Nitrogen and phosphorus losses from agricultural systems in China: A meta-analysis   总被引：2，自引：0，他引：2  

Di Cao  Wenzhi Cao  Jing FangLongyan Cai 《Marine pollution bulletin》2014

Studies worldwide have indicated that agricultural pollution is the main source of nitrogen and phosphorus (N and P) in surface waters. A systematic understanding of N and P sources and sinks in agricultural systems is important for selecting the appropriate remedial strategies to control nutrient losses and water pollution. Based on nationwide data and a long-term monitoring program in Southeast China, the nationwide spatial and temporal patterns of N and P losses and the relationships between such losses and N and P inputs and rainfall were analyzed. The results showed that the annual nutrient losses from agricultural systems in China strongly varied, and the N/P values ranged from 0.01 to 51.0, with a majority at approximately 0–20, and an arithmetic mean of 9.73; these values mostly overlap the suitable range of N/P (6–15) for red bloom algae.  相似文献   

农田氮流失与农业非点源污染   总被引：16，自引：0，他引：16  

仓恒瑾  许炼峰  李志安  任海 《热带地理》2004,24(4):332-336

随着氮肥的过量施用,农田氮流失容易造成农业非点源污染.农业非点源污染是农业环境富营养化的主要原因之一,改变了农业环境的生态结构与功能,造成很大危害.农田氮流失主要通过地表径流、农田排水和淋溶途径进入水体形成农业非点源污染,降雨状况、土壤特性、施肥状况、农业土地利用/土地覆盖和田间管理方式等因素与农田氮流失有密切关系.通过农田管理制度或立法、农田氮流失的源头控制和农田氮流失的扩散途径,可以实现对农业非点源污染的调控,降低施用化肥的环境风险.  相似文献   

Development of a Practical Tool for the Assessment of Biological Performances in Wastewater Treatment Plants          下载免费PDF全文

Francesca F. Malinverni  Barbara Ruffino 《洁净——土壤、空气、水》2016,44(11):1435-1443

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Retrieval of chlorophyll and nitrogen in Norway spruce (Picea abies L. Karst.) using imaging spectroscopy     

Martin Schlerf  Clement Atzberger  Joachim Hill  Henning Buddenbaum  Willy Werner  Gebhard Schüler 《International Journal of Applied Earth Observation and Geoinformation》2010

The research evaluated the information content of spectral reflectance (laboratory and airborne data) for the estimation of needle chlorophyll (C_AB) and nitrogen (C_N) concentration in Norway spruce (Picea abies L. Karst.) needles. To identify reliable predictive models different types of spectral transformations were systematically compared regarding the accuracy of prediction. The results of the cross-validated analysis showed that C_AB can be well estimated from laboratory and canopy reflectance data. The best predictive model to estimate C_AB was achieved from laboratory spectra using continuum-removal transformed data (R²cv = 0.83 and a relative RMSEcv of 8.1%, n = 78) and from hyperspectral HyMap data using band-depth normalised spectra (R²cv = 0.90, relative RMSEcv = 2.8%, n = 13). Concerning the nitrogen concentration, we observed somewhat weaker relations, with however still acceptable accuracies (at canopy level: R²cv = 0.57, relative RMSEcv = 4.6%). The wavebands selected in the regression models to estimate C_AB were typically located in the red edge region and near the green reflectance peak. For C_N, additional wavebands related to a known protein absorption feature at 2350 nm were selected. The portion of selected wavebands attributable to known absorption features strongly depends on the type of spectral transformation applied. A method called “water removal” (WR) produced for canopy spectra the largest percentage of wavebands directly or indirectly related to known absorption features. The derived chlorophyll and nitrogen maps may support the detection and the monitoring of environmental stressors and are also important inputs to many bio-geochemical process models.  相似文献   

Long-term perspective on the relationship between phytoplankton and nutrient concentrations in a southeastern Australian estuary     

Michaela E. Larsson  Penelope A. Ajani  Ana M. Rubio  Kristy Guise  Ross G. McPherson  Steven J. Brett  Kevin P. Davies  Martina A. Doblin 《Marine pollution bulletin》2017,114(1):227-238

