ABSTRACT
In the early part of the Ming period, most of the migration out of the heavily populated areas was still toward the south or into central China. The population in this area continued to rise until the middle of the nineteenth century when the Taiping Rebellion succeeded where migration had failed. Population increases in earlier periods, together with water-control construction activities, played a major role in the expansion of the double-cropped area, particularly the double cropping of rice and wheat, but, in addition, that involving two crops of rice in a single year. Hence, although early ripening seeds played some part in the extension of winter wheat acreage and in the planting of a second crop of rice, the key to increased grain output from the source was population growth and the increasing density of people in the area.
