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211: Vineyard Nutrient Management Across the United States

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When it comes to nutrition in your vineyard, you need to know the environment that your vineyard is planted in including mineral nutrition, soil microbes, nitrogen from rainwater, and nutrients or potentially salt from well water. Fritz Westover, Host of the Vineyard Underground Podcast and Founder of Virtual Viticulture Academy shares a big-picture approach to nutrient management that is practical for any grower. He covers:

  • Why it is important to test tissue both at bloom and veraison
  • How to take tissue samples
  • When macro and micronutrient additions are most essential

If you are a long time Member of our organization then you probably remember Fritz from his days with Vineyard Team in 2013 and 2014. We are thrilled to have Fritz back on air with us for the third time. Plus, I recently had the pleasure of being a guest on his podcast, Vineyard Underground. Search for episode 034: Why Sustainability Certification Programs for Vineyards Matter – with Beth Vukmanic on your favorite podcast player to listen in. And we have that linked in the show notes.

Resources: Vineyard Team Programs: Get More

Subscribe wherever you listen so you never miss an episode on the latest science and research with the Sustainable Winegrowing Podcast. Since 1994, Vineyard Team has been your resource for workshops and field demonstrations, research, and events dedicated to the stewardship of our natural resources.

Learn more at www.vineyardteam.org.

Transcript

Craig Macmillan 0:00

Our guest today is Fritz Westover. He is a Viticulturist, who works around the United States. Especically the the south east and he is the host of the Vineyard Underground podcast, and also the founder of the Virtual Viticulture Academy. And today we're gonna talk about nutrient management. Thanks for being on the show.

Fritz Westover 0:20

Hey, Craig, how you doing today? Good to talk to you and to see you because I get to see you on video while we make this recording.

Craig Macmillan 0:27

You're back. This is another episode for you. Right?

Fritz Westover 0:29

This will be episode number three with Sustainable Winegrowing. So I love coming back. And you know, as you know, I worked with then Vineayrd Team back in 2013, and 14. So, of course, I love what you guys are doing and fully support it.

Craig Macmillan 0:42

Fantastic. So injury management in vineyards is today's topic. Can you give us a definition of what that means and why it's important?

Fritz Westover 0:51

Yeah, and I'm not going to give you the textbook version though, as you know, Craig, I'm going to talk from just how I view it and how I see my growers viewing it that.

Craig Macmillan 0:58

From the heart is that yeah,

Fritz Westover 1:00

I speak about nutrient management from the heart here. In terms of vineyards, you know, we want to see our vines grow healthy. When you plant to vine in the ground, there's certain things in the soil, there's mineral nutrition, there's microbes that cycle nutrients in the soil. So you have kind of a baseline there, you can add things to it. But you have to know what's in the soil. First, we have rain that falls from the sky, hopefully, and hopefully when it needs to, and that has certain mineral nutrient content and nitrogen, things like that people don't count that sometimes nothing will make a plant or like and rainwater. And then if you're pumping water through well, there's different ions, caverns and ions that are in that water, whether it be something that's good, like nitrogen, or magnesium or potassium or something that's not good, like a salt, in large amounts. So there's there's things coming out of the pumping out of the ground on a property that go to vineyard. And then you know, there's things that we put as inputs through a spray program or fertilization program. But before you do that, if you're going to manage the nutrition in your vineyard, you need to know what the content is what where the nutrients are coming from, how the vines take them up. Are you irrigating? Or is it a dry farmed vineyard, and that will determine how much of that nutrition is available to the vine, right, because you can have nutrition in the soil. But during a drought, if the roots aren't actively growing, or if they're pulling away from the soil, they're just not taking it in. It's a very dynamic thing. Management is really just knowing how to read your plants, how to read the environmental conditions, and knowing what you have there and what your inputs are contributing in terms of mineral nutrition to your system as a whole.

Craig Macmillan 2:31

What are some of the considerations then, that growers need to take into account when they're designing the fertilization program? Have you talked about where things come from? You've talked about what you need to look at. But how do you go about it.

Fritz Westover 2:43

I work with several growers all around the southeastern United States and in other states as well through my online academy. So I really get to see a large profile of soil reports, plant tissue reports. And there's certain benchmark measurements we can take in the vineyard that can help us to understand how vines are taking up nutrients. So we can look at a soil test. And we can determine what nutrients are available, we can look at the pH and that will determine the different availability of certain nutrients. We can also take into account the plant tissue samples that we should be doing in the vineyard, whether it's a tissue analysis from a petal, a leaf blade, a whole leaf with petiole attached, which is what I'm using currently, there's more and more interest in SAP analysis. So there's all these different methods of looking at nutrition within an actively growing plant. It gives you the snapshot at best during a certain time of the season. And those are benchmarks. So we're looking at the plants to see kind of what's being taken up from the soil and from the environment and from the water that's being either falling from the sky or going through the irrigation. My best analogy for grape grower would be the VSP probably the most common training system is the VSP so you have the that's vertical sheet positioning, but I use it and say the visual, we look at the soil for moisture, we look at the plants for any signs of higher low vigor to determine usually, if nitrogen is needed in greater quantities, or for certainly for any nutritional deficiencies that show up visually on leaves like magnesium or potassium deficiency, things like that. We know what those symptoms look like, we can look them up easily. And then the P would be the plant tissue test. So I always think of the soil is kind of the bank account of what nutrients are available. And then the tissue test is telling you if your plant is making that ATM withdrawals, so to speak from the soil. And then the visual really just validates if everything is really working as well as that plant tissue test says because I don't know about you, Craig, but I've looked at plant tissue tests that say everything is within the normal range of nutrients, but the plant is stunted. And it could see that the concentration of the nutrients is good in that plant, but the quantity is limiting the growth and production of that vine and it's going to limit the yields in that case. Those are the considerations I look into but there's one one more thing that there are some rules of thumb, what we're taking out of the system. When we ship our grapes out of the vineyard into the winery, whether it's your winery or winery across the state somewhere across the country that is removing nutrients. So you're literally mining your soil and your environment for nutrients, you're putting them into a truck, you're moving them with the fruit, and then they're being made into bottles of wine and someone's drinking those nutrients and they don't get back into the vineyard, if that's what's happening. So, when creating a nutritional budget, a lot of growers will account for the tonnage or whatever measurement of fruit is removed. And there are some tables available. I know Dr. Marcus Keller of Washington State University, in his book on the science of grapevines publishes some of those, but the example would be an average of four pounds of nitrogen. For every tonne of fruit removed from the vineyard, if you do four tons an acre, that's about 16 pounds of nitrogen. So we start to think in these terms of, okay, I just removed 16 pounds with that four ton per acre crop. This is an example of course of an average number, it's really not that simple, because the soil might have three or 4% organic matter in it. And we know from every 1% of organic matter, we're getting x units of nitrogen that are developed and processed within the soil system itself. And so if your organic matter is high enough, you may actually generate enough nitrogen in the soil to replace the nitrogen that was moved out of the vineyard. And this is why growers might go year in and year out without applying some fertilizer, even though they're moving it out of the vineyard in the fruit.

You got a good healthy soil web happening there, you got the relationships that you want, and you're cycling stuff. And so the impact of that removal is less. Yeah, yeah, absolutely. And cover cropping and whatnot.

