密云水库上游流域水体营养物质现状及来源分析

密云水库作为北京地区最重要的地表饮用水水源地,其水质优劣直接关系到首都的社会经济发展,开展密云水库水污染监测和治理研究具有重要的现实意义。以密云水库上游流域为研究区,通过不同尺度流域水体营养物质监测,分析了水库上游河流水体营养物质现状;通过分割流量过程线,划分了水体营养物质来自点源和非点源污染的比例。研究结果表明,依据标准(GB3838-2002)要求,密云水库上游河流水体TN含量几乎全部超标,且15.9%样本的TP含量超标。密云水库的营养物质平均40.3%来自点源污染,59.7%来自非点源污染;入库水体中50.1%的TN,49.1%的NO₃^--N,39.0%的NH₄⁺-N,26.5%的TP和36.8%的COD_Mn来自点源污染;49.9%的TN,50.9%的NO₃^--N,61.0%的NH₄⁺-N,73.5%的TP和63.2%的COD_Mn来自非点源污染。     

水培和土培条件下氮素供应对燕麦生长和磷素吸收的影响

Plants show different growth responses to N sources supplied with either NH₄⁺ or NO₃^-. The uptake of different N sources also affects the rhizosphere pH and therefore the bioavailability of soil phosphorus, particularly in alkaline soils. The plant growth, P uptake, and P availability in the rhizosphere of oat (Avena nuda L.) grown in hydroponics and in soil culture were investigated under supply with sole NH₄⁺-N, sole NO₃^--N, or a combination. Sole NO₃^--fed oat plants accumulated more biomass than sole NH₄⁺-fed ones. The highest biomass accumulation was observed when N was suppliedw ith both NH₄⁺-N and NO₃^--N. Growth of the plant root increased with the proportion of NO₃^- in the cultural medium. Better root growth and higher root/shoot ratio were consistently observed in NO₃^--fed plants. However, root vigor was the highest when N was supplied with NO₃^-+NH₄⁺. NH₄⁺ supply reduced the rhizosphere pH but did not affect P uptake by plants grown in soils with CaHPO₄ added as P source. No P deficiency was observed, and plant P concentrations were generally above 2 g kg^-1. P uptake was increased when N was supplied partly or solely as NO₃^--N, similarly as biomass accumulation. The results suggested that oat was an NO₃^--preferring plant, and NO₃^--N was essential for plant growth and the maintenance of root absorption capacity. N supply with NH₄⁺-N did not improve P nutrition, which was most likely due to the absence of P deficiency.     

淹水土壤中氮素运移与转化试验及其数值模拟

在室内试验的基础上,建立了淹水土壤中NH₄⁺—N和NO₃^-运移转化的耦合数学模型,并对表施于水层中的氮肥(碳铵:NH₄HCO₃)在饱和土中运移与转化过程进行了数值模拟。结果表明:该试验条件下NH₄⁺—N的硝化作用主要发生于土壤表层1cm左右的范围内。     

水培条件下CO2与NH+4/NO-3配比对番茄幼苗生育的影响

升高CO₂浓度能够促进作物的光合作用，提高作物的生物量和产量，但关于CO₂与NH⁺₄/NO^-₃比及其交互作用对作物影响的研究较少，为探索番茄幼苗生长发育对CO₂浓度升高的响应是否对NH⁺₄/NO^-₃配比有较强的依赖关系，本试验在营养液栽培条件下，以番茄(Lycopersicun esculentum Mill)为试材，研究正常大气CO₂浓度(360 μL/L)和倍增CO₂浓度(720 μL/L)与不同NH⁺₄/NO^-₃配比的交互作用对番茄幼苗生长的影响。结果表明：CO₂浓度升高提高了低NH⁺₄/NO^-₃比例处理中番茄叶片的光合速率和水分利用率，提高幅度随NH⁺₄/NO^-₃比例的降低而增强，光合速率增强最大达55%。在同一CO₂浓度处理下净光合速率与水分利用率均随NH⁺₄/NO^-₃比例的增加而显著降低。这说明CO₂浓度升高对番茄幼苗生长发育的促进作用随NH⁺₄/NO^-₃比例的降低而提高，但并没有减弱全NH⁺₄-N处理中番茄幼苗的受毒害作用。综上所述，CO₂浓度升高能提高植物生产的节水能力和水分生产力；水培条件下，NO^-₃-N是最适合番茄幼苗生长发育的氮源，其它NH⁺₄/NO^-₃比例对番茄幼苗的生长发育有一定的抑制作用，仅以NH⁺₄-N作氮源则番茄幼苗很难生长。     

