1. For general property assessment purposes, the true value in money of land which is in use as agricultural and horticultural property, as defined in section 137.016, shall be that value which such land has for agricultural or horticultural use. The true value of buildings or other structures customarily associated with farming, agricultural, and horticultural uses, excluding residential dwellings and related land, shall be added to the use value of the agricultural and horticultural land to determine the value of the agricultural and horticultural property under sections 137.017 to 137.021.

2. After it has been established that the land is actually agricultural and horticultural property, as defined in section 137.016, and is being valued and assessed accordingly, the land shall remain in this category as long as the owner of the land complies with the provisions of sections 137.017 to 137.021.

3. Continuance of valuation and assessment for general property taxation under the provisions of sections 137.017 to 137.021 shall depend upon continuance of the land being used as agricultural and horticultural property, as defined in section 137.016, and compliance with the other requirements of sections 137.017 to 137.021 and not upon continuance in the same owner of title to the land.

4. For general property assessment purposes, the true value in money of vacant and unused land which is classified as agricultural and horticultural property under subsection 3 of section 137.016 shall be its fair market value. This subsection shall not apply to any reliever airport.

5. For general property assessment purposes, the true value in money of a reliever airport shall be that value which such land has for agricultural or horticultural use.