You did not provide much detail about the business or the land, which is good in this public forum, but it limits my ability to answer the question. Who legally owned the land during the period when the business was operating? If it was you, that's fine. If it was a separate business entity, how was the land disposed of when the business ceased operations? Was it transferred to you for value? What type of entity was the business?
Where I am trying to lead you is to the understanding that:
(1) if you were the owner of the land all along, the loss can be taken on your individual tax return, as a capital loss;
(2) if the land was owned by a pass-through entity (partnership, S Corp, or multi-member LLC) the business may not have wrapped-up in 2015 and a final 2016 tax return may be appropriate to show the disposition of the land and to pass-through the tax characteristics of the transaction; or
(3) if the land was owned by a corporation and transferred to you for value, the transaction become much more complex, depending on the FMV at the date of transfer and whether you or the corporation have a loss. In this last case, you may wish to consult your legal counsel.
