The necessary subsistence, supplies, equipment and expenses incident to any active State service, including the transportation of troops, may be contracted for under direction of the Governor as Commander-in-Chief, by the Adjutant General or any other officer designated for that purpose, to be paid for as otherwise provided by law, except when such active service is under the orders of the Department of Defense when subsistence, supplies, equipment and other expenses incident to any active State service, including transportation, is furnished by the Federal Government.