I tend to disagree with Sulpicia. Not only is it possible that Athens relied on their naval empire for a food supply during the Archidamian phase of the Peloponnesian War, it is likely that they did so. The high dependance of Attic farmers on the olive as their main crop means that even during normal times, Athens depended heavily on imported grain. Recent surveys of Attica indicate that only about 30% of the land is arable, ie good for the growing of grain. Since it is likely that Athens used a two field fallow system, less than 15% of Attic land was probably available for the growing of grains. However, remains of terraces indicate that ancient Athenians may have increased through terracing the amount of land they could cultivate. Still, a maximum amount of Attic land probably put under grain crops is 25%, and that is considered high by most.

While Attica was known for its production of barley, it was not well suited for the growing of wheat. Wheat provides far more nutrition per acre than barley. A high estimate of Attica production during the Classical Age of Pericles would have Attic land producing enough grain (wheat and barley) to feed less than half of the probable population. And that would be during a good year. During poor crop seasons, far fewer Athenians would be able to purchase local grain.

For that reason, it is highly likely that Athens regularly imported great amounts of grain, both during times of peace and times of war. Even if they attempted to grow a 3 month wheat crop (evidence for which I am unfamiliar with), the amount they could grow would not be anywhere near what they would need. It is clear that AThens did rely, heavily and almost exclusively on imported grain during the opening years of the war.

I also disagree on what the Spartan policy was used for. Sulpicia stated that the Spartans may have ravaged the land to increase social disunity. While this may have occured (and we know it was on Pericles' mind, which is why he gave his estate - notice the singular - to the state)it also seems clear from Thucydides that Sparta envisioned a quick end to the war by ravaging Athenian lands. Either they would force the Athenians to come out and fight, or the Athenians would just surrender in order regain their lands. Neither, of course, happened. Pericles understood the power of the navy. Unfortunately, he didn't comprehend the idea of sanitation and overcrowding!

I am sorry this rambled on, and also apologize for the lack of sources to back this up. I am away from my desk currently and so do not have access to the names of books, articles and authors from which this information was culled.