Season 3, Episode 11 | Behind the Scenes with Tissue Labs (Part 1)

00:00 Patty Skinkis

This is the HiRes Vineyard Nutrition Podcast Series, devoted to helping the grape and wine industry understand more about how to monitor and manage vineyard health through grapevine nutrition research. I am your host, Dr. Patty Skinkis, Professor and Viticulture Extension Specialist at Oregon State University.

00:22 Patty Skinkis

For the past two years of this podcast, we've talked at length about the importance of understanding nutrient analyses using data. The most common form of data for nutrient analyses comes from grapevine tissue analyses, and most listeners are likely familiar with the process of collecting tissue samples or soil samples that they then use to inform their farm's nutrient management plan. This is a process that is conducted annually or maybe whenever a problem pops up and you have to do diagnosis. However, today we're focusing on what happens after the sample is submitted to the lab.

Did you ever wonder what goes on behind the scenes in agricultural analysis labs? Well, we polled the HiRes Vineyard Nutrition Team for their top questions for tissue and soil analysis labs about the process. As researchers, we use tissue samples all the time, but we recognize that we didn't know all that much about what the nitty-gritty details were behind the scenes. And during this episode, we'll focus on the analysis methods and understand a little bit more about what is included in those and that process behind it.

01:27 Patty Skinkis

I have two individuals with us today from agricultural analytics labs. Both focus on crop and soil analyses, one from the private sector and one from the public sector. Each was chosen because they are involved in tissue analyses for a research team members of the HiRes Vineyard Nutrition Project.

Rachel Brimmer is a plant program lead and method development coordinator at the Penn State Agricultural Analytical Services Lab located on main campus at University Park, Pennsylvania. She joined the lab in 2017 and has been leading a team of six analyzers and a crew of lab technicians since 2019. She has a BS in biology from Valparaiso University and an MS in forest soils from the University of Montana.

02:01.52 Patty Skinkis

Also with us, representing a private sector lab, is Kyle Bair, president and soil scientist of Soil Test Farm Consultants located in Moses Lake, Washington. The company has been conducting agricultural analysis since 1976, and Kyle has been working at this lab for 17 years. Kyle has a BS from BYU and both a master's and PhD from Washington State University, where he's worked on grape nutrition as part of his projects when he was there, and both of his graduate studies focused on nutrient management and analyses.

Thank you both for joining today.

02:50 Patty Skinkis

Well, to start out, I want to give you the opportunity to tell us a little bit more about some of the history of your lab, the crops you analyze, the clients you serve. Rachel Brimmer, I'll have you start.

03:03 Rachel Brimmer

Thanks, Patty. So Ag Analytical Services Lab has a number of different programs. We have soil fertility testing. We do plant nutrition. We have a compost and manure program, as well as biosolids and water testing, and that includes everything from drinking water to pond water and irrigation for livestock.

03:27 Patty Skinkis

All right, great, thank you. Kyle?

03:29 Kyle Bair

Yeah, so we've been operating since 1976, as you said. We service mostly Central Washington, but we do pick up clients from elsewhere, and our main focus is on soil and plant tissue analysis, but we also do a lot of feed analysis, manure, compost, water, and wastewater. Our customers range from whoever wanders in off the street to researchers, agronomists and fieldmen and fertilizer dealers. And most of the tissue that we analyze is quite frankly related to the potato industry—it’s a big cash crop in these parts. So, a lot of the plant and analysis that we do is related to potatoes.

04:16 Patty Skinkis

So, I want to give the audience some background on analytical labs. First, I'm going to start with the land grant universities. Typically, we've seen labs that are serving the industry through research and also through analytical services for things like plant disease diagnostics and nutrient analysis labs. Rachel, can you provide us a little bit of the history behind labs being located at the land grant universities?

04:48 Rachel Brimmer

So, land grant universities had a charter to help develop their state economies, support businesses, and part of that is giving good information to farmers in terms improving their soils, fertilizing appropriately, and adapting crops to the local climate conditions. And so those sorts of activities have been happening at land-grant institutions for a long time. Organizing that sort of research, long-term fertility trials, as well as variety trials, isn't glamorous research. It takes many years and many seasons, but it is incredibly important information for farmers to have access to, both in terms of choosing new varieties or adapting fertilization techniques to those new varieties, as well as maximizing the yield that they get for the most economically viable amount of fertilizer for them.

