红壤丘陵区地表水资源动态与合理调蓄利用研究

以红壤丘陵景观中相对独立且整体性强的集水区为基本单元,重点研究了集水区内降水、蒸散、水量蓄存等地表水资源的年变化。结果表明,降水资源在集水区内的陆面拦截蒸散、塘堰蓄存、排出集水区三者中的分布比例约为7:2:1,在水土保持型坡地的植被拦截、土壤渗流、地表径流三者中的分布比例约为3:5:2;每公顷1m土体中的土壤贮水量,在丰水季节,水土保持型坡地要比非水保坡地高出864.0～1067.0m3,少水季节则高出647.0～855.0m3。研究结果还表明,以集水区为单元的农业灌溉用水量,一般为年降水量的12%左右,蓄存此水量的塘堰面积应占集水区土地总面积的11%左右,对于塘堰面积已占土地总面积10%左右的红壤丘陵区而言,抗御季节性干旱依靠扩大塘堰蓄水已不现实,其主要途径应是充分发挥水库工程和"土壤水库"的巨大抗旱潜力。     

Spatial distribution of surface soil water content under different vegetation types in northwest Guangxi, China

Geostatistical and statistical analyses were combined to examine the spatial distribution of soil water content under four vegetation types during the dry season, in the peak-cluster depression in the karst region in northwest Guangxi, southwest China. The soil water content significantly increased from farmland to plantation, secondary forest, and primary forest; whereas the variation coefficients, the sill (C ₀+C), and total spatial variance increased, although the range decreased. The spatial distribution of soil water content in the different vegetation types had a high spatial autocorrelation. Different models produced a best fit for the semivariograms of the four vegetation types. Elevation and slope position were the primary factors influencing the spatial distribution of soil water content, with other key factors differing between the four vegetation types. Moreover, even though different specific factors influenced soil water content in the four vegetation types, the correlations and degrees of associations between the soil water content and these various factors differed. Therefore, the corresponding strategies for rational usage and management of water resources should be different for the four vegetation types in this region.     

岩石圈地幔含水不均一：来自华南地区白琳和建德的对比

利用电子探针、激光剥蚀电感耦合等离子体质谱和傅里叶变换红外光谱分别测定了华南地区福建省白琳大嶂山新生代玄武岩中橄榄岩包体矿物的主要元素、微量元素和H2O含量。橄榄岩矿物主要元素之间的相关性符合部分熔融趋势，部分熔融程度在0～21%之间。大多数样品（23个样品中的21个）部分熔融程度较低（<6%）并具有亏损的球粒陨石标准化稀土元素模式。单斜辉石、斜方辉石和橄榄石的H2O含量分别为78×10 -6～262×10 -6、37×10 -6～124×10 -6和~0。尽管不能排除橄榄石包体上升过程中的潜在H的扩散丢失，但两种辉石保留了地幔中的H2O含量，这可以从 ① 单个辉石颗粒中的均一的H2O含量和 ② 单斜辉石和斜方辉石之间的平衡H2O分配推断出来。基于矿物模式，并假设单斜辉石和橄榄石之间的H2O分配系数为10，计算出的全岩H2O含量范围为15×10 -6～67×10 -6。水含量与熔融指数、交代指数、氧化还原状态和温度之间缺乏良好的相关性，说明白琳地区岩石圈地幔中水含量的控制因素是复杂的。已有研究表明浙江省建德地区岩石圈地幔具有较高水含量。白琳和建德两地对比显示，两地岩石圈地幔在熔融程度、交代程度、氧化还原状态和平衡温度非常类似，但是水含量差异巨大。华夏地块（以建德和白琳为代表）的岩石圈地幔在主成分和微量成分上可能均一，但H2O含量有巨大差异，体现了地幔的不均一性。     

