* is usually written in or , and it's the word usually used in conversations.
* is a Sino-Japanese word (), and it sounds more technical/formal, as usual. See: Are always more formal than You will find in official documents, scientific articles, and such.
* is not a word commonly used in isolation in sentences (at least in modern standard Japanese). In most cases it appears in compound words such as , , and .
**EDIT:** In some dictionaries, seems to be defined as something like " filled with water", as if dry were not . IMHO you can ignore this definition and think almost always just means "rice field".