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soil moisture sensor plus ET timer experiment

Discussion in 'Irrigation' started by FIMCO-MEISTER, Sep 25, 2007.


    Messages: 18,668

    If I didn't think this had a good chance of being successful I wouldn't attempt. In an effort to fine tune the WM Smartline + weather monitor ET based watering system that I have I'm adding a Baseline Watertec S100 to it.


    Now the limitation that the WM SL has is that it does not accurately measure rainfall. It is a traditional wafer type sensor. An upgrade to a tipping rain gauge would not improve this much since a tipping raingauge isn't going to measure a 2" rain in 30 minutes any different that a 2" rain over 6 hours. A more accurate assessment of watering needs can be made by an accurate and properly installed soil monitor is the basic hypothesis to all this.

    To set this all up I upgraded my WM SL panel to the latest version. This allows me to set the ET monitor rain delay manually. I adjusted my monitor rain sensor to 1/8" which is the most moisture sensitive setting. I zeroed out any rain delay so basically when it drys out watering can resume. Now on the Smartline is a second sensor port for break in the common type sensors. WM tells me it is okay to still use this port and it will also shut down the system. When the system has been shut down by this sensor port the ET data will still continue to accumulate. The ET data is only cleared by rain or manually clearing. The auto adjust setting will not override the secondary sensor unless put on sensor bypass. Anyway I'm not going to describe all the install details but want to mention that one sensor is being used for the whole system. Where Henry is standing is where it was installed. I chose this spot because it drains well, watered by MP rotators, gets dry just a tad faster than the rest of the yard, and the valve isn't too far away. Right now the sensor is going through a 24 hour threshold calibration.






    Messages: 18,668

    The first pic is my neighbors mulberry:hammerhead: :nono: :dizzy: ;) :angry: The others are the install it is 4.5" below the rhizome area of my St. Augustine. (No Kiril I'm not getting rid of the turf) That turf gets two organic fertilizations a year. I'm constantly getting flyers from chem lawn who desperately want to ruin it so the neighbors will quit hassling them about why mine looks so good and theirs looks like crap. :rolleyes:





  3. Kiril

    Kiril LawnSite Fanatic
    Messages: 18,334

    Good deal. Keep in mind it may be next spring before soil conditions around the sensor are representative of the soil in that area again.

  4. Ground Master

    Ground Master LawnSite Senior Member
    Messages: 505

    How much does the baseline system cost?

    Messages: 18,668

    I know. (NOT THE TURF PART, DON'T YELL AT ME) I'm going to adjust the threshold down after the calibration is complete.

    Messages: 18,668

    Seems like it was around 125.00 at ewing.

    Messages: 18,668

    Well the threshold was set at 39.4. The sensor read 44 and in two days has dropped to 41. It will not resume watering until it drops below the threshold. This first watering may take a while since I had to saturate the sensor location. In the meantime the WM SL is still accumulating deficit and adding minutes to the zone run times. I've changed my days allowed to water from twice a week to every day since the sensor will be keeping it from running when it is above the threshold. Debating whether or not to set a higher initial threshold because the area of the sensor has been disturbed and may allow for faster water penetration than the yard as a whole. After 6 months or so I'll set a lower threshold again.
  8. londonrain

    londonrain LawnSite Silver Member
    Messages: 2,129

    I am keeping an eye on this thread so keep us posted ...
  9. Kiril

    Kiril LawnSite Fanatic
    Messages: 18,334

    Quite likely.

    Before you do anything, could you be bothered to setup a small experiment?

    Setup a grid like you would for measuring DU and take some moisture sensor readings with your Lincoln at the same depth as the new SMS.

    Messages: 18,668

    I had the same thought as well. I'm noticing the back St aug leaves are curling a tad but I'll do a grid this afternoon. I probed the area in the vicinty of the sensor and it was all saturated but I think Henry left the hose on the ground running so a large area around the sensor got extremely wet.

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