Field Crop Webinar Series - Nutrient Management to Improve Efficiency

March 9, 2020

Results of 2019 nutrient management research are shared with a focus on strategies to improve use efficiency of fertilizer inputs.  Increasing nutrient use efficiency while implementing best management practices will improve the bottom line and lessen impacts on water quality and other environmental concerns.

Video Transcript

- [Kurt] So hope everyone's doing well this somewhat rainy spring evening. Couple things we wanted to go over tonight. Instead of just focusing on some random research studies and whatnot, there was an idea of what can we do to potentially improve the efficiency of our nutrient management? We'll focus probably specifically more on corn than some of the other crops. Some of the concepts will carry over to some other cropping systems. And we'll focus primarily on nitrogen. Some concepts again, will carry over to phosphorus but it'll be a little bit of a different mindset. Before we get going here, I do wanna remind everyone that we do have a couple of other presentations coming up over the next couple of weeks before we wrap up these series on March 30th, which is just around the corner. So, question and comment question kind of depends which or what you're referring to. Spring has sprung or has it? We had 60 degree temperatures across Good Park part of the lower part of Michigan over the weekend. The picture you see there on the right hand side, as of last Wednesday, Thursday, Friday was fairly common. So couple things before we want to start firing up the equipment and the planter. A couple things to think about before we get too excited for the spring season would be: one, take a look at those current soil temperatures. So I looked just before we got on tonight, even with some of the warm temperatures over the weekend, bulk of the state is still looking at anywhere between about 30 and 33 degrees Fahrenheit, at about a two inch soil temp. So while it seems nice out, we kind of get antsy and wanna get out there and do something with regards to nutrient management, especially on our corn and soy, we probably wanna hold off for the short term. Now for our wheat acres could be a little bit different. We do have or we did have some great nighttime freezing temperatures over the last couple days. So I know some girls probably got out there and put freeze up nature applications on, which is a good idea before the ground begins to thaw. A couple other things. Take a look at the longer term forecast. Looks like through I think middle of next week, St. Patty's Day or the 18th, things look to be fairly warm. After that, it tends to be a little bit more ambiguous. It could be a potential pattern change from what I've read. And the other thing is, look at the calendar. We're still as nice as it is out there this evening, March 9th. April 9th might be a different story. So we're still March 9th where we're still fairly early in the season. So although we wanna do something, we wanna make sure if we do anything, we do it right. And so part of the name of the game is efficiency. Can we impact efficiency? And why are we concerned about efficiency? So if you look at nitrogen loss over the last couple of years, or even over the last decade, nitrogen loss has become what I would consider more of a regular concern or a regular occurrence. You can look at some of the rainfall variability that we've had over the last several springs. We've seen some very wide swings in both our April, May and June rainfall as evidenced by this table that you see right here. So if you go back and look at the last, oh, what do I got on there, 13 years or so, looking at April May and June and this is for the Lansing area. Looking at 30-year norms, anything listed in red is about a 33% or more reduction from our 30-year norm. Anything listed in green would be more than a 33% increase from our 30-year norm. And so I don't consider wet or dry has to be above or below 33%. But it's a good measuring stick. And when you look at specifically April for our wheat acres and June for our corn acres, both of those months, you'd look at that table kind of look like a Christmas tree. They're awfully red and they're awfully green and it's not very normal. May, believe it or not, has been a little bit normal. And some of us might be surprised when you look at 2019 how wet it was, April and May were not abnormally wet, we were within that normal range. It's June where we really started to get the precept to accumulate. April and May, were fairly cool, however, which is why there was moist soil conditions tended to stick around much later in the spring. I looked earlier today, I think last year, we didn't break 50 degrees Fahrenheit permanently for a two inch soil temperature in this neck of the woods so about the third week in May. So a little bit later than usual, which led to some of those prevented planting acres. So that's something to keep in mind. Norm, the new normal is going to be pretty much an equal opportunity to be excessively dry or excessively wet. So when you talk about improving efficiency, we have to account for both wet and dry conditions. And so again, we talk about why the concern for efficiency. Again, those big rains tend to be the norm. They always tend to come right after we apply nitrogen, believe it or not. And so if you wanna improve efficiency, you really have to start taking a look at understanding our primary N loss mechanisms, which primarily are leaching and denitrification. Leaching, much more of a concern on coarse and textured sandy soils. Denitrification. Much more of a concern on our loams and some of our finer textured soils. And so the common question that we usually get, whether you're a consultant, whether you're agribusiness, et cetera is, is that N still available, I.e is it lost? Or is it within reach, and has just moved deeper? That tends to be the question that we get after these bigger rains. And then on the flip side, what we'll talk a little bit about, is about what can we do about it, if that N has moved? And that's a little bit more of that for 4R management: that's right source, right rate, right placement and time tend to come into play. And so I always like to start off talking about the nitrogen cycle. Some of us have seen this quite often. Some of us may have not seen this since we opened a CSS-210 textbook years and years ago. And so there's lots of ins and outs. It's not a closed system; very much an open system, very much a leaky system. So there's definitely room to improve the efficiency specifically of our nitrogen use. What we'll talk about mostly here tonight is focusing on a couple of big loss mechanisms down here, would be leaching and up in that upper left hand corner, would be the denitrification. Volatilization off the soil surface is also another predominant N loss mechanism. We're not gonna talk as much about that this evening. Fertilizer N. So it all starts with what we apply, believe it or not. Most of our fertilizer N is applied as ammonium. Whether we use ammonium nitrate or ammonium sulfate or it becomes ammonium in the soil. That would be anhydrous ammonia or urea. If you talk about some of the urea ammonium nitrate solutions, those would be kind of a mix of both, having both urea and ammonium nitrate mixed together. So when you talk about leaching losses of ammonium specifically can be a concern in some of our very coarse textured soils. And in that case, I'm probably talking