CULTIVATION OF TOBACCO
In the United States, tobacco is often fertilized with the mineral apatite, which partially starves the plant of nitrogen to produce a more desired flavor. Apatite, however, contains radium, lead 210, and polonium 210—which are known radioactive carcinogens.
After the plants have reached relative maturity, they are transplanted into the fields, in which a relatively large hole is created in the tilled earth with a tobacco peg. Various mechanical tobacco planters where invented in the nineteenth and twentieth to automate the process: making the hole, fertilizing it, guiding the plant in—all in one motion.
Tobacco is cultivated annual, and can be harvested in several ways. In the oldest method, the entire plant is harvested at once by cutting off the stalk at the ground with a sickle. In the nineteenth century, bright tobacco began to be harvested by pulling individual leaves off the stalk as they ripened. The leaves ripen from the ground upwards, so a field of tobacco may go through several so-called "pullings," more commonly known as topping (topping always refers to the removal of the tobacco flower before the leaves are systematically removed and, eventually, entirely harvested. As the industrial revolution took hold, harvesting wagons used to transport leaves were equipped with man-powered stringers, an apparatus which used twine to attach leaves to a pole. In modern times large fields are harvested by a single piece of farm equipment, although topping the flower and in some cases the plucking of immature leaves is still done by hand.