基于DRAINMOD-S模型的滨海盐碱地农田暗管排水模拟

在分析农田暗管排水饱和-非饱和土壤水、盐运移数学模型的基础上,对DRAINMOD-S模型的基本原理和参数输入要求进行了详细描述,利用典型滨海盐碱地区实测土壤、气象、作物等资料,用DRAINMOD模型对不同排水暗管布置方案的地下水埋深进行了长序列模拟,在模拟率定参数的基础上,用DRAINMOD-S模型对0~80 cm土壤层剖面含盐量进行了模拟,结果表明:模型具有良好的水文模拟性能,地下水位及土壤含盐量模拟值与实测值拟合精度较高;可用于预测盐碱地地下水埋深、土壤层剖面中盐分含量,是改良盐碱地农田暗管排水工程设计和水管理的有效工具。     

水势理论在四水转化研究中应用时代特征与趋势:纪念ZFP方法引进我国30周年

20世纪80年代零通量面方法在我国应用中解决了"四水"转化研究中参数不确定性带来的问题,发现在降水入渗补给地下水过程中土壤总水势梯度大于1.0cm H2O/cm,且逐渐降低,流入、流出被监测土层的水量相等时土壤总水势梯度趋近于1.0cm H2O/cm。20世纪90年代,利用土壤水势与含水量之间量化关系,指导了农业节水灌溉,提出在灌溉过程中土壤水势梯度等于1.0cm H2O/cm的时间持续愈长,表明过剩灌溉而浪费的水量愈多的认识。进入21世纪以来,水势理论较广泛地用来解决土壤水盐分运移数值模拟与入渗模型中水文地质参数问题和降水入渗土壤水势运移微观机理研究,并发现表聚型、中聚型和底聚型土壤盐分剖面的水动力学特征。通过土壤水动力场调控改变土壤水盐(养分或污染物)运移是未来重要研究方向。     

内陆盆地的盐分布与平衡分析研究

在总结已有研究成果和系统分析水文、土壤、灌溉、水盐监测资料的基础上,应用系统分析方法、水盐运移理论和水盐平衡原理,通过对盆地、流域、灌区、农田和土壤剖面等不同层次盐分分布与盐平衡分析计算,分析了内陆盆地不同层次的“干排盐”形成与特征,认为干排盐是必不可少的,必须系统地考虑不同层次干排盐出路与动力条件,才能有效地治理灌区盐渍化问题。     

基于染色示踪的膜下滴灌棉田水盐运移规律

采用亮蓝FCF染色示踪剂, 研究膜下滴灌条件的水盐运移规律; 分别在灌溉前、灌溉中和灌溉后等不同时间段共开挖13个时刻的剖面, 观察膜下滴灌湿润面的运移情况; 以10 cm间隔的网格, 用MP406土壤水分探测器原位测定3 120个点的土壤体积含水率, 同时取1 430份土样, 利用1∶5土水比浸提法测定土壤盐分; 并利用WATCHDOG气象站监测研究区气象要素.结果表明: 染色示踪能直观表征土壤水盐运动轨迹; 膜下滴灌条件下, 垂直滴灌带方向土壤水流呈点源入渗特征、沿滴灌带方向近似呈线源入渗特征; 现行灌溉模式下, 壤质砂土湿润锋横向运移速率约为8 cm/h; 滴灌对滴头附近土体有一定洗盐效果, 未覆膜区域地表土体出现盐分积累; 灌水时间越长, 湿润锋越深, 横向扩展速率接近无作物小区(8 cm/h); 从土壤水合理利用角度考虑, 满足研究区一膜一带四行的种植模式和土质的单次合理灌水量应为29.4~69.8 mm.      