Soil conditions, too. I mean, if the soil is dry in a drought condition, it's not really you're not gonna have a lot of activity, or if it's really hot, because it's been cleaned, cultivated. And you know, how does that affect the microbes that can then cycle those nutrients and convert organic matter into nitrogen and other other mineral nutrients?

Craig Macmillan 7:05

I want to touch on something, something regarded this and that's timing. So like at the grade school science version that we learn is there's a plant, and it grows and things come up. And there's a plant. Yeah, and grapevines don't work that way. There's certain things that they'll take up at certain times of year, they need to have water, moving through the plant, different nutrients are important at different times of year. What do you recommend? What do you how do you manage that?

Fritz Westover 7:34

Yeah. So you know, when I do a presentation on grapevine nutrition, there's this one slide that I go to from a study in Germany, and where they basically took plants apart at different times of the phenological steps throughout the year, whether pre bloom bloom, fruit set, version, and harvest, and they looked at the total mineral content of these nutrients. And they use that to determine what the demand of those nutrients were at different stages. And so what we see is that nitrogen and potassium sort of follow the same curve, where as you get into bloom, there's a spike in demand for nitrogen and potassium. And then after fruit set, it goes down a little, and then the roller coaster ride goes back up, and the demand goes back up in your veraison as your ripening fruit, you need more nitrogen, potassium, things like that. It's all part of the sugar production system. And then you look at also the quantities you know, nitrogen and potassium, are by far the macronutrients that are needed the most, and then something like magnesium. And we do see a lot of magnesium deficiency, east of the Rockies at many sites, it's needed, but not until after fruit set, really, that's where the bumps starts. So the bumps gonna start afterwards. And it's going to kind of gradually go up and down and up again towards veraison But the amount is not as, let's say the quantity that's needed is not as great as something like potassium. And you could do that for each nutrient and look at it to me that that triggers the kind of the benchmark of when we have to start applying fertilizer. And so the interesting thing about that is if I've got a vineyard, where we can put everything through the drip, irrigation and fertigation, we can wait until either right before the time of highest demand, or right at the time, and we can just slug it through the drip, right. If you don't have irrigation, you might be able to do foliar application, but that's not going to get a lot of nutrients into the vine like it will if you put it into the root system. So you'll you'll hear and I know we're going to discuss this as well, because we discussed it earlier that you know, dry farmed vineyards or vineyards in areas where it rains and they don't have irrigation, have to plan a little bit farther ahead. Because if you're going to put something like magnesium out or potassium, it needs to be worked into the soil with a rain event if you don't have to ration or cultivated in in some cases. So you can't wait until that perfect window. You've got to get it out ahead of time so that it makes its way down to the roots and it's available for uptake at that critical window that I was referring to before in the phenol logical stages.

Craig Macmillan 9:56

Can I wait till I see a forecast that there's a storm coming and then get my material out? Or do I put it up earlier than then just kind of hope that it rains? I mean, how much time do I have?

Fritz Westover 10:08

Yeah, that's a really great question to Craig. And so you don't want to answer every question with it depends, right? So you've got to get some concrete information for a grower to actually follow. So then you start thinking about...

Craig Macmillan 10:19

There's nothing wrong with it depends.

Fritz Westover 10:21

It's okay, as long as you follow up with, but this is what I would do, right. And that's what I like to say. So this is what I would do if nitrogen was the nutrient in question, if you put out especially an ammonia, nitrogen, something like that on the ground or something that is not bound up, like if compost, you have a more stable form of nitrogen that's in organic matter, if you have something like ammonium, it might be readily evaporated, or it's going to it's going to volatilize, and you'll lose it to the atmosphere. So you definitely want to get that out as soon as you can, right before the rain. So the rain can immediately move that nutrient into the soil. And that will secure it, so to speak, and stop the volatilization from occurring. If it's something like magnesium, really not as volatile, right. Or if it's something like phosphorus, or if you're putting out calcium in the form of lime, or gypsum, there's not going to be a lot of volatility. So you can put those types of products out farther ahead of the rain, and hope that the rain will eventually come and work them in. So I guess in that matter, depends on what you're applying. And you can, you can decide based on that, if you want to trust that forecast or not.

Craig Macmillan 11:28

You know, I just started something, I interviewed somebody else recently, and they were working with underlying vegetation issues. It was fascinating to me because of the work that they were doing in there not necessarily chemical burn down, not necessarily inrow cultivation in the comment was it rains enough here that I can do whatever I want. But there's going to be plants growing there two days later, in your experience in parts of the country. And I would love to have some, you know, compare and contrast here. What do I need to do in terms of preparing that area, you know, around the root system, because I'm trying to get top to bottom right down to get in there. And then also, you mentioned system wide things. And so what do I need to do there to make that work?

Fritz Westover 12:12

Let's cover the system wide. First, when I talk about system wide or make creating these, quote unquote, sea changes in the soil, you're not going to make a sea change the soil is the soil. It's got its own living breathing organisms in it. But let's say you were chronically deficient in calcium, or magnesium, right? We'll use those as two good examples. If you apply your calcium, whether it's lime, or magnesium in the form of dolomitic, lime, which is calcium with 10%, magnesium, great way to put magnesium and calcium in the soil to acidifying your soil like you would with a magnesium sulfate. Or if you're putting out a magnesium sulfate in a high pH, soil, anything that you're trying to put out to change the plant uptake. So let's say really high potassium uptake in your plant is undesirable to you for some reason, and you're getting magnesium deficiency. As a result, if we only put that magnesium or that calcium right at the base of the vine, you can only really change the the cation exchange or the base saturation of those cations right in that small area. And that's important because it's a major area of uptake. And this is something a lot of growers don't think about, even when you're dripping something through a system that biggest area of uptake is near the crown of the vine at the base of the root system. And feeder roots will take up stuff too. But that's where if you're going to put a one time slug, you know, it's got to be within 18 inches or so the trunk, but you still have roots, especially on older vines that are moving out into the row middles. Over the years, they get into the row middles. And so they're still getting access to that perhaps high level of potassium in that bass saturation or that cation exchange out there. So they can still kind of pull that up. So if you want to create a wider change and impacts the system as a whole, you're better off applying that product as a broadcast into the middle and under the vines. I have done that with magnesium when we're trying to compete with potassium, because we see magnesium magnesium deficiency, or also if we're aligning soil. So in eastern states, we have acid soil, parts of Maryland, Virginia, Pennsylvania, where I've worked, even in East Texas or north of that in Arkansas, depending on where you're at. You run into these acid soils, and we're talking like 4.5 ph. Yeah, so it is or like wine, right? Yeah, yeah. So we know that nutrients are not as available many nutrients like phosphorus is deficient boron, other cations are not as available. Due to that high hydrogen ion competition. We're going to add lime. Hopefully before the vineyard is planted. You do that before but I often go back and add maintenance applications of lime over the years as well within the vineyard system, and we do that over the whole field. We don't just do that in the rows where we're planting vines, because we want the vines to be encouraged to explore the soil and to mine, if you will, for nutrients outside of that immediate crown zone near the vine. Because eventually that will be depleted, your vines are going to keep growing and searching for these nutrients. So by doing a broadcast application, you create a soil that not only is more amendable, for roots to grow in, because acid soils are actually toxic to root tips that you get a high amount of available aluminum at 4.5 ph. And that will stop a root tip from growing. So if you want your roots to grow and expand, you don't want any chemical barriers, you don't want any physical barriers like compaction, you put something like that out before planting. So in Georgia where I work, very acidic soils, we will put out something around six tons per acre of the dolomitic lime before we plant some of the sites and then within two years, we're coming back with as much as two times per acre, because we're trying to to over time, bring that soil into maybe a 6.0 or 6.5 pH so that nutrients are just more available, so that we don't have to fertilize as much we don't have to put inputs into the soil. Right? We don't want to do that we don't have to cost money, and it could have environmental impacts.

