Family Farm Estate Tax Deferral Act of 2010 - Amends the Internal Revenue Code to: (1) exclude from the value of a decedent's gross estate farmland used by the decedent or a member of the decedent's family for farming purposes for periods aggregating five years or more during the eight-year period ending on the date of the decedent's death; (2) impose a recapture tax on an heir who disposes of such farmland after the decedent's death or who ceases to use such farmland for farming purposes; and (3) increase the limitation on the estate tax exclusion for land subject to a qualified conservation easement to $5 million and the percentage of the value of such land that is excludable.