中文关键词灌排单元沟渠氮磷农业面源污染 英文关键词irrigation-drainage unitditchesnitrogen and phosphorusagricultural non-point source pollution

作者	单位	E-mail
华玲玲	中国农业科学院农业资源与农业区划研究所, 农业部面源污染控制重点实验室, 北京 100081	hualing0329@163.com
张富林	湖北省农业科学院植保土肥研究所, 武汉 430064
翟丽梅	中国农业科学院农业资源与农业区划研究所, 农业部面源污染控制重点实验室, 北京 100081	zhailimei@caas.cn
刘宏斌	中国农业科学院农业资源与农业区划研究所, 农业部面源污染控制重点实验室, 北京 100081
范先鹏	湖北省农业科学院植保土肥研究所, 武汉 430064
王洪媛	中国农业科学院农业资源与农业区划研究所, 农业部面源污染控制重点实验室, 北京 100081

中文摘要 江汉平原稻田多以灌排单元的形式存在，其中，沟渠是灌排单元的主要组成部分.本文以江汉平原腹地典型灌排单元内自然沟渠为研究对象，通过对2015年水稻整个生长季自然沟渠水深、水质的连续原位监测，研究灌排单元内自然沟渠水深、氮磷浓度的动态变化及导致这一变化的主要影响因子.结果表明，整个水稻生长季，沟渠水深维持在30~70 cm之间，灌溉事件增加的沟渠内水深高于降雨事件；水稻生长季，受水稻追肥的影响，沟渠水总氮（TN）浓度分别于6月18日和7月30日出现两个不同程度的峰值，且生育前期氨氮（NH₄⁺-N）浓度高于硝氮（NO₃^--N），施肥是影响沟渠水中氮浓度的主要因子；整个水稻生长季沟渠水总磷（TP）浓度波动较大，主要受颗粒态磷（PP）浓度变化影响，外界扰动（如降雨、灌溉事件）是影响沟渠水TP浓度变化的主要因子.水稻生长后期即收获期，沟渠水中TN和TP浓度分别为0.22 mg·L^-1和0.06 mg·L^-1，水质均达地表水水质Ⅱ类标准.灌排单元内，拦截沟渠与周边河道的路基高约2~2.5 m，无特大暴雨情况下，沟渠水很少漫过路基通过溢流向周边水体排水.水稻移栽直至第一次追肥后的3 d应控制沟渠水的外排.自然沟渠对降雨、灌溉和农田径流带入的氮磷起到一定程度的净化作用，通过在灌排单元出水口人为控制稻季沟渠水外排，直至水稻收获期，将使沟渠水水质达Ⅱ类标准，降低了灌排单元沟渠排水给周边水体带来的环境风险. 英文摘要 The paddy field in Jianghan Plain usually exists in the form of an irrigation-drainage unit, and the natural ditch is the main part of the unit. A continuous in situ monitoring of the natural ditch water level and water quality through the entire rice growing season in 2015 was conducted to investigate the dynamics of ditch water level and nitrogen and phosphorus concentration in the ditch. Another objective was to determine the effect of these factors. Results showed that during the entire rice growing season, the ditch water depth was maintained between 30 to 70 cm, and the water depth was higher during irrigation events than during rainfall events. Fertilization was the main factor affecting the nitrogen concentration in the ditch water. Two peaks of total nitrogen (TN) concentration appeared on June 18 and July 30 because of topdressing. In the early stage of rice growing, ammonia nitrogen (NH₄⁺-N) concentration was higher than that of nitrate nitrogen (NO₃^--N). External disturbances (such as rainfall and irrigation events) were the main factors affecting the total phosphorus (TP) concentration in the ditch water. The dynamic of TP concentration in the ditch water was large, and it was consistent with that of the particulate phosphorus (PP) concentration. Drainage of the irrigation-drainage was mainly controlled artificially. The period from rice transplanting to 3 days after the first top dressing was critical in preventing the outflow of ditch water. During the rice harvest stage, the TN and TP concentration were 0.22 and 0.06 mg·L^-1, and the water quality reached theⅡclass standard for surface water quality. This reduced the risk from drainage from the irrigation-drainage unit to the surrounding water environment.

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