The north was just as much agricultural as the south, believe me. Virtually all foodstuffs consumed in the states were grown in the same said states. The south had more railroad line and was more dependent on the Ohio and Mississippi Rivers, the north had more gun foundaries. The big difference was in the north, the majority of farmhands were hired help, while in the south, they were mainly slaves.
http://www.wwnorton.com/college/hist.../12_02/map.jpg