长江上游紫色母质养分溶出及环境效应预测

对侏罗系沙溪庙组(J2s)、蓬莱镇组(J3p)、遂宁组(J3s)、三叠系飞仙关组(T1f)母质小于0．25mm、0．25～0．50mm、0．50～1．00mm、1．00～2．00mm、2．00～5．00mm、＞5．00mm6个不同粒级，振荡时间为0．5h、1h、3h、6h不同振荡时间养分(全氮、全磷)溶出试验，模拟侵蚀颗粒在水流扰动中养分释放，分析母质颗粒养分溶出对水体富营养化的贡献。结果表明：振荡时间与母质颗粒溶出的全氮和全磷的含量呈正相关关系；粒级的大小对母质溶出的全氮和全磷的含量存在影响，随着粒级的增大，养分溶出量先增加后减小；以振荡6h氮、磷最大释放量与水体富营养化临界值比较分析，以氮释放量计，紫色母岩区泥沙含量临界值在8．30～11．94kg/m^3；以磷释放量计，紫色母岩区泥沙含量临界值在24．10～37．04kg/m^3；长江上游紫色岩区泥沙含量已接近临界泥沙含量。侵蚀母质颗粒由于受到水流的扰动，溶出的全氮和全磷是造成水体富营养化的重要原因。     

Preliminary study on limiting nutrients in seawater ponds

INrnODUCTIONTheaqUacultareindustryofChinaedsfirstintheworld-Fertilizationinfreshwatershasalonghistory,andiseffectivelyaPpliedforfishcultUre.Scholarsfromvchouscotm-trieshaveheenstudytngfertiliZationtheory,tecboqUeandaqUactiltUreecologyinfertilizedPOnds-SPecialattentionisgiventothetwncyandaPPlicationlevelwhenmantireisused,andtothekindandN:PraioOfchethecalfertilizersused(Boyd,l99o;li,I993;MoriartyandPullin,l987).Thedrpthecchacteristicsofphosphorus,andtheroleofureaappliedintoPOndswere…     

中国农用化肥氮磷钾需求比例的研究

本研究以作物能够吸收的有效养分为基础,根据作物生长的养分吸收量计算单位播种面积上农作物养分需要量,逐一差减土壤和有机肥提供的养分量,求出单位播种面积上农作物对化肥养分的需要量,在广泛查阅和搜集前人试验资料的基础上,对搜集到的原始数据进行认真的分析,整理,然后采用计算机模拟方法进行预测,预测结果指出。２０００年农用化肥氮磷钾的消费比例为１：０．３８：０．２５。     

中国南极长城湾及附近海区1993/1994年度夏季表层水样无机氮、磷酸盐的浓度及其分布状况(英)

The concentrations and distributions of four species of inorganic nutrient salts in surface sea water of Chinese Great Wall Bay and its adjacent sea area, Antarctica were surveyed during austral summers of 1993～1994.The results obtained are as follows:The general concentrations of NH4-N, NO3-N, NO2-N and PO4-P are 2. 13, 7. 07, 0. 74 and 1. 12 μg. din-3, respectively. Generally speaking, the concentrations are higher inside the Bay than those　 outside and the higher values of those inorganic salts often appear in December. The time for the station　where their higher and lower concentrations appear are not completely the same. The descending order　of the magnitudes of ΣN/P value according to the arrangement monthly is: Dec. Feb. Jan.. The　 variations of water temperature are mostly consist with the concentrations of NH4-N, PO4-P and ΣN/P, but not often with NO2-N. The low concentrations of nutrient salts as shown in some stations may be related with absorption by phytoplankton, perhaps including autotrophic bacteria.The results suggest that the area surveyed has a typical characteristic of an inner shallow water bay, sub-Antarctica. The nutrients needed for phytoplankton are sufficient, and the Bay surveyed is still in a normal condition.     

湖水-沉积物界面内源物质交换动态复水模拟研究

分布式采集了玄武湖底长期暴露的底泥,分析了底泥营养物的分层分布及其理化特性对湖泊水质的影响强度。通过动态换水试验,研究了复水过程中暴露底泥营养盐的释放过程和上覆水总磷、总氮浓度变化对水土界面物质交换的作用关系以及对水体富营养化程度的影响机制。实验及模拟表明:由于湖泥表层长期暴露,有机及结合态营养盐降解为无机态营养盐,即使复水过程中使用清水,但由于干涸湖床沉积物总磷T-P、总氮T-N的垂直分布,也将严重导致内源营养盐释放总量持续增加,在相对长时间内,上覆水总磷浓度仍维持在较高(01mg/L)水平。研究成果为实施生态修复,治理复水后湖体富营养化提供了理论和实验依据。     

夏玉米田土壤水分-养分-盐分剖面二维数值模拟

以衡水试验场夏玉米田为例，建立了田间沟垄地形条件下土壤剖面的二维饱和－非饱和水流及溶质运移数学模型，对夏玉米生长条件下土壤剖面水分、养分和盐分（以下简称水养盐）的动态进行了模拟，揭示了典型时刻土壤水流动系统特征及其与土壤水分、养分和盐分的关系。结果表明：①所建立的数学模型以及模型中的参数可较好地描述和模拟土壤剖面水养盐的运移过程和变化规律；②土壤剖面水养盐的分布明显受土壤沟垄地形的影响；③在夏玉米生长期，土壤处于“耗养”和“脱盐”状态。     