TDR测定喀斯特地区石灰土含水量的标定研究

土壤含水量是气候、水文、土壤侵蚀等研究中的一个重要参数.TDR法因具有方便、快速、精确且不扰动土壤等优点而得到广泛应用,但因受土壤质地、容重、温度等物理因素的影响而必须对其进行标定.本研究采用室内标定(壤土)和田间标定(粗、中、细质土以及三者的组合)相结合的方式,对用TDR法测定的喀斯特地区不同质地石灰土含水量进行了标定.结果表明:(1)TDR法测定的土壤含水量比烘干法测定值要小,两者最大绝对偏差在室内标定条件下为10.6%,田间标定为12.2%;相应的相对偏差最高分别可达60.3%和32.8%.因此,必须在使用前对TDR进行标定.(2)标定后TDR法测定的土壤含水量精度明显提高,平均绝对偏差低至1.4%~3.1%;室内标定曲线精度略低于田间标定曲线.(3)不同质地组合的TDR法土壤含水量标定曲线的标定精度较高(平均绝对偏差为1.5%~2.6%),可用于不同质地土壤含水量标定.本研究结果可用于修订校正研究区及类似区域TDR法测定土壤含水量的结果.     

大陆玄武岩原始水含量的测定及其对源区组分的制约

理解大陆板内玄武岩的源区组成和成因是认识地幔动力学过程和化学不均一性的重要途径。由于不同地幔端员具有不同的水含量及水与其它不相容元素的比值(如H2O/Ce),原始水含量的测定对于认识玄武岩的源区组成将会提供新的信息。玄武岩玻璃和斑晶中的熔体包裹体是获得海洋玄武岩原始水含量的主要样品,但是不适合于大陆玄武岩,因为大陆玄武岩玻璃由于强烈的去气作用不能反映真实水含量,而大陆玄武岩斑晶中的熔体包裹体少而小,不易获得足量、准确的数据。本文介绍一种最近发展起来的推断大陆玄武岩原始水含量的方法,即利用红外光谱测定玄武岩中单斜辉石斑晶的水含量,然后结合水在单斜辉石与玄武质熔体中的分配系数来反演与斑晶平衡的熔体水含量,进而估计原始玄武质岩浆的水含量。文中详细叙述了方法的适用性、误差的估计以及具体的操作流程,并通过东北双辽和华北太行山新生代玄武岩的研究实例,展示了玄武岩水含量对于源区组成的有力制约。     

Spatiotemporal dynamics of land cover and their impacts on potential dust source regions in the Tarim Basin,NW China

Human-driven dynamics of land cover types in the Tarim Basin are able to affect potential dust source regions and provide particles for dust storms. Analyses about dynamics of potential dust source regions are useful for understanding the effects of human activities on the fragile ecosystem in the extremely arid zone and also provide scientific evidence for the rational land development in the future. This paper therefore selected the Tarim Basin, NW China, as a representative study area to reveal spatiotemporal dynamics of land cover and their impacts on potential dust source regions. The results showed that farmland, desert and forest increased by 28.63, 0.64 and 29.27%, while grassland decreased by 10.29% during 1990–2010. The largest reclamation, grassland loss and desertification were 639.17 × 10³, 2350.42 × 10³ and 1605.86 × 10³ ha during 1995–2000. The relationship between reclamation and grassland loss was a positive correlation, while a highly positive correlation was 0.993 between the desertification and grassland loss at different stages. The most serious dust source region was the desertification during 1990–2010 (1614.58 thousand ha), and the serious region was stable desert (40,631.21 thousand ha). The area of the medium and low dust source region was 499.08 × 10³ and 2667.27 × 10³ ha. Dramatic reclamation resulted in the desertification by destroying natural vegetation and breaking the balance of water allocation in various regions.     

