Transcript

BRAD NEWBOLD 0:00
Hello, everyone, and welcome to office hours with the METER Environment team. Today’s session will focus on CDX technology, and we’re shooting for about thirty to forty minutes of Q and A with our experts, Leo Rivera and Chris Chambers, whom I will introduce in just a moment. But before we start, we have one housekeeping item. If you’re watching this video and you think of a question you’d like to ask our science experts, we encourage you to submit your question on our website at METER Group dot com, and then someone from our science and support team will get back to you with an answer via email. Alright. With all of that out of the way, let’s get started. Today, our panelists are application specialists, Leo Rivera and Chris Chambers. Leo is a research scientist and director of science engagement at METER Group. He earned his bachelor’s and master’s degrees in soil science at Texas A&M University, where he helped to develop an infiltration system for measuring hydraulic conductivity used by the NRCS in Texas. Leo is the force behind application development in METER’s soil hydrology instrumentation, including the SATURO, HYPROP, and WP4C. He also works in R&D to explore new instrumentation for field measurements of water content, water potential, and hydraulic properties of soil. Chris Chambers is a product scientist at METER Group. He draws on over fifteen years of experience as a support scientist and his background in ecology and plant physiology to improve instruments and to help METER’s clients collect the data they need to test hypotheses and make management decisions. Thanks for joining us, guys.

LEO RIVERA 1:53
Happy to be here.

CHRIS CHAMBERS 1:55
Yep. Always excited.

BRAD NEWBOLD 1:57
It’s been a while since we’ve done this, Leo. Alright. Let’s get started taking questions. And again, today, we’re gonna be hitting the topic of CDX. So basically, just right off the bat, can you guys tell us what is CDX?

LEO RIVERA 2:14
Yeah. Well, I’ll start off. So CDX, which stands for complex dielectric through intersections, is a new technology platform for measuring soil moisture and more specifically for measuring dielectric permittivity. And I think, yeah, it’s pretty exciting new technology that we’ve been working on coming out with.

CHRIS CHAMBERS 2:34
One might ask, all right, another sensor, really guys? But not to take anything away from the TEROS line, there’s a reason why we invested so much effort with the sensor, and we’re happy to talk about it some more.

BRAD NEWBOLD 2:51
Yeah. So this first question here, in general then, how is CDX different from, I guess, your standard soil moisture sensing?

CHRIS CHAMBERS 3:00
I think we should start with the complex dielectric part. And this ties directly into an area of math called complex numbers about which Leo is gonna give us all a primer right now.

LEO RIVERA 3:14
Thanks, Chambers. Yeah. So I mean, ultimately what we’re trying to do is separate the imaginary and the real portion of dielectric permittivity. And what we’re doing that is through some pretty cool complex math where we’re essentially taking these measurements and using geometry to solve where these voltage ratio measurements create these circles to intersect, which actually aligns with our imaginary in real portion of the dielectric or whatever media it is that we’re measuring. Of course, we’re typically focused on soils, but that’s what we’re trying to do. And so that’s kind of where it comes in, but ultimately it’s how we separate out those components.

CHRIS CHAMBERS 3:59
And the key term there is intersections. Yeah. And that’s where the math problem becomes a geometry problem. And a diagram would be great right here, but we’re gonna refer you to our website and the instrument manual that have an actual diagram of the transmittance plane. But the key, the real key here is the complex dielectric, which has two components, the real dielectric and the imaginary dielectric. And the trick is that since we’ve made it a geometry problem, those two components are basically vector two vector components of the complex dielectric. And that’s how we get it both of those.

LEO RIVERA 4:42
Yeah. Nice. And if you think about traditional soil moisture sensing technology, I think the important point to understand is that those are primarily measuring typically looking at apparent dielectric permittivity. And that’s an important thing as we get further down the road to understand why we need to separate those things out. And we can sometimes be limited by measuring apparent dielectric permittivity. It’s not to say that these traditional technology are bad because in the majority of situations, they measure really well. It’s when we get into those edge cases and those more complex environments that have more challenging things like salinity that we see the traditional technology tends to not do as well. And that’s where our efforts where we’re continuously to try and continuing to try and improve our measurement tech, always trying to find better ways to make measurements has helped solve some of those pain points.

CHRIS CHAMBERS 5:45
But whether it’s like a TEROS, which is a capacitance sensor and is actually measuring the relative charge time of a capacitor or a TDR probe, which is actually measuring the time that it takes for, an electronic wave to an electric wave to propagate back. The complex dielectric sensor is actually measuring the real and imaginary dielectric. Yep.

