See
http://turbotax.intuit.com/tax-tools/tax-tips/Rental-Property/Selling-Rental-Real-Estate-at-a-Loss/I....
It appears you are correct. I just did a practice problem on TurboTax (TT) and the full section 1231 loss was deductible on this year's return. It will depend on how much of the loss was allocated to land, whether you get to deduct the full $50K. The land sale results in a capital gain/or loss. The building sale results in a section 1231 gain or loss. Just enter your info into TT' it will handle it correctly.
