日本茶叶生产从60年代以来单位面积氮肥施用量逐年增加，致使生产成本日益上升。目前，日本肥料费用占茶叶总生产成本的20％，占茶叶生产物质成本的40％。此外，由于氮肥用量过高，使茶树根系出现腐烂，地下水中硝态氮含量高达12～50mg／L（超过允许标准10mg／L）。与其他作物 Since the 1960s, Japan’s tea production has been increasing the amount of nitrogen fertilizer applied per unit area, resulting in an ever-increasing cost of production. At present, Japan’s fertilizer costs account for 20% of the total cost of tea production, accounting for 40% of the cost of tea production material. In addition, due to excessive nitrogen fertilizer, the root rot of tea tree, nitrate content in groundwater as high as 12 ~ 50mg / L (exceeding the allowable standard 10mg / L). With other crops