水位变化条件下海湾水库盐分达标探讨

针对中国北方海湾水库间歇来水、连续取水和沉积物动态释盐的特点,建立水量与盐分耦合的数学模型,以青岛拟建的沐官岛水库为例,探讨水位变化条件下混合型海湾水库库水盐分的影响因素、超标风险与达标条件。模拟结果表明,在水库水位连续降低条件下,毫米量级的日蒸发量对库水盐分的累积效应显著。在不利水文条件下,受沉积物释盐、水分蒸发与人工取水的影响,混合型海湾水库长期存在盐分超标的风险。与水位不变时相反,水位降低时库水盐分浓度随着取水量的增大而升高;因此,当库水盐分存在超标风险时,可以通过减少日取水量实现库水盐分达标。为保障安全供水,在海湾水库设计与运营管理阶段,均需要综合考虑水量-盐分因素进行水库的日取水量调算。     

室内外土壤水盐动态测试

。土壤盐分传感器一室内水盐动态模拟±柱, 传感器(土柱左侧),张力 计(土柱右侧),红外灯 (土柱顶部)t 正在施工的田间水盐动态观测场t±壤盐分传感髂及配套测试仪器t 在田间开挖土壤剖面安装 盐分传感嚣个 传感器和张力计在田间定位观测点的布置,在田问水盐动态观测筒上安装张力计室内外土壤水盐动态测试@肖振华$中科院南京土壤研究所 @崔荣浩$中科院南京土壤研究所~~     

吉林西部盐碱水田区冻融期土壤水盐运移特征及酶活性变化

为研究冻融作用下水田0~50cm土层水、盐、pH、脲酶活性变化规律及其相关关系,采集吉林西部盐碱土区大安市水田土壤,选取冻结12h、融化12h为一个循环,开展室内模拟试验,模拟昼夜反复冻融条件下土壤水盐运移和酶活性的动态变化,分别用质量法、残渣烘干法、电位法、靛酚蓝比色法测定各层土壤含水率、含盐量、pH和脲酶活性,分析其在不同冻融条件下的变化规律和相关性。研究表明,土壤深度是影响含水率、含盐量、pH、脲酶活性的主要因素之一:20~50cm土层的水分和盐分不断向上层运移,使表层含盐量和pH升高,且水、盐之间具有显著的相关性,说明水分运移在一定程度上决定了盐分的运移;除10~20cm土层脲酶活性略有升高外,其他各层脲酶活性出现不同程度的降低。冻融过程中含水率、含盐量、pH均与脲酶活性呈现显著的相关性,脲酶活性是冻融次数、温度、含盐量、pH、有机质等多种因素共同作用的结果。因此,冻融作用在引起或加重水田表层土壤盐碱化方面起到至关重要的作用,冻融作用降低了土壤脲酶的活性,进而会影响土壤的肥力。     

易盐渍区粘土夹层对土壤水盐运动的影响特征

针对黄淮海冲积平原土壤剖面中粘土夹层普遍存在的现象,在典型易盐渍区开展模拟易盐农田常规种植条件下水盐运移的大型土柱实验,基于长达20年的长系列监测数据分析,系统研究易盐渍区不同土体构型和地下水位等代表性条件下的土壤水盐运移规律和粘土夹层的影响特征.研究结果表明:粘土层有良好的保水和隔盐能力,尤其对表土积盐的抑制效果显著...     

感潮河网二维水流-输运耦合数学模型

感潮河网水流不仅受径流、潮汐动力的双重影响,还常受水闸调度等人类活动的影响,水动力条件极为复杂。针对水闸调度影响下感潮河网复杂水动力及其伴随物质输移扩散模拟,提出了考虑水闸调度并集成输运对流项的水流-输运通量耦合求解器,建立了基于非结构网格Godunov格式的二维水流-输运耦合数学模型。采用具有时空二阶精度的MUSCL-Hancock预测-校正格式,结合变量重构限制器技术,在保证计算精度的同时避免了数值振荡。运用斜底三角单元网格表达水闸线状地形,并通过地形调整模拟了水闸启闭过程。算例研究表明,该模型计算精度高,可有效模拟水闸调度影响下感潮河网水流运动及污染物输运过程,具有较好的推广应用价值。     

