Episode 26: Choosing between water content and water potential

Episode 26: Choosing between water content and water potential
 

Should you be measuring water content or water potential? Like all good scientific questions, the answer is, “It depends.” In some applications, water content measurements will tell you everything you need to know, in others, water potential will get to the root of the issue. Still others require measuring both. So how do you make sure you’re making the measurements you need? In this episode, METER research scientist, Leo Rivera and METER’s ecology and plant physiology specialist, Chris Chambers discuss what you need to know to choose the right measurements.

Notes

Chris Chambers operates as the Environment Support Manager and has been the Soil Moisture Sensor Product Manager for many years at METER Group. He specializes in ecology and plant physiology and has 15 years of experience helping researchers measure the soil-plant-atmosphere continuum.

Leo Rivera operates as a research scientist and Director of Scientific Outreach at METER Group. He earned his undergraduate and master’s degree in soil science at Texas A&M University where his research focused on the impacts of land use and landscape on soil hydraulic properties. He also helped develop an infiltration system for measuring hydraulic conductivity used by the NRCS in Texas. Currently, Leo leads METER’s collaborative research efforts, and focuses on application development in hydrology instrumentation, including the SATURO infiltrometer and the HYPROP. He also works in R&D to explore new instrumentation for water and nutrient movement in the soil.

Links to learn more about Leo Rivera
Links to learn more about Chris Chambers
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The views and opinions expressed in the podcast and on this posting are those of the individual speakers or authors and do not necessarily reflect or represent the views and opinions held by METER.

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Transcript:

 

BRAD NEWBOLD 0:00
Hello everybody and welcome to We Measure the World, a podcast produced by scientists for scientists.

CHRIS CHAMBERS 0:08
So if you have matric potential soil suction, and water content, do you even need to know anything about the soil type anymore?

LEO RIVERA 0:17
You know, when it comes to understanding the hydraulic properties of soil? No, those are the things that we need to get to, to know. Now there are other physical properties that we probably need to understand soil type when it comes to like plasticity index and things like that. But for most people, most applications if you know the water content and water potential, and you understand that relationship, that tells you pretty much everything you need to know.

CHRIS CHAMBERS 0:43
Any comments on that can go straight to Leo Rivera.

LEO RIVERA 0:48
Or Brad just one of us!

BRAD NEWBOLD 0:51
That’s a small taste of what we have in store for you today. We Measure the World explores interesting environmental research trends, how scientists are solving research issues, and what tools are helping them better understand measurements across the entire soil plant atmosphere continuum. Today’s guests are research scientists Leo Rivera and Chris Chambers, both of whom are water content and water potential sensor and application experts here at meter group. Chris chambers operates as the environment Support Manager and has been the soil moisture sensor Product Manager for many years at METER Group. He specializes in ecology and plant physiology, and has 15 years of experience helping researchers measure the soil plant atmosphere continuum. Leo Rivera operates as a research scientist and director of scientific outreach at METER Group. He earned his undergraduate and master’s degree in soil science at Texas a&m University. And there his research focused on the impacts of land use and landscape on soil hydraulic properties. He also helped develop an infiltration system for measuring hydraulic conductivity used by the NRCS and Texas. Currently, Leo leads METER’s collaborative research efforts and focuses on application development in hydrology instrumentation, including the SATURO Infiltrometer and the HYPROPROP. He also works in r&d to explore new instrumentation for water and nutrient movement in the soil. So Leo and Chris, thank you so much for being here.

LEO RIVERA 2:13
Thanks, Brad.

CHRIS CHAMBERS 2:14
Thanks, Brad. Happy to be here.

BRAD NEWBOLD 2:17
All right. So we probably need to start out by talking about the differences between soil water content and soil water potential. Can, can you just give us a brief definition of both these parameters? What is soil water content? And what is soil water potential?

CHRIS CHAMBERS 2:34
Right. And so what we’re talking about is ways to describe the state of water in the soil.

LEO RIVERA 2:40
Yep.