Craig Macmillan 16:12

While we're still on this, this area, you got pre planned, are you recommending that we shank materials in? Or are we incorporated in a disking pass? And then over time that moves down in? And then also, if I've got an established vineyard to incorporate these materials? Or to get these materials there? I mean, do I need to do a cultivation pass and then do a broadcast and then cultivate again to stir it in?

Fritz Westover 16:39

Yeah, so these are all different methods that are used Craig and any grower out there who's developing a vineyard site in the near future or has done it recently, you'll hear conflicting opinions on the best way to do it. But what I like to do is break it down to how did the nutrients move in the soil environment? And how do I put them by the root where they're needed, and make sure they're not going to get washed away right away? So yes, if I'm starting a new site, we're going to look at the soil, we're going to determine what our amendments are going to be, let's say that the vineyard soil is low in phosphorus and need some line that to change the pH but also to increase calcium. And let's say it's a little bit low on potassium as well. Okay. So in that instance, if you just stir the soil up and put the lime in and fix the pH, that would be wonderful, because you've already made nutrient availability, so much better for that for the uptake of that plant root system. So that's good. That's the first step. But if then you go in and plant the vines, and you say, well, we needed phosphorus and potassium. And I know that new plants need nitrogen, so I'm going to take like a triple 10, or a triple 13, that's nitrogen, phosphorus, and potassium at 10 to 13%. And I'm just gonna sprinkle three ounces around the vine. Well, how did those nutrients move down into the soil? Well, the first time it rains, or you irrigate, and it touches those granules, the first thing that moves down quickly through the soil, what we call the mass flow is the nitrogen. And so that's going to be immediately available. So the vines is gonna pick up nitrogen, it's gonna say, let's go, let's grow. The next level of infiltration would be the potassium, we know that potassium is somewhat moderately mobile in the mass flow, but it doesn't move as fast as the nitrogen. So with enough rainfall and frequent rainfall or irrigation, it could move down gradually and get to the root system, that phosphorus on the other hand, it's just going to sit there on the surface like a rock. And it might take years for it really to move effectively. And so if you know your, your soil needs something like phosphorus, and potassium, you might add the phosphorus, whatever form phosphorus, you're using rock phosphate, if you're organic, or PTO five or some, put that on the on the surface, and you amend it with the lime to get it down deep to where the roots are going to be planted to. So maybe it's 15 inches, for an example 30 centimeters, that's all they're ready for the roots. And then later, you can come in and topdress something like potassium, for your final cultivation, just to work it into the topsoil. So it's, it's at a better stage, and I'm giving you an ideal scenario, obviously. And then the nitrogen, you could go ahead and top dress later, or put your drip system or let the rain work it in right before the rain like we talked about with that nitrogen. And that way you're getting things right at the root where it's needed. And you're not doing it in phases where it gets nitrogen grows a lot and then doesn't have enough other stuff like potassium, magnesium or micronutrients to keep up with that growth. And that's where you see these deficiencies starting to set in.

Craig Macmillan 19:26

Actually, that's a great kind of transition. You know, we talked about VSP and I think we do a lot of folks relies primarily upon visual and it's not simply the, you know, the tiger stripes in the leaf and that kind of a thing or the yellowing, but they're looking at how the crop set they're looking at when the sheets tipped start to quit. Because yeah, that's driven by water, but it's driven by by other resources to that kind of thing. Yeah. What can I do to quantify that? And how can I be kind of forward looking? I mean, you talked about removal. is a materials with harvest? So I know I'm I want to order some stuff, you know, but it's a long term kind of project.

Fritz Westover 20:07

Yeah, it is. It is.

Craig Macmillan 20:08

I mean, you walk vineyards with people, obviously. But then also you mentioned you see all these reports of it? What kinds of reports? Do you want to see what time of year? How do you put all that together?

Fritz Westover 20:19

Right. The visual is really important. And the only risky run there is some of these nutrients don't show visually until it's too late. A lot of our micronutrients are really important, as you know, Craig, for fruit set, and pollination, and fertilization rather, boron, zinc, molendinum, copper, all these things. So if you do your plant tissue test at bloom, which is the first time you would do it during the season, it you're already in bloom. So you're late to add that micronutrient, right. So then some growers will say, Well, I'm just going to put up this prophylactic kind of micronutrients, spray two or three weeks before bloom just to make sure they have what they need. And you can do that. But do you really need to. So I really rely on taking the bloom sample, because it is kind of like your progress report. It tells you, you know, how you're doing for the season. And you know, are you destined for an A plus a B minus by the time you get to the end of the season, because you still have a chance to get things in gear and improve your grade, right. So that bloom time sample of what I do is whole leaf sample with blade and petiole attached, some people just do petioles, separate the petiole and the blade, I've had very good success and consistent results with blade and petiole attached. I also, when I have an issue where there's, you know, maybe we're doing intensive fertilization, or I've got a deficiency, I might sometimes separate the petiole from the whole leaf. And that way, I can look at both reports and have two numbers to kind of look at instead of one. But the ranges are different for a blade versus petioles. So you definitely want to look at those. And I tell my growers to just go to my website, and you can download the, the standards there and look at them, because you don't need a consultant to just see what's out of balance, you can look at a table, I do that at bloom, and that gives me the report card. But the second time I do it is that version. And that's your report card for the season, so to speak. So by the time you get to version, you're at entering your maximum stress time, if you take the plant tissue sample too far after version, a lot of the nutrients have moved into the fruit. And the tissue sometimes is already suffering from the seasonal wear and tear. So it can give you these false ideas that you're really low and then you put out too much fertilizer. At bloom, we take a leaf next to a inflorescence or flower, because that is a representative leaf. And then at version, we go about seven leaves down from a shoot tip that has not been hedged or altered. And that is what's considered a representative leaf at that stage of growth. And that's the report card. Now the report card is really important. And I tell my growers if you can only afford or have time to do one sample, do the one version and get the final report card because that's the one that we then use for the next season to say okay, boron was a little low zinc was a little low. So we're going to find some boron and zinc to put into the system either through the drip or through a foliar spray before bloom, to make sure that we don't have issues with fruit set. So that's how we use that if we wait for bloom, it's a little late to make the change. So getting those two phases is really key for me. And then of course, like you said, being in the vineyard observing growth, looking for signs of deficiency, some things do show, you can clearly see nitrogen as pale leaves. Boron is actually important for nitrogen assimilation. So you could have what you think is adequate boron or nitrogen in your program. But if boron is missing, you might not get the assimilation and the you know, the proper use of the boron, or the nitrogen rather within the vines. So there's, you know, things to look for, to give you clues as well. So when I see something visual, sometimes magnesium deficiency can look a lot like potassium deficiency, it's on the order of interveinal, the potassium tends to be more beginning around the margin or outside edge of the leaf. So I always tell my growers, let's send in a sample, it's like 20 bucks, right? Let's just verify it with a lab report before we put the wrong thing down and make the problem way worse, right.

