PURPOSE: To obtain a layer fertilizer capable of eluting a desired fertilizer composition in a desired period and reducing the frequency of fertilizer application by alternately laminating layers of a biodegradable polymer and layers of a fertilizer on the surface of a fertilizer constituting a core part.

CONSTITUTION: This layer fertilizer is produced by forming a layer 2 of a biodegradable polymer (e.g. a polylactic acid having about 50000 average- molecular weight) on a layer 1 of a fertilizer constituting a core part (e.g. a mixed fertilizer of potassium chloride with a calcined phosphate), then forming a layer 3 of a fertilizer (e.g. a potassium chloride fertilizer) on the layer 2 of the biodegradable polymer and further successively laminating a layer 4 of the biodegradable polymer, a layer 5 of a fertilizer (e.g. a mixed fertilizer of ammonium chloride with an oil cake) and a layer 6 of the biodegradable polymer on the layer 3 of the fertilizer. A method for spraying, dipping or coating a solution, an emulsion, etc., of, e.g. the biodegradable polymer, etc., is used as the method for forming the layer 2 of the biodegradable polymer. A method for applying the fertilizer containing a binder solution added thereto onto the layer 2 of the biodegradable polymer and drying the applied solution, etc., is used as a method for forming the layer 3 of the fertilizer.