Stamp duty on land

Agricultural land is not treated as Capital Asset hence if you sale this land in future then no capital gain tax shall arise, provided certain conditions have been fulfilled. Further, the income generated from such agricultural land also exempted from tax U/s 10.

As the business would be of non-agricultural activity, it will be taxable as per normal provisions under the head Income from PGBP.

Earlier one thing I forgot to mention , that is, the agricultural land which is situated in rural area, that will not be treated as Capital Asset. But, if the land is situated in Urban area, then the capital gain tax will be applicable if you sell this in future. 

And the stamp duty paid on purchase of such land will be added in determination of "Cost of Acquisition" or "Indexed Cost of Acquisition", as the case may be, at the time of computing the capital gain on the event of its sale and accordingly will be deducted from the Full Value of Consideration.

Hope this will help you.