内蒙古某矿矿井水重金属污染特征及来源分析

确定矿井水中重金属污染程度及主要来源,对矿井水的再利用及矿区生态环境保护具有重要的理论意义。以内蒙古某矿区为研究对象,采集地表水、第四系潜水、承压水及矿井水水样49组,检测水体中Zn、Pb、Fe、Mn、As、Cu、Cd、Cr、Hg、Se 10种重金属浓度,分析矿井水中重金属污染特征及超标情况,利用HPI模型定量评价重金属污染程度,并综合数理统计、不同类型水样重金属浓度箱形图及煤/顶板重金属浸出试验,分析矿井水重金属主要来源。结果表明:内蒙古某矿矿井水中Zn、Pb、Fe、Mn、As 5种重金属浓度值超标,其中Fe和Zn的超标率高达100%;7个矿井水样中6个矿井水的HPI值大于临界值100,矿井水重金属污染程度较高;矿井水中的Pb、As主要来源于采煤及运输机械油类物质泄漏,Mn主要来源于Ⅲ含地下水,Fe、Zn主要来源于Ⅲ含地下水及煤层中含Fe、Zn矿物的溶滤。该结论将为矿井水中重金属污染防治提供基础与依据。      

Evaluation of nitrate source in surface water of southwestern China based on stable isotopes

Stable isotope tracing and analysis play an important role in interpretation of hydrological and ecological processes at the watershed scale and can provide information regarding the flow path, water source, nutrient loss and biogeochemical cycles of a system. In this study, environmental isotopes (δ¹⁸O-H₂O, δD, δ¹⁵N-NO₃ ^?, δ¹⁸O-NO₃ ^?) and chemical compositions of surface water in Guizhou Province, China, were measured to evaluate the primary sources of nitrate and characterize the processes affecting nitrate as well as its correlation with vegetation cover in karstic areas. The δ¹⁵N and δ¹⁸O-NO₃ ^? levels ranged from +1.3 to +9.8 ‰ and +4.7 to +16.9 ‰, respectively, which indicated that nitrate in water from the investigated area primarily originated from nitrification of soil organic matter during the sampling period. There was also a wide range of isotopes in the water and high contents of nitrate in karstic areas with poor vegetation cover, indicating that water and nutrient loss were serious problems hindering plant growth in the study areas. For example, there was a positive relationship between isotopic composition and nitrate content in the natural forest and negative relationship in Libo County nearby, which suggested that the nitrate fate was affected by land use and human disturbance.     

Using monitoring data of surface soil to predict whole crop-root zone soil water content with PSO-LSSVM,GRNN and WNN

Drought is a significant disaster in Beijing and it is important to find a method to assess the drought condition. First, this paper collected data of 85 soil monitoring stations in Beijing, such as soil dry bulk densities, saturated water contents, field capacities. Then, spatial variability characteristics of soil physics parameters were investigated by GIS and other three factors, 10 cm soil moisture content, organic matter and saturated water content which notably influenced soil moisture were extracted by Principal Component Analysis (PCA). Furthermore, four different nonlinear methods were put forward to predict crop-root zone soil water. 15555 single daily data from 2011 were used in parameters determination, while 15470 double daily data were used to test. The result showed that the Least Square Support Vector Machine coupling Particle Swarm Optimization Algorithm (PSO-LSSVM) (R ²?=?0. 875) did better than BP Neural Network (R ²?=?0. 840), Generalized Regression Neural Network (GRNN) (R ²?=?0. 850) and Wavelet Neural Network (WNN) (R ²?=?0. 853). As so the POS-LSSVM method was used to evaluate the drought conditions from October 2010 to March 2011 of Beijing, and the result showed that from October 2010 to January 2011, the drought conditions were getting increasingly worse while later relieved from January 2011 to March 2011.     

