Lalit Vekaria

In my opinion, the best method for silicon analysis is ICP or you can use a spectrophotometrical analysis based on the formation of silicomolybdate and reduction to blue silicomolybdous acid. Other methods are also available. However. the most important aspect to be taken into account is the selection of the extraction solution. In the case of bioavailable silicon, some of the most useful extractants are acetic acid 0.5 mol/L, ammonium acetate 0.5 mol/L or hydrochloric acid 0.5 mol/L. You shake the soil sample during 1 hr with the extractant, let it rest 15 minutes, decant and filter; afterwards you should wait at least 12 hrs before the ICP or spectrophotometrical analysis. In any case, be careful because the results often do not correlate well with the actual uptake of silicon from the plant, so you have to validate the procedure considering not only the soil type but also the plant physiology and morphology. In summary, more important than the analytical method itself, the selection of the right extractant and the consideration of the soil-plant relationship are of major relevance to a valid result.

www.fao.org/3/a-ar117e.pdf

Lalit Vekaria

In my opinion, the best method for silicon analysis is ICP or you can use a spectrophotometrical analysis based on the formation of silicomolybdate and reduction to blue silicomolybdous acid. Other methods are also available. However. the most important aspect to be taken into account is the selection of the extraction solution. In the case of bioavailable silicon, some of the most useful extractants are acetic acid 0.5 mol/L, ammonium acetate 0.5 mol/L or hydrochloric acid 0.5 mol/L. You shake the soil sample during 1 hr with the extractant, let it rest 15 minutes, decant and filter; afterwards you should wait at least 12 hrs before the ICP or spectrophotometrical analysis. In any case, be careful because the results often do not correlate well with the actual uptake of silicon from the plant, so you have to validate the procedure considering not only the soil type but also the plant physiology and morphology. In summary, more important than the analytical method itself, the selection of the right extractant and the consideration of the soil-plant relationship are of major relevance to a valid result.

I also recommend the methods suggested by Dr. Maynor.

Thanks alot Dr Pal sir and Dr Maynor for giving me a solution on my query.

I have determined silica from acidic soil by all these three methods separately and also with the extractant 0.01 M CaCl2. Most probable acetic acid gives good result that I was thinking and for that confirmation I asked before the research forum.

Thanks alot sir

There are many extracting solution for the estimation of available silica as we know the plant can take up silica in orthosilicic acid form or monosilicic acid form which is the water soluble form and another form which can be easily converted into monosilicic acid is the exchangeable form in the soil and which can be easily extracted with Acetic Acid or Calcium chloride as an extractant.