The history of agriculture in the United States covers the period from the first English settlers to the present day. In Colonial America, agriculture was the primary livelihood for 90% of the population, and most towns were shipping points for the export of agricultural products. Most farms were geared toward subsistence production for family use. The rapid growth of population and the expansion of the frontier opened up large numbers of new farms, and clearing the land was a major preoccupation of farmers. After 1800, cotton became the chief crop in southern plantations, and the chief American export. After 1840, industrialization and urbanization opened up lucrative domestic markets. The number of farms grew from 1.4 million in 1850, to 4.0 million in 1880, and 6.4 million in 1910; then started to fall, dropping to 5.6 million in 1950 and 2.2 million in 2008. Pre-Colonial era Prior to the arrival of Europeans in North America, the continent supported a diverse range of indigenous cultures. While some populations were primarily hunter-gatherers, other populations relied on agriculture. Native Americans farmed domesticated crops in the Eastern Woodlands, the Great Plains, and the American Southwest. Colonial farming: 1610–1775 The first settlers in Plymouth Colony planted barley and peas from England but their most important crop was Indian corn (maize) which they were shown how to cultivate by the native Squanto. To fertilize this crop, they used small fish which they called herrings or shads. Plantation agriculture, using slaves, developed in Virginia and Maryland (where tobacco was grown), and South Carolina (where indigo and rice was grown). Cotton became a major plantation crop after 1800 in the "Black Belt," that is the region from North Carolina in an arc through Texas where the climate allowed for cotton cultivation. Apart from the tobacco and rice plantations, the great majority of farms were subsistence, producing food for the family and some for trade and taxes. Throughout the colonial period, subsistence farming was pervasive. Farmers supplemented their income with sales of surplus crops or animals in the local market, or by exports to the slave colonies in the British West Indies. Logging, hunting and fishing supplemented the family economy. Ethnic farming styles Ethnicity made a difference in agricultural practice. German Americans brought with them practices and traditions that were quite different from those of the English and Scots. They adapted Old World techniques to a much more abundant land