Neb. Rev. Stat. § 81-138.03: Encumbrance; when paid; lapse.

An encumbrance established in one biennium may only be carried over into the subsequent biennium. Any encumbrance shall be paid during the first biennium following the biennium in which established or shall be lapsed to the fund from which appropriated at the end of the first fiscal period following the biennium in which such encumbrance is established.