CHRIS CHAMBERS 2:41
And they are both extremely valuable and give you complimentary information. And so the soil water content is the amount of water there, it’s how much water is in any given volume of soil. And the water potential is the energy state. So when we talk about these things, people will generally say soil moisture, and they generally mean water content.

LEO RIVERA 3:06
Yep.

CHRIS CHAMBERS 3:07
We’re trying to get a little broader view of soil moisture out there. And it really includes both of these parameters.

LEO RIVERA 3:15
Yeah, yeah. And oftentimes, I mean, when people look at water content or water potential, they’re typically looking at it in terms of volumetric water content, how much water is there per volume of soil, but geotechnical engineers often often like to look at in terms of gravimetric water content. So it often depends on the field that you’re coming from and how you want to look at it. geotechnical engineers also like to call soil water potential soil suction, and they look at it in terms of a positive value. So it’s the inverse of water potential, which this takes some time. It takes a little bit to wrap your mind around that sometimes. But depends on the field you’re coming from and what you’re really trying to understand and how you’re using that information.

CHRIS CHAMBERS 3:52
Yeah, but in the end, it’s the mass and the energy state.

LEO RIVERA 3:56
Yep.

BRAD NEWBOLD 3:57
All right. So that being said, what types of situations would you only need soil water content? And in the same, you know, the same vein? What type of situations would you only need soil water potential?

CHRIS CHAMBERS 4:11
Can we play our favorite game for a bit?

BRAD NEWBOLD 4:13
Sure!

CHRIS CHAMBERS 4:13
Okay, water content or water potential? Okay, we’ve done this a couple of times, so you might have seen it before. Bear with us a little bit, okay! Um, so let’s start with maybe maybe not as easy as you might think. A setpoint for irrigation control?

LEO RIVERA 4:30
Ooh, good question. So, ideally, we’re going to control irrigation to hit a target water potential. But we need the water content to know how much water we need to add to hit those target points.

CHRIS CHAMBERS 4:45
See, we threw the curve in too early. Yeah, we’ll come back to that. Yeah. Let’s do a new one. How much? How much tension is going to be on the water column of a plant?

LEO RIVERA 4:59
Water potential.

CHRIS CHAMBERS 5:00
Water potential all the way. Let’s say how, what if what you want to measure if you want to measure the amount? See, I’m giving, I’m giving it away here. It’s hard. It’s hard to phrase these without giving it away in the question. The amount of water loss.

LEO RIVERA 5:18
The amount of… I mean, water content is gonna give us the information there. Right, right. Let me throw one your way. If there’s a risk of slope failure?

CHRIS CHAMBERS 5:27
Woohoo. So once again, we’re back to needing both of those, right?

LEO RIVERA 5:34
Yeah, I think, first of all failure water, the amount of water there is helpful, but the biggest factor is the water potential or the soil suction, as I refer to it, because that kind of gives us that intrinsic strength component.

CHRIS CHAMBERS 5:50
But sometimes the positive pressure is a factor there too, right?

LEO RIVERA 5:53
For sure. How’s it? Yeah, yeah. So we’re really we’re ideally looking at both the negative and positive pore pressures.

CHRIS CHAMBERS 5:59
Great. How about freezing potential in, like, say in like a wheat hardiness study?

LEO RIVERA 6:10
Ooo oh a curveball in there. Yeah. That’s a good question. Freezing potential. I mean, I think water potential is probably going to govern that more. Right. But also, we could use I mean, if it actually frozen, we can use temperature to infer the water potential.

CHRIS CHAMBERS 6:25
Yeah and that will kind of give you the same information. Right? When you when you hit the freezing point, they’re both going to just look like really dry soils.

LEO RIVERA 6:32
Yeah. Yeah. And then from there, you can use temperature to kind of infer guess what, what’s happening there.?

CHRIS CHAMBERS 6:38
So as long as we play this game, you think we’d be better at it by now.

