Is there any empirical evidence for the so-called "law" of diminishing returns The "law" of diminishing returns is usually "demonstrated" with made-up examples (programmers working on a software, farmers acquiring land...), but rarely on evidence. Is there any empirical research on actual data to acknowledge and quantify this law?
The above chart is from Agroecosystems, nitrogen-use efficiency, and nitrogen management by Cassman KG, Dobermann A, Walters DT, and it deals with this sort of question quite extensively for those interested in all the gory details.