* Arado: This is the most common and general word for a plow, especially the kind used in agriculture.
* Subsolador: This refers to a subsoiler, a type of plow that breaks up compacted soil deeper than a regular plow.
* Rastrillo: This refers more to a harrow, which is used to level and smooth the soil *after* plowing. It's not a plow itself.
Therefore, arado is the best general translation for "plow" in most cases.