... sound agronomic research on the most effective cultivation techniques in the context of a system where fertilizer gets a free ride on its external costs downstream in the watershed would not be arriving at the "correct figure" if it is not recommending too much fertilizer use from the perspective of full economic costs.

That is, after all, a direct consequence of taking free rides on external costs and giving free rides on external benefits ... making it rational at the individual level to over-utilize the thing with the net external cost, and to under-utilize the thing with the net external benefit.


I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.