about some of those blow sands, some of those dune sands or some of those CECs might be, in that one to two, maybe approaching three range if you're lucky. You can leach a little bit of ammonium. But ammonium leaching, once you get into a little bit finer textured soils is not nearly as much of an issue. The other thing to keep in mind is nitrification. So all N sources need to be converted to nitrate before loss occurs. And this encompasses most soils. So that nitrification process has to occur. You have to convert to nitrate before that loss mechanism tends to occur. And that nitrification process, going from ammonium to nitrate tends to go fairly quickly if you have a well drained warm soil and also an oxygenated or an aerobic soil system. So all that ammonium has to convert to nitrate for that plant to use it. Once it converts to NO3 or nitrate, then that is when it becomes subject to some of the loss mechanisms that we discussed a little bit earlier with regards to both leaching and denitrification. The thing that you have to remember though, is nitrate often gets a bad name. All right. So, it's subject to loss mechanisms, but it doesn't necessarily mean it will be lost. All right, nitrate does not move by itself, what moves it water. So just because you have nitrate in the system, doesn't mean it's automatically gonna be lost. You have to have that wetting front or that flushing mechanism to move that nitrate in the soil, whether it's vertically downwards in the soil or laterally, or potentially even to a tile line. So big thing to remember is that fertilizer N mostly applied as ammonium. But again, it all has to get converted to nitrate. And that's when some of our loss mechanisms occur. So when does that nitrification process occur? How does that occur? A lot of it depends on soil temperatures. And we'll talk here in a little bit about denitrification. All right, and that's a little bit of the opposite of nitrification. But that again, depends a little bit on soil temperature. So if you look at this chart right here, on the bottom axis, or that x-axis, you can see time in weeks, zero, six, nine and 12. On the y-axis, you can see the percent of N that was nitrified and you can see with a 75-degree Fahrenheit soil temperature you can nitrify a fair, fairly significant percentage of your N quickly, less than three weeks. But as those soils cool offer, as they're slow to warm up second kind of yellow or mustard looking line there. At 52 degrees, you can see how that extends outwards. It takes upwards of nearly close to 10, 12 weeks at 52 degrees to get about 100% nitrification. And you drop down to that red line, 47 degrees Fahrenheit takes 12 weeks and you only end up at about 70% nitrification. And you can see as that line drops, cooler and cooler down to 42 and 37, how slowly that mechanism can occur. So that can be good, that can be bad depending on if it's spring or autumn. But the key number to remember is above that 50 degree Fahrenheit. Once those soil temperatures reach 50 degree Fahrenheit, things really start mineralizing, things really start nitrifying. And until that point, it can happen but it tends to happen much, much slower. So we've talked a little bit about nitrate leaching. Again, what is it? If you don't remember leaching is that downward movement of water containing nitrate, and it moves it out of that rooting zone. Nitrate tends to be very soluble in water. It's fairly mobile, highly mobile. Remember most of our soils are negatively charged. Nitrates are also negatively charged. So like charges repel. So that's one reason why it is highly mobile, and then subject to some of those leaching losses. Now some of those losses, again will be influenced by the rate, time, source and method that we fertilize. That can all have an impact. Or be impacted by the intensity of a cropping system. Whether it's a high management, high input, lower maintenance, lower input, and when that crop N uptake time period tends to occur. So that can differ quite readily if you're talking about wheat N uptake versus something like corn N uptake. They're offset by a number of weeks. And you also have to look at some of those soil profile characteristics that will affect percolation or that infiltration of water into the root zone and how it percolates through that root zone. So as you get an increased clay percentage, you tend to reduce your nitrate losses. Also keep in mind that drain tile can potentially increase your nitrate losses because you decrease the retention time that that nutrient remains in that soil system. So take a look at that soil. Take a look at that soil map. Remember, just because you're sandy on the surface doesn't mean you're sandy all the way through. So quite often, we'll see 15 to 18 inches of sand on the surface and then a clay layer beneath. That clay layer beneath may reduce some of those leaching losses and fix some of those nutrients that might be leaching downwards. The other thing we have to think about is that quantity, pattern, time of precipitation and or supplemental irrigation. Do you get one inch of rain in 24 hours? Do you get one inch of rain in two minutes? All right. So it's not just about that volume. It's about that intensity of that precipitation. So leaching overall is not a quick process in many of our medium and fine textured soils. I know oftentimes, you go out with your nitrogen and you get kind of a rainfall that might be a little bigger than you would like the first gut check or the first thing that you think about is all my N is gone. In your medium and fine textured soils, nitrogen will not leach nearly as quickly as it can in a similar coarse textured soil. So it is not all immediately leaving that system downwards. The other big N loss mechanism that many of us tend to forget is denitrification, which is kind of the opposite of nitrification. So denitrification then is that conversion of nitrate to N gases: NO, N2O and N2. It's that gaseous loss of N from the soil. So when does this occur? This tends to occur more when our soils become waterlogged. Oxygen is excluded, and we get those anaerobic conditions to occur. So when do they occur? We tend to have those anaerobic conditions where we have about 80% of that pore space filled with water. And then microbes use nitrate as an electron acceptor instead of oxygen. We also need to have a decomposable carbon source or organic matter for microbes to utilize as a carbon source. It also is somewhat temperature driven. So those losses tend to increase quite readily when those soil temperatures warm up and when those air temperatures warm up. Although we can get losses when it is cool out. They just do not occur as quickly. And the fourth thing is we have to have nitrate present in that anaerobic zone or in that root zone. So in reality, you need all four of these items to get your peak denitrification to occur. So if you don't have nitrate already present in that root zone, you're not gonna get a lot of denitrification, especially if you're on a lower organic matter soil. So that tends to be a little bit when denitrification occurs, a little bit of how it occurs, and a little bit on the conditions of where we tend to see some of that denitrification become an issue. So I threw a couple pictures up here. We get denitrification, probably to some extent, each and every year, depending on your soil type and or soil texture. We might get in certain pockets of the field. So we know in Michigan, soil texture is quite