to get that 1 " application this week and we're going to say, we have three emitters hitting each of those trees. If we run for 3 hours and do three applications this week, I'd get my 27 gallons. We actually break it down per plant. That's pretty easy to check because then you can actually put a little bucket under the emitters and say, did I actually get the portion that I needed per minute to get that 3 hours and total that 27 gallons for the week. Next slide, please. There's going to be a few people up there out there that say, Hey, this is all way too complicated. I've just got a garden or a half acre out here that I'm irrigating and I just want to know how much water I should put on. I'll say, Hey, it's an art and we never do our best painting on the first try. We need to work on it a few times. One of the quick methods to do that is to do a little digging. If you don't like shoveling, get a soil probe or a soil auger and you auger down and what we're looking for is what they call the wetted front. It would be like the blue line in the blue line test. You get to a point where at that point we didn't get any water pushed any below that. If you're watering adequately, that water line won't change. If that water line is less this week when you water than it was last week, then there was less moisture in the soil and the water that you applied if we're doing the same amount each time is going to be higher up. If I probe down and the water is going further this week than it did last week, last week I probe down and I had water to 4 " and this week is to 80 ". I know I left the soil wetter than before and the same application is going further down. But basically, we want to just know that our application got us about three quarters of the depth of the roots so that we have a little bit of a safety factor, but we adequately irrigated things. Next slide, please. Oh, yeah. Brendan, is that you in that picture? M. Yeah. If you don't know, I know Brendan fairly well. And we started him young where he grew up and we probed out there to do the same type of work. But what we found really quick was if you take a look at an irrigation system, it's hard to tell how much moisture is out there. We talk about the hand test. But most of us can tell which one's wetter. If we take two samples, we take it from a wet area and a dry area, we can easily tell which one's wetter. So here's the concept that one of the growers showed me earlier. I've got it this is on a cornfield here, but it works very good in drip irrigation also. If you take an area and double irrigate it or add a little more capacity. So in drip irrigation, maybe take the end of a couple of rows and double them around, so I have a double tape in that area. Or if you're doing tree emitters, put a couple extra emitters on one tree. Now, all of a sudden I can go to that tree and I can do the hand soil testing and it should be wetter than the rest of the area that you're applying. I'm going to do a sample from the overapplied area and a sample for the rest. If you cannot see a difference in the plant or the moisture, then you're probably over irrigating and you probably could narrow up or go a little longer between applications or put smaller applications on. Okay. And then if you get to the point that you walk out and look at your area and where it's double irrigated, it's immaculately better, then you've underestimated or underwater the rest of the plot that's there. And over time, this is going to make you a better painter, a better irrigator because over a couple of years you've quickly learned, well, we run this plot when I get the tomatoes are half height, they're at waist high, I need to have 34 ", and then you do just a little bit of monitoring to make up the differences and make the changes that are necessary. Brendan, I think that was my last slide. We got a couple of questions very interesting questions. The first one is thinking about watering newly planted fruit trees and over the years, training them to become independent of irrigation and also how to create deep roots. Well, in both of those cases, you can theoretically encourage roots to grow out by adding irrigation to a wider area. Maybe you need more emitters around that tree to get them to spread out and really grow deeper and whatnot. However, in some cases, you don't always get that. Sometimes it's just natural growth. If you're expecting something that doesn't grow past, you know, 36 " deep to grow there, it may never get there. It kind of depends on your crop and variety and whatnot. But in general, roots go where the water is. Yeah. Obviously, you know, most of our crops, if you starve them, they'll grow more roots to harvest more water from a wider area. But the question is a little odd because most of the fruit tree growers I know their goal is to get into production as quickly as possible, especially on the trellis systems. So you have a little bit different growth there. But if you have the irrigation system to keep it alive and you stress it some, it will grow more roots and it will become more self dependent. But then you also rob yourself of the yields that could have been achieved with the irrigation. So Did they mention whether it was apples or fruit veg? Not really, but, Brendan, if you can put your contact information so they can reach out to you. Do you have any other questions, Angie? Yes. So there is one someone asked, any good websites for those in Indiana, assuming this is just for Michigan? If we're talking about the reference ETs, doctor Beth Hall has a website called Climate and on there, she has seven different weather stations that have reference ET. If you're not close to one of those weather stations, then I would go to the National Weather Service one that I showed. The National Weather Service one is really good. There's very little difference between that modeling tool and the locations that we see. We look at both of them because we have the data coming in and it's surprising to be anything more than 100th off one way or the other. So glad to see some Indiana people here. Awesome. There is another one, which I think you mentioned the alerts from environ weather and they asked about to put the link, but I think I was looking at it and there is no sign up on the environment Weather web page. Is that deleted or is because they were having problems with it? You need to update on that. Yeah. Usually that goes up somewhere around the 1st of March that we haven't seen and if you're familiar in viral weather is making a transfer to a new product. I'm not sure if we'd go to the older one or newer one. If you could send me an email, Kelly at dot EDU, that's at dot EDU. I'll get that to you when I see it come out. We get the last one. You talk about DNA ET and they asked, how are we going to be able to trust the new people in the NOA positions to be given correct information in this case, AAA transpiration. First, it's not too new. Doctor Ted Loudoun had a whole website put together in an information sheet giving us reference ETs back in 86, 1986, and we've had some type of tool ever since. I think we've actually tried to make it more accessible. Angie, have you do a weekly update, right? Yes. During summertime, I sent weekly ET recommendations, mostly for corn and soybeans because I work with field crops most of the time. But if we can work together, Brenda and I, we can send for specialty crops this summer as well. Yeah. Yes. So we send them weekly for three different locations. Yeah. Just to give you an estimate. Yeah. If that didn't answer the question, get ahold of one of us and we'd be we're at the point right now where we're putting those things together for next summer. We'd like to do whatever the industry or whatever producers would find most beneficial. Let us know. If you have any other questions, get them to Angie and we will try to answer them offline.