BRAD NEWBOLD 6:09
Okay. What do you mean then by measuring the real and imaginary parts of dielectric permittivity?

CHRIS CHAMBERS 6:16
Mind if I take a stab at this?

LEO RIVERA 6:20
Go ahead.

CHRIS CHAMBERS 6:22
You can go ahead.

LEO RIVERA 6:24
No. Go for it. After you. No. You first, Chambers. Alright.

CHRIS CHAMBERS 6:28
The two components of this, there’s actually, the way that I like to think of it is that the real portion of the dielectric is very much analogous to the capacitance, the storage in the system. And the imaginary dielectric is more is more related to the lossy part of the system where you get conductivity out of the system. So that’s you’ve got your real, which is, you know, basically an electric charge being stored in your soil, and then the imaginary is that is leakage from that storage. And with those two components, then we get dielectric permittivity, which relate the real dielectric, which relates to the water content the most and the electrical conductivity relates more to the imaginary dielectric.

LEO RIVERA 7:20
Yeah. No, I think that’s the exact way to right way to put it. I mean, ultimately, we’re interested in typically the water in the soil Which is primarily the real dielectric permittivity. Of course, we have other components that are part of the mixing model with the soil and air and things like that. But then you have those lossy parts like the solutes and the lossy clays that can cause your essentially add to that or or yeah. Essentially add to that and can cause our readings to go up if we’re not actually separating that out. And ultimately, what we’re trying to get to is the amount of water in the soil and separate out those pieces.

BRAD NEWBOLD 8:09
Okay. With everything that you’ve just said about the real and imaginary parts of dielectric permittivity, why does measuring real dielectric permittivity improve soil moisture readings then?

LEO RIVERA 8:21
I think ultimately it’s because like we’ve said, our ultimate goal is to measure the amount of water in soil. And if we can separate out those things that can affect that measurement like solutes, it makes for a better measurement. Now beyond the fact that we can do a better job of separating out those things, we’ve also done a better job of improving the measurement circuitry itself, which ultimately is also leading to a better water content measurement where we can make more consistent sensors across batch to batch in time. But we can directly reference those sensors against primary standards as well.

CHRIS CHAMBERS 9:05
And I’m gonna push Well, I’m gonna introduce a little bit of nuance to this, because no matter what no matter what you’re doing when you’re using an electrical property to measure water content, so much depends on the calibration For for the accuracy. And if you look through different water content sensors, you’ll see kind of a divergence of, in the accuracy. And a lot of that is plus or minus two to three percent, of the real water content. So you can, like in the case of the TEROS, you know, it still gets at a very good water content even though it’s measuring apparent dielectric. But where the real trick is that the calibration for SOLYX 14 is much more mechanistic than the TEROS 12. Correct me if I’m wrong on that.

LEO RIVERA 10:01
Yeah. Think that’s a great way to look at it. Yeah. And so ultimately it’s just yeah, about separating out those things that impact our measurement and continuing to improve our ability to make more accurate measurements.

CHRIS CHAMBERS 10:16
And really in those marginal marginal areas where salinity becomes a bigger factor and you’re trying to look at the actual pore water electrical conductivity, which we’ll come back to later, that’s where this increased performance is really gonna shine in the SOLYX 14.

BRAD NEWBOLD 10:35
This next question is asking if we will benefit more from the TEROS 12’s verification clip workflow or the SOLYX 14’s onboard diagnostics.

CHRIS CHAMBERS 10:44
Oh, I’m so glad we went there because interestingly enough, the sensor has the verification clip built into every reading. Yeah. Which is awesome. You know how often as a support scientist, I was asked, well, the water content of my sensor hasn’t changed, or I don’t trust the sensor because the reading hasn’t changed. And to know the answer to that, you know, ninety percent of the time, ninety ninety eight percent of the time, some made up percentage of the time, that was almost all the time, the sensor’s working just fine. And you can either be patient until you get some precip or, you know, let the water infiltrate just a little bit further, or you could dig up the sensor, put it in air, test it in a bucket of water or the verification clip, which is the best, find out, okay, yes, the sensor is working. Now I gotta put this sensor six feet back into the ground. Well, every single reading of the SOLYX 14 has a QA/QC check on it. Yep. Leo, how does that work?

LEO RIVERA 12:01
Yeah, it’s a great question. I mean, let’s start with why we did this. And that was, you know, we always have the question of how can I trust that the electronics are working? And you know, as you’ve dealt with this for years, the verification clip was a great step in the next direction to get still confident.

