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排水条件下化肥流失的研究——现状与展望   总被引:14,自引:0,他引:14       下载免费PDF全文
探讨排水对化肥流失的影响;减少排水条件下化肥流失的合理施肥措施及排水方式。根据现有研究成果,从排水条件下化肥流失的野外试验研究和数值模拟研究两方面进行了论述,在此基础上提出该项研究需进一步探讨和解决的问题,为该课题的深入研究提供了有利条件。  相似文献   
2.
The changes of NH3-N, NO3-N, NO2-N and TN/TP were studied during growth and non-growth season in 33 subtropical shallow lakes in the middle and lower reaches of the Yangtze River. There were significant positive correlations among all nutrient concentrations, and the correlations were better in growth season than in non-growth season. When TP>0.1 mgL-1, NH3-N increased sharply in non-growth season with increasing TP, and NO3-N increased in growth season but decreased in non-growth season with TP. These might be attributed to lower dissolved oxygen and low temperature in non-growth season of the hypereutrophic lakes, since nitrification is more sensitive to dissolved oxygen and temperature than antinitrification. When 0.1 mgL-1>TP>0.035 mgL-1, TN and all kinds of inorganic nitrogen were lower in growth season than in non-growth season, and phytoplank-ton might be the vital regulating factor. When TP<0.035 mgL-1, inorganic nitrogen concentrations were relatively low and NH3-N, NO2-N had significant correlations with phytoplankton, indicating that NH3-N and NO2-N might be limiting factors to phytoplankton. In addition, TN/TP went down with decline in TP concentration, and TN and inorganic nitrogen concentrations were obviously lower in growth season than in non-growth season, suggesting that decreasing nitrogen (especially NH3-N and NO3-N) was an important reason for the decreasing TN/TP in growth season. The ranges of TN/TP were closely related to trophic level in both growth and non-growth seasons, and it is apparent that in the eutrophic and hypertrophic state the TN/TP ratio was obviously lower in growth season than in non-growth season. The changes of the TN/TP ratio were closely correlated with trophic levels, and both declines of TN in the water column and TP release from the sediment were important factors for the decline of the TN/TP ratio in growth season.  相似文献   
3.
选择长江中下游49个湖泊进行不同季节的水体溶解无机氮(DIN)、总氮(TN)、总磷(TP),溶解性无机磷(DIP)以及叶绿素a(Chla)等环境参数分析,开展不同营养水平湖泊水体环境变化特征及生物响应机制研究。结果表明:DIN、TN/TP随TP的变化规律反映了不同营养水平和季节下地球化学作用的影响;氨氮(NH4-N)、TP、DIP、Chla尤其是NH4-N的季节性变化规律与营养水平关系密切;TP<0.05 mg/L时,NH4-N随总磷升高的趋势夏季大于其他季节,TN/TP与硝态氮(NO3-N)、TN相关性好,营养源组成和氨化作用是主要影响因素;0.05 mg/L4-N随总磷升高的趋势基本相同,TN/TP与亚硝态氮(NO2-N)、NO3-N、TN相关好,水生植物利用、氨化和反硝化作用是主要影响因素。TP>0.1 mg/L,冬季NH4-N随总磷升高的趋势明显大于其他季节,TN/TP在冬季和春季与TN、NO3-N相关性好,夏季和秋季与TP相关性好,其主要原因在于夏季和秋季水生植物对DIN的利用量、反硝化作用和湖泊内源释放的显著增强。  相似文献   
4.
Abstract

This study presents a new methodology for estimation of input data measurement-induced uncertainty in simulated dissolved oxygen (DO) and nitrate-nitrogen (NO3-N) concentrations using the Hydrological Simulation Program–FORTRAN (HSPF) model and data from the Amite River, USA. Simulation results show that: (1) a multiplying factor of 1.3 can be used to describe the maximum error in temperature measurements; similarly, a multiplying factor of 1.9 was estimated to accommodate the maximum of ±5% error in rainfall measurements; (2) the uncertainty in simulated DO concentration due to positive temperature measurement errors can be described with a normal distribution, N(0.062, 0.567); (3) the uncertainty in simulated NO3-N concentration due to rainfall measurement errors follows a generalized extreme value distribution; and (4) the probability density functions can be utilized to determine the measurement-induced uncertainty in simulated DO and NO3-N concentrations according to the risk level acceptable in water quality management.

