[Farm and range improvement fund; approval of

expenditures.] All money so received by any county shall be placed in a special fund known and designated "the farm and range improvement fund" and shall be expended by the county as herein prescribed for the benefit of the county in the conservation of soil and water, the control of rodents and predatory animals and the extermination of poisonous and noxious weeds, the construction of dipping vats, spraying machines and other structures to control parasites on livestock, and for repair and maintenance of said vats, machines and structures and for the construction and maintenance of secondary roads. In the administration and expenditure of said special fund, the county commissioners shall seek the advice of and may cooperate with state and federal agencies and officials having knowledge of or engaged in activities similar to those for which said special fund may be expended as herein prescribed. Any payment made from said special fund shall first have the approval of the president of the New Mexico college of agriculture and mechanic arts [New Mexico state university], and shall be based on a voucher whereon the items and purposes of the proposed expenditure are stated in detail, and which shall bear in its face the written approval of the president of the New Mexico college of agriculture and mechanic arts [New Mexico state university], or the person who for the time being is performing the duties of that office; provided, however, that such approving officer may designate, by written designation, filed in the office of the county clerk, some person in the county to give, endorse and sign such approval in his name.