CHRIS CHAMBERS 12:25
It was so helpful.

LEO RIVERA 12:27
Yeah. And then the next question was, well, how can we do this in the sensor? And that was what you asked. How can you do this in the sensor? And at first, you know, it was like, that might not be possible. It turns out it was, and Paolo went back and did some amazing stuff to redesign the circuitry and he come up with a way to build it into the sensor where we’re looking at the reference components and essentially doing some really neat math to validate that the reference components are each reading as they’re supposed to. And they’re checking one against the other. If something goes wrong in the circuitry, you know, then that will shift and it’s kind of, you know, analytical algorithm to check against each other.

CHRIS CHAMBERS 13:23
Yeah. And so I think being able to build that directly into the sensor really, I mean, don’t get me wrong, I love the verification clip was a great step in improving confidence in the sensor, but being able to build it directly into the sensor. One, now we don’t have to pull the sensor out field that is a big hole to dig just to see if your sensor is functioning. And odds are you’re going to damage your sensor when you pull it back out. The cable and just nobody wants to spend their afternoon doing that.

LEO RIVERA 14:04
Nope. No, I don’t advise anybody to do that. And so yeah, build it into the measurement gives us confidence that the measurement is working with every measurement that it takes.

CHRIS CHAMBERS 14:17
And now you have an onboard QA/QC.

LEO RIVERA 14:21
Exactly. So I’m really excited with that addition and that new piece that was built into the technology. Me too. Hopefully, will ease some pain.

BRAD NEWBOLD 14:32
All right. With that background, let’s get into a few questions exploring why CDX matters in different situations. So the first question here is asking, just in general, how much does salinity affect traditional soil moisture sensors?

LEO RIVERA 14:47
Yeah. I mean, that’s a great question. I think it really depends sensor type or technology for one But this is true. Yeah. So they’re all gonna be a little bit different. Yeah. You know, let’s talk about the TEROS. Yeah. Because we have a lot of experience with that. And for example, like your water content measurement in any of our TEROS line will basically start to get kind of iffy and you’ll see the water content reading affected by the salinity at saturation extract ECs greater than ten decisiemens per meter.

CHRIS CHAMBERS 15:26
And this is pretty consistent across the TEROS 10, 11 and 12.

LEO RIVERA 15:31
Yep. Yep. And so basically what’s happening is that the water content measurement is pretty robust to salinity. It is factored into the calibration at the lower ECs, But once you cross that threshold, it really starts to affect the water content reading. Yeah. And and some of that has to do with the believe the frequency that we operate at seventy megahertz and things like that. And so to a point, we kind of mitigate some of those effects until you get up to that ten decisiemens per liter saturated extract. EC and that threshold changes for different technologies. But ultimately what happens is when you get into those conditions, you start to typically over predict your water contents. So you typically, that means you’re gonna have to build custom calibrations if you wanna use those sensors in those To point, but that gets, there’s lots of challenges with that as because the EC changes.

CHRIS CHAMBERS 16:36
And at some point you get too much salt in the system. Yep. Too high of an electrical conductivity for a custom calibration to even help.

LEO RIVERA 16:47
Right. Yeah. That limits the range that the sensor can actually operate in to actually make good measurements.

So Okay.

BRAD NEWBOLD 16:55
So explain then why CDX is better in saline soils.

LEO RIVERA 17:00
I mean, I think it comes back down to what we talked about, our ability to separate the imaginary and the real portion of the dielectric and focus in and hone in on that real portion measurement helps improve the range that we can make good measurements into and it minimizes the effects across a range of ECs. And it basically accounts for that EC effect on the on the dielectric of the material. Yeah. Yeah. And so it’s just knowing that we’re trying to build for this, being able to build the tools to actually account for that, separate out those things just helps make better measurements.

BRAD NEWBOLD 17:45
Okay. So does CDX only matter then in high salinity conditions or does it help in normal soils as well?

LEO RIVERA 17:53
I would say certainly doesn’t just help in high salinity conditions. Even in lower salinity conditions, especially when we’re looking at things like trying to measure a pore water EC. This improvement in our ability to estimate dielectric permittivity improves our ability to estimate pore water EC using models like the Hilhorst equation.

