Real or immovable property consists of:

l. Land;

2. That which is affixed to land;

3. That which is incidental or appurtenant to land;

4. That which is immovable by law; except that for the purposes of sale, emblements, industrial growing crops and things attached to or forming part of the land, which are agreed to be severed before sale or under the contract of sale, shall be treated as goods and be governed by the

provisions of the title of this code regulating the sales of goods.