You can have a look at Magdoff and Bartlett 1985 (Soil pH buffering revisited). They made incubation with H2SO4 and CaCO3.

Dear Garg,

If you alter soil pH by adding acidifying fertilizers it will change to acidic again if you putting amendment (Gypsum) it will turns to neutrality, If you putting more of CaCO3 it will turns to calcareous, so you please specify what is the desired pH for your studies and about your research methodology, whether it is pot or incubation or field study.

Dear Colleague Yogendra,

I need acidic soil of pH 3-4 and alkaline soil of pH >10. I want to study the role of alkaliphilic and acidiphilic bacteria in such soils. The study will be conducted in pots initially.

Also please provide me some literature or reference materials regarding this, if any?

Kunal,

Below are two references that are useful in determining the buffer capacity of your soil and to figure out how much CaCO3 needs to be added to raise your soil pH to a particular level. Buffer capacity will also inform how much S to add to acidify. However, I've found that it is difficult to raise the pH above 10. I am trying to do the same thing for a greenhouse experiment. The buffer curves given in these sources do not go that high since they are for agricultural applications, but you can perhaps extrapolate beyond the curves.

Sikora, F.J. 2012. Double-Buffer Methods Revisited with Focus on Ionic Strength and Soil / Solution Ratio. Soil Sci. Soc. Am. J. 76(2).

Sikora, F.J. 2006. A Buffer that Mimics the SMP Buffer for Determining Lime Requirement of Soil. Soil Sci. Soc. Am. J. 70(2): 474

why you would like to alter the soil pH specify your purpose?

Dear Dr. Munnoli,

We are studying the effect of bacteria on plant growth in acidic and alkaline soil. So need to alter the soil pH as we do not find it near to our location.

Regards.

let me also know what is the pH of soil in its natural state

its is around 7.8-8.2