variable. So you can look at some of those pockets that we might get denitrification occurring over smaller rainfall amounts rather than some of the greater amounts. But this picture I took back in June of 2015, where we had quite a wet June and we saw widespread denitrification N losses. You can see in the top left picture there, how sporadic some of these losses can be. That is an indication of some of the variability in soil texture, but that's generally what you're gonna see. It could be low lying areas of the field that's gonna be uniform yellow pockets that are probably like I like to say, non uniformly applied across that field. In the lower right hand corner, we always have the running joke, can you find the tile line? That also goes back to 2015 where we had a very wet June. And corn above the tile line made it through. Corn, that wasn't immediately above that tile line. And our soybeans, as you can see from the picture, really struggled due to some of those denitrification losses, some of those water logging issues and some of that wet foot syndrome. We just did not get a chance for those roots to establish. So the question often becomes, is nitrogen still available or within reach? So, one thing to keep in mind it's very difficult to separate nutrient management from water management. Why? You need water to move N to the plant, whether it's by mass flow or diffusion. Without water, you can't get N to the plant. And on the flip side, you look at you need water to move N away from the plant. So it's as much a nutrient availability issue as it is a water availability issue. And this can apply to both wet and dry soil conditions. So, what can we do after large rainfall events to kind of get some inkling of is a little bit of N still around, how much? It becomes difficult because nitrate is so fluid in the soil system. It can change quickly. You take a sample at point A and move two feet over, that nitrate content might be 180 degrees different in a different direction. So, after a large rainfall event, we're oftentimes not able to sample immediately due to those wet conditions. If you can't sample, the problem then becomes can we sample deep enough? So, even going to that 12 inch or 24 inch depth may not be enough to indicate is there N in that two to three foot, three to four foot range? A lot of us may not soil sample that deep. The other thing we need to think about is root health. That's one thing we really saw this last growing season with the wet spring that we had is, are your roots present and are they present at that specific depth? So a lot of times with a delayed planting season you plant late, you plant into wet soils, corn tends to get that wet foot syndrome, where rooting density and rooting mass may not be there or might take a little bit longer to develop, till a little bit later in the season. So that's something we have to think about. It can be as much a rooting issue as it is an uptake issue. So if you plant early in the season and then we have some saturate conditions for an extended period of time, that nitrate might still be available and higher up in that soil profile. But if you do not have a healthy root system to tap into it, that plant will show signs of N deficiency because it just doesn't have the feet or those roots to uptake that nitrogen. But when you start talking about nutrient uptake, there's four factors to keep in mind. For sufficient uptake, you have to have healthy roots, oxygen, water, and nutrient. And you need all four of those things at the same point and at that same place in that root zone in order to uptake N nutrient. If you're missing one of those things, nutrient uptake will then suffer. So look at that larger rainfall spectrum. That may allow a clear answer as to how much N is not available. Oftentimes we hone in on an individual rainfall event or an individual week or maybe a period of time in late May, early June. When in essence, you gotta look at how is that spring set up? Has it been a wet April and May season? Has been a dry April and May season? And the same thing can apply to an early, mid and late season drought. So I thought it'd be, kind of take a look at 2019 versus 2012. And why did I pick those two years to look at is N's still available or within reach. Well 2019, many of us probably like to coin that year, the year we would probably like to forget, based on growing conditions, both early and in some cases late in the season. And then 2012 was that token drought year where we had very dry conditions for a good chunk of the growing season. And we had that very warm March. For those that don't remember, I believe we had about 80-85 degrees for about two whole weeks towards the end of the month. And I believe that was one of the years I heard a story about a grower in our state who planted corn on March 17th, which would be almost a week from tonight. So if you can believe it or not, it does exist. So if you look at those two years, you can call one a wet year or wetter year, one a dry year. Look at some of the rainfall challenges that we had in 2019. You'd look at between March one and November 30th, we had about 28 inches of precipitation around Lansing. It was only about three inches greater than 2018. It felt much, much wetter than that. But the big pattern is you look at April and May were not excessively wet and then June, right? June, most of us across the state had seven plus inches of rain. Some of us had much more than that. And then you can look at even in the graph, you see where the arrow is, we see June and then all of a sudden the arrows or the bars drop off. If you look down below, July about 2.3 inches, August 0.72 inches, September about normal, then it starts to get a little wetter towards October. So we will dry early or wet early in the season with regards to June. But early on the season, April and May, we weren't excessively wet. That rain did not come till about that June time period. And then the rest of summer we kind of slowly dry it out a little bit. So that's some indication as to wetting fronts. So don't forget, as water moves downward in that soil profile, it can push nitrate deeper. But as evaporation and transpiration outweighs precipitation, you can actually pull and back up in that wetting front. That's a little bit of what we saw in 2019. If you had a healthy root system early in the season and you pushed a lot of that N lower, as that soil dried out, it kind of brought some of that N or some of that nitrate back up into that rooting zone to the point of, even though yields were low across the board for a good chunk of the state in 2019, we did see a little bit of yield recovery later in the season, probably due to those soils drying out and drawing some of that N upwards in that soil profile. So again, look at the circle. Root problems early in the season due to those wet growing conditions followed by, probably what I would consider a mid summer drying, allowed for a little bit of upward N movement with the flow of water from those lower depths. And again, probably allowed for a little bit of that recovery later in the season with regards specifically to some of our corn yields. Now you contrast that with something like we saw back in 2012. If you can't remember, I said 2019 we had about 28 inches. 