Annual variations in the surface radiation budget and soil water and heat content in the Upper Yellow River area

Measurements taken between July 2006 to May 2007 at the Maqu station in the Upper Yellow River area were used to study the surface radiation budget and soil water and heat content in this area. These data revealed distinct seasonal variations in downward shortwave radiation, downward longwave radiation, upward longwave radiation and net radiation, with larger values in the summer than in winter because of solar altitudinal angle. The upward shortwave radiation factor is not obvious because of albedo (or snow). Surface albedo in the summer was lower than in the winter and was directly associated with soil moisture and solar altitudinal angle. The annual averaged albedo was 0.26. Soil heat flux, soil temperature and soil water content changed substantially with time and depth. The soil temperature gradient was positive from August to February and was related to the surface net radiation and the heat condition of the soil itself. There was a negative correlation between soil temperature gradient and net radiation, and the correlation coefficient achieved a significance level of 0.01. Because of frozen state of the soil, the maximum soil thermal conductivity value was 1.21 W m⁻¹°C⁻¹ in January 2007. In May 2007, soil thermal conductivity was 0.23 W m⁻¹°C⁻¹, which is the lowest value measured in the study, likely due to the fact that the soil was drier then than in other months. The soil thermal conductivity values for the four seasons were 0.27, 0.38, 0.55 and 0.83 W m⁻¹°C⁻¹, respectively.     

Lithospheric stress in Mongolia,from earthquake source data

Lithospheric stress in Mongolia has been studied using mechanisms of 84 M_(LH)≥ 4 earthquakes that occurred in the 20 th century and instrumental seismic moments of 17,375 M_(LH)≥2.5 events recorded between 1970 and 2000.The M_(LH)≥ 3.5 earthquakes mostly have strike-slip mechanisms in southern and central Mongolia,with frequent reverse-slip motions in the west and normal slip in the north,especially,in the area of Lake Hovsgol.The principal stresses are,respectively,S_HS_vS_h in the center and in the south;high horizontal compression with S_HS_hS_v in the west;and a heterogeneous stress pattern with S_vS_HS_h in the north.According to seismic moments of M_(LH)=2.5 events,oblique slip generally predominates over the territory,at S_v≈S_HS_h,while frequent strike slip motions in the west record high horizontal compression(S_HS_vS_h).Earthquake mechanisms show the principal horizontal compression S_H to be directed W-E in the east,NE-SW in the central and Gobi-Altay regions,and approximately N-S in the west of Mongolia.The patterns of principal lithospheric stresses in the territory of Mongolia have undergone three events of dramatic change for a few recent decades,and these events were synchronous with three similar events in the Baikal rift system(BRS):in the latest 1960 s,latest 1970 s to earliest 1980 s,and in the latest 1980 s to earliest 1990 s.The seismicity of Mongolia has been controlled by superposition of variable stresses associated with rifting activity pulses in the neighbor BRS on the background of quasi-stationary super-regional compression.     

宁夏中部干旱带露水形成机制及其对表层土壤水分的影响

露水的形成及其对土壤水分的影响是进一步量化水循环和生态水文过程的重要依据。为探明露水发生规律,在宁夏中部干旱带连续3 a观测了每30 min气象资料和表层土壤水分,用叶片湿度传感器测算了露水量。结果表明：该区年露水量可达56.41 mm, 75%发生在6—10月,最大月露水量和日露水量分别为13.40 mm和0.80 mm,主要发生在03:00—08:00;露水发生的气温、相对湿度和风速范围分别为0～24.4℃、50%～100%和0.16～1.74 m/s,风向为30°～60°(东北风)和270°～330°(西南偏西风);气温和露点差与相对湿度之间呈极显著线性逆相关,气温和露点差小于3℃且相对湿度大于80%时极易产生露水;日露水量为0.6 mm、0.7 mm和0.8 mm时表层5 cm土壤贮水量可分别提高0.10 mm、0.20 mm和0.25 mm。该地区年均降露量是降雨量的13.5%,露水年均发生频率为126 d(35%),是当地水循环和生态系统不可忽略的水源。     

Karst water resources and geo-ecology in typical regions of China

The aim of this work is to compare the different karst water features and related water resources in South and North China. In Southern China there are over 3,358 karst ground river systems with a total discharge of about 420 × 10⁸ m³ in the dry season. In North China, there are about 100 larger karst spring systems, each with a catchment area from 500 km² to over 4,000 km², and an average discharge from 1 to 13 m³/s. The basic geo-ecological features of water, soil and air quality are described for typical karst regions of China. The total quality of geo-ecology is evaluated by five important factors.     

