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| DOI：10.13522/j.cnki.ggps.2017.0552 |
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| Effect of Water Depth over Paddy Field on Nitrogen and Phosphorus in the Water After Storms at Tillering Stage |
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WANG Jiao， YU Shuang’en, WANG Mei， ZHANG Yidi， GAO Shikai
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1. College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing 210098, China; 2. Key Laboratory of Efficient Irrigation-drainage and Agricultural Soil-water Environment in Southern China Ministry of Education, Hohai University, Nanjing 210098, China
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| Abstract: |
| 【Objective】Canopy density at tillering stage is low and the biofilm crust has yet formed. Rainstorm splash at this stage could therefore break the fragile soil crust resulting in soil erosion, and nitrogen and phosphorus loss from the paddy field. The purpose of this study is to investigate the impact of water depth over paddy field on this process. 【Method】 The experiments measured the changes in nitrogen and phosphorus concentrations in the surface water following rainstorms under three pre-storm water depths: shallow, moderate and deep. 【Result】 After a rainstorm, the concentration of nitrogen and phosphorus in all treatments increased steadily, especially when initial water depth was relatively shallow. Few days after the storm, the concentrations attenuated. The loads of nitrogen and phosphorus one day after a storm under different treatments were ranked in shallow>moderate>deep. 【Conclusion】 To abate non-point source pollution, drainage immediately after a rainstorm should be avoided. If drainage is indeed necessary, it should wait for at least four days until the concentration of nitrogen and phosphorous in the surface water declined to steady state. |
| Key words: Rainstorm; water depth; nitrogen and phosphorus load; rice |
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