2012 between March and November, we had about 19 and a half inches. And there again you can see, the bars may not look all that different, but March two and a half, April two, May, just over two and a half, June about an inch, July two and a half, August. So what did we see in 2012? It was dry early in the season, and those dry conditions tended to persist as we got into June, July and August. We don't see many big bars on the screen. So a lot of that soil water was used up by that plant. By the time we got to mid July, by the time we hit tasseling those reproductive stages, a lot of that upper soil profile ran out of water and was not able to extract a lot of water from those lower depths, just because it wasn't there. It didn't have that recharge that we saw early in the season. So this would be an example where we probably had maybe okay roots early in the season, depending on when you got planted. We had that early spring. But we had an early season drought. So that's one thing to look at, an early season, mid season, late season drought are completely different. So you have to look at when those drought conditions occur. So in 2012, I would look at that as more of an early season drought followed by what I would consider a dry summer meant probably little upward and movement of water from lower (mumbles) soil profile. A lot of the upper profile ran out of water by the time we hit mid summer and those reproductive stages. And we saw a little yield recovery later in the season because there was little upward flow. So it's something to keep in mind. Look at the general pattern of leaching, denitrification. Look at planting and look at roots. Nobody tends to look at roots anymore. Look at that plant. Pull a couple plants. Do you see white roots? Do you see green roots? Do you see brown root? You don't wanna see brown roots early in the season with some of those immature corn plants that are out in the field. And then look at that wet and dry pattern. When did that dry conditions start or persist? When did those wet conditions start to persist? And then that'll give you a little bit of a better read on will some of that N be available through upward movement, through transpiration, evaporation later in the season? Or if you do have a sufficient root system, will those roots grow deep enough to be able to tap into some of that N that might have traveled a little beyond the upper rooting profile? So I'm gonna switch gears here a little bit and talk a little bit now on our corn N strategies. I've always talked about one size does not fit all. So specifically with corn, we have 14,000 plus corn growers in the state of Michigan. They're gonna fertilize N about 14,000 or more different ways. So it's not about right or wrong, but there has to be an answer to about two different questions that I like to break it down into. Is can we deliver N to the plant timely? And can we reduce opportunities for nitrogen loss? So losses tend to increase as we get a greater time between application and uptake. So oftentimes I'll get the question are pre plant N applications bad? And no, they're not bad. They can be as effective and sometimes more effective than split applications or even sidedress applications. It all depends on both shoulder seasons. So when I talk about a shoulder season, I'm talking about those extremely wet or those extremely dry seasons like we've seen a couple of those years, in both April and June. Those are the years where we tend to suffer a little bit more. And with corn specifically, June tends to be the month where either that extremely dry or extremely wet condition has a much, much greater impact. So some of this will play into some of that 4R nutrient management that many of us have learned over the last several years, which are good principles to be used as guidelines but they need to be locally and regionally implemented. And all those components tend to intertwine when you talk about right rate, source, time and place for an optimal fertility rate. So, since we're upon March madness thought this would be a great picture to throw up there. What's your strategy and can you adjust? And if you're wrong, we're probably fortunate not to have Mr. Iso there cautioning us to what we did right or what we did wrong, right? So I always like to say are prepared for tip off? Okay, are we prepared for planting season? What's your strategy? Have you scripted the first quarter? Have you scripted from pre plant up to V2, V4, V6, something like that. And then have you thought about the ability to adjust at halftime? Go in the locker room, something's not working. What can you do? We have the infrastructure nowadays to apply nitrogen specifically on corn and other crops too. We can apply it very long or late into the season. We can apply it a number of different ways, number of different opportunities that we never had even 10, 15 years ago. So you want to think about efficiency versus efficacy. And there's a difference. Are we becoming more business efficient with our nitrogen application? Because acreages are growing, operations are getting bigger. But are we becoming more business efficient, but less effective with our nitrogen application? That's something to consider moving forward, especially with these variable weather conditions. So consider, I always like to throw out there starting right to finish. Well, this is kind of a bit where some of the starter fertilizer application can come into play. Kind of a little bit of an insurance mechanism to help you set that plan up well, to capitalize on those June and July growing conditions that we have no way of knowing what they're gonna be; if they're excessively wet or excessively dry. The other thing to remember is that 100% certainty of N sufficiency may not be realistic nor may be the most profitable. So, as we go past planting, we get into those early vegetative stages and those late vegetative stages, approaching corn tasseling and that R01 stage, I always get a question now, am I already too late with my N? Or if we happen to get into a wet April or wet May or a mid to late spring pattern, you know what, delaying that N may be a good thing, especially if you're not planting and especially if that seed is still sitting in the shop. So the question becomes, growers always ask, am I too late? Should I've been out there already? Well, if you can avoid those wet conditions, you do avoid some degree of early N loss and you do lower your risk factor to some extent. So you can look at the graph here or the figure here that modeled N uptake by corn. This was released back in 2013. So you can look at N uptake by growth stage. And really, if you look at between emergence of V2, we're only taking up about 3% of our nitrogen between V2 and V6, about 7%, between V6 and V10, about 18%. So even when you're looking at V6 corn, by the time we get to V6, we still have only taken up about 10% of that nitrogen. You get to V10, you're still only about a quarter, about 28%. So it's at V10 to V14 stage where it almost doubles. That that plant really starts developing, really starts shooting out of the ground, and really starts taking up nitrogen to develop that corn ear, that corn cup. So if you don't get out early in the season, it's not the end of the world. On the flip side, a lot of us look at that V10 to V14 at 29% uptake. Well, that's when we should apply N. Keep in mind there's a little bit of a lag time between when you apply N and getting N into the plant. So if you surface supply, remember you still have to have that nitrogen become part of the soil N pool then has to be undertaken by that root then has to be shunted up to the crown up to the plant, et cetera. So there