I plowed a couple acres of reclaimed farm land out back. It is on a hill that in about 600 feet rises probably 30 feet. Not steep, but noticable. I plowed so the furrows run up and down the hill to help with drainage. It is a good ohio clay and we get plenty of moisture so that is why I went that way. When I was reading John Seymours book, he suggested plowing so as to keep the moisture from flowing down the hill, basically and east west (as the hill runs north south). Is that for people who really only have a dry climate?