05:55 Patty Skinkis

Yeah. And usually, the land grant universities were the ones that could use that information, not only for the lab, but for others who are an extension that are then sharing that information. Of course, we see it that a lot of the land grant universities don't necessarily have these labs anymore.

06:13 Rachel Brimmer

That's right. It's very been very dependent on how labs have been set up, and a lot of the states where they initially subsidized those labs, in budget cutbacks have meant that their funding structure wasn't viable anymore. So, Ag Analytical Services Lab is kind of unique. We are in an auxiliary organization within Penn State's umbrella, so all of our service fees fund us. They fund our salaries. They fund our overhead for the building. They fund us purchasing new analytical instruments. And that's a big reason why we're still here today. We have not ever had state subsidies for our work directly here.

06:57 Patty Skinkis

Kyle, you're on the other side. You're in the private sector lab. Can you talk about how these labs have been created? We see a lot more of these sorts of labs pop up over the years. Obviously, it's not brand new. You've been around, or at least the lab has been around for decades. Can you talk about that a little bit more?

07:17 Kyle Bair

Yeah, I think there's a lot of logistical considerations that having a private lab can help with. For example, our nearest land grant university to us is Washington State University, and it's at least a three and a half hour drive to get there. And many times the individuals, the growers, the field men that we work with, they'll bring us a sample on Tuesday and then they'll expect to get a result on Wednesday. And so being closer to where the action is happening as far as what's being grown, I think that's kind of where the private labs come in. And having worked in both private and university programs, we're able to operate a little bit faster, I think. Our focus is a little bit different. So, where others might be focused more on research, we try to get through as many samples as we can at a time. So, I think the logistical areas are where the private labs can help out quite a bit.

08:24 Patty Skinkis

Yeah, absolutely. So, let's talk about the analysis process. So, when a grower or researcher or whoever has a plant sample that they want to drop off and have analyzed, or a soil sample—let's start with tissue samples because I know they're different processes. But walk us through what happens once a sample is dropped off by a client. And this could be anywhere from preparing that sample to what kind of analyses are conducted. So, this can be a high level view of what goes on.

I'll have you start, Rachel.

09:04 Rachel Brimmer

First we have to determine if they brought us enough sample. I perpetually am trying to remind students when we have students come through on tours to think about it. Like plants are 90 to 95% water. If you give me two grams of your plant, I'm going to dry it down, and I'll have maybe 0.2 grams worth of sample to work with. And that's really not enough. So yeah, we try and emphasize to folks to bring us a side salad-sized amount of sample. And then usually that's enough to dry down and grind.

We check that [amount of sample] and make sure that they haven't [decayed]—usually we do get some walk-ins, but we also get a lot of things in the mail. And so mailed samples often, you know, something goes awry in the U.S. Postal Service or something. And if it's decomposed, we have to call them up and ask them to resubmit. But after that, everything looks good. We log it, throw it in the oven at 60 to 70 degrees C, usually overnight to get it fully dry. And then it's ground the next morning to pass a one millimeter diameter sieve. And then from there, we can proceed with the rest of our—whatever analyses they were looking for.

10:22 Patty Skinkis

Sure. Since we're talking about the grape samples coming through the lab, what do you typically see for grapes? Do you typically see leaf blades or petioles or do you see a combination of leaf and petioles?

10:35 Rachel Brimmer

We have typically seen more petioles, but Dr. Hickey and Dr. Centenari here in viticulture [at Penn State] are working on getting nutrient ranges developed for grape leaves as well. So, I am seeing a little bit more of grape leaves samples starting to come through.

10:54 Patty Skinkis

How about you, Kyle? Is the process similar?

10:59 Kyle Bair

It's very similar. Yeah. And one of the common pitfalls that we see is folks will send in samples, especially tissue samples, they'll send them in in a plastic—like a Ziploc bag. And that's always a very bad idea because the plants will sweat and sometimes they'll arrive as a goo. And so I always encourage people to put the samples in something that will naturally allow them to dry out because that's what we're going to be doing with them once we receive them anyway.

11:26 Rachel Brimmer

Absolutely.

11:27 Patty Skinkis

I think that's a great point, that we want them to dry out, unlike a disease sample or something else that you want them to dry out. So, a paper bag. A paper sample bag or a lunch bag or grocery bag, depending on the size of your sample, but paper. Excellent.

