Grist: Maybe this is obvious, but expanding our agricultural footprint to feed the growing population - cutting down forests, plowing prairies - is a really bad idea. Whats less obvious, and more interesting/troubling, is that farmland expansion is so harmful on so many levels that its worth doing just about anything that helps us avoid opening up new land - even things that have their own environmental costs. Ive been reading back through the papers of David Tilman, an ecologist at the University...