is a little bit of lag time there. And whether you go with a dry or wet fertilizer, there could also be a little bit of a lag time. So you can't just look at that high degree of N uptake and aim to apply everything then because it takes a little bit of time to get that N into the plant especially if you don't have control over the water as in something like irrigation. So that's a little bit where that start right to finish. Well can come into play. If you look at about 30 or 50 units or so, event near or at the plant, whether it's PRE PPI or two by two, a lot of that should be sufficient to get that plant to those mid vegetative stages, whenever that sidedress timing might be appropriate for your operation. So starter no starter. What is starter? And we've talked about that. Just to refresh your memory. It's fertilizer placed with or near the seed at planting time. Some advantages to maybe something like a subsurface application, like a two by two, or two by three, one by twos. Number of ways you can do this. Or even in furrow to some extent, a little bit of N and K. The advantage is it can stimulate early plant growth. So if we look at the picture on the right hand side, we're actually looking at a sugar beet that had on the right hand side 40 units of entering a two by two. On the left hand side did not have any starter nitrogen applied at all. And if you look at no matter what you do to those plants on the left hand side of that photo, they will not catch up to those plants on the right hand side. So that's why that component of start right to finish well is so important. When you're planting, that's the last time we have true control over what we can do directly to that plant with regards to how we place fertilizer. So you can stimulate that early season plant growth. May not necessarily cut your emergence time, right but it can hasten plant development once that first leaf or two is out of the ground. It may also aid with weed control depending on some of your row spacing. It can also alter some that test on pollination timing. That's where that band placement, we tend to do a lot of two by two. It can become very efficient. And why? You place that nutrient, whether it's N, whether it's P, or whether it's K interposition, where a high probability of root contact is there. It's a great opportunity, if you can, to also apply perhaps phosphorus. So band application can increase your P efficacy quite dramatically. It's also a great time to apply micronutrients, if you are inclined to do so. And why? 'Cause you can minimize fixation of that micronutrient by placing it in a concentrated band. So, ultimately, you basically create your own diffusion gradient with that subsurface application. So, those nutrients can diffuse from high concentration to low concentration towards that plant. We know with nitrogen, we can also improve uptake of several other nutrients when you do stimulate that early season growth. And it can help to some extent insure against the unknown. And that unknown is that variable, weather; whether it's gonna be wet, whether it's gonna be dry, we don't know. So helps against that. Now, nothing is always 100% positive, right? We all know that. So there are some disadvantages to those subsurface banded applications. One of the disadvantages is bringing more soil to the surface in something like a two by two application. So on these finer textured, heavier textured soils that you plant early in the season, probably a bit more of an issue when you get towards up into the thumb region. Some of the heavier soils up there that tend to be moist for a little bit longer. We get a little bit more surface residue. That can become an issue. You can also see a little bit of delayed planting due to some of those sticky soils or some of that moisture. The other thing is speed. You just can't plant as quickly when you go with a banded application at planning time. So when you get away from that that planting application, and start looking at your sidedress preference, the conversation always turns to early versus late. Again, what you do at planting time may dictate whether you can go early versus late. But remember you wanna set that plant up to do well later in the season. So again, it's not about right versus wrong, but you got to give that plant enough fuel or enough nitrogen to get to your sidedress application timing. So I threw a couple photos up here from this last season. Now yields were down, 2019 suboptimal growing season so we're not gonna see record breaking yields here. But you can see some pretty good differences. When we look at this top photo, we saw 175 units of N applied at V4 looking at about 121 bushel corn. That bottom photo we're looking at about 175 units of N at applied about V12. So you're looking at about a 90% increase in your grain yield based on your sidedress timing and that is it; same N rate et cetera. Now why? Well, we lost the yield on the field by delaying that sidedress application until v 12. All right, it was just too late in the season to recover any yield. And again, it decreased plant development leading up to V12. So it slows down the plant to get to that point in time. So again, it's not about right versus wrong. But about if you go with a sidedress application, can you then adjust that sidedress application timing? The answer is yes. So that's 2019. 2018, we saw something very similar. Again, looking at 145 units at V4 in that left photo, versus 145 units at V12 on that right photo. We saw about a 14 bushel difference just based on that sidedress timing. (coughs) Excuse me, in 2019, again, 175 units at V12 up top. Now you start looking at that start right to finish well. 40 units of N in 2x2 with 135 units of N at V12. So the same total N rate, we recovered about an extra eight and a half bushels by supplying a little N early in the season to try to get to that sidedress application time. Now that 40 units probably was not enough. But again, you start talking about how to increase yield is about incrementally moving up that stepladder. What can we do in baby steps to try to optimize that yield? 2018, same thing left photo, V12 sidedress. Right photo, 40 units of N, two by two with the rest at V12. And you can see there, we saw oh about a 20 was that 23 bushel difference by going with that starter application in delaying that sidedress of V12. 2019 looking at V4 sidedress on a 21 bushel at the bottom there again looking at 40 units in a starter two by two 135 units N V4 so same total land rate. Again, you're looking at about 11 bushel increase. So again, it's those small things that we can do to try to move up that yield, incrementally move up that yield ladder. 