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Mike Howell (00:08):
The Dirt with me, Mike Howell, an eKonomics podcast where I present the down and dirty agronomic science to help grow crops and bottom lines. Inspired by eKonomics.com, farming’s go-to informational resource. I’m here to break down the latest crop nutrition research use and issues helping farmers make better business decisions through actionable insights. Let’s dig in.
(00:38)
Well, hello again everyone, and welcome back to The Dirt. We’ve got a brand new guest with us this week, Dr. Karl Wyant. Dr. Wyant is brand new with Nutrien. He’s been on the job a couple of weeks now and he is the new director of agronomy. Karl, welcome to Nutrien and welcome to The Dirt.
Dr. Karl Wyant (00:54):
Hey, thank you for having me. I’m excited.
Mike Howell (00:55):
Well, we’re excited to have you. If you will give our listeners a little bit of background. Tell us where you’ve been before and what you’ve been doing.
Dr. Karl Wyant (01:02):
As Mike said, I’m the brand new director of agronomy here at Nutrien and on the job for just a few weeks here. I can still count the days on both hands, so that’s how new I am, but I came over here from Heliae Agriculture. It’s a microalgae biostimulant startup in the Phoenix area, and I worked there as the vice president of ag science and I directed trials and helped with new product development and some of the intellectual property development. Before that, I was an agronomist. I am actually a desert agronomist by training. That’s what I started doing right out of school. I was hired to go check on all the cotton and the date palms and citrus trees and lettuce and all these other crops down in the southwest Arizona and southeast California. And so I did that for a number of years and did that at Helena Agri Enterprises. So lot of history out west of the United States and certainly a lot of history with nutrient management and helping growers get the most out of their fertilizer program.
Mike Howell (01:53):
Okay, sounds good, Dr. Wyant. And for those listeners around here, you have dry counties out that way, and that’s a totally different kind of dry county than we talk about a dry county back east. I’m sure our listeners will figure that one out.
Dr. Karl Wyant (02:05):
Some of our counties out west are so dry, they get three inches of rain total a year. That’s how dry they are. So if you’re thirsty, don’t come out my way anytime soon.
Mike Howell (02:14):
I’ll understand. Well, Dr. Wyant, if you’re ready, let’s dive in and get to the dirt. Today we’re going to be talking about magnesium and the importance of magnesium for plant development. If you would, let’s start off and talk about the function of magnesium in a plant. What does it do inside of a plant?
Dr. Karl Wyant (02:29):
Great question. So magnesium is one of the primary macronutrients of a plant, so you have to have it in order to meet sufficient crop yield and crop quality. One question to ask is why is magnesium a primary macronutrient? And really it revolves around what makes plants green. Magnesium lies at the very center of the chlorophyll pigment and that chlorophyll pigment is what gives plants that green color, but it’s also critically important for capturing all that sunlight, energy, all that UV that we’re bathed with every day, and it takes that UV, that chlorophyll can transform it into biologically useful energy that the plant can now do. A lot of its biological work of building tissues and making grain and fruit and all that sort of thing. So really magnesium lies at that center of the whole energy metabolism of a plant.
Mike Howell (03:16):
Okay, very good. Dr. Wyant, what forms of magnesium can be available to plants? We know these nutrients come in all different forms. Well, what forms can the plants take up?
Dr. Karl Wyant (03:25):
Yeah, magnesium has one option. It’s magnesium two plus where magnesium plus plus depending on how you write it out. So that’s the only form that a plant can take up and it has to be dissolved in water. It has to be in the soluble form for a plant root to pull it in and translocate it up through its different leaves and shoots and whatever crop you’re trying to grow. So that magnesium can be tied to different materials. I mentioned it’s roll in chlorophyll, so you can find magnesium in plant residue, plant biomass. You can find it in a fertilizer and we’ll talk about that in a second, but you have to put it in water first. Get a solubilized and soil solution before a plant can actually use it.
Mike Howell (04:04):
Well, that kind of leads into my next question, and I’m assuming because it has to be dissolved in the water that a lack of water could limit the amount of magnesium getting into the plant. What other conditions could reduce magnesium uptake by the plants?
