土壤水溶性有机物与富里酸分子量[2]分布的空间结构特征

用凝胶色谱法测定了16种土类的35个表土样品中水溶性有机物和富里酸的分子量分布。分析了水溶性有机物与富里酸分子量分布的地域分异规律与空间结构特征。结果表明研究区土壤水溶性有机物与富里酸平均分子量大小具有自东北向西南递降的一般趋势，分布的离散性则表现出与此相反的的规律。水溶性有机物分子量沿趋势面倾斜方向的变化幅度较富里酸大，两者在空间的自相关范围基本一致。水热条件是影响水溶性有机物分子量空间分布的主要因素。     

中国东部土壤水溶性有机物荧光特征及地域分异

测定中国东部地区20种土类46个表土样品水溶性有机物的荧光光谱、分子量以及pH值，分析了水溶性有机物荧光光谱的一般特征、荧光光谱与其平均分子量的关系以及荧光强度的地域分异特性，与此同时比较分析了土壤富里酸的相关特征，结果表明研究区土壤水溶性有机物和富里酸具有相似的荧光光谱特征和地域分异特性，即在所研究的浓度范围内两者的荧光发射光值与有机物浓度成良好的线性正相关关系，而荧光强度与分子量分布无直接相关性，研究区土壤水溶性有机物和富里酸荧光强度均具有自北向南递降的趋势；土壤pH可能是影响水溶性有机物荧光特征及空间分异的主要因素。     

土壤水溶性有机物吸着系数及其影响因素研究

测定了中国中、东部地区17种土类45个表土样品中水溶性有机物的吸着系数、分子量分布、腐殖酸含量、粘土含量以及土壤pH值，分析了水溶性有机物吸着系数的分布、地域分异和影响吸着系数的主要因素。结果表明，中国中、东部主要天然土壤类型A层水溶性有机物吸着系数在0．0014－0．0284L/g，中位数为0．0062L/g；研究区吸着系数具有自北向南和自西向东递降的一般趋势。水热的地域分异是影响土壤A层Ks地域分异的根本因素，pH和WSOC分子量分布是直接影响Ks值的两个重要因素。     

西南喀斯特石漠化过程中土壤有机质组分及其影响因素

通过采集我国西南喀斯特地区不同石漠化阶段典型土壤样品,研究了土壤有机质组分及其影响因素.结果表明:(1)喀斯特地区土壤有机质各组分含量中胡敏素>富里酸>胡敏酸,HA/FA一般<0.4,为富里酸土壤,与同水平地带土壤一致.(2)石漠化过程对喀斯特地区土壤中有机质组成有明显的影响,土壤中胡敏素、富里酸与胡敏酸表现出未石漠化＞潜在石漠化＞轻度石漠化＞中度石漠化的趋势.(3)喀斯特地区土壤有机质组分空间分布有较大差异,剖面层次上各有机质组分胡敏素、富里酸与胡敏酸均表现出表土层>底土层,山区不同部位上表现以山坡中下部有机质含量最高,而以山顶最低,且FA/HA表现出从山顶到山脚有明显增加的趋势.(4)喀斯特地区土壤土壤有机碳、酸碱度、碳酸钙、容重、非晶形氧化铝、颗粒组成、有效磷与土壤有机碳组分间表现出显著或极显著的相关性,土壤有机碳和质地是影响土壤有机碳组分含量的主要因素.     

我国水平地带性土壤中有机质的空间变化特征

主要根据全国第二次土壤普查的成果，对我国水平地带性土壤中有机质的含量和胡敏酸与富里酸比值的空间变化特征进行了概括，进而探讨了在不同自然和人因素影响下，土壤有机质的累积状况与稳定性特征。     

闽江河口秋茄湿地土壤腐殖质组成及剖面分布特征

以闽江河口秋茄湿地土壤为研究对象,研究了土壤腐殖质组成和剖面分布特征,并探讨了土壤腐殖质组成与土壤理化因子的关系。结果表明,秋茄湿地土壤腐殖质的组成中,胡敏酸占有机碳变化范围为6%～18%,富里酸占有机碳变化范围为15%～34%,闽江河口秋茄湿地土壤为富里酸型土壤。土壤胡敏酸和胡敏素含量随深度增加而波动降低;富里酸表层的含量最低,中间层最高。表层的HA/FA最高,中间层最低。土壤理化性质中,pH值、有机碳含量、粘粒含量、氮含量与土壤腐殖质分布有显著线性相关关系。     

沉积物中水溶性天然有机物吸着系数的动态测定

探讨了直接测定沉积物中水溶性天然有机物吸着系数的可行性，提出了改变水土比和连续提取两种动态测定方法，从理论上分析了两种方法的操作误差，结果表明，这两种方法均能同时测定样品中水溶性有机物的含量和吸着系数；改变水土比法明显优于连续提取法，用该方法测定了伊春河沉积物样品中水溶性有机物的含量与吸着系数。     

