地黄属玄参科多年草本植物,古名卜芑、地髓。主要产在怀庆府所辖温、沁、孟、武各县。使其根茎入水,浮者天黄,半浮者为人黄,沉者为地黄。地黄药用以根茎为主,叶、花和果实也可入药。药用分生地和熟地两种。其主要成份为木密醇,地黄素、维生素A样物质及多种糖类、生物碱、铁等。地黄性喜阳光充足,土质疏松肥沃、排灌条件良好的中性或微碱性砂壤土。最忌连作。重茬易发生“土锈”,轻者减产,重者无收。前茬是芝麻、油菜、棉花等不宜种地黄;小麦、玉米、红薯茬影响不大;以绿豆和谷子茬为最好。地黄要求适当的温度及水分。 Genus Xuan Sen Branch herbs for many years, the ancient name Bu 芑, marrow. Mainly produced in the jurisdiction of Huaiqing Prefecture, Qin, Meng, Wu counties. Its rhizome into the water, floats sky yellow, half-flushed person is yellow, sink those who Rehmannia. Rehmannia root rhizome-based, leaves, flowers and fruits can also be used as medicine. Medicinal points and rehmannia two. Its main ingredients are wood alcohol, rehmannia, vitamin A-like substances and a variety of carbohydrates, alkaloids, iron and so on. Rehmannia hi sunny, loose and fertile soil, irrigation and drainage conditions of good neutral or slightly alkaline sandy loam. Most avoid making. Heavy crop prone to “rust”, the light cut, the heavy no crop. Before the crop is sesame, rapeseed, cotton and other should not be planted yellow; wheat, corn, sweet potato crop has little effect; mung bean and millet stubble is best. Rehmannia requires proper temperature and moisture.