河北平原表层土壤重金属环境质量及污染评价

土壤环境质量评价是了解土壤环境质量状况、采取保护措施的重要前提,本文用土壤环境质量标准(GB15618-1995),对河北平原表层土壤重金属环境质量进行了评价,结果表明:河北平原表层土壤环境质量优良,一、二级土壤分别占全区93.02%和6.62%。同时又根据重金属元素的环境地球化学行为,采用富集因子,有效地区分了重金属污染的自然影响和人为影响,结果显示,河北平原表层土壤人为污染的面积较大,但以轻微污染为主。     

Atmospheric and soil moisture controls on evapotranspiration from above and within a Western Boreal Plain aspen forest

The Western Boreal Plain of North Central Alberta comprises a mosaic of wetlands and aspen (Populus tremuloides) dominated uplands where precipitation (P) is normally exceeded by evapotranspiration (ET). As such these systems are highly susceptible to the climatic variability that may upset the balance between P and ET. Above canopy evapotranspiration (ET_C) and understory evapotranspiration (ET_B) were examined using the eddy covariance technique situated at 25.5 m (7.5 m above tree crown) and 4.0 m above the ground surface, respectively. During the peak period of the growing seasons (green periods), ET_C averaged 3.08 mm d^?1 and 3.45 mm d^?1 in 2005 and 2006, respectively, while ET_B averaged 1.56 mm d^?1 and 1.95 mm d^?1. Early in the growing season, ET_B was equal to or greater than ET_C once understory development had occurred. However, upon tree crown growth, ET_B was lessened due to a reduction in available energy. ET_B ranged from 42 to 56% of ET_C over the remainder of the snow‐free seasons. Vapour pressure deficit (VPD) and soil moisture (θ) displayed strong controls on both ET_C and ET_B. ET_C responded to precipitation events as the developed tree crown intercepted and held available water which contributed to peak ET_C following precipitation events >10 mm. While both ET_C and ET_B were shown to respond to VPD, soil moisture in the rooting zone is shown to be the strongest control regardless of atmospheric demand. Further, soil moisture and tension data suggest that rooting zone soil moisture is controlled by the redistribution of soil water by the aspen root system. Copyright © 2013 John Wiley & Sons, Ltd.     

松北宾县断陷白垩系沙河子组沉积相与生储盖组合分析

通过野外露头、岩心观察描述和地震相分析,结合测井、录井、分析化验资料综合分析结果表明,宾县断陷中生界沙河子组主要发育4种类型的沉积相:扇三角洲相、湖泊相、河流相和湖底扇相.沙河子组湖侵体系域主要发育4种类型的地震相,对应的沉积相类型有扇三角洲相、湖泊相、和湖底扇相;沙河子组高水位体系域也发育4种类型的地震相,对应的沉积...     

Assessing crop yield and crop water productivity and optimizing irrigation scheduling of winter wheat and summer maize in the Haihe plain using SWAT model

Haihe plain is an important food production area in China, facing an increasing water shortage. The water used for agriculture accounts for about 70% of total water resources. Thus, it is critical to optimize the irrigation scheduling for saving water and increasing crop water productivity (CWP). This study first simulated crop yield and CWP for winter wheat and summer maize in historical scenario during 1961–2005 for Haihe plain using previously well‐established Soil and Water Assessment Tool model. Then, scenarios under historical irrigation (scenario 1) and sufficient irrigation (scenario 2) were, respectively, simulated both with sufficient fertilizer. The crop yield in scenario 2 was considered as the potential crop yield. The optimal irrigation scheduling with sufficient fertilizer (scenario 3) was explored by iteratively adjusting irrigation scheduling based on the scenario 1 and previous studies related to water stress on crop growth. Results showed that net irrigation amount was, respectively, reduced 23.1% and 18.8% in scenario 3 for winter wheat and summer maize when compared with scenario 1. The CWP was 12.1% and 8.2% higher with very slight change of crop yield. Using optimal irrigation scheduling could save 8.8 × 10⁸ m³ irrigation water and reduce about 16.3% groundwater over‐exploitation in winter wheat growth period. The corresponding yield was 18.5% and 12.9% less than potential yield for winter wheat and summer maize but using less irrigation water. Therefore, it could be considered that the optimal irrigation was reasonable, which provided beneficial suggestions for increasing efficiency of agricultural water use with sustainable crop yield in Haihe plain. Copyright © 2013 John Wiley & Sons, Ltd.     

1960-2003年新疆山区与平原积雪长期变化的对比分析

对新疆91个地面站44a(1960—2003年)的>0cm积雪日数、冬季最大积雪厚度、冬季降水量和冬季平均温度统计分析,结果发现:伴随着20世纪80年代以来明显的增温增湿变化,新疆积雪呈轻度增长趋势,90年代增加明显.积雪日数和厚度与冬季降水量呈正相关,但与冬季平均温度没有明显相关关系.将91个地面站分成24个山区站和67个平原站的进一步分析表明,山区积雪增幅大于平原,而平原的冬季温度和降水增幅大于山区.60年代和90年代山区和平原呈两个相反方向的同步变化(60年代少雪、少降水和降温;90年代多雪、多降水和增温),但幅度略有不同.70年代和80年代山区和平原无论积雪还是温度、降水量都呈现明显不同的变化.     