CHRIS CHAMBERS 18:15
For the electrical conductivity, I agree. Yeah. For the water content, I’m gonna push back a little bit since it’s since that’s calibration dependent. Yep. Basically basically, the underlying assumption is that you have one function to convert that real versus that real or apparent dielectric to give you an accurate water content measurement in all soils on the planet Earth. There’s a lot of variability in soils and I don’t think that’s a reasonable expectation. And if you have a consistent a consistent capacitance measurement and a so that you get low probe to probe variability and that you have a calibration that encompasses as much of that soil variability as possible. Then like the TEROS line, can make a sensor to reliably measure water content, across a lot of different soil types, but it’s not reasonable to expect it to capture all of them. And even so in the I think it’s kind of a similar challenge in water content for the SOLYX 14. It’s got a great measurement of the real dielectric, but again, there’s so much variability in that conversion from dielectric to water content that the calibration kind of becomes the limiting factor.

LEO RIVERA 19:38
Yeah. And I think that’s a great point to hit on that. You know, CDX is a great technology, but it’s not going to eliminate everything.

CHRIS CHAMBERS 19:49
What I’m trying to say is don’t feel the need to go out and replace all of your TEROS probes or TDR probes if they’re giving you the good data and the soils that you have.

LEO RIVERA 20:04
Yeah. No, I think it’s a great point and I mean, that’s what we see with in normal conditions, you’re gonna get good measurements from the traditional tools and the new tools. It’s just when you’re getting into these things where you’re trying to do some of these specialty cases, whether it’s estimating better pore water EC or trying to make better measurements in high salinity conditions, or even in some of these areas where you maybe have some of those lossy clays that could potentially cause some challenges. I mean, there are areas where it can help make some improvements, but the traditional tech is gonna perform well in most normal conditions.

CHRIS CHAMBERS 20:51
By normal, we mean relatively low EC conditions and a soil type that fits somewhere within the normal soil texture classes. Yeah. Beware of heavy clays as always.

LEO RIVERA 21:03
Heavy clays and weird mineralogy. Iron rich soils could be challenging too. Things like that.

BRAD NEWBOLD 21:09
Okay, so you mentioned talking about soil specific calibrations. Does the CDX then reduce the need for those, you know, I guess soil specific calibrations?

CHRIS CHAMBERS 21:20
No, reduce maybe in EC situations. In EC situations, yes. As we mentioned in, know, if you hit high organic matter contents, would expect those to be a little bit different than the assumptions in the SOLYX calibration. Volcanic soils are always weird, high iron content soils. There’s still gonna be situations where you need soil specific calibrations in the SOLYX.

LEO RIVERA 21:45
Yeah. And when you think of our dielectric mixing model, what we’re actually taking into account when we’re making those It’s taken into account those things, the mineralogy of the soil and we build our, and the air space and the water and all of these, and some of these other things. When we build our calibrations, we try and build a calibration set that covers the range of soil types. And so that gives us where we even with the best technology, we still fit within that plus or minus three percent accuracy. If you need better accuracy for your measurements, then do a soil specific calibration. Because again, you’re taking something that’s meant to cover a range of soil types and trying to apply it to a very tight thing. And so if you want that plus or minus one and a half, one percent accuracy, you’re gonna need a soil specific calibration.

CHRIS CHAMBERS 22:50
Now tell me more about that. This is really what interests me as like some of the things that interest me as a scientist and, know, the dielectric mixing model. So for our TEROS sensors, and we’ve all we mostly always done this is, for the TEROS, there is an empirical calibration. Right? That is just the best fit, the best observed fit from the observed output for the TEROS to the known water content Yep. You know, observed gravimetrically. And then we fit that best fit relationship and, you know, voila. But it’s not really, it doesn’t really That relationship doesn’t mean anything. Right?

LEO RIVERA 23:33
Right.

CHRIS CHAMBERS 23:35
But this dielectric mixing model Yep. In the SOLYX, is that straight up? Is there any empirical fit to that or is it just straight up the dielectric, what the theoretical mixing model should be?

LEO RIVERA 23:50
Yeah, I know that’s a great question. I mean, so what we’re still doing is we are taking a library of soils and making measurements to create a calibration now from just dielectric permittivity to water content. But you were talking about a library of soils that range from a sand to a sandy loam to a soil to a clay. And within those soils, you have different components of it that impact what that dielectric permittivity looks like. For example, the sand is going to have a slightly different dry dielectric permittivity than the clay and the silt loam. And so we’re trying to take all of that into account in the singular calibration equation and it works pretty well across a range of conditions. But when you get into those specific soil types, because we’re building all of that into that calibration equation, Of course it doesn’t, it’s not gonna perform a hundred percent perfectly in one set condition. We’re trying to build something that covers a range of conditions. Do I think soil specific calibrations are useful? Always if we need to improve our accuracy. Do I think everyone needs to do them? Absolutely not because they’re a lot of work.

