Rice paddy ecosystems contribute greatly to the anthropogenic greenhouse gas (GHG) emissions and reactive nitrogen (Nr) losses. Understanding the impacts of agricultural management practices on GHG and N losses is critical for implementing optimal farming practices and maintaining agricultural productivity. This study examines the influence of agricultural management on GHG and N losses in Tai-Lake Paddy soils of China using the Denitrification-Decomposition (DNDC) model. The DNDC model was validated through the field experiment conducted in Changshu, China. A regional model was constructed for the entire Tai-Lake watershed. Sensitivity analysis was conducted using single-factor analysis. To comprehensively analyze combined carbon and nitrogen footprints and economic benefits, multiple quantitative indicators, including Net Global Warming Potential (NGWP), Total Nr losses (Nrloss), Environmental Damage Cost (EDC) and Net Economic and Environmental Benefits (NEEB), were calculated. The results indicate that the DNDC model can accurately simulate the yield and total greenhouse gas emissions during the wheat-rice rotation period in the target farmland. The NGWP for the Tai Lake Basin ranges from 6035 to 12104 kg CO2-eq/hm2, and Nrloss ranges from 227.37 to 380.82 kg N-eq/hm2. Sensitivity analysis revealed that increased urea application leads to an increase in NGWP and Carbon footprint, while negatively impacting Nrloss and EDC. Additionally, increased precipitation can result in the leaching and runoff of nitrogen from the soil to groundwater or rivers, increasing Nrloss and NGWP. The increase in soil organic carbon (SOC) content promotes Nrloss, and reduces the rate of SOC sequestration. However, the impact of precipitation and SOC on economic benefits is still unclear. High pH values reduce Nrloss, positively affect EDC, but significantly reduce NEEB. In contrast, the influence of clay content on the results is insignificant. It is recommended to reduce the amount of fertilizers and consider the use of organic fertilizers, implement water-saving agriculture to cope with precipitation changes, and appropriately regulate soil pH value and SOC content to reduce GHGs and nitrogen loss.

Dr. Chuanhui Gu is a tenured Associate Professor at Duke Kunshan University, currently serving as a seniorprincipal investigator at the Environmental Research Center. Before joining Duke Kunshan University, he was a professor at Beijing Normal University and a tenured Associate Professor at Appalachian State University in the United States. He has led and participated in research projects funded by the U.S. National Science Foundation, the U.S. Department of Energy, the National Natural Science Foundation of China, international cooperation projects, joint funds, and key research and development projects of China's Ministry of Science and Technology, with total funding exceeding 1.2 million USD. He has published over 60 SCI-indexed papers in top international journals in the fields of Earth and Environmental Sciences. He has served as a panel member for the U.S. National Science Foundation and a committee member of the University of North Carolina system within the Consortium of Universities for the Advancement of Hydrologic Science. He is currently an Associate Editor of HydroResearch. In 2017, he was awarded the Outstanding Reviewer Award for Water Resources Research by the American Geophysical Union. In 2012, he received the Wachovia Environmental Research Award for his outstanding contributions to Appalachian environmental research.