冻融期土壤水盐变化特征分析——以黑河上游祁连县阿柔草场为例

冻融作用是土地盐碱化的形成机制之一,对冻融区春季积盐有明显的控制作用.在冻融过程中,土壤剖面结构发生变异,形成冻结层、似冻结层和非冻结层.以祁连山黑河上游阿柔草场为例,研究了解冻期土壤水盐运移变化特征.阿柔草场隶属青海祁连山地区,地处西北高寒地区,为季节性冻土区,大面积土壤经历冬冻春融的冻融循环.这种循环引起了土壤中水分和盐分运移的特殊规律,即冻结时土壤中的水分和盐分向冻层迁移,使得冻层的土壤含盐量明显增加;而融化时,由于地表蒸发,土壤中的水分和盐分又向地表强烈迁移,从而造成盐分在地表积聚,诱发盐分两次抬升.     

The terrestrial fauna of the Late Triassic Pant-y-ffynnon Quarry fissures,South Wales,UK and a new species of Clevosaurus (Lepidosauria: Rhynchocephalia)

Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco.     

The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts

The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H₂O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H₂O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species.     

Quaternary stresses revealed by calcite twinning inversion: insights from observations in the Savonnières underground quarry (eastern France)

Calcite samples were extracted both from the rock matrix and the superficial coating of a karstified fault plane of an underground quarry, located in the eastern border of the Paris basin. The karstification is dated as Quaternary. Analysis of mechanical calcite twinning reveals that only the calcite matrix has also undergone a compression trending WNW that can be attributed to the Mio-Pliocene alpine collision. Both coating and matrix have undergone a strike-slip regime with σ₁ roughly trending north–south, that could correspond to the regional present-day state of stress, a strike-slip compression rather trending NNW, modified by local phenomena. To cite this article: M. Rocher et al., C. R. Geoscience 335 (2003).     

HYDROGEOLOGY

正20141756 Chen Ruige(Mathematical College,China University of Geosciences,Beijing100083,China);Zhou Xun Numerical Simulation of Groundwater Level Fluctuation in a Coastal Confined Aquifer with Sloping Initial Groundwater Level Induced by the Tide(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(7),2013,p.1099-1104,6 illus.,16 refs.) Key words:confined water,groundwater level     

METAMORPHIC PETROLOGY

正20141408 Cai Jia(Institute of Geology,Chinese Academy of Geological Sciences,Beijing100037,China);Liu Fulai Petrogenesis and Metamorphic P-T Conditions of Garnet-Spinel-Biotitebearing Paragneiss in Danangou Area,Daqingshan-Wulashan Metamorphic Complex Belt(Acta Petrologica Sinica,ISSN1000-0569,CN11-1922/P,29(7),     

SERIALS

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GEOPHYSICAL EXPLORATION

正20142386An Guoying(China Aero Geophysical Survey and Remote Sensing Center for Land and Resources,Beijing 100083,China)Application of Satellite Remote Sensing in Regional Hydrogeological Investigation:Taking Cenozoic Strata in Wenquan Sheet(1∶250 000)of Karakoram Range as an Example(Geosci-     

QUATERNARY GEOLOGY & GEOMORPHOLOGY

正20141016An Chengbang(Key Laboratory of Western China’s Environmental Systems,Ministry of Education,Lanzhou University,Lanzhou 730000,China);Zhao Yongtao Lake Records during the Last Glacial Maximum from Xinjiang,NW China and Their Climatic Impli-     

PETROLEUM GEOLOGY

正20141538 Cao Qing(School of Earth Sciences and Engineering,Xi’an Petroleum University,Xi’an 710065,China);Zhao Jingzhou Characteristics and Significance of Fluid Inclusions from Majiagou Formation,Yichuan Huangling Area,Ordos Basin(Advances in Earth Science,ISSN1001-8166,CN62-1091/P,28(7),2013,p.819-828,7 illus.,3 tables,43 refs.)     

GEOCHEMISTRY

正20142002 Wei Hualing(Institute of Geophysical and Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang065000,China);Zhou Guohua Element Content and Mineral Compositions in Different Sizes of Soil in Tongling Area,Anhui Province(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(11),2013,p.1861