By custom, in several different regions of Europe tenants were the owners of the improvements they carried out on the farm. As a result of such customs, rents usually remained below the Ricardian equilibrium over long periods of time and therefore cannot be used to calculate the total factor productivity in agriculture. This paper examines the logic underlying the functioning of the custom that came into being in nineteenth-century Valencia. This is followed by a brief comparison between the Valencia custom, the Irish tenant right and the French mauvais gré
