The practice of intensive manuring emerged as the dominant mark of the Chinese system. All human and animal nitrogenous wastes were carefully husbanded in large terra-cotta vats where they were aged, and then ladled into irrigation ditches. Every 2,000 pounds of night soil provided 12.7 pounds of nitrogen, 4 pounds of potassium, and 1.7 pounds of phosphorus. Ashes were added to this compost from any kind of fire.
Source: The Gardens of China, 1983 See also: Farmers of Forty Centuries: Permanent Agriculture in China, Korea and Japan. F. H. King.
Contributed by: Zaady