Dr. Karl Wyant (04:17):
That’s right. The primary way that a plant receives magnesium is through mass flow, so just think of a flow of water below ground from the bulk soil moving towards the root zone, and it’s pulling that magnesium with it. This is very similar to how a plant pulls in nitrate. That mass flow moving with the water stream and into the plant. You also have a plant that can, and it’s a very minor pathway, grow roots directly into magnesium and pull it in, but that mass flow is the primary mechanism for plant uptake. So if your soils go dry on you, whether it’s an induced drought from lack of rainfall or you forgot to turn your irrigation pumps on, like you can have out here, that drying of the soil can actually reduce the flow of the magnesium into your plant and cause a deficiency.
(04:58)
There’s a couple of other ways you can get deficiencies of magnesium. One is through sandy soils. We’ve been talking about dry soils, but what if you have sandy soil that gets lots of rain and there’s parts of the country that experience this, you can actually move that magnesium out of the root zone so your plant can go deficient just from the movement downward of that magnesium through the water, so that’s important. If you have those low CEC, high sand soils that are generally low in organic matter, you might run into some magnesium issues. Also, acidic soils, if you have soils below pH of five and a half, they can be prone to magnesium deficiency, and that’s where keeping an eye on your soil pH, making sure it’s upwards towards that neutral number of seven. That’s one more reason to stack on your list of why keeping your pH managed is an essential thing to do in crop production.
Mike Howell (05:43):
We have talked a lot about pH and how we can alter that pH in previous episodes, and we’ve also talked about calcium and magnesium as some liming agents. If you would talk a little bit about how we can use magnesium to buffer that soil pH, get the pH up where we need it to be.
Dr. Karl Wyant (05:58):
That liming is the key. It’s taking the carbonate piece of that liming agent, and I’ll get into the two flavors of the liming agent here in a second, but it’s taking the carbonate, that’s the anti and the negatively charged part of the lime, and it’s actually tying up those hydrogen ions in the soil and that helps to pop your pH up back to where you need it. And there’s full extension booklets on how much to put out, when to put it out based on your soil report and your pH goals, and it’s a pretty easy recipe to follow.
(06:24)
The way you can introduce magnesium in with your liming program is by which flavor of lime you choose because you can choose ag lime, which is calcium carbonate, so you get calcium as the cation, so you can get a little bit of calcium nutrition along with your carbonate. That’s the one that’s doing the pH adjustment. Or you can go with dolomite, which is a mix of the calcium and magnesium carbonate, so you can get calcium, magnesium and adjust your pH at the same time. Depending on your needs, depending on what your soil test report showing you. You have some options here for how you can manage a couple different variables with one product application.
Mike Howell (06:56):
Dr. Wyant, we know a lot of these nutrients have interactions with other nutrients and they work together, or sometimes one can antagonize another, but I know magnesium has a relationship with nitrogen and how those work together. Can you tell our listeners a little bit about that relationship and how they work together?
Dr. Karl Wyant (07:12):
Yeah. A great question to ask yourself is what makes a plant green? And it sounds like a simple question, but the answer will be that nitrogen and that magnesium, so nitrogen as we’ve learned in previous episodes is so important for that overall plant growth, making proteins, driving yield and driving the overall every day-to-day activity of that crop. But I mentioned earlier, magnesium is the center of the chlorophyll, the thing that makes a plant green, the actual physical substance, the chlorophyll, magnesium is the very center of that pigment. So if you don’t have enough magnesium, you won’t be able to make the pigment and your crop will start to show symptoms. If you’re trying to really look for how can I double dip and apply a product or sets of products with magnesium and nitrogen, they’re a great tag team partner because a lot of our research shows and other research in the literature shows that putting nitrogen and a magnesium partner together, great synergy and a great impact on crop yield and crop quality.
Mike Howell (08:06):
With all of our other nutrients. We’ve kind of talked about their mobility in the plant. What about magnesium? Is it going to be mobile in the plant or does it stay in the plant where it finds its home?
Dr. Karl Wyant (08:15):
This is a great question because you have kind of two worlds here. Magnesium is considered mobile in the plant, but the plant is growing quickly and it’s calling for more magnesium, the plant fortunately can take that magnesium from older tissues towards the bottom of the plant and move it up towards the new tissues. It’s relatively mobile, and this contrasts with something like calcium, which once calcium is in the plant in a structure, it’s stuck. It’s not going to move. Calcium is relatively immobile. Magnesium is relatively mobile. This mobility really shows you where to look for deficiencies. On a magnesium deficiency, what you want to look for is symptoms that are at the bottom of the plant or on the older leaves because that plant is mobilizing magnesium and putting it up towards the top on the younger leaves.
