Always be wary of studies conducted by people taking a political assumption and turning it into the basis of their paper.

It's not coincidal that said studies either lack specifics in some areas, while being over-specific in others or are cited in the same manner (leaving out details where it helps the political camp, being over-specific in others).

One can already see this turning up in general rebuttals of agriculture, or citations that leave out the critical detail that soil erosion is caused by corn specifically, not crops in general. Or which kind of geographic reagion was used. Or how well farmes tilled their land (see the picture about erosion down-hill: its just a question of the right tilling-technique to prevent that from happening).

And as a last resort you can always toss it into some meta study to "prove" your point.