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| Hydrology and nitrogen loss characteristics of a typical rice paddy field in the Yangtze River basin |
| Received:March 25, 2022 |
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| KeyWord:paddy field;non-point source pollution;nitrogen loss;hydrologic characteristics |
| Author Name | Affiliation | E-mail | | GENG Fang | State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China | | | LIU Lianhua | State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China | liulianhua@bnu.edu.cn | | OUYANG Wei | State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
Advanced Interdisciplinary Institute of Environment and Ecology, Beijing Normal University, Zhuhai 519087, China | | | ZHU Jianqiang | College of Agriculture, Yangtze University, Jingzhou 434025, China | |
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| Abstract: |
| To investigate the hydrology and nitrogen loss characteristics of paddy fields and the relationship between them, in situ monitoring of field-scale multifactor water and nitrogen loss dynamics was carried out in a typical single rice paddy field in the Yangtze River basin, one of the three major rice planting areas in China. Results showed that field ponding water depth was mainly influenced by rainfall and irrigation. Water and fertilizer management were the main influencing factors for the dynamic changes of soil water content at different depths and nitrogen concentrations in field ponding water and soil water. Surface runoff loss was the main pathway of nitrogen loss from paddy fields in a normal year, with a loss of 8.70 kg·hm-2 in the rice growing season. Leaching loss was the main pathway of nitrogen loss from paddy fields in a dry year, with a loss of 4.86 kg·hm-2 in the rice growing season. The recovering stage was the critical risk stage for nitrogen leaching loss, with a loss of 1.73 kg·hm-2 and 2.14 kg·hm-2 in normal and dry years, respectively; the tillering and jointing- booting stages were the most critical risk stages for nitrogen surface runoff loss, with a loss of 7.10 kg·hm-2 and 1.26 kg·hm-2, respectively. There was a close correlation between paddy field hydrology and nitrogen loss. Changes in the dynamics of field ponding water level can affect the leaching and surface runoff water from paddy fields, which in turn affects nitrogen loss from paddy fields. In conclusion, field drainage in the early rice growing stages（recovering, tillering, and jointing-booting stages）, especially within one week after fertilization, should be avoided. The paddy field drainage level should be raised to increase the field water capacity, thereby reducing nitrogen loss. |
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