Grain Production Per Ton of Fertilizer Use in the United States, 1960-2004. Courtesy of Earth Policy Institute.

January 26, 2011 Leave a Comment

Grain Production Per Ton of Fertilizer Use in the United States, 1960-2004. Courtesy of Earth Policy Institute.

Grain Production Per Ton of Fertilizer Use in the United States, 1960-2004. Courtesy of Earth Policy Institute.

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