不同植被下碳酸盐岩石发育形成土壤属性研究

为探究喀斯特地区不同植被条件下碳酸盐岩石发育土壤属性的分布特征及其影响因素,以贵阳市花溪区范围内的碳酸盐岩石（石灰岩、灰质白云岩和白云岩）发育土壤为研究对象,采集不同植被类型下0～40 cm土壤,分析不同植被类型、基岩类型、土层层次对土壤性质分布特征的影响。结果表明：基岩和植被类型是影响碳酸盐岩石发育成为土壤的主要影响因素,其次是土壤层次。在0～20 cm和20～40 cm土层中,石灰岩、灰质白云岩和白云岩发育土壤的肥力和颗粒均差异显著,而0～20 cm与20～40 cm土层间,除石灰岩发育土壤石砾含量（SLC）和细颗粒比（<0.002 mm）,白云岩发育土壤速效磷（AP）和有机质（SOM）含量外,同类基岩发育土壤性质无显著差异;在0～40 cm土层,基岩类型显著影响土壤pH、AP、SLC、速效氮（AN）、全氮（TN）、SOM、0.2～0.25 mm和0.002～0.02 mm颗粒的分布;植被类型显著影响石灰岩发育土壤pH、AP、TN含量,白云岩形成土壤的pH、SLC、粗颗粒（0.25～2 mm）和细颗粒,灰质白云岩形成土壤的AN、SOM、粗颗粒和细颗粒;土壤层次显著影响石灰岩发...     

牧压梯度下高寒杂草类草甸土壤持水能力及影响因素分析

以祁连山南麓坡地夏季牧场高寒杂草类草甸为研究对象,进行了封育对照（CK,禁牧）、轻度放牧（LG）、中度放牧（MG）和重度放牧（HG）下土壤持水能力及影响因素的分析. 结果表明：牧压梯度下0～10 cm层土壤最大持水量和毛管持水量均在LG最大,土壤自然贮水量LG略小于HG;而在10～20 cm和20～40 cm持水量均在HG最大,说明放牧对表层土壤的持水能力影响比深层更明显. 0～10 cm层土壤容重随牧压强度增加而增大,较深层次土壤容重基本一致,表明放牧对较深层土壤容重造成的影响远小于表层. 牧压梯度下植被地上地下生物量、枯落物、地表半腐殖质随放牧强度增大而减少;0～10 cm土壤有机质含量在MG最大,CK最小,10～20 cm和20～40 cm层土壤的有机质含量CK最大,说明不同土层有机质含量对牧压梯度的响应有所不同. 土壤持水量与多种因素有关,主要受到地下生物量、有机质和容重等因素的影响,表明随放牧强度增大,践踏使土壤表面硬度增加,土壤空隙度减少,同时家畜过度采食使地面植被覆盖降低而增加土壤水分的蒸发. 这些综合作用下引起放牧地土壤持水能力降低.     

桂西北典型岩溶区水稻田成土剖面砷的垂向分布特征及其影响因素

调查分析桂西北典型岩溶矿区及其周边水稻田成土剖面砷含量及相关土壤参数垂向分布特征,研究了岩溶区土壤砷的含量垂向分布及迁移规律,并探讨了岩溶区土壤砷垂向迁移的主要影响因素。结果表明:研究区三个典型土壤剖面的主要土壤类型为石灰岩土,化学风化程度较高,土壤砷自然来源主要为土壤母质;土壤剖面砷含量的垂向分布均为表层相对富集、深层相对稳定,而土壤有机碳是制约岩溶区水稻田土壤砷垂向迁移的关键因素;矿区外围的两个土壤剖面砷含量主要富集在10～20 cm层,而在0～10 cm层砷含量相对较低,土壤砷含量平均值分别为5.5 mg·kg-1 和5.0 mg·kg-1 ;而临近矿区的土壤剖面具有土壤砷高背景值的特点,土壤砷含量平均值为46.2 mg·kg-1 ,且砷主要富集在20～40 cm的次表层,而在10~20 cm层砷含量则相对较低,但在0～10 cm层土壤砷含量又显著高于10～20 cm层,这表明外来源对该剖面表层土壤也具有显著影响。      

青铜峡灌区春灌前土壤盐分与盐渍化特征及空间分布

土壤盐分与盐渍化的特征和时空分布特征研究，对土壤盐渍化防治和土壤开发利用十分重要。根据在青铜峡灌区布设的80个代表性土壤样点0～60 cm分层取样测定的土壤全盐量数据，采用经典统计学、地质统计学，结合GIS技术研究灌区春灌前土壤全盐量、主要化学组分特征与盐渍化空间分布格局。结果表明：(1)青铜峡灌区不同深度土壤全盐量呈偏态分布且都属强变异强度；土壤全盐量与主要盐分离子均存在极显著正相关关系(P<0.01);阴阳离子间的强相关性反映出不同深度土壤盐分阴阳离子组合十分复杂。(2)不同深度土壤全盐量和K⁺+Na⁺、Cl^-、SO₄^2-、HCO^-₃含量具有中等-较强烈的空间自相关性，最大自相关距离均未超过灌区最大直线范围的1/3。(3)灌区0～20 cm土壤属于非、轻度、中度、重度盐化土和盐土的面积分别是437.68 km²、615.43 km²、650.00 km²、2 ...     

