What describes the scenario where a farmer uses the best land first, leading to higher costs when less desirable land is used?

The scenario described reflects the law of increasing opportunity cost. This concept illustrates that when additional units of a good or service are produced, the opportunity cost of production generally increases. In this case, the farmer starts using the most fertile and desirable land, which yields higher productivity at a lower cost. However, as they expand production onto less fertile land, the output per unit of input declines, and the costs associated with producing the same good or service increase due to the lower productivity and potential additional inputs needed.

This principle underscores the idea that resources are not perfectly adaptable to alternative uses. As a farmer continues to place more resources into less optimal land, the costs become higher not just in terms of money but also in terms of the potential yield that the farmer could achieve. This makes the law of increasing opportunity cost the appropriate framework to understand the farmer's shifting resource use and its consequences on costs.