During the Ming–Qing period (1368–1911) the biggest development in the Chinese economy was its transition from a command to a market economy, the latter becoming increasingly more pervasive throughout the Qing's rule. From roughly 1550 to 1800 China proper experienced a second commercial revolution, developing naturally from the first commercial revolution of the Song period which saw the emergence of long-distance inter-regional trade of luxury goods. During the second commercial revolution, for the first time, a large percentage of farming households began producing crops for sale in the local and national markets rather than for their own consumption or barter in the traditional economy. Surplus crops were placed onto the national market for sale, integrating farmers into the commercial economy from the ground up. This naturally led to regions specializing in certain cash-crops for export as China's economy became increasingly reliant on inter-regional trade of bulk staple goods such as cotton, grain, beans, vegetable oils, forest products, animal products, and fertilizer.