Form 4562 Land question

[Ketan Pattani]

I have a non-residential rental property that I leased out last year and I am filling out Form 4562 for figuring out MACRS depreciation(39 years MM, SL).  I assume the basis for depreciation does not include land.  I was going to use a proportional ratio based on county assessment to figure out the value of the building.  I think I got this correct so far.  Please correct me if I got something wrong.

The question I have is, is there a place to report the total cost basis for the property including land?  How will the IRS know when I sell the property how much the land was worth when I purchased it?  How does appreciation of land figure into calculating depreciation recapture?

Also, I am confused about section 179 election to expense.  Does it even apply to real property?

Thanks,

Ketan