Craig Macmillan 24:10

When we're doing this, what are some of the most difficult decisions, some of the biggest obstacles to being successful here? And I'm talking about everything in terms of like you're getting good information, getting picking the right to formulations or the right products, the right individual minerals, and then getting into the plan. Are there regional differences that you've seen? Or are there kind of obstacles that everybody kind of faces?

Fritz Westover 24:37

There's definitely regional issues. You know, I can say that across the board. And this state over here, like I'll say, Georgia, we see magnesium and boron and nitrogen are our three biggest deficiencies consistently in those soils. You go to California, and certain areas where I work there we'd see it's either nitrogen or potassium that are low and sometimes zinc. And then if I go to the high planes in Texas, it's usually nitrogen and zinc, are my lowest. And sometimes, and then I go to the hill country of Texas, where it's cacareous soil. And we see that iron deficiency becomes an issue because it's just that high pH really ties it up, growers will sometimes put a lot of zinc down in the soil, but then we have to be mindful of the competition of certain nutrients with each other, because too much zinc can compete with phosphorus for uptake and vice versa. And then, as I mentioned already before, the pH of the soil varies greatly from one region to the next. And that's why getting the amendments and getting the soil in a pH that's, you know, ideally at that 6.5, for greens, right? That's kind of like, you know, you're good. From seven,

Craig Macmillan 25:40

Have you ever receive a site that was like, exactly 6.5.

Fritz Westover 25:45

I have I have because I've looked at it for their soil reports, I've seen a few but no, usually we're saying we need to add a little or, you know, seven is fine, we can deal with it, we'll put a different rootstock that's better under you know, calcareous soil. You know, I didn't mention that and really emphasize that enough, I talked about plant tissue sampling, and visual evaluation, I don't do soil sampling annually with most of my vineyards, because their soils just aren't changing that much, unless they're really doing heavy amendments of something that that sea change, they're trying to go for it. So we'll do this about once every three years, and just compare them. And so I think the most important thing any grower can do, and this is how I work with it with kind of my long term growers I've been with for 10 years, you know, we have a soil sample every three years. So we can compare what the trend is, over those years, if we see potassium is going down. Well, we know that's one of the greatest Nutrients taken out of the system of the soil with fruit that's much higher than nitrogen much, much, much higher than magnesium or phosphorus. So you're literally mining your soil for potassium, well, I have sites where we have high potassium, and we're trying to get more magnesium in there. So I almost never put potassium back in the soil, I'm happily mining it out of the soil. And that's going to be totally different than maybe a vineyard in California where potassium availability is just not as good or as high. We're kind of looking at it that way. And same thing with plant tissue test, you can really see sometimes more volatile fluctuation in plant tissue tests from year to year. And that's where you have to start asking the question, okay, how much rainfall did we have? Was there good soil moisture, I've run into problems where irrigated vineyards, we hit a drought, and you have normally rained during the season, like let's say, in West Texas, or parts of Arizona, where I work, there's rainfall during the monsoon season. So you go into the winter with a soil profile that's nice and full. And then in the spring, you come out and you really have full access to the whole mineral nutrient profile of the soil and the roots grow throughout the whole soil, then all of a sudden, you have a drought for year two. And this has happened in my West Texas growers, areas where those roots that are in the row, middle, all of a sudden are not able to pull up anything from the soil. So they're shrinking. And as they shrink, they pull away from the soil as a strategy to minimize water loss. And so you're not getting the nutrients that are available out there. So we have to consider that and sometimes increase our fertilizer levels based on the fact that we're losing access to the soil nutrients. And the best way to do that is to take the plant tissue test, and find out if that's really happening, but the plant tissue test can fluctuate. And I guess my point is understanding how the environmental conditions right in and around are leading up to that plant tissue test. really affected nutrient content is important. So we don't have that. Like I'll say it again, that knee jerk reaction like oh my gosh, nitrogen is low, let's put 50 pounds per acre out which is you know, ridiculously high. Yeah, maybe just needs to rain or you need to irrigate more, and that will fix the problem.

Craig Macmillan 28:41

Yeah, what is one thing, the one thing that you would tell growers on this topic, one piece of advice or insight or anything.

Fritz Westover 28:50

In addition to doing your soil sampling every few years, and your plant tissue tissue every year at bloom at veraison and some growers may even do it more often or some growers may prefer to do SAP analysis on a more frequent basis. That's all good and well. Just do it at your regular intervals, and get your long term data so you can see trends and changes. Then take some time to really understand number one, as we mentioned before, with the demand of the plant for each nutrient, okay, when is nitrogen, potassium versus magnesium or other micronutrients? When are they most essential for uptake into the vine? And how could you put them into the ground or into the system or onto the foliage in a method that is going to get that nutrient to the vine in time for its high demand, you need to know that vine needs it, because if it doesn't need it, you don't need to put it in there. And then finally understand how the nutrients move within the soil. That was the other thing we covered. So I had a great podcast on the vineyard underground with Paul Crout who works in the Central Coast a good friend of mine, he's worked with video team to Episode 16 We did a deep dive into Vine nutrition and availability in different forms of nitrogen and how some are immediately available and some are more slow release available. So I won't get into all that now. But understanding the availability of that fertilizer formulation that you're using is really critical. Because that's going to tell you not not only when you're going to apply it, how far ahead of the demand for the vine, but what method you're going to use to apply it. Will it be better off put into drip, apply to the soil? Or maybe as a foliar application.

Craig Macmillan 30:25

Where can people find out more about you?

Fritz Westover 30:27

Ok me? Oh, thanks, Craig.

Craig Macmillan 30:29

Oh, little Oh, me. Oh, me.

Fritz Westover 30:31

Well, you can find me chatting like I am with you on the Vineyard Underground podcast, the vineyardundergroundpodcast.com Or just look for that, wherever you stream podcast on Spotify or for Apple podcast, or if you would like to download some of the past presentations I've done on nutrition management, or the charts to determine the critical levels for nutrients have many of those that are free and available to the public go to virtualviticultureacademy.com The academy is where I teach grape growing and have a membership in there where I advise growers on a week to week basis.

Craig Macmillan 31:05

That's awesome. Our guest today has been Fritz Westover. He is a viticulturist. He's the host of the vineyard underground podcast. He's also the founder of a really great resource. You definitely need to know about this. If you're a grower, and that's the Virtual Viticulture Academy. He's not kidding, a lot of resources there and really good quality resources as well. So thanks for being on the podcast.

Fritz Westover 31:27

Hey, thanks, Craig. You guys are an amazing resource to the industry to and you have tons of free and available information. Keep doing the great things that you're doing. I'm a listener, so I'm a fan. It's really privileged to be on here my friend.