So once the sample is ground, what happens to it then? You know, is there certain ways to extract the nutrients? And if you want to talk about how the different nutrients are analyzed, because there's a whole bunch, are they all analyzed on the same machine or on different machines?

I'll have Rachel start first.

12:04 Rachel Brimmer

We mostly do an acid digest for the macro and micronutrients. And so that is a nitric acid and peroxide digest. We weigh half a gram of material. By the end of the digest, we bring it up to 50 milliliters final volume. And then that digested sample is then run on an ICP instrument. And that gives us everything from the macronutrients to micronutrients. And we can adapt the digest and also do five trace metals. And we keep having more and more people asking us for trace metals, at like food safety level trace metals. And we just can't do that. You need an ICP mass spectrometer for that, and that's not within our scope of operations. So that's the macro and micronutrients.

If people want carbon or nitrogen, then we run those on our combustion analyzers. And again, we weigh 100 milligrams into a reusable crucible and load them up on the combustion analyzer. And then they're combusted about 900 degrees Celsius.

13:21 Rachel Brimmer

I'm the lead technician on the Elementars, so I could go into much more detail. But suffice it to say, the instrument has a number of columns that separate and reduce the gases fully to CO₂ for carbon and then fully to dinitrogen gas to measure nitrogen. And those go through our thermal conductivity detector separately. And so, you get both analyses out of the same sample.

13:48 Patty Skinkis

And that's total nitrogen when it comes off the C&N analyzer.

13:51 Rachel Brimmer

Yeah.

13:52 Patty Skinkis

And so nitrates are handled differently. Do you typically do nitrate analysis, or I guess that would be the petioles?

14:01 Rachel Brimmer

Yeah, we do some, but not on grape leaf tissue. We do more corn stalk nitrate. And then, I have a few researchers who will occasionally have us run nitrate on, say, parsley or basil. But for East coast, so far, we haven't really had people ask for nitrate on [grape] petioles.

14:21 Patty Skinkis

Yeah, mostly I think it's California. I don't know. Kyle, do they—do you look at nitrate, petiole nitrate or just total nitrogen [for grapes]?

14:30 Kyle Bair

We do both. And quite frankly, our process is very similar to what Rachel's described. The only difference is when we do our acid digestion, we use a combination of nitric and perchloric acid. I guess we like to live life on the edge.

14:44 Rachel Brimmer

Live dangerously.

14:45 Kyle Bair

But yeah, when we do the nitrate analysis, it's basically just a water extraction. And then we'll run that by calorimetrically on a flow injection analyzer. Typically when we're doing that, it's on a petiole. You know, we don't see very high concentrations of nitrate in the leaf tissue, and so when we do a leaf tissue analysis, it's in the form of total nitrogen.

15:10 Patty Skinkis

So, one thing that I understand is that when we look at tissue sampling procedures, or not sampling, analysis procedures, there's universal standards for how this is done. Is that correct?

15:20 Kyle Bair

For the most part, yes. Some very small differences here and there, but ultimately the goal of the test is to yield similar, if not the same answer as far as analytical levels.

15:32 Patty Skinkis

So reproducible data across different labs. That brings me to the next question. And this is about, you know, how do labs ensure accuracy and repeatability of soil--or let's focus first on plant tissue test measurements. This is largely done around typical quality control practices in a lab, but also certification. So maybe you can speak to how your labs do this on a kind of daily basis and then also on a certification basis. So maybe I'll let you choose who wants to handle certification versus the daily basis Q&A.

16:11 Kyle Bair

Well, I could take certification for sure. We participate in the NAPT, which is the North American Proficiency Testing Program. It's administered by the Soil Science Society of America. And they have a program where refereed samples are distributed to hundreds of labs across the United States. And then you run your procedures on the same sample that somebody in the Midwest does. And you're able to verify if your numbers fall within an acceptable range or outside. And if outside, then you make adjustments. In addition to that, you know, every matrix has its own kind of program that we're certified for. We also participate in ALP, which is another soil program, but we have state certifications. There's a separate one for compost, another one for manure and feeds, so each one kind of has their own program.

17:12 Patty Skinkis

And the main goal is to ensure that um what one person gets in a certain lab would be similar to output from another lab or an ability to compare across labs, correct?

