2:15 PM - 2:30 PM
[AHW18-13] Assessment Nitrogen Budget in Detailed Spatial Pattern by Modeling Approach with Constructed Accurate Agricultural Behavior
Keywords:Nara Basin, nitrogen balance, groundwater contamination, denitrification, Soil & Water Assessment Tool
This study using Soil & Water Assessment Tool (SWAT) assessed the nitrogen budget in detailed spatial pattern in a rural catchment of Nara Basin. To obtained a detailed nitrogen balance in paddy land, the model constructed a detailed agricultural behavior database to improve the accuracy of the model, and the model was fully calibrated and verified by streamflow, paddy evapotranspiration, nitrate and total nitrogen concentration of river water.
Result shows, in the Nara Basin, the nitrogen leaching in paddy fields was 42 kg/ha, account 65% of total nitrogen leaching of study catchment. The tea fields, which occupy only 0.06% of the land, contributed 1% of the nitrate leaching of catchment because it nitrogen leaching quantity was as high as 187 kg/ha. The annual nitrogen denitrification in paddy field was 7.3 kg/ha, and 85% is occurred in farming season.
Acknowledgment: This research has been supported the Asia-Pacific Network for Global Change Research (APN) under Grant No. CRRP2019-09MY-Onodera (funder ID: http://dx.doi.org/10.13039/100005536), Research promotion for the environmental creation and rehabilitation of Osaka Bay area by Osaka Bay Regional Offshore Environmental Improvement Center (Project No. 010005, 020004, 030003, PI: Mitsuyo Saito). And Grant-in-Aid for Scientific Research (A) by Japan Society for the Promotion of Science (Project No. 21KK0192, PI: Shin-ichi Onodera).