BRAD NEWBOLD 6:43
All right, so you have given us a couple of instances here examples of when a water content and water potential work well together. So are there any other or not are there? But can you give us some other examples or situations when it’s appropriate to measure both of those parameters at the same time,

CHRIS CHAMBERS 7:01
so people are really used to using water content? Because it it’s easy to understand, right? Basically, at the end of the day, you get a percent. And that’s really easy for people to wrap their head around. Yeah, you’re looking at a volume of soil, that’s 25%. water content, volumetric water content, then right about the fraction of quarter of that soil is made up of water. Unfortunately, it’s a lot harder to interpret than many people realize. Because 25% water content in a sand is more water than any plant needs. And in a clay, it’s probably well beyond the permanent wilting point. So you can’t really just use water content. In some situations, you either need the matric potential as well. Or you need to know some more information like the soil type.

LEO RIVERA 7:55
Yeah. And I think I’d even argue that in most situations where people are just using water content, they’re doing it based on historical knowledge of what that means for that soil. And really, it’s because they’ve spent enough time knowing what that means in terms of water potential without knowing that they’re actually trying to understand that they’re like, my plants are happy, my plants are sad. These are my set points for water content.

CHRIS CHAMBERS 8:19
Especially in seasonal areas, we’ve got a couple of years of data, you know, where it peaks out in the wet season, you know, where it flattens out where, where the plants draw as much as they can in the dry season, if you live in a climate like that. So that’s really how the context is giving to a lot of a lot of water content studies.

LEO RIVERA 8:39
Yeah, yeah. And what I mean, one other, you’re looking for a specific application, anytime you’re trying to understand hydrology, and water movement, in soil and where it’s going, you need both parameters, because the governing factor of which way the water is going to move is the water potential. And the amount of water that we’re moving is going to be based on the water content. And anytime we’re doing a hydrology study if like you’re really trying to understand, you know, the Vados zone and and how water moves through the soil, you need to understand both these parameters,

CHRIS CHAMBERS 9:14
The soil storage for one, and then the direction that it’s going to go which is the water water potential, and that you don’t need to know as much so let me ask you this, maybe this question might ruffle some feathers, but I’m going to put you on the spot. So if you have matric potential of soil suction and water content, do you even need to know anything about soil type anymore?

LEO RIVERA 9:41
You know, when it comes to understanding the hydraulic properties of soil, no, those are the things that we need to know. Now there are other physical properties that we probably need to understand soil type when it comes to like plasticity index and things like that. But for most people, most applications if You know the water content and water potential and you understand that relationship? It tells you pretty much everything you need to know.

CHRIS CHAMBERS 10:07
Any comments on that can go straight to Leo Rivera.

LEO RIVERA 10:12
Or Brad just one of us

CHRIS CHAMBERS 10:15
know Yeah, okay, let’s, let’s take that a step further. So now we have and really this is a lot more of an issue because water potential matric potential used to be a lot harder to measure, right? I mean, how long did it How long did we spend developing the terrorists? 21?

LEO RIVERA 10:34
You mean? How long are we still spending?

CHRIS CHAMBERS 10:35
How long? When is the tariffs 21 going to be fully cooked? Yeah. But now we’re pushing the measurements down getting some reliable readings at the permanent wilting point and below. So it’s that readings a lot more accessible. Do people really know what to do with those together? Now we’re kind of getting into, we can get water content and water potential pretty, pretty reasonably and get kind of make accurate soil water retention curves in the in the ground? Yeah. So what? How do people use that? What do we do with this extra with this extra power?

LEO RIVERA 11:17
Yeah, that’s, that’s a really good question. I mean, you’ve talked about the amount of time we spent developing these centers, which has been challenging. And we’re still continuing to push that. In order to really, I mean, we are now at a point where I think we can really utilize these tools in the field, to characterize the soil hydraulic properties in a way that we haven’t been able to do before, and where we’ve relied on laboratory methods to do that. So I think there is a lot more power in our capabilities now. Now, I will say that I think we need to keep pushing the boundaries in terms of what we can do with the sensor. Right. But for most, a lot of applications, these sensors are super powerful now. Yeah. I mean, the with what we’ve worked on what the solid matrix sensors like the TEROS 21, the gen two version. I mean, its capabilities are so much further than they were 20 years ago.

CHRIS CHAMBERS 12:14
Yeah, exactly.

LEO RIVERA 12:15
Yeah.

