CHEN Yao,ZHU Jia-yun,YU Xue-hua,et al.Transformation and Fate of Incoming Nitrogen Associated with Runoff in Bioretention System[J].China Water & Wastewater,2021,37(23 23):129.
Transformation and Fate of Incoming Nitrogen Associated with Runoff in Bioretention System
China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU]
volume:
第37卷
Number:
23 23
Page:
129
Column:
Date of publication:
2021-12-01
- Keywords:
- bioretention system; sponge city; incoming nitrogen associated with runoff; isotopic tracing of 15N; antecedent dry day; immediate transformation; multi-media fate
- Abstract:
- In order to explore the immediate transformation and the fate of incoming nitrogen associated with runoff in multi-media of bioretention systems, such as water, plants, soil, and microbes, the immediate occurrence and content of incoming nitrogen in multi-media were studied with 15N isotope tracing technology. And the transformation of nitrogen under different drying-rewetting regimes which forming through antecedent dry days (ADD) were analyzed. Results showed that there existed denitrification and dissimilatory nitrate reduction to ammonium (DNRA) with cooperativity simultaneously for incoming NO3--N. Appropriate aridity promoted the emission of gaseous nitrogen, and then it became the dominant fate for NO3--N. However, aridity also aggrandized the risk of nitrogen leaching, particularly in overlong drought (ADD of 22 d), in which denitrification and DNRA can be inhibited, resulting in an increase of partitioning ratio in leaching fate (up to 32.30%). The abiotic fixation (AF) and microbial immobilization (MI) of soil to NO3--N was attenuated with the increase of ADD, while rhizosphere microorganism living in an arid environment during an overlong drought could strengthen the fate of nitrogen in the soil, and which facilitated direct assimilation of plants to NO3--N with a synergistic and competitive effect. The incoming NH4+-N was easy to leaching in the state of nitrate during arid soil conditions, but the leaching ratio only up to 0.34%. The soil fate of NH4+-N was dominated by MI, and the fate partitioning ratio was significantly higher than NO3--N. The occurring space and intensity of AF and MI were controlled by the soil moisture content during dry period. The assimilation of plants to NH4+-N was mainly related to plant biomass, and it was found that the dual stress effect of nutrients and water in the soil could accelerate the uptake of plant roots to NH4+-N. This research presented here confirmed that the path of immediate transformation and partitioning characteristic of different nitrogen in multi-media were controlled by ADD, which resulted in a quite different, and the leaching of NO3--N in bioretention system was likely to occur suffering in a prolonged drought.
Last Update:
2021-12-01