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When it comes to nutrition in your vineyard, you need to know the environment that your vineyard is planted in including mineral nutrition, soil microbes, nitrogen from rainwater, and nutrients or potentially salt from well water. Fritz Westover, Host of the Vineyard Underground Podcast and Founder of Virtual Viticulture Academy shares a big-picture approach to nutrient management that is practical for any grower. He covers:

  • Why it is important to test tissue both at bloom and veraison
  • How to take tissue samples
  • When macro and micronutrient additions are most essential

If you are a long time Member of our organization then you probably remember Fritz from his days with Vineyard Team in 2013 and 2014. We are thrilled to have Fritz back on air with us for the third time. Plus, I recently had the pleasure of being a guest on his podcast, Vineyard Underground. Search for episode 034: Why Sustainability Certification Programs for Vineyards Matter – with Beth Vukmanic on your favorite podcast player to listen in. And we have that linked in the show notes.

Resources: Vineyard Team Programs: Get More

Subscribe wherever you listen so you never miss an episode on the latest science and research with the Sustainable Winegrowing Podcast. Since 1994, Vineyard Team has been your resource for workshops and field demonstrations, research, and events dedicated to the stewardship of our natural resources.

Learn more at www.vineyardteam.org.

Transcript

Craig Macmillan 0:00

Our guest today is Fritz Westover. He is a Viticulturist, who works around the United States. Especically the the south east and he is the host of the Vineyard Underground podcast, and also the founder of the Virtual Viticulture Academy. And today we're gonna talk about nutrient management. Thanks for being on the show.

Fritz Westover 0:20

Hey, Craig, how you doing today? Good to talk to you and to see you because I get to see you on video while we make this recording.

Craig Macmillan 0:27

You're back. This is another episode for you. Right?

Fritz Westover 0:29

This will be episode number three with Sustainable Winegrowing. So I love coming back. And you know, as you know, I worked with then Vineayrd Team back in 2013, and 14. So, of course, I love what you guys are doing and fully support it.

Craig Macmillan 0:42

Fantastic. So injury management in vineyards is today's topic. Can you give us a definition of what that means and why it's important?

Fritz Westover 0:51

Yeah, and I'm not going to give you the textbook version though, as you know, Craig, I'm going to talk from just how I view it and how I see my growers viewing it that.

Craig Macmillan 0:58

From the heart is that yeah,

Fritz Westover 1:00

I speak about nutrient management from the heart here. In terms of vineyards, you know, we want to see our vines grow healthy. When you plant to vine in the ground, there's certain things in the soil, there's mineral nutrition, there's microbes that cycle nutrients in the soil. So you have kind of a baseline there, you can add things to it. But you have to know what's in the soil. First, we have rain that falls from the sky, hopefully, and hopefully when it needs to, and that has certain mineral nutrient content and nitrogen, things like that people don't count that sometimes nothing will make a plant or like and rainwater. And then if you're pumping water through well, there's different ions, caverns and ions that are in that water, whether it be something that's good, like nitrogen, or magnesium or potassium or something that's not good, like a salt, in large amounts. So there's there's things coming out of the pumping out of the ground on a property that go to vineyard. And then you know, there's things that we put as inputs through a spray program or fertilization program. But before you do that, if you're going to manage the nutrition in your vineyard, you need to know what the content is what where the nutrients are coming from, how the vines take them up. Are you irrigating? Or is it a dry farmed vineyard, and that will determine how much of that nutrition is available to the vine, right, because you can have nutrition in the soil. But during a drought, if the roots aren't actively growing, or if they're pulling away from the soil, they're just not taking it in. It's a very dynamic thing. Management is really just knowing how to read your plants, how to read the environmental conditions, and knowing what you have there and what your inputs are contributing in terms of mineral nutrition to your system as a whole.

Craig Macmillan 2:31

What are some of the considerations then, that growers need to take into account when they're designing the fertilization program? Have you talked about where things come from? You've talked about what you need to look at. But how do you go about it.

Fritz Westover 2:43

I work with several growers all around the southeastern United States and in other states as well through my online academy. So I really get to see a large profile of soil reports, plant tissue reports. And there's certain benchmark measurements we can take in the vineyard that can help us to understand how vines are taking up nutrients. So we can look at a soil test. And we can determine what nutrients are available, we can look at the pH and that will determine the different availability of certain nutrients. We can also take into account the plant tissue samples that we should be doing in the vineyard, whether it's a tissue analysis from a petal, a leaf blade, a whole leaf with petiole attached, which is what I'm using currently, there's more and more interest in SAP analysis. So there's all these different methods of looking at nutrition within an actively growing plant. It gives you the snapshot at best during a certain time of the season. And those are benchmarks. So we're looking at the plants to see kind of what's being taken up from the soil and from the environment and from the water that's being either falling from the sky or going through the irrigation. My best analogy for grape grower would be the VSP probably the most common training system is the VSP so you have the that's vertical sheet positioning, but I use it and say the visual, we look at the soil for moisture, we look at the plants for any signs of higher low vigor to determine usually, if nitrogen is needed in greater quantities, or for certainly for any nutritional deficiencies that show up visually on leaves like magnesium or potassium deficiency, things like that. We know what those symptoms look like, we can look them up easily. And then the P would be the plant tissue test. So I always think of the soil is kind of the bank account of what nutrients are available. And then the tissue test is telling you if your plant is making that ATM withdrawals, so to speak from the soil. And then the visual really just validates if everything is really working as well as that plant tissue test says because I don't know about you, Craig, but I've looked at plant tissue tests that say everything is within the normal range of nutrients, but the plant is stunted. And it could see that the concentration of the nutrients is good in that plant, but the quantity is limiting the growth and production of that vine and it's going to limit the yields in that case. Those are the considerations I look into but there's one one more thing that there are some rules of thumb, what we're taking out of the system. When we ship our grapes out of the vineyard into the winery, whether it's your winery or winery across the state somewhere across the country that is removing nutrients. So you're literally mining your soil and your environment for nutrients, you're putting them into a truck, you're moving them with the fruit, and then they're being made into bottles of wine and someone's drinking those nutrients and they don't get back into the vineyard, if that's what's happening. So, when creating a nutritional budget, a lot of growers will account for the tonnage or whatever measurement of fruit is removed. And there are some tables available. I know Dr. Marcus Keller of Washington State University, in his book on the science of grapevines publishes some of those, but the example would be an average of four pounds of nitrogen. For every tonne of fruit removed from the vineyard, if you do four tons an acre, that's about 16 pounds of nitrogen. So we start to think in these terms of, okay, I just removed 16 pounds with that four ton per acre crop. This is an example of course of an average number, it's really not that simple, because the soil might have three or 4% organic matter in it. And we know from every 1% of organic matter, we're getting x units of nitrogen that are developed and processed within the soil system itself. And so if your organic matter is high enough, you may actually generate enough nitrogen in the soil to replace the nitrogen that was moved out of the vineyard. And this is why growers might go year in and year out without applying some fertilizer, even though they're moving it out of the vineyard in the fruit.

You got a good healthy soil web happening there, you got the relationships that you want, and you're cycling stuff. And so the impact of that removal is less. Yeah, yeah, absolutely. And cover cropping and whatnot.

