A lot of it is going to depend on where the land is located. Bitcoin has a pretty fixed value at any give moment. The price of a bitcoin in China is basically the same as the price of a bitcoin in the United States.
Land on the other hand can be worth many different amounts depending on where it is located. Land that is on a lake is going to be more valuable than land that is in a swamp, even if it is a much smaller plot.
If you see value as being volatile but also fixed then I think you would probably assume that BTC is more valuable. However you are just looking at it monetarily and you consider the amount of demand there will be for said piece of land, you will probably consider land more valuable.
They are both commodities with a fixed supply, in the end though I would probably consider land to be more valuable.