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科尔沁沙地夺奈曼旗普通风砂土中的粘土矿物 总被引：3，自引：0，他引：3
通过对科尔沁沙地奈曼旗普通风砂土中粘土矿物的研究,结果表明这类土壤中的粘土矿物主要是伊利石,其次为高岭石,绿泥石,伊利石－蒙脱石混层矿物;它们主要来源于母质,其次来自在土过程,降尘输入量极有限。随成土过程不断进行,粘土矿物主要遵循铝硅盐矿物－绿泥石－蒙脱石－蒙脱石顺序演变。由于母质本身贫乏,成土过程较弱以及比重差异使蒙脱石有独特的搬运与沉降行为,共同造成土壤中缺乏蒙脱石。 相似文献
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基于土壤理化性质估计土壤水分特征曲线Van Genuchten模型参数 总被引：2，自引：1，他引：1
在东北黑土区采集了不同侵蚀强度黑土土样,测定其土壤水分、机械组成、有机质和容重等指标,利用Rosetta模型估计了Van Genuchten模型的参数,并将估算土壤水分与实测土壤水分对比,评价了选择不同土壤理化性质指标的模拟精度,及该方法对东北黑土的适宜性。结果表明：选择4个或6个土壤性质指标,尺度参数（α）和形状参数（n）的差异较大,采用6指标时,α增大,n减小。修正VG模型参数m与n的关系后,模型拟合精度明显提高,其中6指标的计算结果好于4指标,但拟合值偏大,需进一步较正。Rosetta模型适用于砂粒含量小于46%,粘粒含量大于28%的东北黑土。 相似文献
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贝壳砂生境典型灌草植被的土壤水分生态特征 总被引：1，自引：1，他引：0
为探讨黄河三角洲贝壳堤岛典型灌草植被的土壤蓄水及持水性能,选取贝壳砂生境的酸枣（Ziziphus jujuba var.spinosa）、杠柳（Periploca sepium）和二色补血草（Limonium bicolor）3种典型植被,以裸地作为对照,测定分析不同植被类型下的土壤颗粒组成、水分物理参数和土壤水分特征曲线,以明确贝壳砂生境不同植被类型的土壤水分生态特征。结果表明：（1）贝壳砂生境下,不同灌草植被均具有减少石砾和粗砂粒、增加细砂粒和粉黏粒含量的作用,其中酸枣林可显著减少粗砂粒、增加粉黏粒含量;杠柳林可显著减少石砾、增加细沙粒含量;草本对减少粗砂粒和石砾含量、增加细沙粒和粉黏粒含量的作用较弱。（2）灌草植被可显著提高贝壳砂的蓄水能力,其中酸枣林最强,杠柳林次之,草本最差。0~30 cm土层的有效含蓄量和含蓄降雨量均值均表现为酸枣林 > 杠柳林 > 草地 > 裸地。（3）0~30 cm的酸枣林贝壳砂持水能力最强,杠柳林次之,草本最差;同一植被类型下0~15 cm贝壳砂的持水能力显著高于15~30 cm的持水能力。贝壳砂生境3种植被类型改善土壤物理性质及蓄水保土功能表现为灌木林优于草地,其中酸枣林的蓄持水分能力最强,杠柳林次之,草本最差。酸枣更适于贝壳砂生境退化生态系统的植被恢复。 相似文献
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为探讨高寒地区生态修复用地土壤颗粒有机碳（POC）分解特征,以祁连山南坡的修复草地和修复林地为研究对象,使用离心法将土壤分为砂粒（2 000—50 μm）、粉粒（2—50 μm）和黏粒（<2 μm）,对土壤颗粒有机碳含量、土壤颗粒有机碳分配及颗粒有机碳稳定同位素组成特征进行了研究。结果表明：（1）两种修复用地均能提高颗粒有机碳的含量,新增的颗粒有机碳在修复草地中以砂粒有机碳为主体,在修复林地以粉粒和黏粒有机碳为主体。（2）3种土壤颗粒δ13C值均随粒径变小而增大,δ13C值与颗粒有机碳含量对数的回归斜率随着粒径变小而降低,修复林地叶片与表土有机碳的δ13C值分馏幅度高于修复草地,根系与表土有机碳的δ13C值分馏幅度小于修复草地。（3）修复草地砂粒、粉粒、黏粒有机碳平均周转时间分为9、20、34 a,修复林地分别为20、29、94 a,且两种修复用地的3种颗粒有机碳周转时间均有随修复年限增加而变长趋势。两种生态修复用地土壤颗粒有机碳的分解程度和周转速率均随着粒径减小而增大,从叶片转换为黏粒有机碳的过程中,修复林地周转速率较大,从根系转换成黏粒有机碳的过程中,修复草地更快。 相似文献
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不同母质发育的紫色水稻土腐殖质分布特征 总被引：2，自引：0，他引：2
研究了川中丘陵区紫色水稻土土壤腐殖质碳的剖面分布及其组成特征,探讨了土壤腐殖质与活性有机碳、土壤全氮含量的关系.结果表明:(1)表层腐殖质碳含量、HA/FA值同时受母质和水分条件的影响,冲沟上部的淹育性水稻土主要受母质的影响,而冲沟交汇处的潜育性水稻土,则主要受水分条件的影响;剖面分布上,土壤腐殖质碳含量、HA/FA总体上随土层深度的增加呈递减趋势.在水分条件的影响下,腐殖质碳含量、HA/FA值表现为淹育性水稻土＜渗育性水稻土＜潜育性水稻土.(2)腐殖质碳、HA、HA/FA值的含量与LOC呈极显著正相关关系(P＜0.01),FA与LOC呈显著的正相关关系(P＜0.05).(3)腐殖质碳、HA、HA/FA与TN呈极显著的正相关关系(P＜0.01),FA与TN呈显著的正相关关系(P＜0.05). 相似文献
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海南岛尖峰岭地区山地土壤发生特性 总被引：5，自引：0，他引：5
