I don't do a lot of work with nitrogen but the way I've done it in the lab was determining the total N through combustion.  Then we determine the organic N through a mineralization incubation study.  That is the organic N fraction.  Then we subtract that from the total value and the difference is the inorganic N fraction. 

What's your email?  I can send you a few methods I have and you can see what is best for your study.  The one I outlined is probably the easiest and most basic.  

Hi Tabrika, have you thought about using the soil method for NO3 and NH4? Where you could extract with 2M KCl and read the extract on flow injection analyzer (or any other colometric technique)

Dimpho hit it quite well. However the extract is likely to contain many soluble organics and a high organic concentration.  Most soil methods will not accommodate these high organic concentrations and I do not suggest heating in the presence of base to distill the ammonia as that may hydrolyse organic N. The solution may be to minimise the soluble organics using activated charcoal. Dazotization methods have the potential to discriminate between nitrate and nitrite.  There are higher tech solutions based on ion chromatography.  It may be possible too to use ion selective electrodes for nitrate and ammonia.  In the case of NH3 I would suggest the gas diffusion type of electrode.

HI Dimphon, this article describes methods that you can use with KCL 2M. (look at the following reference : APHA 1985)

Thanks Patrick for your attention, I'll be blissful to read methods that you have, ([email protected])

 Total N can be estimated by combustion method.But incubation method may not estimate all the organic N.It  may mineralize only 50 per cent of total organic N.So it is difficult to get mineral N by deducting mineralized organic N from total  N.One can extract mineral N by extracting with 2 M KCl and extract clarified by treating with acivated charcoal as suggested by Dr.Paul.After that ammoniacal and nitrate N can be estimated any of the methods suggested by colleagues like Dr.Elephant.

I'm gratefull to you Dr Annangi and Dr Paul for all supports i received

Hello Drs.

Please suggest the dose of botanicals being used for the enhancement of plant growth under field conditions.

Regards

Rizwan Ali Ansari

Is there a specified activated charcoal to use, and is this done post 2M KCl extraction?. Does anyone have a reference paper for this?