Major ion geochemistry and nutrient behaviour in the mixing zone of the Changjiang (Yangtze) River and its tributaries in the Three Gorges Reservoir

Inorganic ions and nutrients were measured at different depths of the Xiangxi and Daninghe Rivers to explore the mixing processes of representative bays in the Three Gorges Reservoir (TGR). HCO₃⁻ and Ca²⁺ are the dominant ions. Carbonate weathering is the most important mechanism controlling the ion water chemistry; however, important differences exist between the main channel and its tributaries. Major ion levels in the TGR bays depend on hydrological mixing. Results show that the major ions of Ca²⁺, Mg²⁺, Na⁺, K⁺, Sr²⁺, SO₄²⁻ and Cl⁻ show chemically conservative behaviour during transit through the bays of the TGR. This means the ions can be used as tracers in the same way that salinity is used in estuaries to explore behaviour of other non‐conservative elements and to indicate specific source waters. In contrast, nutrients are not conserved in the mixing zone. The mixing of the main channel and tributaries and biological utilization in backwater reaches were the key factor controlling nutrient distributions in Xiangxi and Daninghe Bays. Copyright © 2010 John Wiley & Sons, Ltd.     

Spatial evolution of nitrogen and phosphorus loads along a small Mediterranean river: implication of bed sediments

This study addresses the spatial variations in water quality along the River Vène (France). The Vène drains a 67 km² rural basin, with a large karstic area, located in a Mediterranean context. A 1 day sampling campaign was conducted along the river, in winter low‐flow conditions (February 2003). Physico‐chemical parameters and water flow discharge were measured in situ during the sampling campaign. Water quality was evaluated by determining the concentrations of nitrogen and phosphorus in water and bed‐sediment samples. Nitrogen and phosphorus loads were evaluated taking into account the measured concentrations and discharge. The campaign included 18 sampling points and concerned the whole river from the spring to the outlet, plus the main inputs, i.e. sewage treatment works, main tributaries and karstic springs. The spatial evolution of nitrogen and phosphorus loads along the river allowed the significant role of point‐source inputs to be demonstrated. The decrease in nutrient loads along the river occurred mainly in specific reaches where fine sediments had accumulated. In these zones, phosphorus is trapped in the bed sediments in calcium‐bound phosphates due to precipitation processes. Copyright © 2005 John Wiley & Sons, Ltd.     

Application of the SPARROW model in watersheds with limited information: a Bayesian assessment of the model uncertainty and the value of additional monitoring

How can spatially explicit nonlinear regression modelling be used for obtaining nonpoint source loading estimates in watersheds with limited information? What is the value of additional monitoring and where should future data‐collection efforts focus on? In this study, we address two frequently asked questions in watershed modelling by implementing Bayesian inference techniques to parameterize SPAtially Referenced Regressions On Watershed attributes (SPARROW), a model that empirically estimates the relation between in‐stream measurements of nutrient fluxes and the sources/sinks of nutrients within the watershed. Our case study is the Hamilton Harbour watershed, a mixed agricultural and urban residential area located at the western end of Lake Ontario, Canada. The proposed Bayesian approach explicitly accounts for the uncertainty associated with the existing knowledge from the system and the different types of spatial correlation typically underlying the parameter estimation of watershed models. Informative prior parameter distributions were formulated to overcome the problem of inadequate data quantity and quality, whereas the potential bias introduced from the pertinent assumptions is subsequently examined by quantifying the relative change of the posterior parameter patterns. Our modelling exercise offers the first estimates of export coefficients and delivery rates from the different subcatchments and thus generates testable hypotheses regarding the nutrient export ‘hot spots’ in the studied watershed. Despite substantial uncertainties characterizing our calibration dataset, ranging from 17% to nearly 400%, we arrived at an uncertainty level for the whole‐basin nutrient export estimates of only 36%. Finally, we conduct modelling experiments that evaluate the potential improvement of the model parameter estimates and the decrease of the predictive uncertainty if the uncertainty associated with the current nutrient loading estimates is reduced. Copyright © 2012 John Wiley & Sons, Ltd.     

排放强度目标下中国最优研发及经济增长路径

以研发投资为减排手段,在最优经济增长模型框架下构建碳排放强度目标约束下的最优控制模型,并针对中国2009年提出的排放强度目标“2020年排放强度降低到2005年的40%~45%”,研究了同时满足减排目标和社会福利最大化目标下的最优研发投资路径以及经济平稳增长路线。模拟发现: 前轻后重的研发投资路径有利于最大化社会成员的效用,而为了完成减排目标,中国需从2014年开始大幅提高研发投资到2.85%,随后每年都要保持在3%的水平;受此影响,经济平稳增长速度在2014年出现明显回落;排放强度路径呈现从缓慢下降到迅速下降而后降速趋缓的走势;能源消费量和碳排放量总体呈增长趋势,但在2014年继一个小高峰后出现短暂的下调。