CHRIS CHAMBERS 12:16
Okay, let’s take a step back, because I just kind of threw a new term in there, and we didn’t stop. Soil water retention curves. It’s the relationship between the water content and soil suction, you know, hit the matric potential. And it’s my experience with with making that with collecting data, and then fitting the curve to make that relationship is it’s a pretty involved process. And for a long time, it’s been, you know, kind of a specialized area of science. But now it’s more and more available. So why don’t you tell us a little bit more about? Okay, what do we do with the soil water retention curve? How, why is it so important? And yeah, well, how is it traditionally done?

LEO RIVERA 13:06
Yeah. Well, you know, we often refer to the soil water retention curve being the finger fingerprint of the soil, right. And because it is unique, every soil has its own retention curve, because there’s different property and intrinsic properties that shape how that retention curve looks and what that means. Historically, there’s been a lot of different ways that we’ve had to make these measurements and the you can’t use one device, one instrument one tool to make the full retention curve. So typically, you know, in the past, we’ve used tools like pressure plates, and filter paper method, which not a big fan of and if I hear you’re using filter paper method, I will be sad. No, sorry, to all my engineering friends out there. And then we have tools like the dewpoint techniques like with the WP4C that have really pushed our capabilities of understanding the dry end capture the dry end of the of the curve, but we still needed to make improvements. There’s tools like hang water columns, which are great. And one of our colleagues here in METER group absolutely loves his hanging water column. And, and they are really powerful for doing certain things. But then we have tools like the HYPROP now, that have really simplified our ability to characterize the wet end of the soil moisture release curve. And now something that a measurement that historically has taken several months to complete, which is why it’s probably been so specialized, because it takes so much time and it’s not easy to do, can be done in in a week typically right to make characterize the full curve. And we aren’t now have new tools, like the VSA that can help us even further understand what’s happening on the dry end of the moist, really secure fish tells us a ton of information.

CHRIS CHAMBERS 14:56
Okay, and so now we’ve got all the specialized equipment general, generally, generally, the data and using the data and making that thing has been confined to its own special branch of, of science. But now that, like right now we have 1,000’s and 1,000’s of sensors in the field together collecting data that is really parallel to that process. How? How does the how does the field observations that are being collected right now? How would they compare to the lab? Are we sacrificing some data quality on those is the analysis a little bit trickier, because, you know, you have to have a range of basically water states of the soil, right? Saturated to some, some, some spread of data points to capture the variability right to make this curve. And so, you know, you might be waiting some months, if you’re in the wet season, you might not really get much of the curve. So, how do you put that together in the front field data?

LEO RIVERA 16:04
Yeah, it takes time. That’s, I mean, that’s really the the, the, the final answer is that it just to get a proper retention curve in the field, you need a good season, or a couple seasons of data, sometimes you have to give a whole range

CHRIS CHAMBERS 16:21
Or part of the range who so do you need to get down to permanent wilting point, do you think?

LEO RIVERA 16:27
I mean, it depends on what you want to know?

CHRIS CHAMBERS 16:29
Mmm good point.

LEO RIVERA 16:30
Do you care? I mean, do we care about permanent wilting point, which if you’re worried about, you know, plant stress and that type of things? Yeah, I think it’s good to get down there. And, which that’s pretty doable in most cases unless you’re irrigating heavily, or not heavily, I mean, trying to irrigate and keep things within that range, you might never hit that. So it depends on how you have your sensors. Right? And what the field practices. Yeah.

CHRIS CHAMBERS 17:01
So there’s still going to be times when the lab lab analysis is absolutely necessary, because then you control the environment. You can you can make the curve as as broad or as small as, as you like, right.

LEO RIVERA 17:14
Yeah. Now, I mean, you can do quite a bit more within the lab and do it faster, which is the power but you know, there’s more power and also an understanding what’s happening in the field. Right. So

BRAD NEWBOLD 17:30
So I don’t know if we’ve, if we’ve hit this one, but along with moisture release scores, how does how long does it take to make a moisture release curve in the field? With NCT sensors?

