The system of large plantations was in vogue in Virginia from the early years of the 17th century. Even before the days of Sir William Berkeley, many of the colonists possessed extensive tracts of land, only part of which they could put under cultivation. Doubtless the dignity which the possession of land gave in England was the principal inducement for the planter to secure as large an estate as his means would permit. The wealthier Virginians showed throughout the entire colonial period a passion for land that frequently led them into the grossest and most unjustifiable fraud.[43] The tendency was accelerated by the law, made by the Virginia Company of London to encourage immigration, which allotted fifty acres of land to proprietors for every person they brought to the colony, "by which means some men transporting many servants thither, and others purchasing the rights of those that did, took possession of great tracts of land at their pleasure."[44] In 1621 a number of extensive grants were made to persons thus engaging themselves to take settlers to Virginia. To Arthur Swain and Nathaniel Basse were given 5,000 acres for undertaking to transport one hundred persons. Five thousand acres was also given Rowland Truelove "and divers other patentees." Similar tracts were given to John Crowe, Edward Ryder, Captain Simon Leeke and others.[45] Sir George Yeardly received a grant of 15,000 acres for engaging to take over three hundred persons.[46] Even more potent in building up large plantations was the wasteful system of agriculture adopted by the settlers. It soon became apparent to them that the cultivation of tobacco was very exhausting to the soil, but the abundance of land led them to neglect the most ordinary precautions to preserve the fertility of their fields. They planted year after year upon the same spot until the soil would produce no more, and then cleared a new field. They were less provident even than the peasants of the Middle Ages, for they failed to adopt the old system of rotation of crops that would have arrested to some extent the exhausting of their fields. Of the use of artificial fertilizers they were ignorant.