Analysis of urea nitrogen leaching under high-intensity rainfall using HYDRUS-1D
The leaching of nitrogen in farmland could lead to groundwater nitrogen pollution, while precipitation is the driving factor. Nevertheless, the influences of extreme precipitation on soil organic nitrogen leaching, such as urea, is not clear. In this study, we used soil column experimental data to c...
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| Published in: | Journal of environmental management 2022-06, Vol.312, p.114900-114900, Article 114900 |
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| Main Authors: | , , , |
| Format: | Article |
| Language: | eng |
| Subjects: | |
| Online Access: | Get full text |
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| Summary: | The leaching of nitrogen in farmland could lead to groundwater nitrogen pollution, while precipitation is the driving factor. Nevertheless, the influences of extreme precipitation on soil organic nitrogen leaching, such as urea, is not clear. In this study, we used soil column experimental data to construct a nitrogen migration and transformation model. The constructed model was applied to unsaturated zones in farmlands in the Dagu River Basin of China. Three rainfall scenarios, namely rainstorms, heavy rainstorms, and extreme rainstorms, were simulated to analyze the variation in urea nitrogen leaching to groundwater. As the rainfall intensity increased, the quantity of urea nitrogen leaching increased from 0.04% to 18.09%. The cumulative urea nitrogen leaching flux is related to the initial soil moisture content. The time interval between fertilization inversely influenced the urea nitrogen leaching flux. Applying urea-based fertilizers shortly before high-intensity rainfall significantly increases the soil-crop system urea leaching loss and decreases crop nitrogen utilization. These findings imply that urea leaching under extreme rainstorms should not be ignored, and based on weather forecasting, fertilizer application in farmland should be avoided before high-intensity rainfall.
•Numerical model is a useful tool for evaluating accumulated nitrogen leaching flux and nitrogen balance in the unsaturated zone.•The urea nitrogen leaching flux increase with the rainfall intensity increase, and the nitrogen use efficiencydecrease.•Under extreme rainstorms, 18.5% of urea nitrogen can leach to groundwater without hydrolysis.•The urea leaching flux was affected by the initial soil moisture and the time interval between fertilization and rainfall. |
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| ISSN: | 0301-4797 1095-8630 |