3 种挺水植物吸收水体NH4+、NO3-、H2PO4- 的动力学特征比较

本文用动力学试验研究了具有景观价值的3 种挺水植物—— 水生美人蕉(Canna generalis)、细叶莎草(Cyperus papyrus)、紫芋(Colocasia tonoimo)对H₂PO₄^-、NH₄⁺、NO₃^- 的吸收特征及差异。试验结果表明: 3 种挺水植物吸收H₂PO₄^- 时, 美人蕉的吸收速率最快, 且在较低离子浓度条件下也可以吸收该离子, 说明其具有嗜磷特性, 能够适应广范围浓度H₂PO₄^- 环境; 吸收NO₃^- 时, 细叶莎草的速率最快, 但对低浓度NO₃^- 环境的适应能力较差, 美人蕉吸收NO₃^- 的特性与细叶莎草刚好相反; 吸收NH₄⁺ 时, 细叶莎草的吸收速率最快, 且在低浓度NH₄⁺ 环境下仍能吸收该离子, 而美人蕉的吸收速率最慢, 但能在低浓度NH₄⁺ 环境下吸收该离子。说明不同植物对养分的吸收特性存在较大差异, 各自的污染水体修复适用范围也不同。美人蕉可用于各种浓度H₂PO₄^- 污染的水体修复; 而NO₃^- 污染严重的水体最适宜用细叶莎草作先锋植物, 修复到一定程度后再种植美人蕉来维持水质; 细叶莎草在各种浓度NH₄⁺ 污染的水体中均适用, NH₄⁺ 污染较轻的水体也可用美人蕉修复。     

硝态氮促进水稻生长和氮素吸收的生理机制

Rice is being increasingly cultivated in intermittently irrigated regious and also in aerobic soil in which Nitrate (NO₃^-) plays important role in nutrition of plant. However, there is no information regarding the influence of nitrate on the overall growth and uptake of nitrogen (N) in rice plant. Solution culture experiments were carried out to study the effects of NO₃^- on the plant growth, uptake of N, and uptake kinetics of NH₄⁺ in four typical rice (Oryza sativa L.) cultivars (conveutioual indica, conventional japonica, hybrid indica, and hybrid japonica), and on plasma membrane potential in roots of two conventional rice cultivars (indica and japonica) at the seedling stage. The results obtained indicated that a ratio of 50/50 NH₄⁺-N/NO₃^--N increased the average biomass of rice shoots and roots by 20% when compared with that of 100/0 NH₄⁺-N/NO₃^--N. In case of the 50/50 ratio, as compared with the 100/0 ratio, total N accumulated in shoots and roots of rice increased on an average by 42% and 57%, respectively. Conventional indica responds to NO₃^- more than any other cultivars that were tested. The NO₃^- supply increased the maximum uptake rate (V_max) of NH₄⁺ by rice but did not show any effect on the apparent Michaelis-Menten constant (K_m) value, with the average value of V_max for NH₄⁺ among the four cultivars being increased by 31.5% in comparison with those in the absence of NO₃^-. This suggested that NO₃^- significantly increased the numbers of the ammonium transporters. However, the lack of effect on the K_m value also suggested that the presence of NO₃^- had no effect on the affinity of the transporters for NH₄⁺. The plasma membrane potential in the roots of conventional indica and japonica were greatly increased by the addition of NO₃^-, suggesting that NO₃^- could improve the uptake of N by roots of the rice plant. In conclusion, the mechanisms by which NO₃^- enhances the growth and N uptake of rice plant was found by the increased value of V_max of NH₄⁺ and increased plasma membrane potential. Thus promotion of nitrification in paddy soil is of great significance for improving the production of rice.     