BRAD NEWBOLD 25:14
At what point does salinity still become a challenge even for CDX?

CHRIS CHAMBERS 25:20
I haven’t found that limit yet.

LEO RIVERA 25:22
Yeah. We haven’t found it yet. We’re exploring that right now.

CHRIS CHAMBERS 25:27
I was really excited when you had you were showing some data that had added water to the soil at the So the solution was fifty decisiemens per meter? Yep. So at saturation, that saturation extract was fifty decisiemens per meter. Exactly. That is Dude, that’s close to seawater. Yep. That’s crazy.

LEO RIVERA 25:49
Yeah. Those are super high levels and from what we can tell the measurements still performed well.

CHRIS CHAMBERS 25:56
And that it looked, if I remember correctly, just followed the same trend line as thirty decisiemens, the ten decisiemens. Yep. You couldn’t even distinguish between those data points. Yeah. So that opens up possibilities for estuarine research, really compromised site, you know, salt flats.

LEO RIVERA 26:15
Mining applications. Mining applications.

CHRIS CHAMBERS 26:17
Wow. Yeah. Yeah. I mean, every measurement has a limit. We are working on exploring the limits of this technology.

LEO RIVERA 26:25
We’re gonna do a webinar on this, here in the coming future. And if you’re watching this later on down the road, you may find it’s already been run, But this is yeah. We’re continuing to explore the limitations of the technology, but it really does seem to have opened up the range of what we can work within. It’s pretty exciting.

CHRIS CHAMBERS 26:51
That’s awesome.

BRAD NEWBOLD 26:53
So does CDX then improve pore water EC estimation?

LEO RIVERA 26:57
Chambers?

CHRIS CHAMBERS 26:59
Yes. From what I’ve seen, from what I’ve seen, it’s really, really, we still have more, some more testing to do on that. Right? But Oh, for sure. Especially over previous attempts that, you know Well, let’s unpack this a little bit.

LEO RIVERA 27:16
Why would we expect the SOLYX 14 to improve the pore water EC measurement? It’s a great question. Well, let’s start with using the Hilhorst equation for example.

CHRIS CHAMBERS 27:28
Right.

LEO RIVERA 27:30
What is some of the primary inputs into the Hilhorst equation?

CHRIS CHAMBERS 27:35
Dielectric. Dielectric. And it’s the real dielectric.

LEO RIVERA 27:38
It’s the real dielectric. Yep. If we’re using apparent dielectric permittivity measurements To estimate pore water EC, the apparent dielectric permittivity is potentially affected by salts.

CHRIS CHAMBERS 27:49
And temperature.

LEO RIVERA 27:51
And temperature. And therefore it is going to cause an inaccuracy in your estimates of your dielectric permittivity, which then compounds into errors in your estimates of pore water EC.

CHRIS CHAMBERS 28:03
Right. And where we’re measuring the real dielectric very, very accurately in SOLYX 14, then where something like the TEROS 12, especially at low water contents, the TEROS 12 data would be really iffy. Yep. Just because the signal to noise ratio got so small as that the noise from the uncertainty in the dielectric measurement got larger. Yep. At low water contents, the TEROS 12 would kind of give you an idea of where the pore water EC’s, but wouldn’t really be reliable. Yep. Whereas the SOLYX 14 is even down to like four or five percent volumetric water content. From what I’ve seen those pore water ECs are looking really good.

LEO RIVERA 28:50
Yeah. Yeah. So, you know, any improvement we can make in our estimates of the actual dielectric permittivity, we’re gonna make improvements on our ability to estimate pore water EC and we’re really seeing the impact of that from this new measurement.

CHRIS CHAMBERS 29:08
Because that’s what people really wanna know. Right? The bulk EC doesn’t really tell you anything about what’s happening in the in the plants. You want to be able to look into that soil and see how the electrical conductivity of what’s in your soil is changing because of the solute concentrations, Exactly. You don’t wanna be confounded by changes in water content or changes in temperature. Yep. So being able to separate, what is changing in your soil because of the fertilizers you add without having to worry about the water content is what we really want.

LEO RIVERA 29:49
Yeah. Yeah. And this is really gonna open up our ability to do things like salt balance estimates.

CHRIS CHAMBERS 29:57
Salt balance.

LEO RIVERA 29:58
Understand how water is moving through the soil profile.