2018, same treatment structure, V4 sidedress, left. Right hand, 40 units, two by two 105N V4. There we saw about a 27 bushel difference if my math is right there by going with that starter application. So it's something that we've seen year over year. Look at 2019 again, V12, top photo. Bottom photo, looking about 80 units of N in two by two with 95 at V12. So again, 40 units in a two by two in that V 12, we gained about eight and a half bushels. All right, now when we went about 80 units in a two by two with that V12 sidedress, we gained about 37 bushel. So we saw about a 58% increase in our grain yield by what? Choosing the correct starter rate, all right? So again, it's about giving that plant enough gas or enough fuel to get to that finish line. And that finish line is whenever you sidedress. All right, so if you wanna go with a late vegetative application, typically what we've seen over a number of years now is you probably have to be more in that 60 plus units of N probably some are 60, 70. In this case, it was about 80. Some cases that's pushing our two by two top rates but you gotta go in that rate to get that plant to that sidedress application timing. So implications. Couple things to remember. It's not a right versus wrong approach. It's not if you go V12, you're right. And you go late vegetative, you're wrong or vice versa. It's about choosing that right sidedress time that may correlate with what your starter program was. And so meeting those corn N demands early will influence the success of that sidedress and when you can sidedress. So remember, you have to maintain that yield potential early in the season till that sidedress time. Whenever that sidedress time might be, whether it's V4 to six, V6 to 10, V10 to 14 or even later than that, depending where you are. So give that plant enough gas to get to that finish line. And that will influence the success of your (mumbles) N application. In general, a lot of our bulk N applications at V10 or later, we haven't seen many significant positive yield responses or improved profitability when we compare that application specifically to our more traditional V4 sidedress N application timing. And remember, if you go with a later vegetative time, you're probably looking at somewhere about 60 to 80 units of N in that two by two to get to that later sidedress application date. I'm gonna have a couple of slides here to wrap things up. We spend a lot of our time talking about nitrogen. I did want to also mention a little bit about phosphorus. We tend to forget about it a little bit. The old slogan from Jeez, 20-25 years ago, whatever it is, maybe even more than that, "Don't guess, soil test." All right, and why? You have to look at that soil test value to determine the likelihood of seeing a response to P application. So make sure you look at the correct soil test. Oftentimes, when we get in some of these higher pH scenarios 7.4, 7.5 and higher, and you have higher calcium content, you probably wanna start taking a look at that Olson P test, not just Bray or Malik. Look at that report. Understand and interpret that report. Remember, it does not represent, if your report comes back in pounds breaker, it does not represent actually the amount of pounds per acre of phosphorus that is in that soil system. Again, it's an index. There's not much of relationship between soil test P and grain yield. It's based on that index, especially when you're above critical levels. The other thing to think about or keep in mind is know your realistic yield potential. Okay, something that's achievable in one of two years. Anytime your yield potential is not achievable, you're probably going to oversupply nutrients. All right, so that's a good take home point to remember. Those P applications cannot be based simply on uptake, crop uptake and crop removal. You have to look at that soil test and based on the index or the likelihood of seeing that response. That doesn't mean we should not apply phos. Phos will still be a critical part of a balanced crop nutrition program moving forward. So to refresh your memory, look at those bray phos critical levels. For corn, soy and wheat will be about 15 parts per million. For corn and soybean about 25 parts per million. For wheat, those really haven't changed. We did number of on farm trials back in 2016, 17 and 18 and 19 across both Michigan, Indiana and Ohio. We all saw the same thing. Critical levels are pretty much right where they have always been. So those have not adjusted much. Now, a couple of future changes that are coming. We are revising the tri-state fertilizer recommendations. And one thing you should be aware of is that Bray P is changing to Mehlich P. So all the recommendations and guidelines are listed in Bray P right now. We're switching that Mehlich P because we can extract more nutrients with that Mehlich extracted. A lot of the private laboratories have already switched to that many, many years ago. So how do you convert from Bray to Mehlich? You can see from the top chart here, your Bray P multiplied by 1.35 I'll give you a Mehclich-3P. If you wanna go back, that Mehlich-3P divided by 1.35 will give you your Bray P. We're also changing potassium from ammonium acetate to Mehclich-3K. And you can see the conversion factors listed there. So I will also have this listed on our website. So that msu.edu under a heading, talking about Bray to Mehlich conversion. The other big thing that will affect applications a little bit is that green nutrient removal rates have changed. So when you look at Michigan, Indiana and Ohio, the new removal rate to be something more closely resembling for corn about 0.35 pounds of P2O5, 0.2 pounds of K2O per bushel. Soy, phos will stay pretty close to where it's been at about 0.8, potassium would be about 1.15. And then wheat will also adjust a little bit down to about 0.5 of P2O5 per bushel and about 0.25 pounds of K2O per bushel. So that will also affect a little bit some of your P and K applications, especially in a reduced commodity market. You really wanna take a look at how much of each of those nutrients you will be applying. A couple of other changes that are coming. We've always been a proponent of the build up, maintain and drawdown approach to nutrient management. The old framework, we have build up, maintenance and drawdown. The new framework, drawdown is being eliminated. So we will still have the build up and maintain. So build up at those low soil test phos and so test K levels and then maintain from there up to a maintenance limit. But that drawdown value will be going away partially because we're just not drawing down, especially on the phosphorus side, we're not drying down. So test phos levels, as quickly as we should. And the other thing you look at we have a lot more leased land today than we did when a lot of these recommendations were written. So when you look at the lease versus owned component of land can definitely play a difference when you look at that long term, build and maintain approach, specifically with regards to P and K and that long term rotation when you lease versus own land. So that will also be a slight change that will be coming forward. A couple resources to consider. We have all these posted at soil@msu.edu. We have a couple videos posted. A little bit on N rate models, some sidedress timings, some corn N strategies. We also have couple articles posted there. A couple combination articles, strategies, start right to finish well and some guidelines on focusing on the right rate. So I will wrap it up this evening. Again, I wanna thank everybody for attending. I see some information listed on your screen there. And with that, I will probably hand it back over to Ricardo. - Kurt, thank you very much for the amazing presentation. I do have a few questions. And speaking of that, if you have any questions, make sure to put in the Q&A box that Kurt's gonna be able to answer right now. Kurt, my first question is. There is all of this carry data from other places saying that, well, if you apply a full rate of nitrogen at planting, two weeks later, you can lose up to 50%. So the question is right now, do we have any data in Michigan? I know that varies a lot by soil type or so. But do we have any data that tells okay, what's my chance? And what's the percentage