Marr, Charles W.2015-12-232015-12-23http://hdl.handle.net/2097/21701Charles W. Marr, Approximate Composition of Some Natural Fertilizer Materials, Kansas State University, May 1995.NitrogenPhosphoric AcidPotashMaterialsApproximate composition of some natural fertilizer materialsTextKansas State University. Cooperative Extension ServiceSerials (publications)Articles