Sixteen years (1997–2013) of physicochemical, nutrient and phytoplankton biomass (Chlorophyll-a (Chl-a)) data and a decade (2003-2013) of phytoplankton composition and abundance data were analyzed to assess how the algal community in a temperate southeastern Australian estuary has responded to decreased chronic point source nitrogen loading following effluent treatment upgrade works in 2003. Nitrogen concentrations were significantly lower (P < 0.05) following enhanced effluent treatment and Chl-a levels decreased (P < 0.05) during the warmer months. Temperature and nutrient concentrations significantly influenced temporal changes of Chl-a (explaining 55% of variability), while salinity, temperature, pH and nutrient concentrations influenced phytoplankton abundance and composition (25% explained). Harmful Algal Bloom (HAB) dynamics differed between sites likely influenced by physical attributes of the estuary. This study demonstrates that enhanced effluent treatment can significantly decrease chronic point source nitrogen loading and that Chl-a concentrations can be lowered during the warmer months when the risk of blooms and HABs is greatest.  相似文献   

Ambient Precursor Gaseous Pollutants and Meteorological Conditions Controlling Variations of Particulate Matter Concentrations     

《洁净——土壤、空气、水》2017,45(8)

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Influence of Crude Oil on Denitrification in Subtidal Sediments in the Northern Gulf of Mexico     

《洁净——土壤、空气、水》2017,45(9)

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Identifizierung von Stickstoffverbindungen niederer molarer Masse in Abläufen einer kommunalen Kläranlage mit biologischer Reinigungsstufe     

K. Grohmann  E. Gilbert  S. H. Eberle 《洁净——土壤、空气、水》1998,26(1):20-30

Identification of Nitrogen-containing Compounds of Low Molecular Weight in Effluents of Biologically Treated Municipal Wastewater Enriching methods based on reversed phases were developed for the investigation of low-molecular compounds containing nitrogen in municipal wastewater effluent. The enriched mixtures were treated gas chromatographically without derivatization under different conditions. By application of the PBM-algorithm to the GC/MS spectra of the enriched samples (concentration factor 1000...20000), 133 nitrogen-containing compounds could be identified with a probability of occurence of at least 30% put out. Seventeen of these compounds were identified with > 90% probability and another ten with 80...90% probability. 9-Methylacridine was found in nine of ten processed samples investigated. The nitrogen content of the 133 identified compounds was estimated at about 20% of the low-molecular fraction of DON (dissolved organic nitrogen).  相似文献   

闽江河口陆源入海排污口现状及氮磷排放调查          下载免费PDF全文

杨玉波 《海洋开发与管理》2020,37(3):36-40

闽江口海域是福建最重要的经济发展区,但也存在许多环境污染问题。2018年10—12月,对闽江入海口区域的陆源入海排污口开展调查和监测。本次共调查93个排污口,主要分布在琅岐岛（34.4%）和粗芦岛（20.4%）上。入海排污口的类型以设闸排污口为主,共调查有52个,占调查总数的55.9%,主要分布在琯头镇区域（17个）和琅岐岛（12个）。监测结果表明,闽江河口海域陆源排污口的氨氮、总氮和总磷超标严重,五类水质和劣五类水质样品分别占29.9%和37.7%。其中,设闸排污口的劣V类和V类水质样品最多,其次是自然径流。从区域来看,在琯头镇的劣V类和V类水质样品共有18个,占该镇排污口样品总数的90%。水质样品的最高监测浓度为：氨氮-20.2 mg/L,总氮-27.0 mg/L,总磷-2.86 mg/L,氨氮浓度已经超过《污水综合排放标准》的一级标准（15 mg/L）。闽江河口陆源入海排污口的污染物主要来源于农村和农业面源污染。针对排污口排污超标情况严重问题提出了加强农村面源污染监管和控制、开展重要排污口重点治理工程、开展陆源入海排污口详查等相应的措施和建议,为闽江河口陆源入海排污口整治提供科学支撑。  相似文献   

Simple parameterisations for describing N and P diagenetic processes: Application in the North Sea   总被引：1，自引：0，他引：1  

Nathalie Gypens  Christiane Lancelot 《Progress in Oceanography》2008,76(1):89-110

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