The production of tobacco continued to increase in the Piedmont and decrease in Tidewater, and Piedmont Virginia became more firmly established as Virginia's tobacco belt. This change was due partly to the fact that the virgin and fertile soils of the West kept tobacco prices so low that it could not be profitably produced on the manured worn out soils in the East. Tidewater was becoming full of old tobacco fields covered with young pine trees and the industry became concentrated largely in middle and southern Virginia. By 1800 Piedmont Virginia had definitely become the major tobacco producing area. [Illustration: Old Tobacco Warehouse, built 1680 at Urbanna, Virginia Courtesy of Mrs. H. I. Worthington] [Illustration: The mild species of tobacco which Rolfe imported from the West Indies. The harsh species of tobacco which Rolfe found the Indians cultivating. Courtesy of George Arents, and Virginia State Library] Expansion and new developments over a period of years brought about a fantastic increase in tobacco production. When its production was confined to the Tidewater area, Virginia produced about 40,000,000 pounds annually; by 1800 this amount had doubled. Virginia remained the leading producer of tobacco in the United States until the War Between the States, when she was replaced by Kentucky, owing to the devastating effects of the war in the Old Dominion. In the South the nature of the crop usually determines the number of acres that one person can cultivate successfully. Only a small number of acres of tobacco can be cultivated properly owing to its high value of yield per acre and the careful supervision required. The production of tobacco per acre does not appear to have changed very much in the long period from about 1650 to 1800, when 1,000 pounds per acre was considered a good yield. However, the amount that one man could produce increased during this period as the planters became more experienced and the plow and other implements came to be used more extensively. It has been estimated that in 1624 one man could properly cultivate and harvest only about one-half of an acre of tobacco, or about 400 pounds. At the beginning of the eighteenth century the average product of one man was from 1,500 to 2,000 pounds or in terms of acreage, from one and a half to two acres, plus six or seven barrels of corn. Around 1775 one man produced from 2,000 to 2,500 pounds of tobacco besides provisions. Thus it appears that during most of the Colonial period one man could cultivate one and a half to two acres of tobacco, plus provisions; but by the end of this period he had increased the productiveness of his own labor. MANAGEMENT OF THE CROP