金光菊(Rudbeckia laciniata)是原产北美的多年生草本植物,株高可达2米,叶片羽状深裂,头状花序,舌状花金黄色;8—9月份开花,9—10月种子成熟。它适应性强,在北京地区可以露地栽培,在江南各省能四季长青,茎叶繁茂。据分析,叶片含氮2.89％、磷1.08％、钾4.99％,一千斤新鲜茎叶的肥效相当25斤硫酸铵、10斤过磷酸钙和15斤硫酸钾的总肥量。它与紫云英、蚕豆、豌豆、油菜、九月豆等主要绿肥比较,含氮量居第2位。按海南地种植1,200株,每年收割三、四次,年可收获鲜茎叶7,000—8,000斤,相当硫酸铵200斤,真可称之为绿肥之“王”了。 Rudbeckia laciniata is a perennial herb native to North America, with a plant height of up to 2 meters. The leaves are pinnately fissured, with flower heads and golden tongue-like flowers. Flowers bloom from August to September and seeds mature from September to October . It is adaptable and can be planted openly in Beijing. It can grow evergreen in all provinces in the southern part of the Yangtze River with lush stems and leaves. According to the analysis, leaf nitrogen 2.89%, phosphorus 1.08%, potassium 4.99%, a kilogram of fresh stem and leaf fertilizer effect is quite 25 pounds of ammonium sulfate, 10 pounds of superphosphate and 15 kg of potassium sulfate total fertilizer. Compared with the main green manure such as milk vetch, broad bean, pea, rape and September bean, it has the second highest nitrogen content. 1,200 plants planted in Hainan, harvest three or four times a year, the annual harvest of fresh stems and leaves 7,000-8,000 pounds, equivalent to 200 kg of ammonium sulfate, can really be called the “king” of green manure.