Neb. Rev. Stat. §§ 10-711
It shall be the duty of the county board in each county to levy annually upon all the taxable property in each school district in such county a tax sufficient to pay the interest that will accrue or is accruing upon any bonds that have been or will be issued by such school district and to provide a sinking fund for the final redemption of the same. Such levy shall be made with the annual levy of the county and the taxes collected with other taxes and when collected shall be paid over to the county treasurer of the county in which the administrative office of such school district is located and shall remain in the hands of such county treasurer as a specific fund for the payment of the interest upon such bonds and for the final payment of the same at maturity. At the request of the school board of any district, the county board shall omit making a levy to pay the principal of the bonds when no bonds will be due within fifteen years thereafter.
Neb. Rev. Stat. §§ 10-711