长期种植苜蓿对土壤氮素营养的作用

13年长期施肥和轮作试验结果表明，连续种植苜蓿时N肥、P肥、有机肥的配合施用(NPM)较单施P肥对提高土壤硝态氮(NO^-₃-N)含量水平有较好效果；而无论施肥与否，种植苜蓿对土壤深层NO^-₃-N均造成不同程度的亏缺。苜蓿(NPM)连作较小麦(NPM)连作土壤NO^-₃-N利用率高；种植苜蓿对土壤铵态氮(NH⁺₄-N)分布影响与NO^-₃-N不同，深层土壤CK、NPM配施处理NH⁺₄-N含量明显高于施P和裸地处理，不同作物种植系统中以苜蓿连作土壤剖面中NH⁺₄-N含量最高。与其他轮作相比，苜蓿连作在提高土壤剖面供N能力方面有较好作用。     

0.01molL-1CaCl2作为土壤不同N素形态浸提剂的研究

本文用荷兰8种表土测试不同温度下0.01molL^-1CaCl₂提取液和淋滤液中N素各形态。试验结果表明温度对NO₃^--N提取量和淋滤量无影响,但对NH₄⁺-N、可溶性总N和还原态N影响显著;可溶性有机态N的释放服从一级动力学方程:N_t=N₀(1-e^-kt),非线性最小二乘法能满意地拟合动力学实验结果。测定0.01molL^-1CaCl₂提取液中的可溶性有机态N对预测土壤N素矿化、合理推荐施肥及防止N素污染可能是一个很有前途的指标。     

不同铵硝配比对弱光下白菜氮素吸收及相关酶的影响

以黑色遮阳网覆盖模仿弱光环境, 使光照强度为自然光的20%左右, 以自然光照为对照, 采用精确控制水培溶液氮素营养, 研究NH₄⁺-N/NO₃^--N 比例分别为0/100、25/75、50/50、75/25、100/0 对弱光下白菜氮代谢及硝酸还原酶和谷氨酰胺合成酶活性的影响。结果表明, 弱光下, 白菜的鲜重及叶片总氮量以NH₄⁺-N/NO₃^--N 比为25/75 时最大, NH₄⁺-N/NO₃^--N 比为100/0 时最低。随弱光处理的进行, 白菜叶片中硝酸还原酶活性及谷氨酰胺合成酶活性均呈下降趋势, 但NH₄⁺-N/NO₃^--N 比为25/75 时, 可维持叶片内较高的硝酸还原酶活性及谷氨酰胺合成酶活性。试验表明, NH₄⁺-N/NO₃^--N 比25/75 是白菜在弱光下生长的较适宜氮素形态配比。     

铁和不同形态氮素对玉米植株吸收矿质元素及其在体内分布的影响——Ⅰ.对氮、磷、钾、钙、镁等营养元素的影响

用营养液培养方法研究了铁和两种形态氮素(NO₃^--N和NH₄⁺-N)对玉米植株吸收氮、磷、钾等大量元素和钙、镁等中量元素及其在体内分布的影响。结果表明:与NO₃^--N相比,供应NH₄⁺-N促进了玉米对氮的吸收,在缺铁条件下,降低了对磷、钾、钙及镁的吸收。铁和NH₄⁺-N都显著提高了玉米植株各器官中氮的含量。与NH₄⁺-N处理相比,NO₃^--N处理的新叶中磷含量显著增加,但铁的供应对植物体内磷的含量无显著影响。使用NO₃^--N显著提高了玉米新叶和老叶中钾的含量,根和茎中钾的含量无明显影响。铁的供应降低了新叶和老叶中钾的含量。供铁时,NH₄⁺-N处理的玉米新叶中钙和镁的含量显著低于NO₃^--N处理,而在缺铁时则无显著差异。     

太湖地区农田水环境中氮和磷时空变异的研究

试验研究了太湖地区农田水环境中N和P的动态变化结果表明:太湖地区农田水环境均受到不同程度的N、P污染,且3~7月间呈加重趋势;目前地表水特别是太湖水中N、P含量已远远超过富营养化的极限值,富营养化程度十分严重;地下水中总P和NO3--N含量变化明显,NH4 -N已劣于V类地下水质量标准,基本不适合饮用;浅层地下水中的NH4 -N含量与土壤黏粒含量呈负相关关系,深层地下水(井水)中NO3--N含量与pH值呈正相关关系。该研究可为太湖地区水环境保护和农业面源污染治理提供参考依据。     

