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Environmental News

Discussion in 'Environmental Discussion' started by tochatihu, Oct 22, 2015.

  1. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Herbivores?

    Bob Wilson
     
  2. tochatihu

    tochatihu Senior Member

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  3. bisco

    bisco cookie crumbler

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  4. tochatihu

    tochatihu Senior Member

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  5. bisco

    bisco cookie crumbler

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    good on them, i hope it has some kind of good effect on something

    i think what the president doesn't understand is that hybrid cars aren't going to solve this puzzle
     
  6. bisco

    bisco cookie crumbler

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    yeah, thats another concern, there's no panacea.

    all we can do is the best we can do. i trust science for the best outcome possible, if given the opportunity
     
  7. tochatihu

    tochatihu Senior Member

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    Readers, behold Prof. Alvin Smucker of Michigan State. Find your own link. See that he buries new polyethylene sheets in soils. Thus water lingers in rooting zone and surface-applied fertilizer do as well, and crop yields increase.

    (As this is an ego thread) I will instead take polyethylene waste from above-ground use and bury that in Smucker-like trenches. Crops under -80 cm/yr rain and with possible further irrigation will be happier. The linger thing means 'yield' will come from less fertilizer. All that ought to be enough, but as publication in high-impact journals is a co-equal goal...

    I need to measure soil moisture at >>10 points through time. I understand capacitive (soil-moisture) sensors and Arduino, but needed in between is a sensor multiplexer.

    How nice, if I had funds to just buy Campbell AM32B and a 21X behind it. But this is one of those Catch-22 thingees, where serious funding follows Actual Field Results that require front-end investment.

    PC is not the best place to ask, but if any Arduino pros are lurking here, I'd like to chat.
     
  8. hill

    hill High Fiber Member

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    Plastic bed liners for farmers - hmmmm.... There's a lot of natural clay in many farming areas that does the same thing. Don't know - but I'd think that might be a safer/natural way to go. We are on a man-made lake in SoCal, and the bedding is clay. Very little percolation through it. The lake not only keeps our community several degrees cooler than the rest of the city, saving AC costs, but the lake now serves the local fire departments when the summer dry brush lights up from all of the local pyros.
    .
     
  9. bisco

    bisco cookie crumbler

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    any leaching from polythene pam?
     
  10. fuzzy1

    fuzzy1 Senior Member

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    ... and many other farming areas are without such clay layers.
    -------------------

    That Arduino angle sounds interesting, but I did only one such project, my very last thing before retirement. And it was also to measure an environmental parameter over an extended period, recording to an SD card. But just a single design means I was never a pro. And nearly eight years faded and stale, and not having migrated the development tools forward to my current machine, means I'd be restarting almost from scratch.
     
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  11. 3PriusMike

    3PriusMike Prius owner since 2000, Tesla M3 2018

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    Of course you need to bury deep enough to allow tilling for many years.

    Crops like strawberries, IIRC, are already grown with plastic on top of mounds to minimize evaporation and water via drip tubing.

    Mike
     
  12. fuzzy1

    fuzzy1 Senior Member

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  13. tochatihu

    tochatihu Senior Member

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    @1111 thanks just the same.

    Buried plastic trough in soil has been expounded by Prof. Smucker for a long time. We are talking about -20 and -40 cm soils, below plow action.

    If you are working soil with much clay, this is not for you. My spot has an amount so small it is not trivial to measure.

    As it so happens, other research here is on microplastics effects soil biology. Polyethylene is unlikely to be a bad player, but we will put it down there. Later to ask how nematodes etc. feel about that.

    One top-end* soil-moisture sensor (time-domain reflection) costs 8000 RMB in China. For this project and others related, 100 sensors would not be enough. So I am shopping (far) down market. A basic capacitive sensor including 1-chip transceiver at 70 MHz (more or less) costs a buck (amazing). Getting a large number of them to stand in line is the multiplexer (MUX) problem. After that, Arduino does 'analog to digital' and does comm to USB memory.

    So, both ends look easy, but MUX in the middle will stretch my skills. Arduino, for those who might care, is less than a microcomputer but does a lot of useful things and is basically a 20-dollar thing.

    For one project I would substitute a 3-pole, 20-throw rotary-contact switch for MUX. It's not a solution that post-boomers would ever imagine.

