Neb. Rev. Stat. §§ 23-132
The county board, after the adoption of the annual county budget statement, may issue warrants against the various funds provided for in such budget statement within the limitations prescribed in this section. It shall be unlawful for the county board of any county to issue any warrants on any fund or contract any indebtedness against any fund, prior to the annual levy made by the county board, in excess of fifty percent of the fund provided for in the adopted budget statement for the ensuing year unless there is money in the treasury to the credit of the proper fund for the payment of the same. After the tax levy has been made by the county board, it shall be unlawful for the county board of any county to (1) issue any warrants for any amount exceeding eighty-five percent of the aggregate of the amount provided by the budget as finally determined when the levy is made unless there is money in the treasury to the credit of the proper fund for the payment of the same or (2) issue any certificate of indebtedness in any form in payment of any account or claim, make any contracts for or incur any indebtedness in any form in payment of any account or claim, or make any contracts for or incur any indebtedness against the county in excess of the amount provided for and appropriated to any or all of the several funds by the annual county budget statement for the current year except as provided in section 13-511.
Neb. Rev. Stat. §§ 23-132