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Transport and distribution of chlorpyrifos in soil-water-plant system of paddy field developed from red soil |
Received:February 03, 2020 |
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KeyWord:chlorpyrifos;3,5,6-trichloro-2-pyridinol (TCP);paddy field;reactive transport;irrigation regime;rice |
Author Name | Affiliation | E-mail | YAO Ying-lei | School of Ecological Engineering, Shanghai Institute of Technology, Shanghai 201418, China Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China | | LIU Hui-yun | Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China | | CHENG Jian-hua | Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China | | TANG Xiang-yu | Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China | | GENG Chun-nu | School of Ecological Engineering, Shanghai Institute of Technology, Shanghai 201418, China | gengchunnu@hotmail.com | GUAN Zhuo | Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China | |
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Abstract: |
The transport and distribution of pesticides in paddy field soil-water system constitute a serious danger to human and ecosystem health. This study investigated the transport and distribution of chlorpyrifos as a commonly used pesticide in paddy field of red soil through laboratory batch equilibrium adsorption experiments and field study. The study was conducted under continuous and intermittent flooding conditions through field pesticide application and subsequent continuous monitoring. The results showed that chlorpyrifos leached strongly to a depth of 50 cm in the paddy soil and the high daytime temperature caused increases in concentrations of chlorpyrifos and its main degradation product, 3,5,6-trichloro-2-pyridinol(TCP), in the pore water of the surface soil layer. Rain events promoted the transport of chlorpyrifos and TCP toward the deep soil layer. Chlorpyrifos residue in the soil at the time of rice harvesting was high and it was uniformly distributed in the soil profile. Intermittent irrigation reduced the chlorpyrifos contents in rice grains and stems. Chlorpyrifos contents in rice grains and stems under intermittent irrigation were 0.69 and 0.84 times those in rice grains and stems under continuous irrigation, respectively. This study suggests that chlorpyrifos could leach in paddy field developed from red soil, and different irrigation methods have a significant effect on the content of chlorpyrifos in harvested rice. |
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