Soil conditions, too. I mean, if the soil is dry in a drought condition, it's not really you're not gonna have a lot of activity, or if it's really hot, because it's been cleaned, cultivated. And you know, how does that affect the microbes that can then cycle those nutrients and convert organic matter into nitrogen and other other mineral nutrients?

Craig Macmillan 7:05

I want to touch on something, something regarded this and that's timing. So like at the grade school science version that we learn is there's a plant, and it grows and things come up. And there's a plant. Yeah, and grapevines don't work that way. There's certain things that they'll take up at certain times of year, they need to have water, moving through the plant, different nutrients are important at different times of year. What do you recommend? What do you how do you manage that?

Fritz Westover 7:34

Yeah. So you know, when I do a presentation on grapevine nutrition, there's this one slide that I go to from a study in Germany, and where they basically took plants apart at different times of the phenological steps throughout the year, whether pre bloom bloom, fruit set, version, and harvest, and they looked at the total mineral content of these nutrients. And they use that to determine what the demand of those nutrients were at different stages. And so what we see is that nitrogen and potassium sort of follow the same curve, where as you get into bloom, there's a spike in demand for nitrogen and potassium. And then after fruit set, it goes down a little, and then the roller coaster ride goes back up, and the demand goes back up in your veraison as your ripening fruit, you need more nitrogen, potassium, things like that. It's all part of the sugar production system. And then you look at also the quantities you know, nitrogen and potassium, are by far the macronutrients that are needed the most, and then something like magnesium. And we do see a lot of magnesium deficiency, east of the Rockies at many sites, it's needed, but not until after fruit set, really, that's where the bumps starts. So the bumps gonna start afterwards. And it's going to kind of gradually go up and down and up again towards veraison But the amount is not as, let's say the quantity that's needed is not as great as something like potassium. And you could do that for each nutrient and look at it to me that that triggers the kind of the benchmark of when we have to start applying fertilizer. And so the interesting thing about that is if I've got a vineyard, where we can put everything through the drip, irrigation and fertigation, we can wait until either right before the time of highest demand, or right at the time, and we can just slug it through the drip, right. If you don't have irrigation, you might be able to do foliar application, but that's not going to get a lot of nutrients into the vine like it will if you put it into the root system. So you'll you'll hear and I know we're going to discuss this as well, because we discussed it earlier that you know, dry farmed vineyards or vineyards in areas where it rains and they don't have irrigation, have to plan a little bit farther ahead. Because if you're going to put something like magnesium out or potassium, it needs to be worked into the soil with a rain event if you don't have to ration or cultivated in in some cases. So you can't wait until that perfect window. You've got to get it out ahead of time so that it makes its way down to the roots and it's available for uptake at that critical window that I was referring to before in the phenol logical stages.

Craig Macmillan 9:56

Can I wait till I see a forecast that there's a storm coming and then get my material out? Or do I put it up earlier than then just kind of hope that it rains? I mean, how much time do I have?

Fritz Westover 10:08

Yeah, that's a really great question to Craig. And so you don't want to answer every question with it depends, right? So you've got to get some concrete information for a grower to actually follow. So then you start thinking about...

Craig Macmillan 10:19

There's nothing wrong with it depends.

Fritz Westover 10:21

It's okay, as long as you follow up with, but this is what I would do, right. And that's what I like to say. So this is what I would do if nitrogen was the nutrient in question, if you put out especially an ammonia, nitrogen, something like that on the ground or something that is not bound up, like if compost, you have a more stable form of nitrogen that's in organic matter, if you have something like ammonium, it might be readily evaporated, or it's going to it's going to volatilize, and you'll lose it to the atmosphere. So you definitely want to get that out as soon as you can, right before the rain. So the rain can immediately move that nutrient into the soil. And that will secure it, so to speak, and stop the volatilization from occurring. If it's something like magnesium, really not as volatile, right. Or if it's something like phosphorus, or if you're putting out calcium in the form of lime, or gypsum, there's not going to be a lot of volatility. So you can put those types of products out farther ahead of the rain, and hope that the rain will eventually come and work them in. So I guess in that matter, depends on what you're applying. And you can, you can decide based on that, if you want to trust that forecast or not.

Craig Macmillan 11:28

You know, I just started something, I interviewed somebody else recently, and they were working with underlying vegetation issues. It was fascinating to me because of the work that they were doing in there not necessarily chemical burn down, not necessarily inrow cultivation in the comment was it rains enough here that I can do whatever I want. But there's going to be plants growing there two days later, in your experience in parts of the country. And I would love to have some, you know, compare and contrast here. What do I need to do in terms of preparing that area, you know, around the root system, because I'm trying to get top to bottom right down to get in there. And then also, you mentioned system wide things. And so what do I need to do there to make that work?

Fritz Westover 12:12

Let's cover the system wide. First, when I talk about system wide or make creating these, quote unquote, sea changes in the soil, you're not going to make a sea change the soil is the soil. It's got its own living breathing organisms in it. But let's say you were chronically deficient in calcium, or magnesium, right? We'll use those as two good examples. If you apply your calcium, whether it's lime, or magnesium in the form of dolomitic, lime, which is calcium with 10%, magnesium, great way to put magnesium and calcium in the soil to acidifying your soil like you would with a magnesium sulfate. Or if you're putting out a magnesium sulfate in a high pH, soil, anything that you're trying to put out to change the plant uptake. So let's say really high potassium uptake in your plant is undesirable to you for some reason, and you're getting magnesium deficiency. As a result, if we only put that magnesium or that calcium right at the base of the vine, you can only really change the the cation exchange or the base saturation of those cations right in that small area. And that's important because it's a major area of uptake. And this is something a lot of growers don't think about, even when you're dripping something through a system that biggest area of uptake is near the crown of the vine at the base of the root system. And feeder roots will take up stuff too. But that's where if you're going to put a one time slug, you know, it's got to be within 18 inches or so the trunk, but you still have roots, especially on older vines that are moving out into the row middles. Over the years, they get into the row middles. And so they're still getting access to that perhaps high level of potassium in that bass saturation or that cation exchange out there. So they can still kind of pull that up. So if you want to create a wider change and impacts the system as a whole, you're better off applying that product as a broadcast into the middle and under the vines. I have done that with magnesium when we're trying to compete with potassium, because we see magnesium magnesium deficiency, or also if we're aligning soil. So in eastern states, we have acid soil, parts of Maryland, Virginia, Pennsylvania, where I've worked, even in East Texas or north of that in Arkansas, depending on where you're at. You run into these acid soils, and we're talking like 4.5 ph. Yeah, so it is or like wine, right? Yeah, yeah. So we know that nutrients are not as available many nutrients like phosphorus is deficient boron, other cations are not as available. Due to that high hydrogen ion competition. We're going to add lime. Hopefully before the vineyard is planted. You do that before but I often go back and add maintenance applications of lime over the years as well within the vineyard system, and we do that over the whole field. We don't just do that in the rows where we're planting vines, because we want the vines to be encouraged to explore the soil and to mine, if you will, for nutrients outside of that immediate crown zone near the vine. Because eventually that will be depleted, your vines are going to keep growing and searching for these nutrients. So by doing a broadcast application, you create a soil that not only is more amendable, for roots to grow in, because acid soils are actually toxic to root tips that you get a high amount of available aluminum at 4.5 ph. And that will stop a root tip from growing. So if you want your roots to grow and expand, you don't want any chemical barriers, you don't want any physical barriers like compaction, you put something like that out before planting. So in Georgia where I work, very acidic soils, we will put out something around six tons per acre of the dolomitic lime before we plant some of the sites and then within two years, we're coming back with as much as two times per acre, because we're trying to to over time, bring that soil into maybe a 6.0 or 6.5 pH so that nutrients are just more available, so that we don't have to fertilize as much we don't have to put inputs into the soil. Right? We don't want to do that we don't have to cost money, and it could have environmental impacts.

