巢湖沿岸典型圩区夏季水稻生长期营养盐输出特征研究
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摘要
巢湖及其主要支流沿岸分布着很多地势低洼、靠排灌站抽排水进行排涝和引水灌溉的圩区。为探明圩区农业非点源营养盐输出特征,本研究选择巢湖沿岸某典型圩区,于2009年水稻生长期进行了较系统的野外调查、观测、取样和室内水质分析。2009年夏季该圩区较干旱,有3次共70.8mm的排水和3次共34mm的进水。排水总氮(TN)和总磷(TP)浓度分别在0.8～6.5mg N/L和0.05～0.6mg P/L之间,高于受纳河流柘皋河水质。TN和TP排水事件平均浓度EMC分别为4.28mg N/L和0.3mg P/L,水质总体处于富营养化和超富营养化水平。排水营养盐浓度与降雨排水量、施肥水平和距离施肥时间有关,并呈现复杂的动态变化。夏季水稻生长季节(6-9月)TN和TP净输出通量分别为2.10kg N/hm2和0.13kg P/hm2,占施肥总量的1.2%和0.4%。圩区的特殊地势和排水过程,使得圩内水稻田和沟渠具有较大的蓄水容量和较强的滞留效应,加上实验时期相对干旱,营养盐输出通量总体较低。由于农业非点源污染输出受排水量影响大,圩区又多为距离天然水体很近的敏感地带,圩区农业非点源污染对受纳水体的潜在和长期影响不容忽视。圩区各类污染输出对受纳水体的长远影响及如何有效控制还有待更深入的研究。
Around Chao lake there are many polders,the low lying land reclamations surrounded and protected by dikes.The inflow and outflow of water into and out of the polder area are controlled by the culvert and pumping station.Agricultural activities dominate these polders which drain important non-point source pollutants to their receiving water: Chao lake.These polders form the critical area for non-point sources pollution control.To understand nutrient export from these areas,a typical polder was chosen to make a detailed study.Water drainage outflow and inflow from nearby river were measured in the summer of 2009.Water flow in the ditches and the outflow by pumping of these events were sampled for the analysis of total nitrogen (TN),ammonia(NH4-N),nitrate(NO3-N),total phosphorus (TP) and dissolved phosphorus (DP).The results showed that there were totally 70.8 mm outflow and 34 mm inflow during the whole summer period,indicating that it was a dry summer.The TN and TP levels of drainage water were 0.8~6.5 mg N/L and 0.05~0.6 mg P/L respectively,higher than its receiving river.The event mean concentrations(EMC)were 4.28 mg N/L for TN and 0.26 mg P/L for TP,attaining eutrophic-hypereutropic status.The net loads were 2.10 kg N/hm2 and 0.13 kg P/hm2 respectively for TN and TP during this summer rice growing period (from June 1 to Sept.30),representing only 1.2% and 0.4% of nitrogen and phosphorus fertilization input.But in the long-term,it could be a treat to its final receiving water considering the important location and the strong influence of the drainage volume.The special water drainage way and the retention effect of the ditches might play an important role for restricting water nutrient export,which needed further study.
Around Chao lake there are many polders,the low lying land reclamations surrounded and protected by dikes.The inflow and outflow of water into and out of the polder area are controlled by the culvert and pumping station.Agricultural activities dominate these polders which drain important non-point source pollutants to their receiving water: Chao lake.These polders form the critical area for non-point sources pollution control.To understand nutrient export from these areas,a typical polder was chosen to make a detailed study.Water drainage outflow and inflow from nearby river were measured in the summer of 2009.Water flow in the ditches and the outflow by pumping of these events were sampled for the analysis of total nitrogen (TN),ammonia(NH4-N),nitrate(NO3-N),total phosphorus (TP) and dissolved phosphorus (DP).The results showed that there were totally 70.8 mm outflow and 34 mm inflow during the whole summer period,indicating that it was a dry summer.The TN and TP levels of drainage water were 0.8~6.5 mg N/L and 0.05~0.6 mg P/L respectively,higher than its receiving river.The event mean concentrations(EMC)were 4.28 mg N/L for TN and 0.26 mg P/L for TP,attaining eutrophic-hypereutropic status.The net loads were 2.10 kg N/hm2 and 0.13 kg P/hm2 respectively for TN and TP during this summer rice growing period (from June 1 to Sept.30),representing only 1.2% and 0.4% of nitrogen and phosphorus fertilization input.But in the long-term,it could be a treat to its final receiving water considering the important location and the strong influence of the drainage volume.The special water drainage way and the retention effect of the ditches might play an important role for restricting water nutrient export,which needed further study.