CHRIS CHAMBERS 30:02
I this I you know, we think of this in such small frame, but I think this is really gonna improve our understanding of so many different things in soil.

BRAD NEWBOLD 30:15
Okay. We will move on to some questions about field use and installation. And this first one is asking, is installation still critical for accuracy even with CDX?

CHRIS CHAMBERS 30:27
Yes. Always. Installation for a sensor that measures the electrical properties of the soil to get at water content or EC, getting good contact with the soil is gonna be just as critical in SOLYX 14 as in any other sensor.

LEO RIVERA 30:44
Yeah. I mean, I maybe unfortunately, but with this, any type of this measurement tech, we need good soil contact. We need to minimize air gaps. And honestly, we also want to minimize sight disturbance. And so we’ve said this, I can’t count how many times we’ve said this, but regardless of how good your sensor is, if your installation isn’t good, you’re not gonna get good measurements. And that doesn’t change with the CDX tech, it doesn’t change with anything.

CHRIS CHAMBERS 31:18
Yep, that’s right.

BRAD NEWBOLD 31:20
So does CDX with the SOLYX 14 require any kind of different installation practices than our TEROS sensors?

CHRIS CHAMBERS 31:27
No. No. Use the same things, use the same considerations. It works with the TEROS borehole installation tool, which is highly recommended, especially in deeper installations. And rule number one is make sure you get good contact between the soil and the pins.

LEO RIVERA 31:45
Yep. If all else remember rule number one. But you know, when we said about designing the CDX and the SOLYX 14 sensor specifically, we had a couple of goals. One of the goals is that it worked with the borehole installation tool because we know the power of the borehole installation tool and getting good installations, especially at depth and minimizing site disturbance. And so we designed it that it’s gonna work similarly with those tools. And so nothing really changes there. I think the only other thing that really does change is we’ve made this sensor a little more robust. And so it just kind of helps improve our ability to install the sensors without damaging things. It doesn’t mean you should get reckless with it, but it is Still watch out for rocks.

CHRIS CHAMBERS 32:42
Yeah. Watch out for rocks. Rocks are gonna be a challenge always. And but yeah, for the most part, you know, the same principles that apply to the TEROS 12 or the TEROS line of sensors are gonna apply to the SOLYX 14 when it comes to installation.

BRAD NEWBOLD 33:02
So if I’m installing both TEROS 12 and SOLYX 14 sensors in the field, how could I best compare the measurements that are coming from both those sensors?

CHRIS CHAMBERS 33:14
Custom calibration.

LEO RIVERA 33:15
You can do a custom calibration. I mean, the one thing to remember is that both of these sensors, the library of soils that we use to develop our calibration is the same library. And if you’re measuring in normal soil conditions, like we talked about low EC, and typical mineralogy, Normal soils.

CHRIS CHAMBERS 33:38
Is the definition normal Every soil is normal.

LEO RIVERA 33:41
But from what we see is that comparing these sensors, they compare fairly well. If you’re getting into situations where you’re outside of those ranges, soil specific calibration is going to help where you can do better cross comparisons. And if all else fails, follow the guidelines that we’re putting together as a part of the National Soil Moisture Network, which is in install sensors where they overlap for a period of time. So you can do inter comparisons while they overlap and see how they’re performing against each other. But I think in many cases you should be able to do comparisons in most conditions, but if not, soil specific calibrations are great.

CHRIS CHAMBERS 34:29
And do bear in mind that even if it’s a fairly typical soil, you know, there’s uncertainty around the measurements. They both rely on on a relationship over several points from the electrical properties to the water content. And so anytime you get an uncertainty like that, a particular soil might fit high for one sensor and low for the next sensor. Both sensors are working perfectly well and you have a five percent difference. That’s, it’s just part of the reality when you’re comparing different types of sensors, and in that case do a custom calibration.

LEO RIVERA 35:09
Yeah. And we can’t ever throw out just the fact that there is also spatial variability. Yeah. Even when you have these sensors installed in a site close to each other, it’s also possible that the water content just naturally varies from point to point. We know that this happens. So you have to remember that too when doing comparisons in the field.

BRAD NEWBOLD 35:35
Okay. That’s gonna wrap it up for us. Thank you again for joining us today, and we hope that you enjoyed the discussion. And thank you again for all the great questions. And again, if you have any questions that we didn’t answer, please contact us via our website at METER Group dot com. Finally, subscribe to the METER Group YouTube channel and accept notifications to see previous episodes of Office Hours and to get notified when future videos are available. Thanks again. Stay safe, and have a great day.