Hi, my name is Dr. Colin Campbell. I’m a senior research scientist here at METER Group, and today we’re going to be talking about water content. Let’s now talk about some practical matters.

Let’s focus in on installation. When you’re installing a sensor, you’ve basically got a couple of choices. You can use push-in sensors like the TEROS 12 or profile probes like the TEROS 54. Profile probes need to be slid or hammered down into the soil.

Now, that can be pretty effective in a lot of soils, but I’m showing you a soil here that I had a lot of problems on. This is up at a site that has a lot of rocks. It’s in a prairie, and honestly, I could only dig down to about 30 centimeters deep in the soil. Beyond that, my shovel, my fingers, it just wouldn’t work.

So a TEROS 54 isn’t going to do you a lot of good in this soil. Instead, I had to dig a fairly large hole, but I couldn’t even use an auger. I very carefully installed these sensors into the side of the hole. Now you notice in this install, all those sensors are still stuck into undisturbed soil. And we’re going to talk about that again.

That’s really important. Now, if you have a nice silt loam soil with few rocks, if you have a sand not a lot of rocks, one of the best tools we have out there is the TEROS 54. Put that sensor in, you’ve got 15, 30, 45, and 60 centimeter depths, and you’re good to go. It even has a de-install tool that gets you out of the field quick.

But maybe you don’t want those exact depths, or maybe you can’t get that probe into your field. So let’s talk about what you might do if you need other choices. If a profile sensor is not going to work for you, you’re going to want to check out something like the TEROS Borehole Installation Tool. A lot of people out there are still digging pits in the soil. I went on a customer visit just recently, and we talked about it.

Now, if you really need to do that, you should especially where you got a lot of rocks, like I did up on the Wasatch plateau. But one of the things that we’ve done lately is made progress in this ability to install sensors at depth. In fact, with this tool I’m showing you here, you can install any depth you want to, down to a couple of meters or more. Now, what it does is simply use a mechanism on the bottom here to insert the sensors into the undisturbed side wall of a borehole.

What borehole you ask? Well, we just can bore down with a 10 centimeter or four inch auger and get to any depth we want. If you have a lot of rocks in your soil. This is going to be challenging, but if you got a decent soil, I’ve installed a lot of these sensors at depth with this install tool, and it’s amazing.

Let’s talk a little bit about best practices when you’re in the field, it’s easy to forget great installations when METER gives you such an easy system to take in the field and install. In fact, my last installation took about 25 minutes at the several sites I was installing. It was amazing. But if it goes so quickly, sometimes we forget about the things we have to do to make sure it lasts a long time so let’s talk about that.

The first thing you want to do is make sure you install those sensors right in the pit wall into undisturbed soil. Now here we were going in a sports turf field, and we didn’t use the installation tool because of the application, but you can see we were sticking those sensors right into undisturbed soil right there. So that’s job one. The next thing is, and we didn’t do it here, use an installation tool.

As I just mentioned, these tools can reach down to a meter, two meters or even more, and get your sensors into undisturbed soil. In fact, I don’t see any reason why you wouldn’t be using an install tool if the soil was appropriate, if you’re not fighting through rocks, etc. One other application you might think about is that if you’re in a really fine sand, you might get the bore hole to collapse on you.

So a couple things that might challenge you, but in general, use an installation tool. Another thing, take care of your cables.

Your cables need to be protected by wire loom, by some kind of plastic tubing, or if you are like me, I put aluminum conduit out there. And notice in this image, they’ve got a nice length that’s going all the way up their T-post here, near their data logger, and it’s going over into the soil. Notice they have a length of tubing right nearby, and they can bury it 10 centimeters deeper, more in the soil, so the rodents just can’t get to their cables.

Now, a couple other things to think about as you’re out in the field, you often know, think about this when you set up your data logger, but pick a measurement interval that meets your needs. If you measure at one minute intervals or five minute intervals, you’re gonna have a lot of data, soil water content doesn’t actually change on that frequency, typically. Maybe if you have preferential flow down to your sensor, but typically, you’re going to see it change over 5, 10, 15, 20 minutes or more. I typically run my field sites at around 15 minute intervals.

And finally, how many sensors you’re going to put out in the field? This is something you’re going to think about way before installation, but something you got to consider, how much variability are you trying to capture out there? Also, how much budget do you have to make those measurements? Now, I’m not going to tell you a great solution to this problem, but it’s something out of think about, and it’s also a thing you could go learn more about in our knowledge base.