Nitrogen Management

Welcome. This webinar is part of a series presented by the agonomic crops team from Auburn University in Alabama Cooperative Extension System. The series is brought to you by Optima Fields, [music] helping producers make smarter datadriven decisions on the farm. We're glad you're here and hope you leave with practical researchbased knowledge you can put to work this growing season and beyond. Hello and welcome everybody into this video about nitrogen management. My name is Chandler Ger. I'm an assistant professor and extension specialist in soil health with Auburn University Alabama Cooperative Extension System. So today we're going to be talking about nitrogen management. And so it's important for many crops, not only cotton, corn, soybeans, and everything else. And so you're probably wondering a little bit about soybeans, why nitrogen management come in there, but we'll talk about that here in a second. So, first off, just kind of why does nitrogen matter? It's important for yield components. You know, increases yield. As we know, as we put more nitrogen out there, we see an increase to a point, but then there's a point where we actually go over. It's important for protein content in the grains and fibers. It's also important for early crop growth. So, if we're low on nitrogen, we don't see that early crop growth, and we actually don't see good growth throughout most of the season if we get low on nitrogen. Another thing that occurs when we start thinking about nitrogen is the cost. How much does nitrogen fertilizer cost? how much is it going to be benefiting us and how much is going to stay there from year to year. How much is lost? And so all them cost factors start going in there and also it's easy to lose. That's another common thing people think about when they start thinking about nitrogen out there. It's easy to lose. It could volatilize off. It could run out the soil. It could be erosion or whatever. They're starting to think about all these different mechanisms for loss. And so we'll talk a little bit about that first here. And so how is nitrogen lost? Voltization is one of the mechanisms. And so this is when you know you put ura on the soil surface it converts to ammonium gas and leaves the system. So as a gas it just floats away you don't get any of the use out of it. So this is common when temps are warm no rain and high residue systems this can occur but we'll talk about some solutions for that here in a second. Another mechanism for loss is leeching. So nitrogen moves through the soil with the water and so it can especially in these coastal plain soils pictured here on the right hand side. And so you can see the sandy nature of that soil right there. There's some organic matter content at the top that can hold nitrogen, but oftentimes, you know, of course sandy soils, a lot of nutrients will flow through, especially in these high rainfall systems like we have here in Alabama. And so, we can see a lot of loss denitrification. That's another mechanism of loss. And this is when nitrate goes to the gas and when soils are ponded or saturated. So, this is can be common in poorly drained fields and high rainfall at one time. So now that we know some of the main loss mechanisms, so how do we prevent this? So using the four R management method is a good way to do this. And so that's something we talk about here in the soil fertility world is the four Rs. So what are they? They're the right source, right rate, right time, and right place. But with them four words, maybe we don't know what all of them cover, what all of them mean. And so we'll work one by one through each of them as we go through this video. So applying more, you know, doesn't always translate to higher yields, but sometimes results in higher risk for losses. So that's why it's important to use this 4R management method. And so first of all, and so you can put more and more product out there, but if you're not putting the right product out, you're not going to see the results you want. So that's where the right source comes in. So pick a product that works with the equipment you have and also has all the items you need. What do we mean by items you need? So in many cases, we need sulfur out there in the soil. So having a sulfur source combined with your nitrogen like an AMS is a good choice. Or if you have URA or UAN, also getting a sulfur source in there. Maybe you need phosphorus and potassium to make sure you're not limited in another nutrient. So you know, if you're nitrogen management, you're doing all the great things to keep your nitrogen in the right levels, but you don't have your other fertilizers that are going out there in that blend, you could be limiting yourself in another way and not take a full advantage of that nitrogen. So how do we stop the loss? And so the next mechanism is the right rate of the four Rs. So soil testing for nitrogen, you know, we can't really do a lot of that information. We don't always know what's going on, but we can use yield maps from previous years. We can soil test to know our organic content, our soil texture and some of that information to help us kind of plan out how much nitrogen is good for our system and what are some of the mechanisms for loss that we need to be looking out for. Also, crop removal. So this is a you know comes into when you put out you know the corn and takes up nitrogen or cotton or soybeans or whatever it removes nitrogen from the field and so that's a loss mechanism. So make sure you have the right amount to help cover that cuz from year to year you're losing a little bit of nitrogen you need to account for. Also the cover crops. So cover crops is a great tool we can use in the winter time. So this can actually help increase nitrogen from a fixation standpoint like an Austrian winter pee shown here in this righth hand photo on the left side or it can take up nitrogen prevent loss during the winter time like grass species as you can also see in the righth hand photo more towards the right hand side. So there's kind of