洪河国家级自然保护区补水水质的评价研究

简要介绍了洪河国家级自然保护区补水方案的工艺流程,农田地表径流是该方案的补水水源。分别采集洪河国家级自然保护区核心区和浓鸭截洪总干(补水水源点)同一地点地表水样并进行了分析测试,核心区水质监测数据结果表明:①该保护区核心区水域不存在工业废水特征污染物;②水质与水位和水流关系密切;③水质与湿地植被所处的生长季节有关;④水体中COD和BOD5值分别在37.73～63.08mg/L和15.2～28.70mg/L,不属于外源人为污染引起,应是沼泽水体的背景值的真实反映;⑤沼泽水体的TN和TP较高,可能与湿地生物地球化学元素循环的内在规律有关,不是农田地表径流污染进入引起的。浓鸭截洪总干处水质监测数据显示:①水质表征出明显的农田径流特性;②水质总体上较好,这可能与浓鸭截洪总干对农田地表径流有较好的净化能力有关。通过比较分析洪河保护区核心区水质和浓鸭截洪总干水质表明:补水水源水质整体上好于该保护区核心区水质。基于保护区核心区水质特征来确定补水水源水质在工程设计上具有一定的指导意义和实践价值。基于当前的监测数据,初步认为现有补水水质符合洪河保护区水质要求。建议今后在洪河国家级自然保护区和浓鸭截洪总干开展有关农药残留动态实验,并结合水域生物多样性调查,为流域农业产业结构和农药的安全使用提出政策性建议。研究认为在三江平原通过生态水利工程蓄积农田地表径流,并采用湿地生态氧化塘处理系统净化水质,可以作为退化湿地的补水水源。     

晚新生代地壳构造运动研究

通过地球表面清、新的构造地貌与现代水文网记录, 研究晚新生代年轻地壳构造运动。研究发现高原-山带-盆地排列有序形影相依的定式, 与现代水文网的演化相辅相成, 揭示高原边缘山带本质上就是高原边缘流水深切割的产物。论证了于晚中新世时期全球曾准平原化, 发育了全球统一的准平原, 散布全球不同高度的高原面、齐平山顶面与盆地底面时代相当可广泛对比。现代构造地貌演化始于导致晚中新世准平原面分裂解体的上新世以来, 同时证明晚新生代地壳构造运动属垂直拱曲块断差异升降构造运动, 仅在某些特定部位局部派生次级不同规模的引张构造变形和层间滑动薄皮挤压构造变形。现代水文网发育经历了上新世-早更新世属盆地向心水系伴以河湖相沉积, 以及中更新世以来串珠状水系与相关的河流相沉积, 两套地层呈假整合或不整合, 明确记录了晚新生代地壳构造运动进程的两个主要阶段。约近70~80万年的中更新世以来, 新一轮强烈的地壳的差异升降构造运动, 显著的改造了已有的格局。自俄罗斯远东山地, 经蒙古高原和青藏高原至印度西北阿拉瓦利山, 地球表面规模最雄伟的、分开太平洋水系与北冰洋水系的亚洲巨型分水岭的出现, 标志新兴的全球现代构造地貌与水文网的形成, 奠定了今日构造地貌与水文网的景观。研究表明, 大陆与大洋晚中新世全球统一准平原面一脉相承, 晚新生代地壳构造运动完全可以对比。深入系统研究年轻的晚新生代地壳构造运动不仅有实用价值, 同时也有重要的科学意义, 特别是为探究全球构造运动本质和地球动力学提供了一个新的视角。      

藏北尼玛县阿索乡上白垩统马莫勒组的建立及其意义

在青藏高原中部尼玛县阿索乡马莫勒地区识别出一套紫红色辫状河三角洲平原亚相地层,岩性主要为紫红色砂岩中砾岩、紫红色复成分中砾岩、紫红色砂岩细砾岩,局部夹含砾粗砂岩或岩屑杂砂岩。在剖面测制和区域对比的基础上建立了上白垩统马莫勒组。对马莫勒组岩屑杂砂岩层进行碎屑锆石采样和U-Pb定年,得到最年轻的碎屑锆石年龄为99Ma。碎屑锆石主要存在3个年龄峰值,其中主峰值在125Ma左右,代表了班公湖-怒江中特提斯洋演化的岩浆活动,其他2个弱峰值分别为550Ma和980Ma,且分别代表了泛非期和格林威尔期—晋宁期的岩浆活动热事件。研究认为,马莫勒组的沉积时代应介于99~90Ma之间,马莫勒组的出现标志着尼玛地区在晚白垩世初期完成了由洋到陆的转换,进入陆内环境。     

河北平原土壤中汞的地球化学分布特征

基于多目标地球化学数据,研究了河北平原土壤内Hg的空间分布特征,制作了表层土壤和深层土壤Hg的分布图。结果显示:河北平原Hg含量均值在表层土壤为43.77×10-9,深层土壤为17.58×10-9;根系土Hg的形态以惰性态为主,有效态比例仅为3.24%,土壤环境安全性较高。 Hg含量在河北平原表层土壤中呈现出西高东低的趋势,明显表现为因自然原因形成的沿太行山麓平原的显著高值区;低值区有沿河道相分布的特点;城市周边因人为原因形成点状高值区。     

北京平原区新构造活动及其引发的不良地质现象分析

在地质环境综合调查及地质灾害调查区划工作基础上,结合物探、钻探、槽探及区域地质等资料,对北京平原区的新构造活动及其引发的不良地质现象进行了认真地分析和探讨。