> There are 1.9 Billion acres in the USA alone. Not all acres are equal. Not even within the same state; an acre in California's Central Valley is very differ

> There are 1.9 Billion acres in the USA alone. Not all acres are equal. Not even within the same state; an acre in California's Central Valley is very different from an acre in California's Mojave Desert. And further, this presupposes that there is adequate water for all those acres, which - as Californian farmers have learned over the last couple decades - ain't quite true. Some acres therefore have to remain unused in order for the other acres to remain usable.