بسم الله الرحمن الرحيم
If you are already sahib-e-nisab and pay your zakah every year then whatsoever money you have got after selling the land, include it in your wealth and pay the zakah of total money together. And if you are not sahib-e-nisab already then zakah will be wajib on this amount after passing of one complete year.
Allah knows Best!
Darul Uloom Deoband
This answer was collected from the official ifta website of Darul Uloom Deoband in India.