人类活动对太湖地区地表水水质的影响

Taihu Lake region is one of the most industrialized areas in China, and the surface water is progressively susceptible to anthropogenic pollution. The physicochemical parameters of surface water quality were determined at 20 sampling sites in Taihu Lake region, China in spring, summer, autumn, and winter seasons of 2005-2006 to assess the effect of human activities on the surface water quality. Principal component analysis (PCA) and cluster analysis (CA) were used to identify characteristics of the water quality in the studied water bodies. PCA extracted the first three principal components (PCs), explaining 80.84% of the total variance of the raw data. Especially, PC1 (38.91%) was associated with NH₄-N, total N, soluble reactive phosphorus, and total P. PC2 (22.70%) was characterized by NO₃-N and temperature. PC3 (19.23%) was mainly associated with pH and dissolved organic carbon. CA showed that streams were influenced by urban residential subsistence and livestock farming contributed significantly to PC1 throughout the year. The streams influenced by farmland runoff contributed most to PC2 in spring and winter compared with other streams. PC3 was affected mainly by aquiculture in spring, rural residential subsistence in summer, and livestock farming in fall and winter seasons. Further analyses showed that farmlands contributed significantly to nitrogen pollution of Taihu Lake, while urban residential subsistence and livestock farming also polluted water quality of Taihu Lake in rainy season. The results would be helpful for the authorities to take sound actions for an effective management of water quality in Taihu Lake region.     

西苕溪流域健康状况的模糊诊断

西苕溪是太湖上游的重要支流,由于人类活动的干扰,河流健康状况受损,功能下降。基于河流健康的内涵,选取河流形态结构、河流社会经济功能和河流生态功能3类诊断河流健康状况的1级指标。针对西苕溪流域健康现状和可获取的资料,构建了诊断西苕溪健康状况的18个2级指标。选用多目标多层次模糊模型诊断西苕溪健康状况,建立了各指标标准特征值,确定了各指标权重。计算和分析结果表明,西苕溪综合健康状况大部分处于中等和良好状态,河流形态结构的改变和较差的水质是影响其健康的主要原因。西苕溪流域的生态修复措施主要包括创建多样性生物栖息地,有效控制面源污染,建立水库适应性管理程序等。     

基于时间序列分解方法的太湖未来特征水位预测

基于太湖沿湖5个水文台站1956—2006年的逐日平均水位数据,提取得到了逐年特征(平均、最高和最低)水位,运用时间序列分解方法模拟和预测了太湖未来15a的特征水位,并探讨了太湖未来洪灾情势。将水位序列分解为趋势成分、周期成分和随机成分,得到时间序列分解模型,并进行了水位序列模拟和预测。分析结果表明,该模型的模拟精度比较理想,可以实现未来较长期的特征水位预测。预测得到未来15a后的最高水位可能达到4.05m,显著超过太湖警戒水位,因此需引起相关部门的重视。     

Nutrient Retention in a Northern Prairie Marsh (Frank Lake,Alberta) Receiving Municipal and Agro-Industrial Wastewater

Agro-industrial wastewater and municipal sewage wereused to restore Frank Lake, a 1246 ha northernprairie marsh in southern Alberta, Canada, to providewaterfowl habitat and improve water quality. Meanannual inflow wastewater nutrient concentrations were17 mg L^-1 NH₃-N, 30 mg L^-1 NO₃-Nand 11 mg L^-1 SRP. Mean flows greater than 5000 m³ day^-1 loaded the marsh with 23 000 kg of P annually. Summer NH₃-N, NO₃-N andtotal phosphorus (TP) surface water concentrationswere decreased by 76, 87 and 64%, respectively, aswaters flowed through the first basin of the marsh.Winter treatment was less successful, with surfacewater NH₃-N, NO₃-N and TP reductions of46, –26 (export) and 26%, respectively.Short-circuiting of water flow through the marsh andcold seasonal conditions with ice cover caused spatialand temporal variation in marsh treatment. Continuedhigh loadings to the marsh may lead to sediment saturation, eutrophication or phosphorus export from the marsh.     

