The United States Agricultural Extension Fund shall consist of all money which may come into the possession of the State Treasurer for use or expenditure by the University of Nebraska by reason of any laws, now existing or subsequently enacted by the United States, whereby money is appropriated to or provided for agricultural extension purposes. The agricultural extension fund when appropriated by the Legislature shall be applied exclusively to the uses and objects designated by any laws now existing or subsequently enacted by the United States relative thereto. It shall at all times be subject to the orders of the Board of Regents for expenditure for said uses only.