分叉波痕在广西上泥盆统钙质浊积岩中的发现及意义

小型不对称分叉波痕(简称分叉波痕)发现于桂林杨堤剖面上泥盆统弗拉斯阶linguiformis牙形石带，桂林碳酸盐台地东南缘斜坡相钙质浊积岩鲍马序列C段。波长7．5～8．0cm，波高0．5～0．8cm，波痕指数15～10；向流面长5．0～7．0cm，背流面长2．5～4．0cm，波痕对称指数2．0～1．8；背流面向东倾；波脊较圆滑、缓曲，且具明显的分叉现象。是浊流流速减缓，密度流转化为牵引流后在低流态条件下，并叠加有推进型风暴浪作用形成的复合成因波痕。根据该波痕和寄主地层特征，推断含分叉波痕的阳朔碳酸盐盆地的最大水深约100m，极限水深小于200m。这一估计值应能代表广西乃至华南板块泥盆纪广泛发育的含牙形石动物群和钙质浊积岩碳酸盐沉积盆地的定量水深，可能也代表了弗拉斯阶一法门阶之交受集群绝灭事件重创的浅水海相生物与基本未受影响的深水海相生物的水深分界线。     

鼎湖山亚热带森林土壤有机质^14C年龄初步研究

对鼎湖山亚热带森林土壤有机质（SOM）放射性碳进行了核爆效应校正。各层位年龄值与土壤深度呈线性递减,成壤过程是连续的,也是全新世时期的产物。五棵松剖面和坑口剖面成壤速率分别为0．0233cm／a和00488cm／a。成壤速率的差异可以用微地形和植被等主要因素的不同来解释。红壤有机物由活跃和稳定两种组分组成,其分解速率分别为0.25—0．57a-1和1．51×10－3—18×10-3a-1,平均滞留时间分别为1．8—4.0a和556-667a。     

基于SHAW模型的祁连山高寒草甸土壤水分储量及通量的模拟研究

高寒草甸是祁连山国家公园青海片区的重要植被类型之一,量化该下垫面土壤水分储量及交换过程是评估区域水源涵养功能的关键科学基础。基于2017年8月1日至2018年7月31日的祁连山南麓高寒草甸生态系统水热特征的连续观测数据,对SHAW(simultaneous heat and water)模型进行了参数优化,分析了0～100 cm土壤水分储量及通量的变化特征及环境影响。结果表明:SHAW模型可以相对准确地模拟高寒草甸土壤温、湿的季节变化特征,土壤水分的模拟效果略好于土壤温度的模拟效果。日均0～100 cm土壤水分储量(SWS_0-100)为(274.99±19.57,平均值±标准差)mm,5—10月植被生长季的平均SWS_0-100较非生长季低21.92 mm。SWS_0-100的季节变异主要受控于群落叶面积指数的正效应和蒸散发的负效应,二者通过调控浅层(0～20 cm)和中层(20～60 cm)土壤水分储量间接影响SWS_0-100。日均0～100 cm土壤水分通量(SWF_0-100)...     

长江入海口浅层沉积物中典型有机氯农药分布特征

对长江入海口包括江苏启东,上海崇明岛、长兴岛、横沙岛等地区的浅层沉积物中典型有机氯农药(OCPs)的分布情况进行了研究。采用气相色谱-电子捕获检测器进行检测,方法检出限为0.10 ng/g,回收率为62.4%～116.7%,精密度(RSD)为2.7%～8.3%。调查分析结果显示,长江入海口沿岸均存在轻度和中度的OCPs污染,主要检出物总滴滴涕(DDTs)浓度范围为1.22～626.43 ng/g。深度(0～80 cm)采样检测结果表明,研究区表层及深度样品中DDTs均有不同程度检出,浅层沉积物中DDTs在0～20 cm区域占检出总量的58.1%;其次是20～40 cm区域,DDTs占总量的30.8%;40～60 cm区域DDTs占总量的8.2%;60～80 cm区域DDTs占总量的2.9%,即浅层沉积物中DDTs主要集中在0～40 cm区域,部分点位40～80 cm能够检出少量DDTs。本研究提供的数据为该地区OCPs垂直分布提供参考。     