Craig Macmillan 16:12

While we're still on this, this area, you got pre planned, are you recommending that we shank materials in? Or are we incorporated in a disking pass? And then over time that moves down in? And then also, if I've got an established vineyard to incorporate these materials? Or to get these materials there? I mean, do I need to do a cultivation pass and then do a broadcast and then cultivate again to stir it in?

Fritz Westover 16:39

Yeah, so these are all different methods that are used Craig and any grower out there who's developing a vineyard site in the near future or has done it recently, you'll hear conflicting opinions on the best way to do it. But what I like to do is break it down to how did the nutrients move in the soil environment? And how do I put them by the root where they're needed, and make sure they're not going to get washed away right away? So yes, if I'm starting a new site, we're going to look at the soil, we're going to determine what our amendments are going to be, let's say that the vineyard soil is low in phosphorus and need some line that to change the pH but also to increase calcium. And let's say it's a little bit low on potassium as well. Okay. So in that instance, if you just stir the soil up and put the lime in and fix the pH, that would be wonderful, because you've already made nutrient availability, so much better for that for the uptake of that plant root system. So that's good. That's the first step. But if then you go in and plant the vines, and you say, well, we needed phosphorus and potassium. And I know that new plants need nitrogen, so I'm going to take like a triple 10, or a triple 13, that's nitrogen, phosphorus, and potassium at 10 to 13%. And I'm just gonna sprinkle three ounces around the vine. Well, how did those nutrients move down into the soil? Well, the first time it rains, or you irrigate, and it touches those granules, the first thing that moves down quickly through the soil, what we call the mass flow is the nitrogen. And so that's going to be immediately available. So the vines is gonna pick up nitrogen, it's gonna say, let's go, let's grow. The next level of infiltration would be the potassium, we know that potassium is somewhat moderately mobile in the mass flow, but it doesn't move as fast as the nitrogen. So with enough rainfall and frequent rainfall or irrigation, it could move down gradually and get to the root system, that phosphorus on the other hand, it's just going to sit there on the surface like a rock. And it might take years for it really to move effectively. And so if you know your, your soil needs something like phosphorus, and potassium, you might add the phosphorus, whatever form phosphorus, you're using rock phosphate, if you're organic, or PTO five or some, put that on the on the surface, and you amend it with the lime to get it down deep to where the roots are going to be planted to. So maybe it's 15 inches, for an example 30 centimeters, that's all they're ready for the roots. And then later, you can come in and topdress something like potassium, for your final cultivation, just to work it into the topsoil. So it's, it's at a better stage, and I'm giving you an ideal scenario, obviously. And then the nitrogen, you could go ahead and top dress later, or put your drip system or let the rain work it in right before the rain like we talked about with that nitrogen. And that way you're getting things right at the root where it's needed. And you're not doing it in phases where it gets nitrogen grows a lot and then doesn't have enough other stuff like potassium, magnesium or micronutrients to keep up with that growth. And that's where you see these deficiencies starting to set in.

Craig Macmillan 19:26

Actually, that's a great kind of transition. You know, we talked about VSP and I think we do a lot of folks relies primarily upon visual and it's not simply the, you know, the tiger stripes in the leaf and that kind of a thing or the yellowing, but they're looking at how the crop set they're looking at when the sheets tipped start to quit. Because yeah, that's driven by water, but it's driven by by other resources to that kind of thing. Yeah. What can I do to quantify that? And how can I be kind of forward looking? I mean, you talked about removal. is a materials with harvest? So I know I'm I want to order some stuff, you know, but it's a long term kind of project.

Fritz Westover 20:07

Yeah, it is. It is.

Craig Macmillan 20:08

I mean, you walk vineyards with people, obviously. But then also you mentioned you see all these reports of it? What kinds of reports? Do you want to see what time of year? How do you put all that together?

Fritz Westover 20:19

Right. The visual is really important. And the only risky run there is some of these nutrients don't show visually until it's too late. A lot of our micronutrients are really important, as you know, Craig, for fruit set, and pollination, and fertilization rather, boron, zinc, molendinum, copper, all these things. So if you do your plant tissue test at bloom, which is the first time you would do it during the season, it you're already in bloom. So you're late to add that micronutrient, right. So then some growers will say, Well, I'm just going to put up this prophylactic kind of micronutrients, spray two or three weeks before bloom just to make sure they have what they need. And you can do that. But do you really need to. So I really rely on taking the bloom sample, because it is kind of like your progress report. It tells you, you know, how you're doing for the season. And you know, are you destined for an A plus a B minus by the time you get to the end of the season, because you still have a chance to get things in gear and improve your grade, right. So that bloom time sample of what I do is whole leaf sample with blade and petiole attached, some people just do petioles, separate the petiole and the blade, I've had very good success and consistent results with blade and petiole attached. I also, when I have an issue where there's, you know, maybe we're doing intensive fertilization, or I've got a deficiency, I might sometimes separate the petiole from the whole leaf. And that way, I can look at both reports and have two numbers to kind of look at instead of one. But the ranges are different for a blade versus petioles. So you definitely want to look at those. And I tell my growers to just go to my website, and you can download the, the standards there and look at them, because you don't need a consultant to just see what's out of balance, you can look at a table, I do that at bloom, and that gives me the report card. But the second time I do it is that version. And that's your report card for the season, so to speak. So by the time you get to version, you're at entering your maximum stress time, if you take the plant tissue sample too far after version, a lot of the nutrients have moved into the fruit. And the tissue sometimes is already suffering from the seasonal wear and tear. So it can give you these false ideas that you're really low and then you put out too much fertilizer. At bloom, we take a leaf next to a inflorescence or flower, because that is a representative leaf. And then at version, we go about seven leaves down from a shoot tip that has not been hedged or altered. And that is what's considered a representative leaf at that stage of growth. And that's the report card. Now the report card is really important. And I tell my growers if you can only afford or have time to do one sample, do the one version and get the final report card because that's the one that we then use for the next season to say okay, boron was a little low zinc was a little low. So we're going to find some boron and zinc to put into the system either through the drip or through a foliar spray before bloom, to make sure that we don't have issues with fruit set. So that's how we use that if we wait for bloom, it's a little late to make the change. So getting those two phases is really key for me. And then of course, like you said, being in the vineyard observing growth, looking for signs of deficiency, some things do show, you can clearly see nitrogen as pale leaves. Boron is actually important for nitrogen assimilation. So you could have what you think is adequate boron or nitrogen in your program. But if boron is missing, you might not get the assimilation and the you know, the proper use of the boron, or the nitrogen rather within the vines. So there's, you know, things to look for, to give you clues as well. So when I see something visual, sometimes magnesium deficiency can look a lot like potassium deficiency, it's on the order of interveinal, the potassium tends to be more beginning around the margin or outside edge of the leaf. So I always tell my growers, let's send in a sample, it's like 20 bucks, right? Let's just verify it with a lab report before we put the wrong thing down and make the problem way worse, right.

