RE: [compost_tea] Re: Water Quality

From: John Cowan <vivax_at_northlink.com>
Date: Sat, 10 Apr 2004 12:52:48 -0700

Yes, it is confusing. Labs and analytic tests make it seem so accurate.

Salts are solids. In wastewater and other water situations, dissolved salts
are by far the dominant dissolved solid. To check water, simply stick the
meter or its probe in and read. For soil, the situation is different. Reams,
Skow, and Pike use the 1:1 ratio for measuring the conductivity of soil.
That it 1 part settled soil to 1 part pure water. Shake in a seal jar for 1
min and let settle for 1 min then take a reading. Other labs use different
ratios. The same goes for pH measurements.

Salts in a soil solution are not necessarily problematic. Increasing
microbes can release salts as well as chelate salts incorporating them into
tissue. This varies greatly on the area and soil. The bottom line for plants
is are they healthy. Taking a simple brix reading of the plant juice is by
far the simplest method for a quick assessment. Generally, though, you
aren't going to have high brix without a strong and diverse microbe
population along with mineral diversity (especially trace minerals).

By the way, some people fear sodium in the soil yet sodium is a necessary
nutrient. The question is how much, in what form and in relation to other
minerals.

John Cowan
  -----Original Message-----
  From: Ted Peterson [mailto:ted.peterson_at_tcsn.net]
  Sent: Saturday, April 10, 2004 12:22 PM
  To: compost_tea_at_yahoogroups.com
  Subject: Re: [compost_tea] Re: Water Quality


        John:

        I work a lot with the Wastwater industry and they commonly refer to
TDS for salts not solids. It seems that the two mean the same thing and I
guess it's just a semantical problem. Every citation I can find on the net
for TDS talks about measuring salts from whatever source. The lab I use for
testing is A & L in Fresno, CA. I asked them about a year ago what TDS
meant and they said Total Dissolved Salts however, the book they sell to
interpret their reports lists TDS as both solids and salts and the index
lists the same page. So, I'm not as wrong as I thought. That's kind of a
relief.

        You know it is funny because Elaine says the biology will take care
of the salts. However I have tests that show that ACT worked as it should,
the plants are healthier and root systems extended yet the salts are higher
in the soil tests.

        Anyway, below is one citation and following your message is another.

        Ted Peterson
        Earth-Wise/Spirit of the Earth
        Dissolved Salts Meters
        High levels of soluble salts in the soil can be caused by excessive
fertilization, insufficient watering, poor drainage, or by some contributing
salt water intrusion. High concentrations of soluble salts can inhibit plant
growth and will reduce overall crop yields. Greenhouse plants and other
sensitive crops may be damaged if soluble salts exceed 2000 ppm.
        Soluble Salts, or Total Dissolved Salts, are measured by means of a
Conductivity Meter. A conductivity reading measures the capacity of a
solution to conduct an electric current and is directly related to the total
ionic concentration of dissolved substances in the solution. Thus, the
conductivity reading of a soil extract can be converted into a reading of
Total Dissolved Salts to indicate combined levels of sulfates, chlorides and
other salts in the soil. Extract is prepared using distilled water, not
included with meters.




       Digital TDS Meter

       Waterproof TDS PockeTester 1



  ----- Original Message -----
    From: John Cowan
    To: compost_tea_at_yahoogroups.com
    Sent: Saturday, April 10, 2004 10:36 AM
    Subject: RE: [compost_tea] Re: Water Quality


    Ted,

    TDS does stand for total dissolved solids

     John:

    Also See below. . .
    Total Dissolved Solids

    General Information:

    Measures the amount of salt dissolved in the water. Salts are chemical
ionic compounds. Salts affect the survival chances of marine life through
controlling osmotic pressure. If a water body has a high level of salt,
aquatic pants and animals that are not adapted to high levels of salt will
not be able to retain water.

    Different species require different levels of different salts. Some need
low levels, while low levels of other salts can be inhibiting to other
species.

    Generally a high flow will lead to lower TDS readings, while a slow flow
has the opposite effect.

    Sources of pollutant?

    Dissolved solids occur in:

      a.. ground water seepage
      b.. industrial and sewage discharge
      c.. Urban, industrial and agricultural runoff
    Test Method:

        1.. Submerge the twin probes of the meter in sample
        2.. Record the result as displayed on the LED display in mg/L.
    Results interpretation:

    Adverse biological effects can be expected in Australia if the result is
above 1000 mg/L. The desirable limit for humans is 500 mg/L. (ANZECC, 1992)


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Received on Sun Apr 11 2004 - 23:15:05 EDT

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