I am not sure to fully understand what you mean by the "kind of parameters" or "type of organic matter", as theoretically you could apply any techniques on the different sizes classes (although the amount of the size classes that you obtain usually limit what you can do). The question is more about how wet sieving will affect your result. Wet sieving tends to remove soluble fraction of organic matter which is lost in water. So you underestimate the organic matter in your different classes. There is also problem of contamination between classes during the sieving as the silt+clay fractions is likely to be in receipt of soluble and fine organic matter from other classes. So, you need to keep in mind these problems when you interpret your results with wet sieving (and in general with soil sieving either dry or wet).

To measure soil organic matter in the different size classes, you can measure C and N content and then calculate the C/N to obtain a coarse indicator of the state of decomposition of the organic matter in the different classes. If you want to know if the organic matter is different between classes you can use NIRS, MIRS or FTIR which can tell you if you have different organic matter between samples and for some of these methods the type of organic matter.

Thanks sir,

My intention is towards soil carbon (like permanganate oxidisable carbon,mineralisable carbon,total organic carbon,water soluble carbon,intra particulate organic matter carbon,interPOM carbon,intraPOM carbon) in aggregates obtained after wet sieving.But I have no idea that which type of carbon is present in aggregates (whether only soil organic carbon or inorganic carbon also) after wet sieving.can I analyse all types of organic carbon in each size class aggregates obtained after wet sieving,with the help of Walkley Black method.What measures should I will take to minimize contamination between size classes.

which method is better for carbon analysis in aggregates-dry sieving or wet sieving.

Is organic matter is analysed both qualitatively and quantitatively by the techniques mentioned by you,please describe.

You will find in soil aggregates both organic and mineral C (although is depends of the soil studied).

You can use the Walkley Black method to determine organic C of your aggregates. There is no better method really, it just depends on what you want to measure. Soil aggregates are soil, so it is not because you isolated aggregates that they truly differ from soil. You can apply similar methods

You can't avoid contamination between size classes as smaller sizes will receives materials and compounds from bigger classes, just keep in mind that size classes obtain are just related to the sieve you use.

The methods I mentioned are mainly qualitative. The NIRS for example use Near-infrared spectroscopy to obtain a profile of your soil. You can compare profiles between samples to see if they are different. Some peaks can be related to specific compounds of the organic matter.

Thank you sir,Can I also analyse these all different types of carbon in all size class aggregates obtained with dry sieving. Is there occur any difference between aggregates obtained by dry sieving and wet sieving.

You can perform these measurements on soil aggregates obtained by either dry or wet sieving. However, both methods will give you different results. Wet sieving is a stronger method than dry sieving to isolate aggregates. So, the aggregates distribution that you will obtain can be different between these 2 methods, as well as the C content. There is no better methods or one strongly advised, despite soil fractionation being performed for decades. See the articles attached comparing both methods.

Thanks sir ....for your valuable suggestions.