Distribution of nitrogen forms in surface sediments of lakes from different regions,China

The characteristics of nitrogen fractions in the surface sediments of lakes from Eastern Plain Region, Yunnan-Guizhou Plateau Region, Northeast China Region, Qinghai-Tibet Plateau Region and Mongolia-Xinjiang Plateau Region were investigated and the differences of five lake regions on nitrogen fractionation were discussed. The results indicated that organic nitrogen (N_org) was the major nitrogen fraction accounting for 76.38–92.02 % of N_tot in sediments. The rank order of average N_org and N_tot of sediments in five lake regions was: Yunnan-Guizhou Plateau Region > Northeast China Region > Mongolia-Xinjiang Plateau Region > Qinghai-Tibet Plateau Region > Eastern Plain Region. The exchangeable nitrogen had a similar distribution as organic nitrogen in the studied sediments. NH₄ ⁺–N is the main exchangeable nitrogen of sediments in the studied lakes except in Lake Qinghai and Lake Yamdrok which contained higher nitrate concentrations than ammonium. Fixed ammonium (N_fix) in the sediments of studied lakes was irregularly distributed with the values ranging from 99.45 to 329.02 mg/kg. TOC was significantly and positively correlated with ammonium, nitrate, N_org and N_tot, while N_fix was negatively correlated with nitrate probably due to electrostatic attraction between N_fix and nitrate in layers of sediments.     

土体内聚力随含水量、粘粒含量及干密度变化关系探讨

在室内试验条件下,改变土体含水量、粘粒含量及压实度等物性参数,分析了土体内聚力随土体含水量与粘粒含量比值m及土体干密度ρd变化关系.结果表明,土体内聚力C随土体含水量与土体粘粒含量比值m的增大,总体上呈减小趋势.当比值m≥1.33时,内聚力C随m的增大变化已不明显,其值小于5.0kPa(少数小于10.0kPa);当m＜1.33时,土体内聚力C随m的增大具有明显的线性降低趋势.     

内蒙古岱海表层沉积物中孢粉的分布及来源

岱海位于半干旱区东部边缘及东亚夏季风的尾闾区，生态环境体系脆弱，气候和环境变化敏感，是研究环境变化的理想地区。65个湖泊表层及入湖河流冲积物样品的孢粉分析揭示了岱海表层孢粉沉积特征及孢粉来源。岱海表层孢粉主要来源于区域性植被的孢粉，其总体特征反映了区域植被的组成，但不同部位孢粉组合的差异反映了湖滨当地植被的变化。受沉积环境的影响，岱海湖区孢粉浓度总体上要低于入湖河流孢粉浓度，湖区中部孢粉浓度最高。岱海孢粉以河流携带的为主，同时受风力传播的影响。蒿、藜科、桦、虎榛子等花粉和蕨类孢子以河流搬运的为主，松、禾本科及莎草科花粉可能还受风力传播的影响。一些仅在个别样品中出现且百分比很低的花粉类型如豆科、十字花科等还有可能是昆虫、鸟类或人类活动携带而来。     

利用土壤温度估算土壤有效热导系数和水流通量

土壤有效热导系数和水流通量是研究大气-土壤系统水分转化的重要变量。采用动态回归模型（DHR）获取土壤温度的振幅和相位变化,联合土壤水热耦合方程的解析解估算土壤有效热导系数和土壤水流通量,并将该方法应用于毛乌素沙地的土壤水流通量估算中。结果显示,实例研究估算获得的有效热导系数在10-7m2/s数量级变化,且随振幅比的增加呈指数增加,随相位差的增加呈指数衰减。当土壤含水率小于0.08时,有效热导系数呈线性增加;当土壤含水率大于0.08时,接近恒定值（定量0.08）,土壤水流通量随土壤含水率的变化无明显的线性关系。     

