Green Prisons

I was doing some research for a paper on prisons and came across some interesting stuff here. The study is old but I like the idea. Prisons could be used more efficiently to help them be self-sustaining and help solve some environmental issues. Prison population keeps growing and they don't have anywhere to go. Why not use these numbers to our advantage? Locate the prisons at places where farming and agriculture is possible and put inmates to work with scientist and farmers to solve problems such as irrigation and fertilization. Find new and better technologies which produce more for less. The food grown at the prisons could be used there and/or sold. Many inmates would be more than willing to work and get out of their cell. They would be learning a trade to help them find a legal job when released from prison. Basically run the prisons more like envirovnmental laboratories. I know the government already hires the inmates out as cheap labor, why not do something for the benefit of everyone. What do you think of this? Problems/Benefits