two different the ways that cover crops can help them both from fixing nitrogen and also for preventing from being lost from the system through leeching or other me mechanisms. So overall with the right rate, you need to know how much you need and then also account for either additions into the system from cover crops that can increase it or crop removals that are being lost from last year's. So that carryover that may not be there. Applying at the right time. So apply when the crop needs is kind of the key aspect there when it's actively growing and for uptake. So use measure to prevent loss until the plants can actually take it up is key to help not lose that fertilizer off there. Otherwise, your rates aren't going to be reflective of what you put out there. rate of uptake to rate actually put out there. One method is using split applications to help with this. And so the last R of how do we stop the loss is a bright place. Placing in the furrow near the plants can help take it up, but also you got to remember nitrogen can be what we call hot. It can be a little bit hard on seeds. And so if you get it too close to the plants, it can cause stand issues. So you got to have a little bit of distance but not too far away so the plants can get to it but without impacting that early plant when they're first emerging. And then surface apply for some rain. So if you're surface applying ura, you know, maybe you have a light rain coming up that can be great to help incorporate it into the soil and prevent some of that loss off from that volatization we were talking about. So overall having the four hours in mind increases the nitrogen use efficiency. And so tools to improve this nitrogen efficiency. So urase inhibitor. So as we were talking about earlier that volatilization that loss when you're putting that ura on the surface or UAN on the soil surface it can volize off especially if you have these long periods of hot dry days surface residues like in noil systems. And so here we got showing a no till system where we just have small little strips. We planted corn into it. We had nitrogen that needed to be surface applied. And so using a uras inhibitor greatly benefits this cuz we weren't going to have rain for the next few days. this happened in 2026 here. We had, you know, a long spell of no rain for much of the state. And so we needed just that coating on there to help slow down that urus inhibitor. And so some of that stuff can last between 3, 14, sometimes a little bit more depending on conditions. And that can really help extend the life before your fertilizer is being lost out there. So if you're putting your fertilizer out there, even though you may have had the right rate which you initially attended, but if it vifies off before it gets in there, your right rate didn't make it to your plants and that can be an issue. So that's tied back to that four Rs we're talking about. And so and so these uras inhibitors which are MBPT and duramide and oftentimes they're combined together to increase the overall effectiveness. They reduce the volatization losses. So another tool is nitrification inhibitors. They reduce the ammonium to nitrate conversion. So this is key for reducing leeching and ditrification in the soil. And so these can happen on wet and sandy soils. So there's a couple products out there. You just need to talk to your local retailer or hear us talk to us at Allurn Alabama Crawford Extension System. We can walk through some of the nitrification and urase inhibitors that are available out there on the market and find the best solution for you. Another method is split applications. Apply more than one time but in smaller amounts planting and then again at side dress. You know split applications you know reduces your risk from being out front. So it meets the crop needs as they're able to uptake it. So once your plants are able to uptake it, that's the best time and also reduces your loss risk as it's being applied right at the time of need. So timing, that's that key factor we're talking about here. Happens right away and high amounts of leeching. So if you put it all at the beginning, you have a high amount of leeching that could occur. No rain for a long time, you have the volatilization risk. I know we don't have crystal balls, we can't always predict what's going to happen, but minimizing the risk as much as we can and using them tools that we I mentioned just now can help increase success. And so we start think about the Alabama soil regions here in the state. And so what are the kind of the three main areas? We have that coastal plain sandy soils. We have the black pelpra soils. And then the northern Alabama we have the Pedmont soils. Kind of how I'll talk about them. So sandy soils you have a high risk of leeching below the rooting zone. So on the right hand side here some coastal plain soils. Put a little blue dye. Put some water just to show how easy water and then that water is carrying your nutrients moves through that soil. blue dye was attached on to the water moves through the soil. So you can see that leeching started happening within a short amount of time pictured here on the right hand side. Also we have some long dry times here in the coastal plain soils and any of the soils here like in 2026 after corn planting. S items to prioritize would be a uras inhibitor or nitrification inhibitor depending on the situation and then split applications. Black belt soils these heavy clay soils these shrink swell verticol soils. So these have a high risk of standing water and then denitrification due to that standing water drainage and reduce applications and high wet conditions. So make sure you have good drainage of your soil and try not to put it out on standing water. The last region kind of the northern Alabama the peont clay soils or lomy soils that can be occurring up there. So like all the soils in Alabama runoff loss is a concern. Just like up there sometimes the terrain in northern Alabama is a little hillier and so that increases your chances of runoff loss. Also