that I can lose if I go from a full rate planting to go to sidedressing? So I just put a starter in and I would try to start at V4 or V5 or later. Do we have any data that can help us, to the farmer to make that final decision? Because it's too (mumbles). So if I lose 20 or so let's say, I lose 20%. So that's 50 cents a pound, it's still a lot of money. So do we have any data on that? - [Kurt] Yeah. So we've looked at all those timings over a number of years. And the thing you have to ask yourself, that pre or PPI, or at plant application can be as effective as a sidedress in many, many years. What we're up against the wall with in Michigan, is we don't have widespread soil uniformity. So when you start talking about maybe three to five different soil textures, or types in a field, which all have different cat exchange capacities, we don't have that six foot mile of soil that some states are lucky to have. So we probably have a little less wiggle room as compared to some of those states. So when you start getting into a thicker, overall soil profile and a larger horizon, you can get away with that pre or that early application, and you're not gonna see much of an impact with sidedress. But when we have our shallower soils, and we have a lot more coarse, textured soils, so sandy soils, that really throws a monkey wrench into that equation of what I should and what I should not do. The question I always ask growers to ask themselves or consultant is, do you know more 30 to 40 days into the growing season than you did at planting time? So think about that. So you look at weather models, you look at weather forecasting, we still are not nearly as precise with our weather forecast as we should be. Look at the models still are not nearly as precise as they need to be. Do you know more a month, a month and a half after planting than you do at planning? Oftentimes the answer is yes. So what can change 30 to 40 days into the season from planting time, your yield potential. So look at 2019 be a great example. You might have started off the season. In early May, there's about a seven to 10-day window where a lot of people got into plant with a, let's say 200, 250 bushel yield potential. Then the writing was on the wall with that later May precipitation that June precipitation, (mumbles) growing conditions. Your yield potential come June 15th, June 20th, was probably not nearly what it was at planting time, a lot of us lost hope. So if you look at that split application, what does it offer you to do? It allows you to kind of recover some of those costs by not fertilizing at a yield potential that you initially had back in early May. So that's probably where the biggest difference comes in with that split application system. So usually that two split system tends to work better whether it's combination of pre and at plant, or at plant sidedress. That's where we tend to see probably the best return on our investment. Is it gonna happen each and every year? Absolutely not. And until you can predict that weather, probably six to eight to 10 weeks in advance, that's where the problem's gonna come into play. Unless we get to a point, perhaps you start thinking futuristic nitrogen application where we have individualized maybe robots going through a field, something like that, where you individually inject a plant with nitrogen. We all hear stories about this. Yeah, okay, that could be a viable option. But you have to look again, focus on those shoulder seasons, those extremely wet and extremely dry seasons. And that's when usually that split application tends to outperform that singular pre plant N application. - Kurt, so if you wanna take the risk and if you wanna go with at planting, then come later an V4 or V5 or so, what would be the minimum that you would apply at planting? So let's say you wanna focus as much as you can at V4 or V5. So what would be the minimum you as a farmer would go with at planting? - [Kurt] If you're at plant, whether it's a two by two, something like that, your at plant N rate will be impacted by when you choose to sidedress. So if you're gonna sidedress a little earlier, again, I'll say that V4 to V6 traditional window, you probably cut back on that at plant application timing. So probably, you know anywhere 20 to 40 units of N, we like to go with probably closer to 40 because we don't know what those weather conditions are gonna be. And we've seen some years where that 40 units of N will outperform 20 units of N in a two by two, depending on those weather conditions. If you're gonna push that sidedress maybe to that V6 to V10, or V 10 to V14 and later stage, you're probably then pushing it closer to, (clears throat) if that V16 to V10, probably at that 50 to 60 range in that two by two. If you're gonna go beyond that, probably closer in that 70 maybe knocking on the door of 80 units of N to get to those really late vegetative sidedress application timings. And there's a number of ways you can do that. Oftentimes, you think of the older school way of Coulter inject, but with things like drop nozzles, stream jet nozzles, there's all sorts of options that can get your N on sidedress post plant as compared to something like a Coulter inject. And they can be quite effective, surprisingly, some of those newer application technologies. - And so just to finalize so if I'm doing at planting inside (mumbles) PSNT is essential or right to a farmer to make sure that they are applying the right amount. - [Kurt] Yep, so the question becomes the PSNT. The problem with PSNT is if you put any sort of mineral fertilizer out, it really lessens the impact of a PSNT test. Because you don't know what you get back, how much of it came from that fertilizer that you applied, unless you apply in something like a two by two and you're 100% certain that you stay out of that two by two band. And you're 100% certain that that two by two N application hasn't migrated north, south, east or west from that band and is in your sampling zone. So when you talk about that PSNT, it's much more of a useful tool to look at manure contributions from fall applied manure, spring applied manure, or perhaps even if you look at a leguminous cover crop N credit from the fall or early spring growth. - Awesome. Well, I do have a few questions here. Let's go and ask them. So Dan asked a question between dry or liquid starter in two by two. So he's saying that usually more bland options with dry. He said that because they have to have higher levels of K. And he said that higher efficacy of K in two by two where a versus broadcast. So he's asking that if two by two is better than broadcast if you're going to have to apply K? And he said that dry is a pain to handle, especially in weather that's got a lot of rain. And he's asking if you have any thoughts on wet versus dry starter in general. - [Kurt] With regards to nitrogen or potassium or both? - I think it's both. - Okay. So the big thing is, when you band apply K or potassium at planting time, usually it's only effective if you're below critical on your soil test K values. When you're above critical, very rarely will we see a positive yield response. Not necessarily plant response, there's a difference between plant response and yield response. When those STK levels are above critical, we very rarely see a positive benefit, yield wise to that band in K application. So in that scenario, if you're above critical, you probably wanna take a better look at those pre plant perhaps, broadcast