My mistake or bad English.
1 gram of ammonium nitrate (solid) or any other fertilizer has a standard EC ( that is a standard made by dissolving 1 gram of ammonium nitrate in 1 dm3 in distilled water at 25�) That means all products sold as ammonium nitrate must have the same EC the importance of EC is there because in your way it will be always be 1 gram per liter or 1 kilo even if it isn�t ammonium nitrate.
I have a standard for liquid ammonium nitrate which is 18.0% N, EC 0.86 for magnesium carbonate it is the same process sorry I cannot help with the standard EC. This is a quick way of knowing is the fertilizer is within its standards. I know that you probably use also PPM instead of mmol as I am used to.
Regards
Martin
At 04:16 p.m. 17/01/05, you wrote:
I disagree, Martin. While those various international conversions may be "norms," they are by no means "standards" as they simply cannot be:
If I dissolve magnesium carbonate in one beaker of water and ammonium nitrate in another, adjusting so the true dissolved solids contents are equal, I guarantee you that the EC's won't be! That has nothing to do with a "standard conversion," it has to do with the charges and mobilities of the ions in solution.
Ray Barkalow - First Rays Orchids - www.firstrays.com
Plants, Supplies, Books, Artwork, and Lots of Free Info!
.
----- Original Message -----
From: Martin Boekholt
To: the OrchidGuide Digest (OGD)
Sent: Monday, January 17, 2005 1:39 PM
Subject: Re: [OGD] EC & TDS
Ray,
EC is used by most growers and companies to have an international standard because TDS is not a standard worldwide so the conversion factor depends on manufactures and countries for example.
USA 1 mS/cm (EC 1.0) = 500 ppm
Europa 1 mS/cm (EC 1.0) = 640 ppm
Australia 1 mS/cm (EC 1.0) = 700 ppm
Because of the difference in those conversions EC is a safer unit to avoid problems that�s why most fertilizer have a standard EC value. The value of fertilizers in ec in based upon 1 gram in 1 dm3 distiled water at 25�C.
Regards,
Martin
At 05:36 a.m. 17/01/05, you wrote:
Thanks for the input Steve, but my discussions with several commercial growers (all non-orchid) in the area, plus the local field guy for the Pennsylvania Dept. of Agriculture (who primarily deals with food crops and bedding plant nurseries) give me the opposite - interesting enough in its own right.
Besides, if that was the case, why is it that labels on commercial fertilizers or their bulk components typically provide an EC table, but not the TDS?
In any case, my inquiry was not intended to start a debate on the relative importance of the measurement, just how it came to be the predominant one of the two with orchid growers. Maybe I should narrow that to "hobby" orchid growers, as I have not heard from any large-scale commercial growers.
Ray Barkalow - First Rays Orchids - www.firstrays.com
Plants, Supplies, Books, Artwork, and Lots of Free Info!
.
----- Original Message -----
From: Steve Topletz
To: the OrchidGuide Digest (OGD)
Sent: Sunday, January 16, 2005 11:46 PM
Subject: Re: [OGD] EC & TDS
In speaking with my friend who has a degree in horticulture, he says
that TDS isn't unique at all to orchids, and that TDS, EC, and pH are
very important for all commercial greenhouses, orchids aside.
Ray> In speaking with scientist at several fertilizer companies, I have
Ray> learned that focusing on TDS is pretty much unique to orchid growers, while
Ray> just about everyone in any other horticultural segments thinks in terms of
Ray> the EC (electrical conductivity) of the nutrient solutions.
Ray>
Ray> Given the facts that TDS meters are just EC meters with built-in
Ray> conversions, and that the ionic makeup of solutions affect the EC, giving
Ray> different conductivities for the same true TDS, it is a poorer measurement
Ray> in the first place.
Ray>
Ray> Does anyone have any factual background as to why we focus on TDS?
Ray>
Ray> I'm not looking for the usual comments about some plants needing very
Ray> pure water or anything like that, but instead, some specific basis for TDS
Ray> rather than EC.
Ray> Ray Barkalow - First Rays Orchids - www.firstrays.com
Ray> Plants, Supplies, Books, Artwork, and Lots of Free Info!
Ray> .
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http://orchidguide.com/mailman/listinfo/orchids_orchidguide.com
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http://orchidguide.com/mailman/listinfo/orchids_orchidguide.com
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