The Wealth of Nations by Part 5 Chapter 2 Page 44

discouraged, to the no small advantage of all the different parties concerned, of the landlord, of the tenant, of the sovereign, and of the whole community.

Some leases prescribe to the tenant a certain mode of cultivation and a certain succession of crops during the whole continuance of the lease.

This condition, which is generally the effect of the landlord’s conceit of his own superior knowledge (a conceit in most cases very ill founded), ought always to be considered as an additional rent; as a rent in service instead of a rent in money. In order to discourage the practice, which is generally a foolish one, this species of rent might be valued rather high, and consequently taxed somewhat higher than common money rents.