applications et cetera. Sometimes you can go with like a liquid application at planting just to again support some of that starter fertilizer. And so if you're gonna go pre, you're probably gonna go with granular. If you're gonna go at plant, you're probably gonna go wet. But again, what drives that is that soil test K concentration. Are you below critical? Are you above critical? If you're below critical, you probably want to go with perhaps a banded application and a broadcast maybe pre plant or previous to the ensuing crop. But if you're above critical then that at plant potassium application, really, we don't often see a yield response. Sometimes a plant response or a biomass response, not a yield response. With regards to N, there again. You start talking about wet versus dry. Remember, I'll talk about maybe urea versus something like UAN, okay. So if you look at 28% versus urea, there's a little bit of a lag time for urea to break down. But you're not gonna see typically, many growers go with a dry two by two. I always get that question. There is some interest in that, but oftentimes, we don't see it due to some of those application issues, some of those caking issues that are very common with urea, that 28 just becomes a little bit more efficient, more effective, easier to handle. The other thing with 28 you probably mix it with a little bit more stuff. Whether it's regard to a macronutrient or something like that. When we look at a breakdown and getting into the plant, when we look at root crops, we've seen this many, many times, like it's something like urea versus UAN, we see about a seven to 10 day lag time for that urea to break down and get into the plant versus something like 28. So that would be the other item to consider is which cropping system you're talking about? Can you afford that lag time? And then again, how much N you're putting out. And make sure, especially with something like urea, you wanna make sure you're probably in that two by two, and not getting it much closer to the plant, because you can have some toxicity and some siltation to that plant with a high salt compound like urea. - Awesome. Kurt, I have a few more questions here. They are really interesting questions. So Steve is asking if the excessive application of synthetic N weaken microbial fixation of a natural N? He left me with the other common problem, or if that even happens. - [Kurt] Can you repeat that again, Ricardo? - Does the excessive application of synthetic N weaken microbial fixation of natural N? - [Kurt] So, the question about the application of inorganic mineral fertilizers, does it weaken fixation? Yes. So if you're talking about something like soybeans, leguminous crop, something like that, RN applications what we've seen, we can get away with up to about 20 units of N without impacting nodulation. The minute we get above 20 units of N, we tend to see decreases in nodulation. So in that essence, you're robbing Peter to pay Paul, You're applying more N, you're just gonna cut back on that fixation ability of that plant. We've seen that both in something like soy beans and something like dry edible beans. The other thing that always comes up is, does inorganic fertilizer impact the microbic community? And, we've done quite a bit of work on this through some of the more modern DNA extraction technologies. And what we've seen is when you apply fertilizer to a plant, whether it's wet, whether it's dry, you get a growth response, right? And that growth response is impacted by a root development. And those roots exude certain compounds. And those compounds will dictate the microbic communities that are there that like that environment versus the ones that are not there. And so what we've seen in many cases is when we apply a nutrient and get a plant response above ground, oftentimes, some of that microbial diversity may go away below ground, because, for instance, that corn is selectively choosing who is and who is not there. So that is a probably a much longer explanation that I can offer. So it's not necessarily simple. We actually will have a publication or two coming out on that plant response with regards to inorganic versus organic nutrient application and the impact on the microbial community. - Awesome. Thanks very much. Two more questions here. Next to one. Is there a preferred form of N for the different growth stages of the crop? Like for example, ammonia versus urea versus UAN? Is there something like that? - [Kurt] You know what the key is? Yeah, I get this question every spring about N sources, you know a lot of it. Sharpen your pencil on your bottom line, see where you can get the better deal, maybe the better bulk deal on one versus the other. Or if you look at purchasing in the fall or early spring versus later spring when everyone wants it at the same time. You know the big thing is, there's very little difference in N sources, as long as they're applied in the right manner, right? And we have to get the N to the plant, not to the ground or on the ground. We wanna get it in the ground and to the plant. So there's very little difference. Bigger difference comes in application, right? So if you're looking at surface applications, you're subject to much more volatilization which could be a little bit more of an issue with urea because it casts a complete to convert over to nitrate. On the flip side, you look at something like 28 or UAN, and if you apply that on the surface, you got a bit of urea, ammonium and nitrate there. But typically we're going to broadcast, spray that on the surface which maximizes surface area, which can maximize volatilization. So I always say pay more attention to what your bottom line is on what kind of deal you might be able to get in N source and then apply it in the right manner, 'cause that will dictate how effective that specific N source can be. - Awesome, thank you. Last one, from Terry. He said, you note that soil temperature as being potent. How is the correct way to determine our soil temperature two inches deep, average for the day, highest for the day or the lowest for the day? - [Kurt] Yep. So there's number of ways to do that. Sometimes you look at some of the weather stations that are out there. You can look at the mean for the previous day. What I tend to look at in the springtime myself. So I always get concerned of when do we stay above 50 degrees Fahrenheit permanently? So what I'll look at typically, is that minimum soil temperature for a specific day. Did it get below 50 degrees at any point in time? It could be just for an hour or two over the course of a day. So it's cool off at night, et cetera. But that's what I'll typically look at is typically that two inch temperature. You can also look at four inch. But I'll look at when was the last date that that two inch temperature actually dropped below 50 degrees or when did it stay above 50 degrees permanently. And just because it drops below 50 degrees for an hour over the course of 24 hours, doesn't mean soils are cold and microbial activity has dropped off. It's not a black and white issue. There's not a clear cut line like that. Well look at general trends. Are we trending warmer? Are we trending cooler? But using that 50 degree threshold gives you a good indication as to when your nitrate might be starting or when some of that ammonium might be nitrifying and, or when some of that organic N might be beginning to mineralize in that soil system.

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