对地处热带的海南岛尖峰岭地区的山地土壤的发生和发育特性进行了研究。因母岩因素以及较弱的成土作用和较强的侵蚀作用 ,土壤质地普遍较粗 ,石砾含量高。由于山地气候的垂直分异 ,不同海拔高度土壤间的发生特性存在较大差异。高海拔地区土壤易风化矿物含量高 ,低海拔地区土壤中抗风化能力强的锆石含量高 ;高海拔区土壤中粘土矿物以三水铝石和埃洛石为主 ,含有一定量的铝蛭石 ,低海拔土壤以高岭石为主 ,有一定量的水云母。伴随海拔高度的增加 ,阳离子交换量 (CEC7)、盐基总量、盐基饱和度、pH下降 ,而代换性酸H 、Al3 却逐渐增多。高海拔区湿润的水分状况和酸性成土环境导致粘粒的硅铝率、硅铁铝率较低海拔土壤小。尖峰岭地区土壤类型以雏形土为主 ,山麓分布有淋溶土。 相似文献
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为探讨干旱区作物灌溉对盐碱土无机碳传输的影响,通过选择不同含盐量的土壤,即耕地土（F）、混合土（C）和原生荒漠土（D）,分别种植水稻（R）和棉花（C）,进行了一个生长季的淋溶实验,并定期收取且分析土壤淋溶液中的可溶性无机碳（DIC）含量。结果表明：（1）水稻处理无机碳的淋溶主要集中在秧苗分蘖期和幼穗发育期,而棉花处理则集中在花铃期和吐絮期;（2）不同含盐量土壤在同一灌溉量下,土壤含盐量越高,其淋溶过程得到的无机碳总量越大,最高约为8.4 g·m-2·a-1,最低仅约0.7 g·m-2·a-1;（3）同种土壤不同灌溉量,其水稻高于棉花,高出值范围为2.9～4.1 g·m-2·a-1;种植作物处理得到的无机碳总量均大于其相应对照处理的量（p＜0.05）。研究结果表明,土壤的盐含量及作物灌溉量对土壤无机碳淋溶有重要影响。 相似文献
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新疆西藏干旱区的灌耕土及其在土壤系统分类中的位置 总被引：1，自引：0，他引：1
本文应用中国土壤系统分类的原则和方法，对新疆以及西藏干旱灌溉农业区域实际存在的准耕土作一次再认识，并讨论了该土在土灌系统分类中的位置。 相似文献
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On the Vantage Peak nunatak in the Juneau Icefield of southeastern Alaska, grus and soils display evidence of extensive chemical alteration in a self-evidently periglacial environment. Accompanying the alteration of bedrock to grus and soil is a decrease in grain size. Grus is dominated by very coarse sand while the soils are predominantly fine sand. Grain-size reduction is attributed primarily to mineral grain dissolution. Total chemical analyses show that alkali earths (calcium and magnesium) and alkalis (sodium and potassium) are lost as weathering progresses, while silicon and iron increase relative to resistant elements. Secondary clay minerals present in the grus and soils appear to have been derived from clay-size primary minerals. Vermiculite is the principal secondary clay mineral and appears to have formed by the alteration of biotite. Scanning electron microscopy shows that quartz and feldspars are primarily weathered by dissolution with no evidence of feldspar transformation to secondary clays. Superimposed on these weathering transformations is evidence of eolian processes. Chemical weathering processes, notably dissolution and clay mineral transformation, do occur in the periglacial environment of the Vantage Peak nunatak and are clearly an important component of the periglacial geomorphic process suite. 相似文献
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Susquehanna River terraces are used to establish time lines along a 150 km reach of the river, from the Lower Piedmont to the edge of the Appalachian Plateau. This is achieved by generating soil chronosequences at two locations — Marietta, PA, in the Lower Piedmont, and Muncy, PA, near the glacial border on the boundary between the Valley and Ridge province