17:23 Kyle Bair

Correct. And the correct answer is what everyone else is getting. So, you just try to aim for the middle and that's what the right number is.

17:33 Patty Skinkis

And Rachel, if you could talk about kind of the day-to-day quality assurance, because I know that's part of your specialty.

17:41 Rachel Brimmer

So any method we have in the lab, we have an SOP for standard operating procedures, and everything is batched. For a given method, you know, we might have a larger or smaller batch, but each batch is going to have a blank. It's going to have a duplicate—depending on the analysis, we might have a spike, which—that's just adding a known quantity of the analyte we're interested in and then checking how well we recover that analyte compared to an unspiked sample. So, then we also have a known quality control sample added to that. So, like Kyle was saying, you know, we also participate in APT and ALP along with additional proficiency programs for various departments. And so one of the things we do is we use NIST standards for some things, which—those are National Institute of Standards and Testing—I think that's what that stands for, which are very expensive. So, for example, I'll check a NIST standard at the beginning of every daily run of our combustion analyzer.

18:58 Rachel Brimmer

But then throughout the course of the day, I may run 20 batches or not 20, but, you know, multiple batches of 20 samples, which will have their own QCs added, and duplicates, internally. So, we use a slightly less expensive standard for [each] batch, but every batch has its standard and we have our acceptable ranges of limits on each analyte. If you're too far out, then you get to rerun your batch, and if your dupes don't match, you rerun the dupes. If they still don't match, you rerun the batch as well as doing other things like recalibrating an instrument or remaking reagents and things like that.

19:35 Patty Skinkis

And so you bring up a really good point about having to rerun samples. And that's another reason why you want enough tissue being sent in.

19:42 Rachel Brimmer

Exactly. Yep.

19:43 Patty Skinkis

So you can rerun, otherwise you don't have [enough]. So how long do you keep a sample? Once you're done and all the data looks good, do you keep the ground remainders of that sample? Or how—what's that process of keeping extra?

19:59 Rachel Brimmer

We do hang on to our samples for a while. When I first started here, we hung on to them for, I think, six months. And that got to be way too big of a backlog of archived samples. So, we do hold on to samples for about three months. Generally, that should be well long enough for, you know, any researcher or home gardener or whatever to take a look at their data and then come back and say, “Something doesn't look right. Can you retest?” So, we do hang on to them. We don't pitch them immediately.

20:34 Patty Skinkis

That's good to know, good to know. So, I have another question that I thought of with samples when they're received is, you know, sometimes we let growers know they should wash their samples before they're submitted. So, talking about leaf or petioles, is that something that you do at your lab? Or you know if they're already coming in dried out, that's probably too difficult to do—do you recommend growers wash their samples? And a couple things come to mind—if they've got really dusty locations where they have a lot of soil on their leaves, or if they have certain fungicides and pesticide products that like to adhere to the leaves, how much does that influence the nutrient results and how much should they worry about that prior to sending in a sample?

21:23 Kyle Bair

Yeah, I can take that one. I generally ask folks not to wash them wherever they're at because it's very easy to go overboard, and you end up losing some of the soluble elements out of whatever tissue that you're talking about. And so, when we get a sample in that's fresh, we will give it a quick rinse to wash it. And I just worry about people doing that on their own and being a little bit too aggressive. But at the same time, when things are very dusty or if you've had—you know, I see samples come in that have—you can see copper on the leaf. And so, you know, there is potential there for some contamination. So, we do our best to wash them at our facility and hope that they come in fresh. If they do come in already dried, I'm probably not going to go through the bother of getting them wet again and, you know, potentially causing some issues that way.

22:21 Rachel Brimmer

Definitely the same. We used to do a little more washing. That was when my predecessor was still here, and our director has also been quite concerned about removing too much potassium with that sort of thing. Generally when we do get samples, and—I'm like speaking specifically to grape research, they're already ground. So, we don't, you know, we don't have to worry about that process. But the dirtiest samples I see are corn ear leaves at tasseling time, and we try and brush off as much of that excess pollen that's on them as possible.

23:01 Rachel Brimmer

And then, yeah, I do see a lot of copper fungicide contamination on, say, the tomatoes that we get around here. You know, we don't try and remove it. It's just like—they know they applied it. We're not going to look at copper as, you know you know, potentially deficient in this situation. And we already know, like, the copper application isn't going to hurt the plant that's actually protecting. So we just kind of throw copper out the window in terms of thinking about nutrition at that point.

