Good for current statistics, mostly on U.S. agricultural production and consumption, but some international data on major commodities. Also contains helpful reports, for example. "How Transportation Costs Affect Fresh Fruit and Vegetable Prices" and "The Role of Fossil Fuels in the U.S. Food System and the American Diet."
Good for comparing data over time. Lots of statistical tables - always check for more statistics from the agencies that produced these. Also some good overall historical essays on topics like "Agricultural Policy."