Abstract
Nitrogen purification function of paddy is attracting much attention against eutrophication of rivers and lakes. This study investigated the nutrient purification function of paddy by field tests and analysis of 1D, 2D.1D nitrogen removal equation was derived from the law of conservation and compared to field tests. The results obtained are very much in agreement with the field tests. Then, Nitrogen purification function and flow in the paddy was examined by plane two-dimensional analysis. As a result, nitrogen purification function was improved on condition which prepared waterway in the paddy. However, the nitrogen purification function was decreased on condition that flow becomes fast near the outlet.
