Excess agricultural capacity is generally a good idea. If we have zero excess in the system, then when a hiccup occurred we might find ourselves in famine. Wit

Excess agricultural capacity is generally a good idea. If we have zero excess in the system, then when a hiccup occurred we might find ourselves in famine. With corn-for-ethanol, the US gov is paying to keep farmland productive that has no human-or-livestock feed value. But you could imagine a situation where more human or livestock feed is needed (massive disruption of cropland, say), and in those or subsequent years we could convert basically-for-ethanol fields to consumption fields. Or if you are running out of fertilizer instead of running out of food, then you can divert expected and stored fertilizer for ethanol fields onto human-and-livestock feed fields. Once again the excess capacity acts in your favor. (Or ought to) This is assuming that governing bodies and farmers are making coherent rational decisions and in addition responding to local conditions. I have no opinion on that. Just explaining why subsidizing what looks like superfluous excess capacity is not necessarily a dumb thing to do.