LEO RIVERA 17:41
Yeah, I kind of touched on a little bit. But really, ideally, you’re going to need six months to nine months worth of data in most cases. Because if you’re really trying to get a proper retention curve in the field, you need a good wetting and drying period. And, and, for example, we have some sensors installed on the soccer field right now. And our sorry, we have a soccer field that we outside of our building. Just to explain that we’re we’re we have an irrigation project in place where we’re trying to control based on evapotranspiration and the water content, water, potential data, and really fine tune our irrigation practices. But you know, it’s going to I won’t have a full in situ retention curve from those until probably November. And I installed the sensors a couple weeks ago, actually a week ago now. So it just, it takes time, it also depends on your climatic conditions, which you’re going to hit. But but it also is, you know, something that you need to understand is that water, so much release curves, we talk about letting versus drying curves, but there’s really the scanning function that happens when you’re going back and forth. That’s why when, you know, we oftentimes see people try to use one portion of the soil moisture release curve to try to understand what’s happening in that completely in the soil. And there’s risks when you do that, because wetting and drying behaviors are different. And then when you’re in that scanning curve, it can be different and that’s why when you have that actual physical measurement of water potential in the soil, you know exactly what’s happening. And then we can fully understand those properties and how that and how that behaves. And yeah, anyways.

BRAD NEWBOLD 19:21
You have talked about some of the practical applications for soil moisture release curves. Are there any, any others that that you feel like our audience would would really need to know or understand about how soil moisture release curves would be able to impact or affect or help their their research and their studies?

CHRIS CHAMBERS 19:42
And not just research for this? Because there’s a lot of, one, and this is where we’re kind of on the cusp of, you know, making these data, making these data presentable and, and presenting it in a way where people can absorb the information from the soil water retention curve and decisions on it. And there’s there’s a lot of really interesting possibilities coming up. A few years ago, how long was it get when we had the big floods?

LEO RIVERA 20:14
Oh, yeah. It was right around the Palouse here that was probably four years ago now?

CHRIS CHAMBERS 20:19
Gosh, doesn’t seem that long ago. But as a center company, you can imagine what like we install stuff all over the place. And just to see, well, how’s this gonna react here and there. So we, when we had a torrent of rain, just over a short span of time, I can’t remember it was over a couple of days. Yeah. And a week for sure. And, you know, but it wasn’t, it wasn’t an insane amount of rain, we’ve gotten that much precipitation before without flooding. And in this particular case, all of downtown Pullman flooded, there was flooding all across this region, Moscow and, and we went back and looked and looked at some of our sensor data across the region. And what was interesting is that, we could see that in this case, we’d had a freeze, a lot of the pore spaces had filled up. And the different part about this was that there was no place for the water to infiltrate into the ground. And our if we didn’t have both tension to realize that, hey, we’re at saturation, and the water content for how much water was in the pore spaces, you know, that, that there was a large volume of water there. We also had some stream depth type sensors around and looking back, it was easy to see that, oh, of course, this is going to flood if we get this much more precipitation. Yeah. And so that’s an area where not just soil water retention curve, but the soil water retention curve, plus some stream depth and some precipitation. And we can start making really good models without having to do extensive soil, you know, soil type, yeah, kind of classifications to be able to predict this kind of event. But getting that information in a consumable form is kind of a trick at this stage.

LEO RIVERA 22:17
Yeah. Yeah. It was funny when this was all happening. When the floods were starting to occur. We were all nerding out looking at everybody. Yeah, and, but what’s really, I mean, when you go back and look at it, if you look at the storage that was occurring in the soil, and how you could actually see the profile filling. And we saw that in both water content and water potential data where we were approaching saturation at deeper depths, and it was moving its way up to the surface. That was like, oh, yeah, there’s not much storage, capacity storage capacity left in the soil. And now we have a much greater risk of flood and then we got more rain, and we had flooding, right. And so that’s, you know, I think we’re seeing more of this, we’re seeing more adoption of soil moisture sensors and things like that, and water and water potential to in these big weather networks now, because they’re starting to see that this is an important parameter for understanding things like this and also understanding other weather dynamics. And so it’s, it’s I’m really excited to see the future where that goes and how they start utilizing that information. And when we start getting these big networks of water, water content and water potential out there, how it’s going to unlock so much.

