Are you sincere in your belief that only a dictatorship could lead to more environmentally responsible agriculture and land use in the US? It seems like trolling, but if you're sincere, I could point you to some references on how our current laws reward irresponsible water and land use in many cases. There are many things a "capitalistic democracy" (if that's really what we are living in, which I also think is debatable) can do, and many things that are already being done, to guide how land owners utilize their land. The unintended consequences of current agricultural and water-use law in places like some parts of California, which have experienced more years of drought than years of normal rainfall for more than a decade, have been pretty significant. Government at local, state, and federal levels, have helped create the problems I'm talking about, so why shouldn't they be able to help alleviate them?
Presumably those laws were put in place because somebody benefits from them. Possibly somebody who makes campaign donations.
In that case, the government may technically be able to solve the problem in a way that's better for everyone, but not willing to, as the politicians who make the change could lose their campaign donations or their seats.