with all the soils crusting or can happen but also compaction layers. You know a lot of times when we start getting the high clays old tillage from down below can actually have these compacted layers and that's limits movement into the soil and it can lead to either issues of denitrification or other losses mechanism. Volatilization. So if you're doing you know no till high residue on the surface that can be a concern. That's common for all the soils. For all these soils weather is a big factor whether you're going to get a bunch of rain whether you're not going to get a bunch of rain for a while. So that kind of determines some of the different aspects a little bit, especially with how warm it is and how much moisture it has. Changes the rate of breakdown of that residue on the soil surface. That can change how effective your fertilizers are too. And so sulfur, so that's one of the nutrients, you know, maybe we're not thinking about, but when we it's really important when we start think about nitrogen management. So they're key. So nitrogen and sulfur are used in a lot of the same mechanisms in plants. So if your plants are going to have optimum nitrogen efficiency, you need to have sulfur available. So you need optimum sulfur efficiency. So if you're working with optimum nitrogen efficiency and optimum sulfur efficiency, it can take full advantage of the nitrogen. So you may be thinking, oh, sometimes I put all my nitrogen out, I got the right rates, but I didn't use, you know, a sulfur product this year and I didn't quite see the response for my nitrogen I normally would occur. And so maybe you didn't think about I didn't put the right amount of sulfur, but sometimes we deduct back to that and realize that could be occurring out there is we're not having enough sulfur out on the soil. Uh soybeans also fix nitrogen and so we don't need to worry about applying the nitrogen, but where they come into nitrogen management is sulfur. So they're needed to complete many of the same processes in the plant. All plants need the sulfur. So if you don't have adequate sulfur, it may not be able to fix the nitrogen and see that full advantage we normally would think about. You're like, "Oh, we've got some of the process going. We should be fine. and I inoculated my soybeans. Should be able to fix the nitrogen, but maybe we don't have enough sulfur to actually help with the process of nitrogen and plant. And so that's why we're seeing some issues that occur. And so sulfur is used to increase protein and quality for plants, you know, the grains or the fibers depending on what we're talking about. And then we start thinking about sulfur deficiency and nitrogen efficiency. So nitrogen management. Sometimes you go out there and you look at plants and we see that, you know, yellow striping on the leaves of corn plants, you know, especially plants when they're on the lower leaves, but sulfur is actually on the upper leaves. So even though they have the same look, they have show the deficiency in two different locations. One shows it on the lower leaf and one shows it on the upper leaf. And sometimes them two things can get mixed up and a lot of times they're interrelated to each other because they're using the same process. Either not enough nitrogen or not enough sulfur. So one one or the other is low. you actually sometimes have the issues occurring from both ends. And so also sulfur is in kind of four main pools in the soil. You know, it's also susceptibleization loss and leeching and other loss mechanisms just like nitrogen and should be considered when you're out there applying sulfur. So the Alabama nitrogen management key takeaways, don't apply all at once if your operation allows. Look at that split application. Try to apply some at the beginning and some in season. If you're going to put a URA or UAN or surface supply fertilizers, look at uras inhibitors. It's going to be high rainfall events, you know, and you don't have that timing laying fall and you have that dry period. Then erase inhibitors are greatly beneficial. If you're going to have beneficial if you're going to have a lot of rainfall all at once, maybe you want to look at inhibitors to prevent leeching losses out there that are occurring. And so, you know, you could select different products whether you need a volatization inhibitor or some other inhibitors or different enhance efficiency fertilizers. Or maybe if you know big rainfalls coming the day after you plant and you're like, "Oh, I'll cut back a little bit on nitrogen and come back in a couple days after that when maybe a lighter rain's going to come and help incorporate and reduce your loss." And be realistic about your rate for nitrogen. You know, just be, like I said earlier, just because you put more and more out there doesn't mean you're going to increase your yield. There is a certain point where you have so much out there, you're not actually going to keep increasing your yield. You're just increasing your losses potentials. So keep that in mind. Have a realistic goal when you're out there applying the nitrogen. And know your soil type and conditions. So if you know your organic matter and you know your soil texture, if you're sandy, lomy, and how your soil kind of holds the nitrogen, that can help management a little bit better. Makes it a little bit easier. And then using the four Rs will help improve efficiency and returns. Uh here's my contact information. Once again, my name is Chandler Gruner. I'm an extension soil health profer. I'm an extension soil health specialist with Auburn University Alabama Crawford Extension Service. Thank you for watching this video. >> That's all for today's session. Thank you for joining us and a special thank you to Optima Fields for organizing and producing the webinar [music] series. For more resources from Auburn University and the Alabama Cooperative Extension Agonomic Crops Team, please visit our website at aces.edu or reach out to your local extension office. We look forward [music] to you joining us again next time.