CHRIS CHAMBERS 23:29
It’s with the irrigation potential to precisely manage irrigation. You know, it’s the, it’s really kind of the simplest way to set your irrigation set points based off of matric potential, right. But then with other factors, like the VPD, you’ve got your refill points with matric potential, and then you have how much water is stored in the soil with water content? Yeah, so you can calculate with a few estimates of ET, how long it’s going to be before you hit your refill point and how much water you’ll need to add precisely. So this, the soil water retention curves can be extremely valuable in that type of an that type of application as well.

LEO RIVERA 24:11
Yeah. And Brad to add one more to that, you know, list of areas that retention curves are starting to bring a lot more power. We’re seeing on the geotechnical engineering side of things and what we’ve learned from the the drying characteristics of the soil moisture release curve, that not only can we use it to understand, you know, plant stress and things like that and potential for flooding, but also soil mechanical properties and in properties about the clay, the type of clay that’s in the soil, the can ion exchange capacity, the specific surface area like there’s all these properties that all that information is actually in the retention curve. and combining that with a few other things is really going to unlock a lot of things in terms of simplifying the way we characterize soils for engineering purposes as well. And there’s researchers like Ningaloo, Bill Lycos, and others that are doing some really awesome work in this area. And, and putting a lot of papers out and working on new methodology to simplify these. These tests that sometimes also, again, take time, take weeks take months to collect data on and, and being able to do all of that with one curve that takes less than 24 hours to to get oh its going to be so cool.

BRAD NEWBOLD 25:37
All right, anything else you want to add about soil moisture release curves that we feel we didn’t touch on?

LEO RIVERA 25:43
No, go out and measure so much release curves, they’re fun.

CHRIS CHAMBERS 25:48
Or they Yeah, or just think about the way that the the water stayed in your soil is develops over time, right? And you’re gonna have inputs and outputs. But these two variables are just kind of bring back what we’ve been talking about these two variables are the, the state of your water. And so if you can pay so much attention to the fluxes, the precipitation, the evapotranspiration, then the the model of how the water behaves in your soil is going to be more complete.

LEO RIVERA 26:28
Yeah. And I’ll just add that, you know, historically, I understand why people have steered away from making some of these measurements, especially water potential, because it involves tools that took a lot of maintenance so they are not easy to use, and um

CHRIS CHAMBERS 26:43
And -20 kPa is a little bit trickier to understand than 20%.

LEO RIVERA 26:48
Yeah, for sure. Yeah. And water potential is still one of the hardest things to teach in soil science. Like, it’s the thing that takes the longest time for people to comprehend. But once they do, they see like, oh, wow, this is such a powerful parameter. And now we’re working, you know, tools, the tools are getting easier to use, they’re getting better, they’re getting more accurate, more reliable. And, and so hopefully, it’s going to make it easier to adopt. And as we work on making them easier to install, the hope is that these are going to become more powerful tools for your more general users of this information. And so that’s, you know, we’re gonna keep working on that and trying to make the tools better. But it’s really fun to see what people are doing with it.

BRAD NEWBOLD 27:30
With everything that you guys have been saying about what a potential, and we feel and believe and understand it to be so critical. Why does it seem like we’re just now starting to talk about it so much versus, you know, compared to water content? Which is, you know, been around forever?

LEO RIVERA 27:48
It’s a good question. I think some of it has to do with the tools, like just how challenging it has been to measure them. But I also think, you know, if we think about, let’s just use the food industry as an example. And water activity, which is the same thing is, it’s the same with water potential, a different way of looking at it, in food. And what they’ve learned is that water activity tells us so much more about what actually is going to happen with that food product is the risk for mold risk for bacteria, how it affects the texture and taste of the food. And, you know, it took them a long time to move away from water content measurements of food to water activity. And sometimes it’s just, it takes a long time to change mindsets. And some of it is that again, water potential has been so hard to understand. Like, of course, they’re gonna be scared of it.