基于马尔可夫链的太湖流域典型地区年降水量分析与预测

[目的]为了探讨如何预测太湖流域的年降水量,发现年降水量的规律。[方法]对太湖流域1960—2010年年降水量进行了分析,运用加权马尔可夫链方法建立了该区年降水量预测模型。[结果]太湖流域20世纪60,70和80年代研究区的年平均降水量均低于多年平均降水量;该降水序列满足马尔可夫链的要求。建立了加权马尔可夫链模型,并预测了2011年和2012年的年降水量,预测值与实测值的相对误差分别为6.59%和-10.74%;平水年、偏枯年、偏丰年、枯水年和丰水年出现的概率分别为0.268 5,0.206 7,0.184 5,0.166 1和0.174 2。[结论]马尔科夫链预测平水年的年降水量相对误差较小,偏枯年和丰水年年降水量的相对误差较大;平水年、偏枯年和偏丰年出现的概率较大。     

固体废物处理厂地下水污染预测及控制模拟

[目的]以江苏省镇江市新区大港片区某固体废物处理厂为研究对象,对地下水污染情况进行模拟研究,为同类建设项目及企业的地下水污染预测和防治提供参考。[方法]通过系统分析该固体废物处理厂野外水位和水质观测数据以及水文地质条件等资料,利用Visual Modflow软件构建了地下水水流和溶质运移模型。[结果]对厂区污水处理站防渗破损后特征污染物CODMn和氨氮运移情况以及地表硬化污染控制措施对污染物的阻隔效果进行预测评价,数值模拟预测污染物的影响范围、超标范围和最大运移距离。预测时间20a后,污染物影响范围最大,运移距离最远,且CODMn影响范围较氨氮大,运移距离较远;地表硬化后,20a后污染羽未超出评价范围。[结论]污染物主要沿水流方向迁移,对水环境的影响随时间逐渐增大,污染物浓度随着迁移距离的增加而减小,不同污染物在地下水含水层中的溶质运移范围和迁移距离不同。地表硬化措施能有效控制污染物扩散。     

千岛湖水质变化特征与趋势分析

对千岛湖水质综合污染指数分析表明,近10年来千岛湖多数监测项目和各断面污染指数都呈现显著下降的趋势,全湖综合水质趋好,表明千岛湖总体水质的变化正处于相对低的风险状态之中。各断面水污染综合指数的对比分析显示,代表千岛湖主要来水水质的街口、航头岛和百亩畈3个断面分列前三,河流污染物的输入是千岛湖水质下降的主要风险来源,其中街口指标显著高于其他断面,是污染输入强度最大的来源。各监测项目污染指数的对比分析表明总N是影响近期千岛湖水质的首要因子。趋势分析表明,除街口和西园码头外其他各断面负荷比均呈现出不同程度的下降趋势。各监测项目综合污染指数分担率的分析表明,总N、溶解氧和高锰酸钾指数排在前列,3项分担率之和占全湖的71%,其中总N接近49%,显著高于其他项目。趋势分析中总N分担率出现显著下降趋势,其他项目也都表现出不同程度下降趋势,大肠杆菌的变化趋势尚不明确。     

基于综合营养状态指数和BP神经网络的黑河富营养化评价

[目的]探究黑河流域富营养状态,为黑河流域水体污染综合防治提供基础数据和理论依据。[方法]选取叶绿素a(Chl.a)、总氮(TN)、总磷(TP)、高锰酸盐指数(COD_{Mn_})、透明度(SD)作为评价因子,使用综合营养状态指数法和BP神经网络对黑河流域的富营养化进行综合评价。[结果]黑河富营养化状况主要以中营养级为主,其中野牛沟和张掖湿地的营养指数接近轻度富营养程度,东居延海处于重度富营养化,尤其是总氮指数很高,应该及时进行治理和保护。[结论]相对于综合营养状态指数法,BP神经网络对黑河流域的评价结果更加贴近实际结果,较为客观可靠。