Re: [compost_tea] Re: Water Quality

From: kevin john richardon <kmagic_at_backpacker.com>
Date: 11 Apr 2004 13:36:37 -0000
How does Dr. Maynard Murray's work with sea water and agriculture relate to this dicussion.  Ive been trying to make time to study this yet havnt much so far. 

My impression is that salt is not just salt.  That type and concentration will be factors.  Possibly conversation necessitates plant and/or biology category specific distictions?  Sweeping generalities are nice to work/learn with in order to use/comprehend the basics.

Any body got the qwik and dirty?

~K

On Sat, 10 Apr 2004 12:22:21 -0700 Ted Peterson <ted.peterson_at_tcsn.net> wrote:
      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)



Kevin John Richardson    
Local Solutions
(781) 834-0474

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Received on Sun Apr 11 2004 - 23:15:14 EDT

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