Abstract
Pollution load from paddy fields was estimated using the data measured in Tsukuba city. Observation had been done from April 1984 to Sep. 1986. The observed load was closely related to rainfall. When it was rain, the pollution load, especially nitrogen load, from the paddy field had increased dramatically. Over half of the load generated in one year was flushed only in the three rainy days. COD, Nitrogen and phosphate load from the paddy field including rainy days were 51.3, 56.4, and 1.3 [kg ha-1 y-1] respectively. As the most of the previous studies paid little attention on rain, the load from the paddy field reported previous would be underestimated, especially in nitrogen load.
