Hi all, I really appreciate the insights into the different soil moisture systems that are available. In addition to a lot of first hand experience and recommendations I received a number of requests to share the string of responses. As a result I have listed the responses and associated links below. If people are interested in following up with a specific comment they can reply to this string and I will forward your email to the person that replied to me.
Again thanks for all your insights, Eli *Response1:* We have an experiment where we use SML with remote capability so that you can receive data online. Spectrum Technologies has them. Check it out below. http://www.specmeters.com/soil-and-water/soil-moisture/soil-moisture-sensors/ *Response2:* These guys are new but their very affordable equipment comes online this summer - check it out. We will be testing it out this coming field season, so I can't offer any firsthand experience with their monitoring equipment, but we helped with some beta testing of their early prototypes. http://www.arable.com/ <http://www.arable.com/> *Response3:* I spoke to a colleague of mine at Colorado State University (Ryan Webb, Phd Candidate in Civil Engineering/Watershed Science, studying water movement in the vadose zone under snowpack) about your question. He said: I was really happy with the Decagon loggers and sensors, but I was not using the remote access loggers, though they do make them. The logger I was using with the soil moisture sensors lasted quite well from December 2013 through June 2015 and I never had to change out the six AA batteries. Ryan was working at a semi-remote mountain site near Steamboat Springs called Dry Lake. *Response4:* I have some soil moisture loggers installed in the Peruvian Andes, they have been operating for over a year now. I used these loggers and probes: https://www.instrumart.com/products/37241/madgetech-smr101a-soil-moisture-data-logger which I purchased from Madgetech directly: http://www.madgetech.com/ Unfortunately I don’t see them listed on their website anymore, but you could contact them directly to ask. They also offered a pretty good educational discount (20% I think). A similar option is this: http://www.omega.com/pptst/OM-CP-SMR101A.html I ended up enclosing each logger in a small pelican case and burying the entire unit for security purposes, which worked well even in a 90%VWC wetland. Deriving your own soil specific calibration curve is important for good results. I have also used the Onset Hobo probes (in reality all these options above use a decagon devices probe) connected to the microstation logger. This is a good (and cheaper) option if you want to install (up to four per logger) in a vertical profile. I also buried the entire logger once sealed in a pelican case. Batteries on this a fine for over one year. http://www.onsetcomp.com/products/data-loggers/h21-002 http://www.onsetcomp.com/products/sensors/s-smc-m005 I haven’t used any with remote data access (due to security concerns). However, there are some good options that use the Iridium satellite network. Alternatively decagon devices https://www.decagon.com/en/ offer some loggers that communicate via cell phone (assuming you have reception) and they also offer probes (which the companies above use). *Response5:* I had access to a site equipped with sensors from those guys: http://www.decentlab.com/#home Basically, if you have some kind of Internet access at your sites, you can have real-time monitoring of your data. I think that Campbell scientific (https://www.campbellsci.com/) also has some solutions. *Response6:* Sensorscope with Decagon sensors! http://www.sensorscope.ch/ https://www.decagon.com/en/soils/volumetric-water-content-sensors/5tm-vwc-temp/ *Response7:* I’m not sure if I’ll be a ton of help to you, but my previous research group had a long term soil moisture network (>5 years) that they recently set up to send real time moisture data across the country. The real time setup will have been running for about 2 years and as far as I know they are happy with it. I believe they sent the data using a cellular network and the equipment was all purchased from Campbell Scientific. Just make sure if you go this route to put a password on the cellular network or you may get hackers. Unfortunately, I wasn’t directly involved in this set up, but you could try contacting Dr. Aaron Berg or Dr. Tracy Rowlandson at the University of Guelph. *Response8:* In the past I have used Decagon data loggers and will use them in a research project I am starting in the fall. Here is a link to their website https://www.decagon.com/en/data-loggers-main/data-loggers/. I think the biggest problem with decagon data loggers is you either need to transmit the signal via radio device but you must be less than 1 mile away (I've never done this) or have a site that has access to a cell tower, which you probably do not have. It might be worth it, however, to call Decagon or maybe even Onset (I've worked with them as well, http://www.onsetcomp.com/products/data-loggers-sensors/soil-moisture), to see if they have any creative solutions for you. *Response9:* we