23:33 Patty Skinkis

So, the takeaway is send in fresh viable leaves if possible. Don't worry about washing them. That's good to know.

So, next question, what kind of error can be expected on a nutrient sample or nutrient values from a single sample? And how is that term determined? I'll give an example. If you ground up and mixed a large sample of leaves that came in to you and divided it into a number of different individual samples, what would be the spread in the measured values of, say, N, P, or K?

24:09 Rachel Brimmer

Well, you would hope, like, if you ground it up finely and mixed it really well, you would hope to have, like, 5% variation or less.

24:19 Patty Skinkis

That makes sense to me.

24:19 Rachel Brimmer

Yeah.

24:20 Patty Skinkis

Yeah, you know, this is one of our research group questions. We're always thinking about that. Could it be handled in a different way? But I think, yeah, if you're grinding up a large sample and you're breaking it down, that's good to know. Any other comments, Kyle, on that variability?

24:36 Kyle Bair

No, and quite frankly, tissue samples are one of the more homogenous of the samples that we do get in. So for soils, we might allow a little bit more slop than we do with a plant tissue, but plant tissue is really, really solid as far as an analysis goes in and repeatability especially.

24:58 Patty Skinkis

What do you think is the biggest preventable cause of nutrient measurement or imprecise nutrient measurements? Assuming that everything goes on well in the lab and something comes up kind of unexpected, do you think it's the sampling procedure in the field? Sample preparation on the part of the person submitting it, or maybe time that's elapsed since sampling to when it's received in the lab. Do you have some kind of idea what you think might be the biggest cause of error there?

25:32 Kyle Bair

For me, I'd say that getting a good sample in is paramount because we can't take a bad sample and somehow make it good. So, that's a huge consideration. And then after that, the procedures are pretty repeatable. And so, we don't really worry about things going wrong in a grind or in a drying process. The only real issues that we see quite often is whenever humans get involved is when we have errors. So, either the wrong sample is weighed up in the wrong location or something like that. And I always tell people that in those situations, our carbon unit failed. And that sounds that sounds pretty snazzy, but I'm just talking about a person, you know, that's made a mistake.

26:20 Patty Skinkis

Nice. Yeah. Is there any last step that—or a step that you think growers should know about in that process of sampling in the field? Like, what can they do better? You know, there's a lot of assumptions. Let's put it that way. There's a lot of assumptions when we don't, we aren't the one out there collecting the sample. And I should preface this with information that we obtained from growers when we started the HiRes Vineyard Nutrition Project. We did a national survey and we asked, what do you typically sample your vineyard for? What unit area are you representing?

And the range was anywhere from one acre to 20 acres per sample. And so, what is your comfort level for—what you might recommend to growers for choosing an area that would represent the samples?

27:11 Rachel Brimmer

That's going to be really different, you know, based on where you are in the country. Take Pennsylvania, for example, you know, we have such varied topography. We have very different soils from the northwest of Pennsylvania to the southeast, and then everything in the Appalachians and the Ridge and Valley is--it's very, very different. So, you know, depending on the size of the vineyard here, a small vineyard could potentially cross, you know, three or four soil types. Whereas if you've got some, you know, big outfit out west where the soils are just not that variable because your one farm is all on the same topography, the same geologic strata and everything. You know, somebody out there could probably just easily go for the 20-acre sampling unit, whereas somebody out here might want to block by block sample, especially if they're on a hill slope where the soils are shifting as you go up and down the hill.

28:13 Patty Skinkis

Kyle?

28:14 Kyle Bair

Yeah, I think Rachel's hit the nail on the head. And I'd probably also add that it depends on goals too, that if you've got an area that you're working with that's problematic, you might want to separate that area from another that represents maybe a good chunk of the vineyard or whatever you're working with. So, keeping goals in mind is important in problem areas. And I always encourage people that, if they do have a problem area, to send in good and bad tissue, because a lot of the ranges that are given for sufficiency are really wide, and it can be difficult to make a good comparison. But if you've got an example of a good tissue from the same vineyard, then you can really hone down on what might be going on.