and the Appalachian Plateau. These sites preserve the most complete record of fluvial incision on the Susquehanna River with flights of seven Quaternary terraces ranging in elevation from 3 m to 51 m above the modern river.Soil characteristics used to develop the soil chronosequences include complexity of horizonization, thickness of B horizon, clay content of B horizon, soil color, CBD extractable Fe, Al, and Mn, total extractable Fe, and clay mineralogy. Terrace age constraints are based on soil development, correlation to regional glacial stratigraphy, correlation to dated fluvial and glaciofluvial deposits, and by paleomagnetic analysis of sediments. Terrace ages at the Muncy site range from modern (< 150 ybp) to Middle Middle through Early Middle Pleistocene (∼ 300 ka to ∼ 770 ka). Marietta has terrace ages ranging from modern (< 150 ybp) to Early Pleistocene through Late Pliocene (∼ 770 ka to ∼ 2400 ka). 相似文献
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土地利用方式对土壤有机碳和团聚体组分特征的影响 总被引：4，自引：0，他引：4
以广东省内第四纪红色黏土、玄武岩和花岗岩母质发育的土壤为研究对象,采集不同土地利用方式（水田、旱地、林地、果园/草地）下表层（0~15 cm）和亚表层（15~30 cm）土壤,研究土壤有机碳及其组分（腐殖质碳、易氧化有机碳）、土壤团聚体及其稳定性,分析土壤有机碳及其组分与土壤团聚体及其稳定性之间的相互关系。结果表明：土地利用类型、成土母质等影响土壤有机碳及其组分。3种母质发育的土壤中,各腐殖质组分占有机碳的比例是胡敏酸碳（HAC）＜富里酸碳（FAC）＜胡敏素碳（HMC）,第四纪红色黏土母质发育土壤腐殖酸碳（HAC＋FAC）以草地最高、水田最低;玄武岩、花岗岩母质发育土壤腐殖酸碳以果园最高。土壤中易氧化有机碳所占比例均高于惰性态,第四纪红色黏土母质发育土壤易氧化有机碳占有机碳比例以草地最高、旱地最低;玄武岩、花岗岩为果园最高、林地最低。3种母质发育土壤团聚体（湿筛）主要以＜0.25 mm微团聚体为主,表层土壤＞0.25 mm团聚体所占比例、团聚体平均重量直径（MWD）、团聚体破坏率（PAD）大于亚表层。土壤有机碳各组分均随着有机碳质量分数的增加而增加,＞0.25 mm团聚体质量分数和团聚体MWD随着土壤有机碳及其组分质量分数的增加而增大;PAD随着土壤易氧化碳组分质量分数增加而降低,易氧化有机碳组分有利于土壤中形成较大的团聚体,并增加团聚体水稳性。 相似文献
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西南地区水耕人为土诊断层土壤特性及SEM特征 总被引：3，自引：0，他引：3
对我国西南地区代表性水耕人为土诊断层土壤特性进行研究,并采用扫描电镜(SEM)进行土壤微形态研究,结果表明:不同母质和发育程度的水耕人为土,在土壤特性及在剖面上的变化特征都有明显差别.通过SEM观察研究表明:粗、细颗粒物质形态与矿物组成密切相关,如以薄片状、针条状等细粒物质为主的土壤,在水耕条件和外力作用下,易于定向、粘结聚合而引起土壤压实和板结.水耕人为土的微团聚体含量少而分散,对肥力的贡献有限.长期培肥的水耕人为土能够形成丰富的各类微孔隙和微结构类型,是调节土壤水、热、气和养分状况的主要机制. 相似文献
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Weathering, mineralogical evolution and soil organic matter along a Holocene soil toposequence developed on carbonate-rich materials 总被引：2，自引：0，他引：2
Markus Egli Christian Merkli Giacomo Sartori Aldo Mirabella Michael Pltze 《Geomorphology》2008,97(3-4):675-696
