The strength of the agriculture was that it remained the core of the economy and wealth accumulation. In the 1850s, the main advantage of the South was its developing agriculture, which supported the rapid economic growth of the country. Owners of the cotton plantations were interested in cheap labor in order to extend their crop areas. African slaves were the only source of cheap labor supply meeting the needs of growing economy. Africans were strong and able to work long days in the plantations. Also, "Tobacco, cotton, and rice, which require many hands to tend, stimulated slavery" (Chronology on the History of Slavery and Racism, 1999).
Another economic cause of slavery was decline in immigrants labor supply connected with changing economic situation and urbanization. Many European immigrants settled in the North or returned to Europe where the processes of urbanization and distribution of wealth were faster than in the South. The North economic development and new wave of industrialization was higher and more stable attracting white immigrants and poor from the South. Industrial development and new production modes required cheap labor supplied from Africa.
Another economic factor was importance of trade between Europe and America which demanded rapid industrial and agricultural growth of the Southern and Northern states, and transatlantic slave trade which became the important source of power and wealth accumulation for European and American sl