In a new country where land is abundant and absolutely free, it would pay just to work it to the point of diminishing returns. If it were of the quality represented in the table above, six units of capital and labor should be applied to a hundred and sixty acres of it to get the best results. But in older countries where land has become scarce and where a rent must be paid for its use better results can be had by applying six units of capital and labor to less than a hundred and sixty acres of the land of our illustration or more than six units should be applied to a hundred and sixty acres. In other words, wherever rent must be paid it is profitable to cultivate land beyond the point of diminishing returns. Where a rent is demanded for the best land there may be other poorer lands to be had for which no rent is charged and which when cultivated just to the point of diminishing returns will give as good results as the better land will give when cultivated below the point of diminishing returns. This poorer land for which no rent is charged and which just barely pays for its cultivation is said to be at the extensive margin of cultivation. There may be still poorer land than this which can be had for nothing but which is so poor that it does not pay to cultivate it at all. This is said to be below the margin of cultivation. On the other hand, when we cultivate the better land beyond the point of diminishing returns and just up to the point where an increase in our outlay of capital and labor would not be paid for in increased product we say that we have reached the intensive margin in the cultivation of the land. The extensive margin of cultivation may be thought of as a line separating the land which it pays to cultivate from the land which is so poor or so unfavorably situated that it does not pay to cultivate it. The intensive margin may be thought of as a line separating the capital and labor which it pays to apply to a given piece of land from additional capital and labor which it would not pay to apply to that land.