Re: [compost_tea] low phosphate?

From: Vida na Terra <vida-na-terra_at_oninet.pt>
Date: Fri, 17 Sep 2004 22:29:11 +0100

Hi Lynton,

It sounds to me that the data given is for available P. When samples are se=
nt to the labs you should specify that you want also to know the Total P.

For example:
                Available P Total P
                   (mg/l) (mg/Kg)
                     52.8 High 1099 High
                    114.0 V. High 1644 High
                      40 OK 275 V. Lo=
w

My question is:
        
Is there a maximum or a High for the Total P ?

Joao


  ----- Original Message -----
  From: soilfoodweb_at_aol.com
  To: compost_tea_at_yahoogroups.com
  Sent: Friday, September 17, 2004 1:40 AM
  Subject: Re: [compost_tea] low phosphate?


  Hi Lynton -

  I'm not really clear on what the reply from the person was, because the f=
ollowing is not a reply that makes any sense.

  Also total P (Bray-2, as done by agri-energy www.agrienergy.net) is
  very low (77kg/ha - compared to 620 kg/ha 'desired').--->

  Do they understand what a Bray -2 extraction actually measures? It does =
NOT give total P. Not by a long shot.

  Total P has to be extracted using a strong acid, like sulfuric, or hydroc=
hloric. A Bray 2 only gives tiny proportion of the P that is actually pres=
ent in the soil.

  A huge number of species of bacteria and fungi can extract P from the soi=
l. All those mycorrhizal fungi are great at doing this in addition. They =
can access literally thousands of micrograms of P that a Bray 2 will not ev=
en begin to extract, if you gi vetheorganismsthechance. Just like people, =
however, soil organisms need air, water, food and housing.

  Supply these things, and what is extractable by a Bray 2 will suddenly in=
crease by many fold.


  Elaine R. Ingham
  Soil Foodweb Inc., Corvallis, Oregon
  Soil Foodweb Inc., Port Jefferson, New York
  Soil Foodweb Institute, Lismore Australia
  Soil Foodweb Institue Cambridge, New Zealand
  Soil Foodweb Inc., Hilversum, The Netherlands
  Laboratorios de Soil Foodweb, Culiacan, Mexico
  Soil Foodweb Inc., Jerome, Idaho


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Received on Fri Sep 17 2004 - 19:32:07 EDT

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