Mike Howell (08:59):
Great lead into the next question, and I was going to ask you to talk about some of the deficiency symptoms. What do we look for when we’re looking at magnesium deficiency?
Dr. Karl Wyant (09:07):
The classic symptom is something called interveinal chlorosis. It sounds like a cool band name, I don’t know if anyone’s taken it yet. I’ll have to check later. But this interveinal chlorosis looks like Christmas trees of dark green on the veins of the leaves in sort of a field of a pale yellow or creamy yellow color, or maybe even saffron looking yellow. So it looks like someone drew a Christmas tree on the leaf, and that’s early to medium deficiency. If you let it go too long, you’ll start to get chlorosis of the full leaf and eventual necrotic spots and eventual death of the leaf. Your first telltale sign, look on the bottom of the plant, look for that interveinal chlorosis and that could tell you, hey, I’ve got an issue. If you’re looking to spot it earlier, then that’s where a plant tissue programming could help show you where your numbers are, where your concentrations are, and let you make a decision before the deficiency actually shows up physically.
Mike Howell (09:56):
Okay. Great information. Dr. Wyant, one last question I’ve got here. Growing up, I was around the cattle business predominantly all of my life, but still work with the cattle guys a lot and try to help them get their forages where they need to be, and from time to time we run into a problem in cattle and other livestock. I know sheep can get it as well, but grass tetany and I understand that has to do with low levels of magnesium. What can you tell us about this disease in livestock and how can we manage that?
Dr. Karl Wyant (10:24):
Grass tetany has a couple different names. Grass staggers, wheat pasture poisoning. If you’re looking to become a vet, you would know it as hypomagnesia. It’s low magnesium in the animal, and it’s because they’re not consuming forage, whether it’s pasture or provided to them, in a manner that has low magnesium in the plant tissues itself. This condition occurs generally in the spring when it’s cool out and grasses in particular are pushing growth really hard and they’re outpacing that plant’s ability to pull in magnesium and put it in those new tissues, so as a result, all that new growth is deficient in magnesium. Your livestock eats it, and they have low magnesium in their diets.
(11:03)
One thing to think about is just who’s mostly susceptible to this, and this is cows and ewes that are either in late gestation, they’re prone to this grass tetany or those that have are in heavy lactations. There’s some timeframes that you can work with in terms of which animals and which stage of their life that you can avoid some of this grass tetany and make some decisions. It’s all about magnesium availability, so if you’re just putting down nitrogen and you’re growing this lush, green grass and your soil test is coming up low magnesium, that could be a thing to think about of how might I improve this pasture management program, especially if that grass tetany keeps popping up.
Mike Howell (11:37):
Okay. Dr. Wyant, we’ve covered a lot of information today. I appreciate you talking with us about magnesium and the importance of it. Is there anything else you want to talk about about magnesium and anything else we need to make sure our listeners understand before we wrap this up?
Dr. Karl Wyant (11:50):
I just wanted to mention that we talked about the lime source of magnesium, that dolomite, that calcium magnesium carbonate. There’s also some other forms of the fertilizer. One of them is magnesium sulphate. If you’re ever in a pinch for some magnesium fertilizer, you can go right to the spa section of target and pick up some Epsom salts. They’re great for your bath, but they’re also magnesium sulphate. Put that in water and get that out on your plants, or you can even use it as a Foley or spray and correct that magnesium pretty quickly.
Mike Howell (12:16):
Yep. A lot of homeowners do that with tomatoes. Real common practice in tomatoes. Well, Dr. Wyant, we sure appreciate you being with us today and we’ll have you back before very much longer. I’m sure you’ve got a lot of interest in information you want to share with our listeners, and we’ll make sure we get you on the program pretty regular.
(12:33)
Listeners, thanks for joining in. I really hope you enjoyed this podcast. If you did, please pass a link on to your friends and neighbors so they can enjoy it as much as we have. I want to invite everybody back next week when we visit with Dr. Christie Preston, senior agronomist with Nutrien. We’ll be discussing current agronomic issues and different crops and talking about double crop soybeans. Until next time, this has been Mike Howell with The Dirt.