Editor D. Koutsoyiannis

Citation Patil, A. and Deng, Z.-Q., 2012. Input data measurement-induced uncertainty in watershed modelling. Hydrological Sciences Journal, 57 (1), 118–133.  相似文献   
5.
Land-use and soil management affects soil organic carbon (SOC) pools, nitrogen, salinity and the depth distribution. The objective of this study was to estimate land-use effects on the distribution of SOC, labile fractions C, nitrogen (N) and salinity in saline-alkaline wetlands in the middle reaches of the Heihe River Basin. Three land-use types were selected: intact saline-alkaline meadow wetland, artificial shrubbery (planting Tamarix) and farmland (cultivated for 18 years) of soils previously under meadow wetland. SOC, easily oxidized carbon, microbial biomass carbon, total N, NO3--N and salinity concentrations were measured. The results show that SOC and labile fraction carbon contents decreased significantly with increasing soil depth in the three land-use wetlands. The labile fraction carbon contents in the topsoil (0-20cm) in cultivated soils were significantly higher than that in intact meadow wetland and artificial shrubbery soil. The aboveground biomass and soil permeability were the primary influencing factors on the contents of SOC and the labile carbon in the intact meadow wetland and artificial shrubbery soil, however, the farming practice was a factor in cultivated soil. Agricultural measures can effectively reduce the salinity contents; however, it caused a significant increase of NO 3--N concentrations which posed a threat to groundwater quality in the study area.  相似文献   
6.
2016年以来太湖总磷浓度高位波动而总氮浓度持续下降,藻细胞内源性磷释放是湖泊水体总磷的重要来源,而多聚磷酸盐作为藻细胞内磷的储存库,其含量变化会显著影响藻细胞内源性磷的释放量.针对上述现象,开展了不同硝态氮浓度影响野外水华蓝藻及实验室纯培养的铜绿微囊藻(Microcystis aeruginosa)利用磷特别是合成多聚磷酸盐(PolyP)的研究,并通过测定低硝态氮浓度下铜绿微囊藻的光合活性以及抗氧化系统活性,探索低硝态氮浓度促进微囊藻合成PolyP的生理机制.研究结果表明,当水体硝态氮浓度低于2 mg/L时,水华蓝藻和铜绿微囊藻均能大量吸收磷酸盐,并在胞内累积PolyP.同时,由于水体中可利用氮浓度下降,铜绿微囊藻胞内蛋白质干重(0.6 mg/mg)也显著下降.此时,铜绿微囊藻细胞的光合活性仍能达到高氮对照组的75.1%~88.7%,但由于碳和氮同化潜力的下降,较强的光合活性导致细胞内活性氧累积,使细胞处于氧化应激状态,导致藻细胞内蛋白质、核酸和细胞膜结构受损.而由于PolyP具有保护作用,微囊藻合成大量PolyP,以适应缺氮的水环境,导致蓝藻奢侈吸磷.因此,低硝态氮促进微囊藻累积多聚磷酸盐,从而提升细胞内总磷含量,而高含磷蓝藻衰亡释放磷,就会增加水体中总磷浓度.  相似文献   
7.
通过对分离的滇池北部海埂湾春季蓝藻水华时期的两株水华束丝藻(Aphanizomenon flos-aquae)进行研究,探讨了滇池水华束丝藻在低浓度硝酸盐下的生长特征,以及无氮条件下藻丝异形胞的诱导分化过程与固氮能力.实验结果表明:两株水华束丝藻在各浓度硝酸盐中均能够生长,并且生物量能够增加到较高水平.硝态氮浓度高时水华束丝藻的生物量也较高,但是硝酸盐浓度超过0.5 mg/L时,各组生物量无显著性差异.无氮BG-11培养基培养条件下,水华束丝藻可以快速分化形成异形胞,含有异形胞的藻丝比例在3 d以后即可达50%左右,最高可以达72%,之后开始下降,但是仍能维持较高比例.水华束丝藻在无氮条件下通过异形胞固定的氮元素从第7 d开始逐渐增加,在生长43 d后,培养基中增加的氮浓度接近30 mg/L.  相似文献   
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