土地整理对岩溶区土壤微生物生物量碳、氮及酶活性的影响——以重庆丰都县三坝乡为例

文章以重庆市丰都县三坝乡土地整理项目为例,分别对土地整理前（2012年12月）52个采集点和土地整理后（2013年3月）28个采集点,采用野外采样和室内分析相结合的方法,研究了土地整理对岩溶区土壤微生物群落结构、土壤微生物生物量碳(SMBC)、氮(SMBN)及酶活性(过氧化氢酶、脲酶、蔗糖酶)的影响,结果表明:（1）土地整理对土壤微生物影响显著,土地整理后比整理前土壤中的放线菌数量降低,真菌数量增加。（2）在0～20 cm土层,整理前后SMBC和SMBN含量变化显著,SMBC含量整理后比整理前降低了20.33%,SMBN含量整理后比整理前减少了47.84%;土地整理改变了整理前SMBC、SMBN含量随土层深度变化递减的规律,使SMBC、SMBN含量分别在亚表层（20～40 cm）出现最小值68.34 mg/kg和最大值33.58 mg/kg。（3）整理前后土壤脲酶和过氧化氢酶均在0～20 cm和20～40 cm同一土层差异显著,蔗糖酶活性在各土层差异均显著。土地整理使土壤脲酶和过氧化氢酶活性降低,蔗糖酶活性提高。（4）有机质对表层SMBC、SMBN含量和脲酶活性呈显著正相关,pH值与土壤酶活性呈显著正相关。      

重金属污染元素在天津土壤剖面中的纵向分布特征

文章阐述了天津市不同地貌单元8个土壤剖面中重金属污染的纵向分布特征,并对土壤中重金属污染的形成原因进行了分析.结果表明,重金属元素随土壤质地不同而有所不同.镉、汞、铜、铅、锌等在城市附近污染比较重,污染主要集中在0～50 cm土层内.污水灌溉、污泥施用和城市降尘是造成土壤多种重金属元素污染的主要原因.     

Bio-climatic imprints on a Holocene loess palaeosol from China

Micromorphology, heavy minerals, pollen and soil properties were examined in a typical Holocene loess profile in the north of the Loess Plateau, consisting of a palaeosol (locally known as the Ansai palaeosol) underlain by the Malan loess and overlain by modern loess. The palaeosol consists of an upper humus-rich (AB) horizon over a clay-rich (Bt) horizon. The humus-rich horizon is intensely weathered, contains precipitated calcitic material derived from the overlying modern loess, and has both high pollen content and diversity. Clay coatings in the clay-rich horizon indicate formation by eluviation–illuviation of clay. Pedogenetic characteristics and pollen analysis imply that the vegetation during the time of most intensive soil development is likely to have been a warm-temperate forest. A complex interpretation of the loess–palaeosol sequence recognizes several development stages. The phase of soil development, maximum and minimum limiting ages for which are ca. 8800 and 4400 ¹⁴C years BP, involved continuing but reduced loess deposition, and successive Holocene bio-climatic environment overprinted new features on the palaeosol.     

A new simple approach to evaluate pedogenic clay transformation in a Vertic Calcisol

The aim of this study is to characterize the pedogenic clay minerals by using simple approach: mixing mineralogical and geochemical findings.The fine clay fractions (< 0.1 μm) of a Vertic Cambisol profile were studied by means of X-ray diffraction (XRD), infrared spectroscopy (FTIR) and cation exchange capacity (CEC).Qualitative and quantitative mineralogical compositions of the clay mixture were determined.Moreover, chemical equilibria and thermodynamic stabilities of minerals (calcite, gypsum, kaolinite, smectites and illites) were studied using results of ionic activities obtained from total concentration of various aqueous species in water extracts from soil-saturated pastes.XRD analysis shows a good homogeneity in the mineralogical composition of the soil material, with depth of soil profiles. The identified clay minerals are mainly illite–smectite mixed layers (I/S) and kaolinite. The chemical analysis of saturated paste extracts with clay minerals shows a slight undersaturation of the illitic phase while smectites and also calcite and gypsum reach the thermodynamic equilibrium along the soil profile.     

