The AGSD System was the core of Jiangsu coastal management
in the 16e19th centuries. Within the AGSD framework, the large
areas of coastal land could only be used for producing grass for the
salt production. Because the coastal salt production relied on a
large number of firewood to decocted brine in the traditional periods,
which in turn depended on the coastal grass land, the AGSD
system monopolized both the coastal land and the newly formed
tidal land; these areas were allocated for use by the government, to
guarantee the abundant source of firewood grass for decocted salt
production. Such a system had a profound impact on the Jiangsu
coast, which had greatly promoted the development of salt production.
In the 16e19th centuries, the coastal salt industry had
experienced prosperous development (Fig. 2) and provided a huge
amount of salt tax sources for the authorities in the Ming and Qing
Dynasties. For instance, in 1746, about 2.87 million taels of silver
were contributions from Jiangsu coastal salt industry, which
accounted for about 50% of total salt tax income of the empire
(Chen, 1988). In 1820, the annual production of salt reached up to
450 thousand tons, representing a peak and golden age of Jiangsu
coastal salt industry in history.