29:06 Patty Skinkis

Yep, absolutely. So, sampling in the problem areas as well as the healthy areas. I want to go back a little bit to the lab quality assurance through the certification. Typically, we recommend that growers use a lab that has certified procedures. Is there any benefit to a lab to not being certified? It sounds like no, there's not a benefit. Are there even labs that exist out there that don't certify?

29:38 Kyle Bair

I can't see the benefit of not doing it. I mean, I think most people want that assurance that you're doing the procedures properly. There are a number of labs that that probably aren't. And, you know, you can never—it's hard to make meaningful comparisons with data that's coming from an unknown process or an unknown methodology. So for me, I think that's quite important.

30:04 Patty Skinkis

Yeah, and I think that's a really important topic that we're seeing more samples being—not a high percentage—but more samples being analyzed for xylem sap, so sap analysis. And that's a little bit deviating from what we typically see for analysis in tissue and certainly for grapes. Do your labs analyze sap and do a sap analysis or is that a completely different methodology altogether?

30:34 Rachel Brimmer

We do not do sap analysis. A little bit I've worked with a student who was working up some data from an internship. They were using some highly proprietary sorts of instruments to test the sap. So, it's not something we can—I think the major issue would be like people getting samples to us fast enough for that to be a reliable measure. Those sorts of instruments, and I don't have any names off the top of my head, but they tend to be used in like greenhouses where you can just test your tissue immediately right there and you have, you know, a valid living sample to be testing off of. So like for, you know, a physical lab to do that, we'd have to be right next to, you know, the place, the plants growing.

31:30 Kyle Bair

Yeah, I'm in the same boat. We don't do any sap analysis here. And for the very reason that was pointed out before is, I don't know who oversees that and what kind of certification goes into that at all, so it kind of seems like the Wild West to me. If the concentration of your element depends on the moisture level of the plant, that seems highly problematic to me.

31:56 Patty Skinkis

And problematic from a standpoint—from just being able to get a sample and keeping it durable enough for analysis. Correct? [guests nodded yes].

Yeah, and the other concern, because this has come up numerous times in talking with growers, is that the, you know—just trying to get them to understand that historically, we've got a lot of data on tissues. And not just for grapes, but other crops. And then these methods have been tried and true. And so we're working with a whole bunch of data that we can then generate these interpretations from.

And we don't see that with some of the sap analysis. So that's one of my concerns when I'm approached by growers who say, “Here's my results. What does it mean?” And I'll say, I have no idea because it's not what we have all of our criteria based on from years and years of research with these tissue samples.

The next question I have is about these nutrient guidelines. I know that you generate nutrient guidelines that go with your report and guidelines meaning those sufficiency levels or critical values. Can you talk a little bit about how you get those internal numbers that you give to growers with your results?

33:11 Rachel Brimmer

So, ag analytical services funnels a lot of data to Extension, and we work really closely with some of our Txtension teams, particularly for me, the horticulture team. Sometimes they have inputs on the recommendations that we have, or for example, we had someone who is so highly involved with the orchard program, who—he retired a couple years ago, but we have incredibly detailed recommendations on our orchard reports based on his work. And then we also have worked enough with a few of the consultants in Maryland that we have recommendations based on what they want to see. So, Maryland apples get logged in differently. Maryland berries get logged in with their own listing. And so there's some of that. And then there's some that we have kind of historical data that's been passed down to us. And that's what our recommendations are based on. I would love to have our, you know, our extension agents come and tell me, oh no, we need to update that, that's not as true for our more modern varieties. So, we do have a huge range of critical values for things as different as Christmas trees, the spruce and firs to tomatoes and peppers and things like that, that were developed long before I was here or our current director was here.

But then every year I get a new plant, so a lot of times I'm just digging through, you know, plant analysis handbooks, editions two through four to find just a survey range set of data for people. And then we kind of give them that and tell them to talk to their Extension agent and hopefully they can get some more information that way on what they should or shouldn't do.

35:11 Patty Skinkis

That's great to hear that all of that research information that are generated from field trials and experience are incorporated.

So how about you, Kyle?

35:21 Kyle Bair

Yeah, very similar. We use the university guidelines as our base. I wouldn't go as far to say that there's no home cooking involved either, because we do work with a fair amount of producers and field men. From time to time, we'll send out a report with an interpretation on it, and they'll say, hey you might want to think about changing this up a little bit because it's too low or it's too high. So, there is some of that that goes on behind the scenes. And I think it's important, it kind of underscores the importance of getting the right plant part when the samples come into the lab because as we know, the range of nutrients can vary based on what plant part is sent in and even where that plant part is located, say on a vine or a cane or anything else. And so that goes into the interpretation quite a bit.

