PROBLEM TO BE SOLVED: To provide a method for applying a soil-conditioning material, which can inhibit the generation of methane gas, when saccharification residues or distillation residues obtained in an ethanol-producing process are used as a soil-conditioning material.SOLUTION: The method for applying the soil-conditioning material, comprising separating saccharification residues contained in a saccharification solution, recovering a distillation residue solution left after distilling a fermentation solution, and applying the saccharification residues or the distillation residue solution as a soil-conditioning material to paddy soil, when saccharifying rice straws as a substrate with a saccharification enzyme, fermenting the obtained saccharification solution to obtain a fermentation solution, and then distilling the fermentation solution to produce ethanol, is characterized by applying the soil-conditioning material to paddy soil, and then keeping the oxidation-reduction potential of the paddy soil at ±0 to +500 mV.【課題】エタノール製造過程で得られる糖化残渣又は蒸留残液を土壌改良材として用いるときに、メタンガスの発生を抑制することができる土壌改良材の施用方法を提供する。【解決手段】稲藁を基質として該基質を糖化酵素により糖化処理し、得られた糖化溶液を発酵処理して発酵溶液を得た後、発酵溶液を蒸留してエタノールを製造するときに、糖化溶液に含まれる糖化残渣を分離すると共に、発酵溶液の蒸留後に残された蒸留残液を回収し、糖化残渣又は蒸留残液を土壌改良材として水田土壌に施用する。前記土壌改良材を水田土壌に施用した後、水田土壌の酸化還元電位を±０～＋５００ｍＶに維持する。【選択図】 図１