Discovery and Significance of Malan Loess on the Piedmont Plain in Pinggu District,Beijing

The platforms on both sides of the Malangou River （a lateral ditch of the Qingshui River that is a tributary of the Yongding River） where Malan Village in Zhaitang Town of Mentougou District of Beijing is located are the place of China＇s typical section of the Quaternary Malan loess. During the investigation in the eastern suburbs of Beijing City, the authors not only clarified 5 grades of terraces on the Pinggu piedmont plain, but also found a clayey silt section mixed with a small amount of alluvial-diluvial gravel layers at a height of 15-25 m above the river level near a Fishpond in Xinli Village of Nandule Town. Results of the study of grain size of the section document that the loess mostly is silty soil （0.05--0.005 mm）, and that the grain size probability cumulative curves of the section are dominated by single-peak, coarse-grained segment I and coarse-grained segment II types, reflecting that its depositional environment is similar to eolian phase. Identification results of heavy minerals from the section show that their contents account for 0.01%-0.11%, averaging 0.04%. There are 24 kinds of heavy minerals, most of which are stable heavy minerals, and the clay minerals mostly are illite, which is consistent with the Malan loess on the Loess Plateau. The chemical composition data reflect that the source area of the loess is relatively arid. The six grade classification of sporopollen in the section further shows the subdivision of the history of alternating warm and humid phases in this geological period. The thermoluminescence dating results range from 21.0 ka to 59.2 ka, convincingly demonstrating that the section indeed consists of Malan loess. The above studies provide a new basis for overall understanding of the distribution of the Malan loess at the northeast margin of the North China Plain and its environment change in the Late Pleistocene.     

The ultrafine component in Chinese loess and its variation over the past 7·6 Ma: implications for the history of pedogenesis

Grain‐size data from different climatic zones across the Chinese Loess Plateau show that the loess generally contains an ultrafine component, which has a consistent modal grain size of ca 0·37 μm and a variable proportion of 4 to 10%. The variation of the ultrafine component through a loess section is characterized by a high proportion and fine grain size in palaeosols, and by a low proportion and coarse grain size in loess layers. Its proportional content in a stratum roughly increases from north‐west to south‐east across the Loess Plateau. Quantitative X‐ray diffraction analysis indicates that the ultrafine component is composed mainly of clay minerals (ca 70%), which are mostly illite (ca 80%), and with significant amounts of kaolinite (ca 8%) and chlorite (ca 2%). The temporal and spatial variations of the ultrafine component, and the degree of illite crystallinity, suggest that this component in aeolian sediments is linked closely to the process of pedogenesis. Weakly altered loess on the north‐western margin of the Loess Plateau contains considerable amounts of detrital clay minerals derived from the aeolian source areas. Results from a loess section with a basal age of 7·6 Ma in the central Loess Plateau show that the ultrafine component increased from 7·6 to 5 Ma, and progressively decreased thereafter. This trend was punctuated by two abrupt changes at 2·6 and 0·6 Ma. These variations reflect to a considerable extent the history of pedogenesis during the Late Cenozoic.     

秦皇岛地区奥陶纪硅质岩地球化学特征及沉积环境意义

秦皇岛地区位于华北地台东北缘,该区奥陶系亮甲山组和马家沟组主要由细晶白云质灰岩、细晶白云岩、豹皮状灰岩、砾屑灰岩组成,灰岩中普遍含有结核状、条带状和团块状硅质岩。XRD分析显示硅质岩主要矿物成分为石英、方解石和少量白云石,硅质岩显微镜下为蠕虫状、球状、针状玉髓集合体,个别样品可见交代结构。硅质岩贫Mn、Fe,Mn/Ti...     

The ‚loess’︁ section at Borden,Kent, SE England

A 5.3m profile originally described as loess with a buried interglacial soil is reinterpreted from petrographic evidence and thermoluminescence dating as a Holocene colluvial accretionary soil. Mineralogical analyses of coarse silt (16–63 μm) fractions suggest that most of the silty colluvium was derived from weathered Thanet Beds upslope, though some loess was incorporated during the final depositional phase. Thin sections show that clay illuviation occurred penecontem-poraneously with deposition of colluvium. Thermoluminescence properties suggest partial optical bleaching of the grains during rapid deposition, which is consistent with a Holocene colluvial origin.     