CHRIS CHAMBERS 28:40
Let me throw this out there. Let me challenge you with this though. Because is it just the accessibility of the information? Because sometimes you can if you’ve got matric potential, and this was this came up. Last year, I was just Well, I wanted to learn about some set points for growing tomatoes. You get into you dig into the literature, and it’s like, oh, you know, you can you want it at -20 kPa for this part of this development cycle and -40 kPa for this part of its development cycle. There’s a lot of information like that that’s already been done research is already available. Is it just not getting to the right places? And if not, how? How do we how do we get that message out further?

LEO RIVERA 29:25
Thats a good question. If you were to ask somebody, just let’s say somebody calls you up on the phone. Yep. And you ask them, Hey, do you know what your target market potential ranges are for your tomatoes? Oh, but they know the answer right now.

CHRIS CHAMBERS 29:38
I guess not. But you know, that information is there and is done.

LEO RIVERA 29:42
Yeah, it’s there. But how accessible is it and how, you know, this is in research. This is the challenge is writing research and getting the information in front of general users, which is oftentimes a role like extension groups and things like that. And I think that’s where we’ve maybe missed The mark a little bit is, you know, yeah there is a ton of… We see this in other industries, too, where people are trying to repeat work that was done in another industry 30 years ago. Yep. But that information, either is not easy to find, or they just didn’t take the time to find it, of course, right. But yeah, it’s just I, you know, I think it’s up to us as we educate, not just I mean, not just ourselves, but other folks that are teaching these things that there is this information out there and, and how you have to get it out there. Now, you’ll find those niche people who like dig through the dig through Google and find this information. But how many people actually do that?

CHRIS CHAMBERS 30:40
I don’t know!

BRAD NEWBOLD 30:42
All right. And so in this, in this instance, then if we have people if it’s an issue with, with getting that information information out there, or, you know, adoption of of this of this information, how would you then explain water potential to, you know, colleague or somebody who has already used water content? And then doesn’t see the need to use anything beyond that?

LEO RIVERA 31:05
Yeah, that’s a good question. And there’s, the first thing that comes to mind for me, is, is great if you know what your water content means, at that spot in the field? Can you apply it to another area if you move to another field? Or the thing is, we know that these properties are the we’re seeing the term a lot now, dynamic soil properties change around so as practices change on the land. As land use changes, or as we start, yeah, improving our growing practices, whatever, like starting move towards no tillage, or other things, these dynamic soil properties, which that moisture release curve is a dynamic soil property change. So what you thought the water content meant, a while back, doesn’t mean the same thing as these properties change. And so like, if you really want to understand what’s going on, you need to understand these values. And when we see this all the time with people who think oh, yeah, I’m doing great, my my turfs looking good, my potatoes are looking good. And then when you actually look at what they’re measuring in terms of water potential or water content, they’re either way over irrigating. So they’re wasting water, risking more chances for disease, or in like turf, turf. Areas where these invasive species can compete better if it’s too wet. This is a lot of things where if you actually were measuring and knew what was going on, you could still improve your practices, even though you think you know it so well.

BRAD NEWBOLD 32:35
As we come to the close of this episode, is there anything else that you feel like we need to cover hit when it comes to water potential water contents, or soil moisture release curves? Any final thoughts?

CHRIS CHAMBERS 32:51
I think at this stage, it’s a game of it’s a game of communication. Right? We we we actually know a lot about how to build these and how to collect the data. And we’re getting better at making the data available. It’s it’s the putting the information in the contact where people can, can make decisions based off of based off of the information or pull it all together in one place and be able to be able to add the context for either decision making or understanding the other variables in the process. So that’s, that’s where it that’s where it falls for me. And I hope we’ve got plans to work on that over the over the future and help to make that easier for people.

LEO RIVERA 33:42
Yeah, I think that about sums it up. I mean, we need to make this information, easier to understand easier to digest and, and continue to make these tools easier to use.

BRAD NEWBOLD 33:52
All right, well, our time is up for today. Thank you again, you and Chris, for taking time to share your insights with us and everybody in the audience here. Stay safe, and we’ll see you next time on We Measure the World!

 

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