In the 19th century the crop rotation method practiced in Chos?n proved greatly superior to that practiced in the same age in Europe. By contrast as time passed the marginal productivity of labor for dry field crops declined. Increasingly additional labor was needed to produce the same quantity of grain. The increase in the productivity of land in the late Chos?n period was not based on increased use of fertilizer, but rather from the increased use of labor. The increase in varieties and the small-scale of production that marked the diversification of dry-field farming was not done for the purpose of send goods to market but rather for self-consumption. After cultivating small quantities of a variety of crop according to a plan for consumption, if any surplus remained farmers took it to market for sale. In this way the trends in development of agriculture in the late Chos?n may be summarized as intensification marked by increased productivity of land and decreased productivity of labor, and the diversification of agricultural crops grown for the purpose of self-consumption.