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In modern tobacco farming, ''Nicotiana'' seeds are scattered onto the surface of the soil, as their germination is activated by light, then covered in cold frames. In the Colony of Virginia, seedbeds were fertil with wood ash or animal manure (frequently powdered horse manure). Coyote Tobacco (''N. attenuata'') of the western U.S. requires burned wood to germinate. Seedbeds were then covered with branches to protect the young plants from frost damage. These plants were left to grow until around April. Today, in the United States, unlike other countries, ''Nicotiana'' is often fertilized with the mineral apatite to partially starve the plant for nitrogen, which changes the taste of the tobacco. After the plants have reached a certain height, they are transplanted into fields. This was originally done by making a relatively large hole in the tilled earth with a tobacco peg, then placing the small plant in the hole. Various mechanical tobacco planters were invented throughout the late 19th and early 20th centuries to automate this process, making a hole, fertilizing it, and guiding a plant into the hole with one motion. The cultivation of tobacco usually takes place annually. The tobacco is germinated in cold frames or hotbeds and then transplanted to the field until it matures. It is grown in warm climates with rich, well-drained soil. About 4.2 million hectares of tobacco were under cultivation worldwide in 2000, yielding over seven million tonnes of tobacco.〔FAO projections of tobacco production, consumption, and trade to the year 2010 (2003) http://www.fao.org/DOCREP/006/Y4956E/Y4956E00.HTM〕 == Sowing and growth== Tobacco seeds are scattered onto the surface of the soil, as their germination is activated by light. In colonial Virginia, seedbeds were fertilized with wood ash or animal manure (frequently powdered horse manure). Seedbeds were then covered with branches to protect the young plants from frost damage, and the plants were left alone until around April. In the 19th century, young plants came under increasing attack from certain types of flea beetles, ''Epitrix cucumeris'' or ''Epitrix pubescens'', which destroyed half the U.S. tobacco crops in 1876. In the years afterward, many experiments were attempted and discussed to control the flea beetle. By 1880, growers discovered that replacing the branches with a frame covered with thin fabric effectively protected plants from the beetle. This practice spread, becoming ubiquitous in the 1890s. Shade tobacco is the practice of growing the plants under a screen of cheesecloth fabric. The thin leaves were used for the outer wrappings of cigars. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Cultivation of tobacco」の詳細全文を読む スポンサード リンク
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