The document discusses the rise of cotton as the dominant crop in the Southern economy. Tobacco cultivation declined due to soil depletion and price fluctuations. Other crops like rice, sugar, and wheat faced limitations and restrictions to certain regions. Cotton proved hardy and could be grown across varying climates and soils. The invention of the cotton gin made processing cotton much easier. As cotton production spread across the South, it became the primary export and driving force of the Southern economy, comprising two-thirds of total US exports by the Civil War. The cotton economy led to a dramatic increase in the slave population across the Deep South as cotton cultivation expanded. However, Southern manufacturing remained underdeveloped, leaving the region economically dependent on the North.