罗北凹地富钾卤水中锂、硼的空间分布和富集规律研究

文章基于自组织神经网络（SOM）和Kmeans耦合（SOM-KM）方法,利用罗北凹地65组富钾卤水水化学数据,对富钾卤水中锂（Li）和硼（B）资源空间分布和富集规律进行了系统性研究。研究发现富钾卤水中Li,B含量表现出一定的垂向分异性,自上而下B浓度增高,Li浓度降低。聚类结果表明,罗北凹地富钾卤水可聚为4类,各类地下水中Li、B浓度具有明显的空间差异性,高浓度的Li、B集中分布在罗北凹地中东部区域。此外,水化学特征离子分析结果表明,罗北凹地富钾卤水中Li、B元素富集主要受到蒸发浓缩及盐岩溶滤作用控制。     

不同类型人工林土壤肥力变化的研究

湿地松纯林、湿地松木荷混交林、木荷阔叶林下土壤中的有机质、速效氮、全氮、速效磷、全磷、速效钾和腐殖质酸（胡敏酸、富里酸）变化进行了研究。结果表明：９年生的湿地松纯林、由于凋落物较少，且分解能力较慢，土壤肥力呈下降趋势。而湿地松林荷混交林和木荷阔叶林为的凋落物分解能力较好，能有效地改善林地土壤肥力状况。     

基于多源遥感数据的武汉市人口空间分布格局演化

基于DMSP/OLS夜间灯光指数和SPOT-VEGETATION逐旬NDVI数据构建人居指数,模拟武汉市2000,2012年人口空间分布。采用空间自相关模型,从时空角度分析2000—2012年武汉市人口的空间分布格局及演变规律。结果表明:1利用夜间灯光强度估算方法可快速准确模拟武汉市人口空间分布。2人口空间分布格局有向武汉市中心城区集聚的趋势,具有"中间高周围低"的特征。3武汉市人口空间分布表现出较强的空间自相关性,根据局部自相关分析,"高-高"类型区主要分布在武昌、硚口、江汉、江岸等中心区,"低-高"类型区主要出现在江河流域附近;随着时间的推移人口分布的"高-高"类型区扩大,表明武汉市人口在向中心城区聚集的过程中远城区也形成了相应的人口集聚中心。     

Relations between interrill erosion processes and sediment particle size distribution in a semiarid Mediterranean area of SE of Spain

Erosion and sediment characteristics were measured using simulated rainfall on two cultivated soils of contrasting lithology (Quaternary calcareous colluvium and Tertiary marls) in a semiarid Mediterranean area of SE Spain. Two rainfall intensities, high (56.0±2.4 mm h⁻¹) and medium (31.4±1.4 mm h⁻¹), were used in order to know the mechanisms involved in each selected condition. For each simulated event, runoff and sediment were sampled at 1-min intervals on a 1-m wide by 2-m long erosion plot. The erosion rate was calculated as the total amount of soil lost divided by the time period of the test. The duration of the test was that needed to reach steady state runoff, an average time of 24.5 min for Quaternary calcareous colluvium and 17.7 min for Tertiary marls. The size distribution of the transported sediment in the field (effective size distribution) was compared with equivalent measurements of the same samples after chemical and mechanical dispersion (ultimate size distribution) to investigate the detachment and transport mechanisms involved in sediment mobilisation. The results showed that the soil type determined the hydrological response, regardless of the rainfall intensity. The erosional response was, however, determined by the rainfall and soil surface characteristics.In Quaternary calcareous colluvial soils, the predominant erosion process depended on the rainfall intensity, with a prevailing detachment-limited condition in high-intensity events and prevailing transport-limited conditions in those events of medium intensity. These differences in the main erosion processes were reflected in the size of the transported material and in the change in sediment size within the storm. Thus, a time-dependent size distribution of the eroded material (decreasing coarse fractions and increasing fine fractions with runoff time) was observed for high-intensity events. In medium-intensity events, on the other hand, the time-independent size distribution of the eroded material indicated transport-limited erosion.Due to the rapid surface crusting on the Tertiary marl soil, no differences in the main erosion processes or in the sediment size distribution occurred for the different rainfall intensities tested. The erosion of marl soils was determined mainly by the limited quantity of available sediment.The effective size of material was a more sensitive parameter than the ultimate size of the sediment to study the way in which the sediment was transported.     