    Separate from burying plastic trash in soils, there is a lot of water-limited global agriculture done that cannot buy expensive soil-moisture technology. Disrupting that might not be a small thing.

    * Actually neutron-attenuation sensors are top end, but we'll let that go...
     
  14. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Sorry for being dense, a couple of requirements questions:
    1. Anything above the surface allowed or all buried?
    2. If buried, now deep?
    3. Is moisture as a function of depth required?
    4. Distance between sensors?
    5. Dimensions of field?
    6. Cultivated?
    7. Sampling duration and sample rate?
    8. Duration of operation before maintenance?
    Bob Wilson
     
  15. tochatihu

    tochatihu Senior Member

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    Dr. Smucker buries polyethylene at 20 and 40 cm depth and I'll do that under corn. Soil moisture vs. depth depends on a lot of things. Sensors will be as dense as I can manage, in few-meter-scale treatments. Bearing in mind that this pilot project has no grant funding. Smucker suggests that polyethylene will work for about 20 years. Its biggest enemy is UV light. After much less time I will take soil samples and give to folks looking at soil microbial functions. Will they like it, hate it, or not care? Also by then we hope to be doing metagenomics on soil critters.

    If I can make the MUX work, individual sensors will cost ~$10 each with import duties maybe doubling that. Very good time-delay reflectometers cost about $1000 each. Neutrons? Don't ask.

    Buried plastic is intended to increase time that rain (or irrigation) stays in rooting zone. Especially in highly permeamable soils, which mine (can I call them that?) manifestly are. Water-soluble fertilizers should act the same, so there will be low-fert treatments. Crops including corn are fertilized at higher rates here than any other country.

    It is a common arduino project to have one sensor in a potted plant with an LED going red when one is to add water. This is planned to take those toys out to real world and make them do useful work.
     
  16. fuzzy1

    fuzzy1 Senior Member

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    I am familiar with TDR from my first career, for tasks such as locating damage in a long electrical cables, or compensating the input impedance along an amplifier input's switching and attenuator section. But I hadn't heard of it being applied to soil moisture sensing.

    The first unit to come up said "The shortest TDR manufactured in the world is ideal for soil moisture measurements in scientific and engineering experiments such as soil columns." The sensing waveguide portion is merely 6 cm long. :eek: That means the primary signal (excluding multiple reflection bounces, if such are useful) is only 0.4 nanosecond long in air, somewhat longer in the medium being sensed. That is much shorter than anything I ever looked at, or could look at with the equipment on hand.
     
  17. bwilson4web

    bwilson4web BMW i3 and Model 3

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    If you were to consider:
    http://www.ti.com/tool/EZ430-F2013
    [​IMG]

    The Target Board is very affordable with:
    • 4 analog inputs, 10 digital
    • very low sleep current
    • wide input voltage (easily photo cell-capacitor powered, zinc cell-capacitor)
    • has an LED output light (flash counter or encoded data)
    • one USB emulator can handled all the programming
    • target board about the size of a USA quarter
    • very affordable
    • very rugged (automotive grade)
    Are you thinking of the KeeYees soil moisture sensors?
    https://media.digikey.com/pdf/Data%20Sheets/DFRobot%20PDFs/SEN0193_Web.pdf

    Bob Wilson
     
    #1118 bwilson4web, Dec 8, 2019
    Last edited: Dec 8, 2019
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  18. fuzzy1

    fuzzy1 Senior Member

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    I'll vouch for this series too, for very low power needs, at least as it existed before I retired.

    I don't know if such low power is needed for the soil monitoring application, but if so, this series was in a different universe than the Arduino cards I used for something else. These TI units (the target board at the tip, not the whole USB dongle) can be used with ambient energy harvest if the software is carefully built.

    The Arduinos I used were severe power hogs in comparison, requiring a plug-in power source (USB power adapter) for long term applications. Though much of that consumption was from the provided firmware environment, which could be tuned or rewritten (maybe some are already available) with energy conservation in mind. And the hardware I used was also not selected for lower power, there should be more choices now.

    If a continuous or otherwise adequate power source is available, then I see no problem in staying with Arduino, no need to consume valuable effort chasing down microamps.
     
    #1119 fuzzy1, Dec 8, 2019
    Last edited: Dec 8, 2019
  19. tochatihu

    tochatihu Senior Member

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    Digikey looks possible, but I do not want to power all sensors all the time. This is why I seem to need a multiplexer.