Description based on: Jan. 1993.
Microfiche. <1993-> [Washington, D.C.] : Supt. of Docs., U.S. G.P.O. microfiches : negative.
Vols. for 1993-<Apr. 1994> issued by: U.S. Dept. of Agriculture, Soil Conversation Service; <Mar. 1995-> issued by: U.S. Dept. of Agriculture, Natural Resources Conservation Service.