Open Door policy, statement of principles initiated by the United States in 1899 and 1900 for the protection of the same privileges between countries that are related to China`s trade and to the support of Chinese territorial and administrative integrity. The statement was sent in the form of circulars from US Secretary of State John Hay to the United Kingdom, Germany, France, Italy, Japan and Russia. The open-door policy was welcomed in the United States with an almost universal agreement and has been a cornerstone of U.S. foreign policy in East Asia for more than 40 years. The Open Door policy – first launched in 1899 with follow-up in 1900 – played a decisive role in the United States` attempt to create an international protocol on the same privileges for all countries that trade with China and to support China`s territorial and administrative integrity. Politics was a cornerstone of U.S. foreign policy in East Asia until the mid-20th century. The results show a 17-fold increase in N exports (7 times more in P) for the period 1900-2010. Space variations over time from the N and P sources in YRB were simulated for 1900-2010. The open door policy began with the publication of a circular (marginal diplomatic note) by US Secretary of State John Hay in the United Kingdom, Germany, France, Italy, Japan and Russia on September 6, 1899. On July 3, 1900, Hay issued a second circular to the same countries. Politics was a cornerstone of U.S. foreign policy in East Asia until the mid-20th century; Politics was meaningless in 1945, after Japan`s defeat in the Second China War and World War II, which brought about changes in the world order, and in 1949, after the Communist victory in the Chinese Civil War, which ended all special privileges for foreigners.
In response to the presence of European armies in northern China to quell the boxer rebellion (1900), Hay`s second circular of 1900 stressed the importance of preserving China`s territorial and administrative integrity. Hay did not ask for answers, but all the powers, with the exception of Japan, accepted these principles. Nitrogen (N) and phosphorus (P) from countries at sea in the Yangtze River basin were simulated for the period 1900-2010 by combining hydrology models, nutrient-containing inputs in surface water and storage in water sources. This study shows that the basin-wide nutrient budget, surface water intake and river storage increased during this period. Since 2004, the Three Gorges Dam has contributed 5% and 7% respectively to support for Basin N and Basin P. With the dramatic increase in nutrient intake, even this additional retention was not enough. to avoid an increase in river export from 337 Gg N yr-1 and 58 Gg P yr-1 (N:P-Molar – 13) to 5896 Gg N-An 1 and 381 Gg P-An 1 (N:P-Molar – 35) to the East China Sea and the Yellow Sea (ECSYS).