Around 1880, the arrival of large quantities of American corn. made the agricultural policies of European countries develop in different ways. The defensive protectionnism in France and Germany and the « laissez-faire » of Great Britain contrast with, the constructive attitude of Denmark, transforming corn, at low prices into animal products. The crisis of the thirties affected, agriculture very hard and brought about a greater state intervention. France, Germany, Great Britain and even Denmark' increased their protection and ways of support. Since 1945, price and income support has been adopted, which make agricultural policies still more complexe. However, it has finally been admitted that price policy is not sufficient to resolve, the agricultural problem. Rural migration is necessary. Agricultural development programs undertaken by, the various countries do not seem capable of adapting agriculture to modern conditions.
