Section 20. For any purpose, other than the provisions of this chapter, for which the assessed value of land is relevant, including exemptions under the provisions of chapter fifty-nine, land qualifying for taxation under this chapter shall be valued and deemed to have been assessed by the same standards, methods and procedures as other taxable property.

In determining the equalization required by section nine of chapter fifty-eight, the commissioner of revenue shall determine the value of such land on the basis of its agricultural and horticultural use.