36:19 Patty Skinkis

In terms of looking at plant parts, so we typically see leaf blades, petioles, or whole leaves for grapevines. Do you ever run analysis on non-traditional tissues from grapevines or any other plants? I'm thinking more of berries or juice. Do you ever run analysis, nutrient analysis on those types of samples?

36:44 Kyle Bair

Yeah, we do. Like I said, anything that we can grind up or get into a liquid, we can do the analysis on. And normally when we do, it's for the researchers, which takes the burden off of me of having to interpret what they're getting. I can just provide them with the data, and they can make heads or tails of it. I'd say for the for anyone that's a grower or a field man or something like that to stick with the traditional plant parts, because I can help interpret that.

37:14 Patty Skinkis

That's great.

37:15 Rachel Brimmer

I would say Ag Analytical could run berries and juice, but we would put it through a different program. Cause we're not set up to—in my program's database, we're not set up to do moisture content or total solids or anything like that. So we'd have to shove them through the compost or manure program. Which, that's where all the oddballs go.

Speaking of strange things that you analyze, I think that the most unique thing in recent years was an entomology researcher wanted some basic information on spotted lanternflies. And so we—someone here got the lovely task of blending up spotted lanternflies.

37:59 Patty Skinkis

Interesting. So yeah, that question was mostly for research. That's my interest and the team's interest, sometimes we want to look at the elements, you know, especially things like potassium in berries or juice. And so it's good to know that it's possible, maybe not in every lab if you're not set up for it, but it is possible to run that. But certainly, that's not the recommendation for growers if you're trying to keep tabs on what your nutrient levels are in the field.

So, are there any other key things that you would like the audience to know about nutrient analyses? And we've mostly been talking about tissue analyses, are there any things like takeaways that you would recommend?

38:43 Rachel Brimmer

Mostly just, if you're having a problem, we need soils and plants from good areas and bad. A lot of times what I see around here is not necessarily that the good area is all that good--it's just that it's not symptomatic yet. Sometimes people find out they've got a bigger problem than they anticipate, at the beginning.

39:08 Patty Skinkis

So not spot sampling, but comparative sampling.

39:11 Rachel Brimmer

Right.

39:13 Patty Skinkis

Yeah, that's good advice.

39:14 Kyle Bair

Yeah, that is good advice. I totally recommend that also. And if I maybe could just add that a plant tissue and a soil test is great because especially with some of these crops that—you know, like a grapevine has these very large storage organs and maybe we're working to treat a problem, not maybe necessarily for this year, it might be something that we have to address the next year. That's important. Whereas something with like a potato, we take a petiole sample every week because we can address that problem that week because it's a fast growing thing. And so understanding the how the plants grow, that plays an important part in how we interpret and what actions are taken to address the issues.

40:02 Patty Skinkis

We've talked mostly about tissue analysis, but how about soil analysis? Is there any takeaways that—with the sample that's received? Do you see some issues with too little or too much soil, errors that can happen with soil sampling?

40:19 Kyle Bair

Generally for us, it's too little. I never complain when someone sends in too much sample because we can work with that at least. We do recommend that our interpretations for the most part in Washington State are based on a one foot sample, so if a different depth is taken, we'd like to know that ahead of time so that we can make some adjustments on how different things are calculated and also how they're interpreted. Because if a six inch sample is taken, but the recommendations are based on a one foot sample, we need to kind of take that value with a grain of salt and adjust accordingly.

40:57 Patty Skinkis

Okay. How about you, Rachel? Any suggestions for soil samples?

41:01 Rachel Brimmer

Take a lot of cores and mix them well. I don't really see like the soil samples as they come in, so I don't—I can't really speak to any particular problems that might be specific to vineyards, but yeah, people are always like “how many cores are you—you really want me to take that many?” and yeah, if you want a good average of the block that you're testing, you have to take that many cores.

41:29 Patty Skinkis

Yeah, it's harder to get soil samples depending on the soil moisture level and conditions.

41:35 Rachel Brimmer

Right. Yes.

