Any landowner owning land, upon which there now exists special assessments levied by any drainage district organized under the laws of this state, has the option, upon any date upon which the landowner pays such special assessments, to pay all or any part of the unmatured amount assessed against the tract or tracts of land owned by the landowner; provided, that no rebate or reduction shall be made for unearned interest upon such assessments.
T.C.A. § 69-5-911