Fluorescence characteristics of water soluble organic carbon in eastern China

1 Introduction Water soluble organic carbon (WSOC) was defined as the entire pool of water soluble organic carbon either sorbed on soil or sediment particles or dissolved in interstitial pore water[1]. It has been recognized that dissolved organic carbon acts as a carrier for trace metals and persistent organic contaminants in soil and surface water[2,3]. Besides, dissolved organic carbon in water is one of the important precursors for generating trihalomethanes and other chlorinated produc…     

浑善达克沙地榆树种群结构、格局及动态研究

以浑善达克沙地榆疏林为研究对象,研究了沙地榆疏林种群结构、分布格局与动态特征。结果显示：①丘间低地沙地榆种群呈衰退型种群。固定沙丘沙地榆种群呈增长型种群;②沙地榆种群总体分布格局呈聚集分布,都随着尺度的增大,聚集强度呈减小的趋势;③种群空间分布动态分析表明,丘间低地沙地榆种群,幼、中树随着立木级增大其聚集强度逐渐减弱,大树则在5 m×5 m尺度上呈现出随机分布;固定沙丘沙地榆种群,小、中树随着立木级的增大其聚集强度呈现逐渐增强的趋势,而大树则在10 m×10 m的尺度上呈现出随机分布。物种分布格局主要与物种本身的生物生态学特性和生境有关,育林作业面积应不低于25 m²。     

库布齐沙漠恩格贝沙样中磷的化学赋存形态

通过采用七步连续萃取法对库布齐沙漠恩格贝沙样磷形态的分析,揭示了恩格贝沙样中磷的各种存在形态及含量分布。结果表明：所取沙样中总磷 (TP) 含量在94.33~251.04 μg·g-1 之间,且含量随沙样粒径的减小而增大。无机磷（IP）含量在 88.75~234.83 μg·g-1 之间,占TP含量的 94.08%~93.54%,其中以自生钙结合磷（Ca-P）和原生碎屑磷（De-P）为主,二者占到TP 含量的82.81%~86.13%。有机磷（Or-P）含量在5.58~16.21 μg·g-1之间,占总磷的5.91%~6.46%。在所有不同粒径沙样中各形态磷含量的高低顺序为：原生碎屑磷（De-P）、自生钙结合磷（Ca-P）、有机磷（Or-P）、吸附态磷（Ads-P）、铁磷（Fe-P）、铝磷（Al-P）、闭蓄态磷（Obs-P）,其中Obs-P含量极微。在所取沙样中 Ads-P、Fe-P、De-P、Or-P、Al-P、Obs-P 各自含量都随颗粒物粒径的减小而增大,但Al-P和Obs-P的变化幅度很小。而Ca-P含量受粒径影响较小,粗颗粒沙样中含量略高一些。     

砾石直径和补灌量对砂田西瓜根系分布的影响

采用剖面取样分析方法对砂田西瓜4种补灌量（0 mm,23 mm,4 mm 5和68 mm）和三种粒径（2~5 mm,5~20 mm和20~60 mm）砾石覆盖及不覆盖对照的根系分布进行了研究。结果表明,砂田西瓜有一个发达的根系,根系最长可扩展到1.5 m的深度,但83%以上的根系集中在1 m以上的土层,西瓜田覆盖砾石比对照的根系长度密度增加75%以上。砾石直径20~60 mm的覆盖处理,RLD显著高于2~5 mm直径的处理,降雨量较高的2002年,顶部50 cm土层有更多的根系,降雨量少的年份,下部土层的根系明显增多,但整个土层的总根系长度低于降雨较多的年份。2001年补灌45 mm和68 mm处理的根系长度密度明显高于不补灌的处理,但2002年随补灌量的增加,下部土层根系长度密度减少。降雨少的2001年,补灌增加了西瓜根系的长度密度、蒸散量、产量和水分生产率,而降雨多的2002年,补灌后根系长度密度减少,水分生产率降低。不同直径的砾石覆盖,产量没有显著差别,但由于大粒径砾石覆盖增加了土壤蒸发,虽然根系长度密度增加,但水分生产率降低。结果说明,砾石直径、降雨和补灌量对砂田西瓜的根系分布有明显的影响,用5~20 mm粒径砾石覆盖,并保持适度的水胁迫不仅有利于根系的扩展,而且能提高西瓜的水分利用率。     

Sedimentology and sequence stratigraphy of the middle Jurassic Tarbert Formation, Oseberg South area (northern North Sea)

This paper describes the development of a regressive-to-transgressive shoreline wedge within the Middle Jurassic Tarbert Formation in the Oseberg South area (northern North Sea), as interpreted from core and log data from more than hundred wells. The wedge is described in terms of four facies associations (FA1–FA4). The lower, regressive portion of the wedge (FA1–FA2) contains both coarsening upward wave/storm-dominated shoreline deposits as well as coal-bearing paralic deposits, and was deposited during ascending regression. The upper, transgressive portion of the wedge (FA3–FA4) is characterised by wave-dominated estuarine deposits, exhibiting an upward change from inner to central to outer estuarine deposits. In contrast to some earlier studies, it is argued that this part was deposited during accretionary transgression. The present study documents an estuarine system that developed without any preceding fall of relative sea level and valley incision. It is argued that differential fault-induced subsidence created a broad gentle sag wherein one or several estuarine systems developed as the depositional system became transgressive. The subtle fault-induced subsidence is related to the tectonic evolution in the North Sea Basin.