Q.According to Ricardo, what is rent?

Ricardo built his theory of rent on the idea that land parcels differ in fertility, and this difference is what gives rise to rent.

David Ricardo defined rent as the payment made for the use of "the original and indestructible powers of the soil." He located its source in the fact that land is not uniform -- some land is more fertile than other land -- so that when cultivation is extended, under the pressure of a growing population, from the best land to progressively poorer land, the more fertile plots yield a surplus over the produce of the least fertile (marginal) land under cultivation, even when both are worked with the same amount of labour and capital. This surplus, in Ricardo's theory, is rent.

Students often answer with the modern (scarcity) definition of rent instead of Ricardo's own fertility-based definition when the question specifically asks 'according to Ricardo.'