Craig Macmillan 24:10

When we're doing this, what are some of the most difficult decisions, some of the biggest obstacles to being successful here? And I'm talking about everything in terms of like you're getting good information, getting picking the right to formulations or the right products, the right individual minerals, and then getting into the plan. Are there regional differences that you've seen? Or are there kind of obstacles that everybody kind of faces?

Fritz Westover 24:37

There's definitely regional issues. You know, I can say that across the board. And this state over here, like I'll say, Georgia, we see magnesium and boron and nitrogen are our three biggest deficiencies consistently in those soils. You go to California, and certain areas where I work there we'd see it's either nitrogen or potassium that are low and sometimes zinc. And then if I go to the high planes in Texas, it's usually nitrogen and zinc, are my lowest. And sometimes, and then I go to the hill country of Texas, where it's cacareous soil. And we see that iron deficiency becomes an issue because it's just that high pH really ties it up, growers will sometimes put a lot of zinc down in the soil, but then we have to be mindful of the competition of certain nutrients with each other, because too much zinc can compete with phosphorus for uptake and vice versa. And then, as I mentioned already before, the pH of the soil varies greatly from one region to the next. And that's why getting the amendments and getting the soil in a pH that's, you know, ideally at that 6.5, for greens, right? That's kind of like, you know, you're good. From seven,

Craig Macmillan 25:40

Have you ever receive a site that was like, exactly 6.5.

Fritz Westover 25:45

I have I have because I've looked at it for their soil reports, I've seen a few but no, usually we're saying we need to add a little or, you know, seven is fine, we can deal with it, we'll put a different rootstock that's better under you know, calcareous soil. You know, I didn't mention that and really emphasize that enough, I talked about plant tissue sampling, and visual evaluation, I don't do soil sampling annually with most of my vineyards, because their soils just aren't changing that much, unless they're really doing heavy amendments of something that that sea change, they're trying to go for it. So we'll do this about once every three years, and just compare them. And so I think the most important thing any grower can do, and this is how I work with it with kind of my long term growers I've been with for 10 years, you know, we have a soil sample every three years. So we can compare what the trend is, over those years, if we see potassium is going down. Well, we know that's one of the greatest Nutrients taken out of the system of the soil with fruit that's much higher than nitrogen much, much, much higher than magnesium or phosphorus. So you're literally mining your soil for potassium, well, I have sites where we have high potassium, and we're trying to get more magnesium in there. So I almost never put potassium back in the soil, I'm happily mining it out of the soil. And that's going to be totally different than maybe a vineyard in California where potassium availability is just not as good or as high. We're kind of looking at it that way. And same thing with plant tissue test, you can really see sometimes more volatile fluctuation in plant tissue tests from year to year. And that's where you have to start asking the question, okay, how much rainfall did we have? Was there good soil moisture, I've run into problems where irrigated vineyards, we hit a drought, and you have normally rained during the season, like let's say, in West Texas, or parts of Arizona, where I work, there's rainfall during the monsoon season. So you go into the winter with a soil profile that's nice and full. And then in the spring, you come out and you really have full access to the whole mineral nutrient profile of the soil and the roots grow throughout the whole soil, then all of a sudden, you have a drought for year two. And this has happened in my West Texas growers, areas where those roots that are in the row, middle, all of a sudden are not able to pull up anything from the soil. So they're shrinking. And as they shrink, they pull away from the soil as a strategy to minimize water loss. And so you're not getting the nutrients that are available out there. So we have to consider that and sometimes increase our fertilizer levels based on the fact that we're losing access to the soil nutrients. And the best way to do that is to take the plant tissue test, and find out if that's really happening, but the plant tissue test can fluctuate. And I guess my point is understanding how the environmental conditions right in and around are leading up to that plant tissue test. really affected nutrient content is important. So we don't have that. Like I'll say it again, that knee jerk reaction like oh my gosh, nitrogen is low, let's put 50 pounds per acre out which is you know, ridiculously high. Yeah, maybe just needs to rain or you need to irrigate more, and that will fix the problem.

Craig Macmillan 28:41

Yeah, what is one thing, the one thing that you would tell growers on this topic, one piece of advice or insight or anything.

Fritz Westover 28:50

In addition to doing your soil sampling every few years, and your plant tissue tissue every year at bloom at veraison and some growers may even do it more often or some growers may prefer to do SAP analysis on a more frequent basis. That's all good and well. Just do it at your regular intervals, and get your long term data so you can see trends and changes. Then take some time to really understand number one, as we mentioned before, with the demand of the plant for each nutrient, okay, when is nitrogen, potassium versus magnesium or other micronutrients? When are they most essential for uptake into the vine? And how could you put them into the ground or into the system or onto the foliage in a method that is going to get that nutrient to the vine in time for its high demand, you need to know that vine needs it, because if it doesn't need it, you don't need to put it in there. And then finally understand how the nutrients move within the soil. That was the other thing we covered. So I had a great podcast on the vineyard underground with Paul Crout who works in the Central Coast a good friend of mine, he's worked with video team to Episode 16 We did a deep dive into Vine nutrition and availability in different forms of nitrogen and how some are immediately available and some are more slow release available. So I won't get into all that now. But understanding the availability of that fertilizer formulation that you're using is really critical. Because that's going to tell you not not only when you're going to apply it, how far ahead of the demand for the vine, but what method you're going to use to apply it. Will it be better off put into drip, apply to the soil? Or maybe as a foliar application.

Craig Macmillan 30:25

Where can people find out more about you?

Fritz Westover 30:27

Ok me? Oh, thanks, Craig.

Craig Macmillan 30:29

Oh, little Oh, me. Oh, me.

Fritz Westover 30:31

Well, you can find me chatting like I am with you on the Vineyard Underground podcast, the vineyardundergroundpodcast.com Or just look for that, wherever you stream podcast on Spotify or for Apple podcast, or if you would like to download some of the past presentations I've done on nutrition management, or the charts to determine the critical levels for nutrients have many of those that are free and available to the public go to virtualviticultureacademy.com The academy is where I teach grape growing and have a membership in there where I advise growers on a week to week basis.

Craig Macmillan 31:05

That's awesome. Our guest today has been Fritz Westover. He is a viticulturist. He's the host of the vineyard underground podcast. He's also the founder of a really great resource. You definitely need to know about this. If you're a grower, and that's the Virtual Viticulture Academy. He's not kidding, a lot of resources there and really good quality resources as well. So thanks for being on the podcast.

Fritz Westover 31:27

Hey, thanks, Craig. You guys are an amazing resource to the industry to and you have tons of free and available information. Keep doing the great things that you're doing. I'm a listener, so I'm a fan. It's really privileged to be on here my friend.

Nearly perfect transcription by https://otter.ai

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