I am not clear on the query. Are you asking whether capital gains is chargeable as the land was agricultural earlier but was non-agricultural on the date of transfer? (The answer to this is that the position prevailing on the date of transfer has to be seen).
Or are you asking whether s. 50C is triggered off because of a difference in valuation from agricultural to non-agricultural? How does this difference arise? Was it agricultural on the date of the agricultural but became non-agricultural on the date of conveyance.
The decisions cited by Mr. Goel are quite relevant but a few more facts would help.
Please do provide more facts.