陕北晋西砂黄土的胶结物与胶结作用研究

在野外调查的基础上,采用SEM、XRD、土壤物理和土壤化学等方法,对陕北晋西12个县市的48个马兰黄土样品进 行了全分散法粒度组成测定、聚集体分析以及黄土胶结物组成的测试分析。结果表明,砂黄土中的粘土矿物和超细碳酸盐、 游离氧化物和有机质等胶结物质主要是以聚集体包膜的形式存在于碎屑颗粒表面,并构成砂黄土骨架间的结构联结,具有弱 胶结特性。砂黄土中粘土矿物和有机质为非水稳性胶结物质,仅在干燥状态具有较弱的胶结作用;黄土中的CaCO3呈粗颗粒 骨架和细分散超细碳酸钙两种形式存在,并分别起着骨架作用和胶结作用,超细碳酸钙为不可逆的胶结材料,在聚集体形成、 保存以及聚集体与碎屑颗粒之间的联结方面发挥着重要作用;非晶质游离氧化物(SiO2、Fe2O3、Al2O3)含量虽低,但由于他们 是以薄膜形式分布在颗粒表面,在黄土胶结作用中也是不可忽视的,并与上述各种胶结物共同起作用。通过统计分析认为, 凝聚系数可以较好地反映黄土的胶结程度,成为联系黄土胶结特性与黄土物理力学性质之间的桥梁。黄土胶结物组成及其 胶结机理的研究不仅有助于深化砂黄土工程特性的认识,而且对揭示黄土高原表生地球化学环境具有重要意义。     

Cation exchange capacity of loess and overlying soil in the non-carbonate loess sections, North-Western Croatia

The adsorption properties in terms of cation exchange capacity and their relation to the soil and sediment constituents (clay minerals, Fe-, Mn-, and Al-oxyhydroxides, organic matter) were investigated in loess, soil-loess transition zone, and soil at four loess-soil sections in North-Western Croatia. Cation exchange capacity of the bulk samples, the samples after oxalate extraction of Fe, Mn and Al, and after removal of organic matter, as well as of the separated clay fraction, was determined using copper ethylenediamine. Cation exchange capacity (pH～7) of the bulk samples ranges from 5 to 12 cmol _c /kg in soil, from 7 to 15 cmol _c /kg in the soil-loess transition zone, and from 12 to 20 cmol _c /kg in loess. Generally, CEC values increase with depth. Oxalate extraction of Fe, Mn, and Al, and removal of organic matter cause a CEC decrease of 3–38% and 8–55%, respectively, proving a considerable influence of these constituents to the bulk CEC values. In the separated clay fraction (<2 μm) CEC values are up to several times higher relative to those in the bulk samples. The measured CEC values of the bulk samples generally correspond to the clay mineral content identified. Also, a slight increase in muscovite/illite content with depth and the vermiculite occurrence in the loess horizon are concomitant with the CEC increase in deeper horizons, irrespective of the sample pretreatment.     

Holocene soil chronoassociation in part of the Middle Gangetic Plain: morphological and micromorphological characteristics

Systematic variations in soil characteristics related to degree of soil profile development in part of the Middle Gangetic Plain suggest a soil chronoassociation similar to the soil chronosequences observed on some river terrace formed by tectonic uplift. This chronoassociation has five members QG1 to QG5, the youngest being QG1 (< 500 yr BP). Variations in degree of horizon differentiation, profile thickness, clay accumulation, plasma separation, argillan thickness, weathering stage and day mineralogy have been used to determine the degree of soil development.
Pedogenic processes active in these soils are decalcification, translocation of clay, sesquioxide and organic matter, plasma separation and weathering of minerals. The amount and variability of clay minerals are significantly related to the type and duration of pedogenesis in different parts of the area. The oldest soils with pedogenic calcite (10 000 yr BP) developed during a dry period. Since 8000 yr BP climatic conditions of higher rainfall and better drainage have prevailed in the area.
Neotectonic movements have tilted the Gandak megafan block and have caused shifting of the Gandak river to the east about 105 km from its original course, leaving behind numerous channels, ponds, lakes and other features of impeded drainage.     

The weathering of norite at Black Hill,South Australia

Black Hill is a boulder‐strewn residual of norite standing 45 m above the Murray Plains about 80 km northeast of Adelaide. Between the boulders, the crystalline rock has weathered to a dark‐brown terra rossa‐rendzina soil with calcite, illite, kaolin, and hematite as the principal secondary minerals. At one site on the smooth lower slopes of the outcrop, the material above the norite consists of partially weathered granular fragments with considerable dolomite and some calcite in nodular form. Below the surface, the rock has been weathered along joints to produce the clay mineral nontronite, and between each corestone and this plastic clay there is a zone of laminated but essentially unaltered rock 10–25 cm thick. Pieces of amorphous silica occur sporadically in some joints and on the surface.

The dark‐brown soil appears to be related to the present environment but the nontronite in the joint weathering, the dolomite, and the amorphous silica are all consistent with the norite having been inundated, possibly during the Miocene marine transgression.

Calculations based on the retention of elements such as aluminium, potassium, titanium, and iron have been used to predict quantitatively the amount of certain minerals such as quartz, calcite, and dolomite introduced to the weathering profiles.