引文
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[13]Yoshinaga I,Miura A,Hitomi T,et al.Runoff nitrogen from a large sized paddy field during a crop period[J].Agricul-tural water management,2007,87:217-222.
[14]Kim M Y,Seo M C,Kim M K.Linking hydro-meteorological factors to the assessment of nutrient loadings to streamsfrom large-plotted paddy rice fields[J].Agricultural water management,2007,87:223-228.
[15]Van Huet H J W J.Phosphorus loads from peaty polders in the SW Frisian lake district,the Netherlands[J].Water,Air,and Soil Pollution,1991,55:321-335.
[16]梁新强,田光明,李华,等.天然降雨条件下水稻田氮磷径流流失特征研究[J].水土保持学报,2005,19(1):59-63.
[17]Yang X E,Wu X,Hao H L,et al.Mechanisms and assessment of water eutrophication[J].Journal of Zhejiang Universi-ty,2008,9(3):197-209.
[2]于涛,孟伟,Edwin O,等.我国非点源负荷研究中的问题探讨[J].环境科学学报,2008,28(3):401-407.
[3]Olli G,Darracq A,Destouni G.Field study of phosphorous transport and retention in drainage reaches[J].Journal of Hy-drology,2009,365:46-55.
[4]Krger R,Holland M M,Moore M T,et al.Agricultural Drainage Ditches Mitigate Phosphorus Loads as a Function ofHydrological Variability[J].Journal of Environmental Quality,2008,37:107-113.
[5]程文娟,史静,夏运生,等.滇池流域农田土壤氮磷流失分析研究[J].水土保持学报,2008,22(5):52-55.
[6]樊娟,刘春光,石静,等.非点源污染研究进展及趋势分析[J].农业环境科学学报,2008,27(4):1306-1311.
[7]Yoon C G,Ham J H,Jeon J H.Mass balance analysis in Korean Paddy rice culture[J].Paddy Water Environment,2003,1:99-106.
[8]莫祚年.圩区水文特性分析及其水位预报[J].水文,2001,21(4):35-37.
[9]徐爱兰,王鹏.太湖流域典型圩区农田磷素随地表径流迁移特征[J].农业环境科学学报,2008,27(3):1106-1111.
[10]王鹏,徐爱兰.太湖流域典型圩区农田氮素地表径流迁移特征[J].农业环境科学学报,2008,27(4):1335-1339.
[11]Littlewood I G.Estimating contaminant loads in rivers:a review[R].Institute of Hydrology,Crowmarsh Gifford,Wall-ingford,Oxfordshire,OX10 8BB,UK,1992.
[12]Merritt W S,Letcher R A,Jakeman A J.A review of erosion and sediment transport models[J].Environment Model&Software,2003,18(8/9):761-799.
[13]Yoshinaga I,Miura A,Hitomi T,et al.Runoff nitrogen from a large sized paddy field during a crop period[J].Agricul-tural water management,2007,87:217-222.
[14]Kim M Y,Seo M C,Kim M K.Linking hydro-meteorological factors to the assessment of nutrient loadings to streamsfrom large-plotted paddy rice fields[J].Agricultural water management,2007,87:223-228.
[15]Van Huet H J W J.Phosphorus loads from peaty polders in the SW Frisian lake district,the Netherlands[J].Water,Air,and Soil Pollution,1991,55:321-335.
[16]梁新强,田光明,李华,等.天然降雨条件下水稻田氮磷径流流失特征研究[J].水土保持学报,2005,19(1):59-63.
[17]Yang X E,Wu X,Hao H L,et al.Mechanisms and assessment of water eutrophication[J].Journal of Zhejiang Universi-ty,2008,9(3):197-209.
目录