normally use soil moisture sensors from Campbell Scientific moisture sensors https://www.campbellsci.com/cs655 https://www.campbellsci.com/dataloggers you can set up a data logger to hook up many sensors and leave them in remote locations. there are several options to collect data remotely. In some cases you can leave them with a good battery/ and they might go on to store data for long time. *Response10:* I work at NC State University, and we use Campbell Scientific TDR probes to measure soil moisture in situ- they are pretty robust and very common, and you can hook up more than one probe to one Campbell Scientific data logger. We also use Raven cellular modems to communicate remotely with the Campbell loggers. If you have cell service at your site, these are reliable over the long term. *Response11:* If you're a bit technically inclined, you can do this with an Arduino or better yet an ESP8266/ESP32. The trick would be getting the data onto the internet from a remote location. The ESPs come with built-in wifi, but that does you no good in the middle of nowhere. All of them could be potentially hooked into a cell network data module, but then you'd probably have to pay for the data. If you can manage internet access, you can send the data to thingspeak.com very easily. Alternatively, you could have the ESPs set up as a wireless router, that could run a webserver as soon as you got within wifi range. They're pretty low power and could run on solar and store 3-4MB of data with their integrated storage in the meatime. I put these sorts of things in plastic butter containers, which have a gasket in the lid and are pretty waterproof, ran one in our greenhouse for several months with good success. *Sensors:* -There are cheap soil moisture resistance sensors on amazon/ebay etc, but they don't have a long/accurate life: - A better option would be a capacitive sensor. You can make your own, or here's a relatively cheap one: https://www.tindie.com/products/miceuz/i2c-soil-moisture-sensor/ - Another DIY capacitive sensor: http://zerocharactersleft.blogspot.com/2011/11/pcb-as-capacitive-soil-moisture-sensor.html Regardless of the route you take, I'd recommend educating yourself on the difference between capacitive and resistive moisture sensors. And think about what your ideal sensitivity curve will look like. Most aren't linear, which means that the lower or higher end of the moisture gradient will end up with more resolution. Going the hobby electronics route means you may have to calibrate them yourself and spend a bit more time on them. The advantage though is that it would be much cheaper and more flexible--you could build an entire system for maybe $20. And you could add many more sensors cheaply, eg: temp/barometric pressure/humidity/light intensity. *Response12:* I read your question re soil humidity loggers. There might be a commercial solution, but if you are happy to get a tailored solution made for you I can point you to a company that is making weather stations that are solar powered and can send data remotely. They can be very easily upgraded with a soil humidity sensor and get all the data for you, store it on a SD card and send it to you remotely/upload to the cloud. Last time I asked them the weather station was about 400 EUR but it might have changed. As they are solar powered and use radio communication (not GSM) there are no other costs involved. The company name is SODAQ (sodaq.com) and the device is called Kukua (http://www.kukua.cc/) Btw, I don’t have any links to the company, but they were very helpful when I was look for a similar solution. *Response13:* In response to your Ecolog inquiry about remote soil moisture monitoring: Service providers might be region-specific, but we have had a fairly good experience with PureSense, owned by Jain Irrigation. They provide cloud-based data storage, an intuitive interface (and slightly less intuitive app) and installation. The probe models vary : we use AquaCheck which are straightforward to move/reinstall yourself. Senteks are a bit newer, but have the option of additional salinity measurement. Depending on the probe model selected, some will report soil moisture capacitance, some won't--be it's just a matter of including a correction factor for however you want to present the data. Depending on funds, you can also select more sensor-dense probes for finer resolution at various depths. We solicited bids from a few different service providers, including Hortau, but found they didn't meet our specific needs as well. Data can be downloaded from the platform, over long time frames as csv files. One caveat: most remote sensing platforms use wifi or a cellular network to send pulse data, so hopefully you have reliable coverage in your field sites. On Mon, Jan 11, 2016 at 4:05 PM, Eli Rose <[email protected]> wrote: > I was wondering if anyone had experience using soil moisture loggers to > measure changes in soil moisture over long periods of time. Our study > sites are remote, so ideally we would like to be able to access continuous > readings from a cloud based data system. Any suggestions would be > appreciated. > > Thanks, > Eli >
