Nitrogen flow associated with food production and consumption and its effect on water quality in Japan from 1961 to 2005

作者：Shindo Junko^*; Okamoto Katsuo; Kawashima Hiroyuki; Konohira Eiichi

来源：Soil Science and Plant Nutrition, 2009, 55(4): 532-545.

DOI：10.1111/j.1747-0765.2009.00382.x

• food trade
• nitrogenous fertilizer
• nitrogen mineralization
• numerical model
• water pollution

Using statistical data, we evaluated food supply and consumption in terms of nitrogen flow to clarify its effects on water quality from 1961 to 2005 in Japan. We revised a nitrogen flow model to incorporate food production, trade and consumption as well as nitrogen mineralization of crop residues and livestock manure and denitrification. Food consumption increased steadily from 1961 to the mid 1980s and has been almost stable since then. There was a notable increase in the consumption of livestock products. By 1996, consumption had risen to fivefold the 1961 level of consumption, but it has been stable since then. We concluded that the demand for food reached a maximum in the 1990s. The increasing demand for animal feed was filled by an increase in the imports of coarse cereals until the 1980s and of oil cakes until now. As the consumption of food and animal feed increased until the mid 1980s, the nitrogen load to the environment also gradually increased during this period, after which it tended to decrease. We estimated the nitrogen concentration in river water for 8 km x 8 km grid cells from 1961 to 2005 and compared these estimated values with measurements taken at more than 4000 points from public bodies of water in 1998. The spatial distribution and prefectural average of the estimated nitrogen concentration roughly corresponded with the measured values, and both indicate that food supply and consumption have had considerable effects on water quality in Japan.

• 出版日期2009-8