I understand your concerns but unless OM is destroyed it will inhibit dispersion and affect the measured particle size ratios.  What it may do to clay structure I don't know but this work was almost certainly done 40 or more years ago when it was hoped that clay mineralogy would explain fertility

Thank you sir for your valuable reply. Sir can you site some references. I will be of great help to me. Best wishes.

You need some repeated treatments of hydrogen peroxide in clay soils having such amount of organic carbon . And , Paul is right , unless organic carbon is completely removed , it will later interfere with dispersion of soil particles. Interestingly , in clay soils , especially smectite soils , even sand particles also seen black due to coating of organic matter.

Hydrogen peroxide addition in soil oxidizes organic carbon present  clay and its aggregates. C + H2O2 -------> CO2 + H2O.

Dispersion highly influenced by diffusion double layer formation and zeta potential creation. Presence of organic carbon coating over soil separates, it does not follow above said phenomenon. Thats why it is suggested to ensure the removal of OC from soil soil separates analysis. 

Thank you

 Ms. Kaur,good question in the light of new developments in soil science.I wish to added three points-one the H2O2 treatment may not affect the clay for the purpose of texture determination by any of the two popular methods.Second point-by H2O2 (30%) treatment you may not be able to oxidize all the carbon in fine or heavy textured soils.Can be checked with alternate methods.Third point- from soil resilience point of view,the near complete oxidation of organic matter in soil may destroy the soil structure , related soil properties and the soil may get hardened.

Thank you all for your reply.. But can you site some research papers or books for reference. It would be of great help to me.

 Ms.Kaur.Your question has made me to looked around for some clarification and learn or gather some new information.One should not believe in routine work and raise new issues whenever there is some doubt.I have across a reference which shows that H2O2 treatment is inefficient in removing/oxidizing organic matter from soil.'The sodium hypochlorite treatment is much more effective than hydrogen peroxide used lone except for most acid samples for which the difference between the treatments is small.Also the hydrogen peroxide used alone(without prior removing carbonates) is,quite ineffective for calcareous soils'.The author studied the mineralogical changes with the two methods.

An improved pretreatment for mineralogical analysis of samples containing organic matter. by J.U.Anderson

lawr.ucdavis.edu/classes/ssc 220/Anderson.pdf

Another important publication is'Review of particle size distribution analysis methods 'by Jorge Guevara,University of Florida Gainesville,FL

http://soils.ifas.ufl.edu/docs/.../Guevara_Jorge_one_year_Embargo.pdf

This reference provides good  comparative information of the different methods used for organic matter oxidation/removal.This review also proves that H2O2 treatment is inferior to sodium hypochlorite treatment.

You may find several other papers if you search on internet.

Hydrogen peroxide has been shown in some circumstances to generate oxalic acid that may attack poorly crystalline mineral phases (see Lavkulich and Wiens 1970 doi:10.2136/sssaj1970.03615995003400050025x). If you're expecting a significant fraction of poorly crystalline constituents (e.g. imogolite, ferrihydrite), sodium hypochlorite may be a better choice. Good luck!

Nice question and discussions. I guess H2O2 may have its effect over the oxidation of organic matter, not on the soil minerology. So that we can estimate the content of fine soil and sand particle contents. But I am not very sure about the exact mechnisms involved.

Dr.Singh, the paper of Anderson which I mentioned(available online) provides  X-ray diffraction data after treatment with both H2O2 and NaOCl.' The X-ray diffraction patterns resulting from NaOCl treatment have shown to have generally higher peak/background ratios for 14 A minerals than those from other treatments' .For more details the papers mentioned can be consulted(available online).The structure of organic  compound,pH and concentration of H2 O2 influenced the extent of organic matter oxidation in soils(review of J.Guevara).

Thank you Dr. Rao for the suggesting the potential literatures. I'll follow them.

Regards,

Rishikesh