|Author:||Shiratani, E ; Yoshinaga, I ; Feng, Y ; Hasebe, H|
|Book Group Author:||NA|
We reviewed rates of nitrogen (N) removal in paddy fields and wetlands. Then we developed a numerical model to simulate N flow in an agricultural paddy field area and analyzed scenarios for recycling the agricultural run-off, including field drainage, from an agricultural area with an irrigation/drainage system. In it, we considered N removal in paddy fields, a regulating reservoir, and canals. The review showed that the rate constant for N removal in paddy fields and wetlands was 0.025 m/d under natural conditions and 0.01 m/d under dark conditions. The scenario analysis of recycling paddy field run-off within the model area indicated that a large amount of the effluent load occurred during the transplanting period and that recycling could reduce the effluent N load. The effluent N load would be equal to the inflowing N load at a 48% recycling rate. In this scenario, paddy fields accounted for most of the reduction in the effluent N load, and the mean removal rates per unit area of paddy field and regulating reservoir were 53.6 g ha(-1)d(-1) and 222.6 g ha(-1)d(-1), respectively.
|Journal:||WATER SCIENCE AND TECHNOLOGY|
|Journal ISO:||Water Sci. Technol.|
|Publisher:||I W A PUBLISHING|
clay bottomed canal; denitrification; irrigation system; paddy field; wetland
|Source:||Web of Science|