Japan is a country with a large population and little arable land, and the arable land area is still decreasing. Japan's cultivated land area decreased from 6 million hectares in 1965 to 4.69 million hectares in 2005, a decrease of 22%. The decrease in cultivated land area has also shown an intensifying trend. Between 1975 and 1985, the cultivated land area decreased by 13.5 hectares; between 1985 and 1995, it decreased by 24.4 hectares; between 1995 and 2005, this number decreased by 38.6 hectares (reaching the total cultivated land 8% of the area).
Another characteristic of Japan’s agricultural cultivated land area is that the average cultivated land area per farm household is small. The agricultural land area per household in Japan was 1.8 hectares in 2006, while the average in EU countries was 16.9 hectares in 2005, the United States was 180.2 hectares in 2005, and Australia had 3,423.8 hectares per household in 2004.
The direct reasons for the reduction of Japan’s cultivated land area are: first, farmers abandon farming and leave the land abandoned (the main reason); second, cultivated land is used as residential land. According to reports, the reasons behind the serious abandonment of farmland include that land and manpower are expensive in Japan, but the price of agricultural products is relatively low; farmers are aging, but their children do not want to engage in agriculture, and there are no successor cultivators of farmland.
The fertility of farmland continues to decline. At the same time, a large amount of chemical substances are lost into the water and air, causing environmental pollution. In recent years, the eutrophication phenomenon of some lakes in my country has been extremely serious, which is also caused by the inflow of pesticides and fertilizers during the cultivation of farmland in the upper reaches of the lakes and around the lakes. In Japan, the delegation visited Lake Biwa, the largest lake in Japan, and its management experience is worth learning from. The Japanese government has adopted legislation and other measures to stipulate various aspects such as fertilization, drainage, field water surface, and livestock house structure. For example, farmland irrigation is not flood irrigation, but water-saving measures such as infiltration irrigation, sprinkler irrigation, and drip irrigation are adopted, and chemical fertilizers and pesticides are used rationally. Some measures such as green coverage and no-till planting have also been adopted to control the pollution of Lake Bipa from the source.