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| DOI：10.13522/j.cnki.ggps.20180628 |
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| Impact of Irrigation Methods on Saving Water and Alleviating Pollutant at Different Scales in Paddy Field |
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XU Yi， WU Yongxiang， WANG Gaoxu， XU Rongrong， GUO Ting
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1.State Key Laboratory of Hydrology-water Resources and Hydraulic Engineering， Nanjing 210098, China；2.Nanjing Hydraulic Research Institute， Nanjing 210029, China
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| Abstract: |
| 【Objective】 Soil water modulates root uptake of water and pollutant dynamics in soil. This paper presents a experimental study on the impact of irrigation methods on water saving and pollution attenuation at different scales in a rice field. 【Method】The experiment was conducted in 2017 at Pinghu in Zhejiang Province. We compared three irrigation methods: traditional irrigation, water-saving irrigation and rain-storage irrigation. In each treatment, we measure water flow and concentration of TN, TP, NH+4-N and NO-3-N in drainage water and leaching water.【Result】 Rain-storage irrigation was most efficient in saving water and ameliorating pollution, and compared to other irrigation methods, it reduced water usage by 43.4%~87.7% and TN load in drainage water by 22%~90%. The rice yield at plot scale was slightly higher than that at field scale due to its improved management. When the irrigation amount was the same, the pollutant load in the drainage system at field scale was 37%~57% lower than that at plot scale, while its load in the leaching water was 4%~61% higher than at plot scale.【Conclusion】 The rain-storage irrigation method was most efficient in better use of water and ameliorating pollution, but care needs to be taken in choosing the timing and height of rain storage in the field, as prolonged flooding could have detrimental impact on the rice yield. |
| Key words: irrigation; scale; water-saving effect; pollution-reducing effect |
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