Re: [compost_tea] Re: barometric pressure and compost tea Oxygen levels

From: David Loring <dloring3_at_cox.net>
Date: Thu, 9 Oct 2003 09:09:12 -0700

Tom - Thanks, that table is great. If you had that why do you say barometr=
ic pressure from one day to the next would account for changes in tea Oxyge=
n levels of more than about 0.5-1.0ppm? The second part of the question ha=
s to deal with how much the barometric pressure changes from day to day. =
 

I plugged in the numbers from the extreme low and high isobar map lines for=
 the entire United States again and and the range of dissolved Oxygen was o=
nly 11.1 to 11.4ppm from extreme low to high. So I don't understand what t=
he concern is about varying barometric pressure unless you're in a hurrican=
e?? It seems likely that it only accounts for a small percentage of the va=
riation in Robert Norsen's test results.

I think Roberts results are probably not caused by sampling errors (he seem=
s to be familiar with the use of his DO probe) or barometric pressure varia=
tions, but I do think there could be a lot of significant information tease=
d out of the data if all the conditions of the test were known. For instan=
ce, if the amount of compost added was small so that the lag time to maximu=
m Oxygen demand was more than 10-12 hours then I wouldn't look to the compo=
st materials to be significantly different given they were from the same ba=
tch. If the starting materials added were large, say more than 4oz per 5 g=
als. then it is more likely to make a difference in the way the bacteria co=
mpeted from the very start. I expect the answer lies in air flow, either f=
rom worn air pumps or older diffusers, if such were used. The diffuser in =
my Sotillo tank seems to have changed over the last year, not a lot, but ma=
ybe enough to make a difference if the demand due to high sugar additions w=
as high. If the air pumps used were of the cheap variety then their output=
 may have varied widely.

Dave
  ----- Original Message -----
  From: tomjasz
  To: compost_tea_at_yahoogroups.com
  Sent: Wednesday, October 08, 2003 7:13 PM
  Subject: [compost_tea] Re: barometric pressure and compost tea Oxygen lev=
els


  --- In compost_tea_at_yahoogroups.com, "David Loring" <dloring3_at_c...>
  wrote:
> Stop making me do so much math :-} >
> Dave



  OK,
  http://water.usgs.gov/software/dotables.html




        Yahoo! Groups Sponsor
       
       

  To unsubscribe from this group, send an email to:
  compost_tea-unsubscribe_at_yahoogroups.com



  Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.





Received on Thu Oct 09 2003 - 21:35:01 EDT

This archive was generated by hypermail 2.3.0 : Tue Feb 07 2012 - 14:14:49 EST