41:36 Patty Skinkis

And yeah, so it's harder to get people, encourage people to get the distribution of samples across space to be representative.

Okay, so one last question I have is about more on the research end. So, you're generating a lot of this data, for, you know, across soil, tissue, other cropping systems. When you analyze data, are those data ever used in for other purposes than just returning the information to the client or the researcher? Do you run reports by crop to get a sense of any patterns or trends? You kind of look at the analytics is what I'm getting at within your specific lab.

42:13 Kyle Bair

We don't, and the main reason why is I generally don't know the background on the samples. And so I couldn't make any specific inference about it, not knowing that. And also, I do get a lot of weird—not weird, but, you know—plant parts that aren't normally used for how we interpret the results. Like I said before, I'm usually just happy to turn it over to the researcher. The last reason too is I've got a love-hate relationship with our LIMS system, our information management system. And so extracting data out of it can be kind of a headache for me. I'm sure others do it a lot better than we do, and I just stay away from it for that reason.

42:59 Patty Skinkis

That's good to know.

43:00 Rachel Brimmer

I agree. And in general, you know, our database, like it's hard enough for it to get people to fill out, you know, their address correctly sometimes. So, like we would never be able to collect enough data on each specific sample for it to be usable in like some sort of meta analysis. We get so much stuff from researchers where we just get the sample IDs and we don't have any information about what their treatments or their plots were. Frankly, that would be way too much for us to deal with it anyways, so we don't really have the depth of information that would make you know a broad set of data pulled from multiple years or multiple species you know all that useful.

43:46 Patty Skinkis

Sure.

43:47 Rachel Brimmer

And we do our best with quality controls and you know make sure their data looks good across the set and then we let it go.

43:55 Patty Skinkis

Yep. So this is really great to hear because one of the things we did for the HiRes vineyard nutrition project was we proposed as part of it to use meta-analysis of data and figuring, you know, all this data is out there. And our biggest challenge was finding complete data sets. And who had those, of course, were researchers. But even then, we did not have full data with like what cultivar, what rootstock, what yield, what pruning weight, with all the nutrient data. Sometimes it was just the nutrient data. So, it basically was useless. So, the takeaway message for growers and researchers alike is to make meaningful use of data, you have to keep that background information. Don't rely on the analytical labs. That's not their job. Their job is to give you good solid numbers. Just, you have to keep the rest of the information together with it if you want to make inferences off that data over time.

Well, thank you both for the information you shared with us today. It's really good to hear about some of the background behind what goes on in the analysis labs.

I just want to ask you if you have questions. Any takeaways that we didn't cover already for growers who might be listening to this podcast, and what they can do better in documenting and getting some of their data?

45:17 Kyle Bair

Well, I think I kind of spoke my piece already. You know, the quality of samples is important. Getting the right plant part in a timely manner with the right information. We love to get paperwork in with our samples. One time I got a sample, and it was a potato petiole. It was a single potato petiole about, you know, less than the size of a pencil. And it had a piece of tape around it, and it said, number one. I didn't know where it came from. So, for everyone's sanity, you know, good documentation and good sampling procedures are going to get you the very best data.

45:57 Patty Skinkis

Rachel, any last words?

46:00 Rachel Brimmer

Well, we are always happy to help. We are always happy to answer questions. I love it when people call me and ask their questions before their sample shows up moldy or, you know, or not enough. I really do enjoy talking to folks and learning about their projects and that sort of thing.

Communication is good, and we're happy to help.

46:26 Patty Skinkis

I think that's a great way to end is just, it sounds so simple to take a sample, but often times the devil is in the details. And hopefully everyone learned a few things today. I know I have. And kind of—what people think happens with a sample and what actually happens and some good takeaways. So thank you both.

I'll have information about both the Soil Test Lab and the Pennsylvania State Agricultural Testing Lab in the show notes. And if you want to learn more about the HiRes Vineyard Nutrition Project, I'll have that included with our website link and our links to social media in the show notes. Thank you both for joining.

This podcast was funded through the National Institute of Food and Agriculture’s (NIFA) Specialty Crop Research Initiative Coordinated Agricultural Projects (CAP) grant. Project Award Number: 2020-51181-32159. The continued efforts of the podcast are funded by the Viticulture Extension Program at Oregon State University.

Audio mixed by John Adams.