内蒙古清水河水源地地下水允许开采量计算

为解决内蒙古清水河县城新区供水问题, 在分析水源地水文地质条件的基础上, 利用勘察获得的资料, 对评价中相关水文地质参数的确定进行了讨论。经计算, 研究区的降水入渗系数为0.19, 河流补给量为873.13 m3/d。采用均衡法进行地下水资源评价, 确定了研究区地下水允许开采量为 40 769.14 m3/d, 能够满足该区未来需水量。     

Stable carbon isotope characteristics of different plant species and surface soil in arid regions

The stable carbon isotope composition in surface soil organic matter (δ¹³Csoil) contains integrative information on the carbon isotope composition of the standing terrestrial plants (δ¹³Cleaf). In order to obtain valuable vegetation information from the δ¹³C of terrestrial sediment, it is necessary to understand the relationship between the δ¹³C value in modern surface soil and the standing vegetation. In this paper, we studied the δ¹³C value in modern surface soil organic matter and standing vegetation in arid areas in China, Australia and the United States. The isotopic discrepancy between δ¹³Csoil and δ¹³Cleaf of the standing dominant vegetation was examined in those different arid regions. The results show that the δ¹³Csoil values were consistently enriched compared to the δ¹³Cleaf. The δ¹³Cleaf values were positively correlated with δ¹³Csoil, which suggests that the interference of microorganisms and hydrophytes on the isotopic composition of surface soil organic matter during soil organic matter formation could be ignored in arid regions. The averaged discrepancy between δ¹³Csoil and δ¹³Cleaf is about 1.71%in Tamarix L. in the Tarim Basin in China, 1.50% in Eucalytus near Orange in Australia and 1.22% in Artemisia in Saratoga in the United States, which are different from the results of other studies. The results indicate that the discrepancies in the δ¹³C value between surface soil organic matter and standing vegetation were highly influenced by the differences in geophysical location and the dominant species of the studied ecosystems. We suggest that caution should be taken when organic matter δ¹³C in terrestrial sediment is used to extract paleovegetation information (C₃/C₄ vegetation composition), as the δ¹³C in soil organic matter is not only determined by the ratio of C₃/C₄ species, but also profoundly affected by climate change induced variation in the δ¹³C in dominant species.     

基于碎屑锆石的黄土高原—毛乌素交界区石峁黄土粉尘物源估算*

对于黄土高原粉尘物质的来源以及沙漠和河流对粉尘的贡献,仍未达成一致的认识。本研究以毛乌素东神木市石峁剖面为研究对象,利用碎屑锆石年龄谱,对末次冰消期以来的风成粉尘堆积和河流沉积物展开源区分析,并使用逆蒙特卡罗模型进行物源的定量计算。结果显示,粒径分布和阴极发光(CL)图像显示石峁黄土为典型风成沉积。其粗颗粒碎屑锆石(>40 μm)年龄峰值集中在190~300 Ma、300~600 Ma、1700~1900 Ma和2300~2600 Ma,年龄谱显示近源(局地基岩碎屑)、中源(黄河河沙)和远源(阿拉善地区沙漠)均有贡献; 定量计算表明,三者分别贡献71%、21%和8%的风成粗颗粒。中、近源中,黄河及其支流侵蚀基岩后搬运沉积的漫滩物质成为粉尘输移的中转站,为黄土的形成提供了主要的物源。光释光测年结果表明,石峁剖面河流沉积物及其上覆的黄土物质分别形成于倒数第2次冰消期和末次冰消期,两者之间的沉积间断可能指示了末次冰期至冰消期的侵蚀事件,导致了河滩物质暴露,从而形成了潜在的局地尘源。这些结果表明,包括黄河干支流在内的河流系统对黄土粉尘有重要的物源贡献。