山药即薯蓣[Dioscorea.opposita(D.batatas)],又称薯药、怀山药,自生于山野者亦称野山药,可作蔬菜,也可入药,具有较高的经济价值和营养价值。山药属薯蓣科,多年生蔓性草本,很壮茎短,根直生、肉质肥厚,呈圆柱状棍棒形。叶片形状多变,通常耳状3裂,叶腋间常生有珠芽(亦称“零余子”或“山药豆”),用以繁殖,也可食用。夏季开花,花单生,乳白色,花序穗状,下垂。原产我国,全国大部分地区都有种植,主要产于河南、山西、河北、陕西等省,上海以崇明为多。一、山药栽培要点山药性喜高温,遇霜枯死,春末栽种,晚秋收获,生长期约为150天。由于山药是根深、根多、生长期长的作物,宜选择排水良好、表土深厚、疏松肥沃的砂质壤土栽培。播种前,山药田应耕翻1尺 Yam Dioscorea (Dioscorea.opposita (D.batatas)], also known as potato medicine, yam, self-born in the wild also known as wild yam, can be used as vegetables, but also medicine, with high economic value and nutritional value. Yam is Dioscoreaceae, perennial creeping herb, very strong stalk, root straight, succulent, was cylindrical stick shape. Leaf shape changeable, usually 3-ear, leaf axillary often pearl (also known as “Zuobuzi” or “yam bean”), for breeding, but also edible. Summer flowering, flowers solitary, white, spikes inflorescence, drooping. Originated in China, most parts of the country have planted, mainly produced in Henan, Shanxi, Hebei, Shaanxi and other provinces, Shanghai Chongming as much. First, the main points of yam cultivation Yam hi like high temperature, frost dead, late spring planting late autumn harvest, the growth period of about 150 days. As yam is deep root, root and more, long-growing crops, should choose well-drained, topsoil deep, loose and fertile sandy loam cultivation. Before sowing, yam field should be plowing 1 foot