The purchase of land is a capital asset. Unless you are in the business of buying and selling real estate, (which the land then becomes inventory), the purchase price is capitalized and carried as an asset on the balance sheet.
There is no current deduction for the purchase of land. When and if the land is sold, you would subtract the purchase price of the land from the selling price and would then have a capital gain/loss.
If used in a trade or business, it might be subject to any rules for Section 1250 property if the property has had substantial improvement made that were subject to depreciation or if the land you purchased has depreciable property on it.