A toposequence of Holocene soils located between 1100–2400 m asl in the Italian Alps served as the basis for the following analyses: the weathering of limestone and dolomite, the calculation of mass balances, understanding the formation of pedogenic Fe and Al, the determination of soil mineral and clay mineral reactions and transformation and the measurement of accumulation and stabilisation mechanisms of soil organic matter. Leaching of carbonates is most intense at the lower elevations, although calcite and dolomite have a higher solubility at low temperatures. The pCO2 in the soil is higher at lower elevations and weathering is driven mainly by carbonic acids. At higher elevations, organic acids appear to determine the mineral transformations and weathering reactions to a greater extent. This suggests that two very different weathering regimes (carbonic and organic acid weathering) exist along the toposequence. The transformation of mica into vermiculite is the main process in both the clay and fine-earth fraction. Weathering of silicate minerals started even before the carbonates had been completely removed from the soils. The transformation mechanisms of silicate minerals in the A and O horizon at higher elevations was at least as intensive as that at the climatically warmer sites. The neoformation of pedogenetic clays at climatically cooler sites was slightly greater than that at the warmer sites. However, the formation rate of secondary Fe and Al phases was more pronounced at lower elevation, which means that this process seemed to be driven dominantly by carbonic acid (weathering of primary minerals). Soil organic matter (SOM) abundance in the mineral soil is nearly 15 kg/m2 at all sites and, surprisingly, no climate-driven effect could be detected. In general, the preservation and stabilisation of SOM was due to poorly crystalline Al and Fe phases and vermiculite, regardless of some variations in the composition of the parent material (varying calcite/dolomite ratio). 相似文献
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《自然地理学》2013,34(5):407-422
High-intensity forest fires can degrade, collapse, or completely destroy clay minerals in soils, with signatures of these changes remaining for years after the burns. To ascertain immediate impacts of high-intensity fire on soil clay minerals and mineral recovery over time, soil from the 2002 Hayman, Colorado, fire was analyzed by X-ray diffraction. Sample locations included burned soil from within the perimeter of the fire, unburned soil near the origin, and soil from adjacent historic burns. The unburned soils contain mixtures of illite, mixed-layer illite/smectite and illite/vermiculite, kaolin, and mixed-layer chlorite. Surface soils (surface-7.7 cm) contain illite, mixed-layer illite/smectite, and kaolin. Sub-surface soils (7.7-13.0 cm) contain mixed-layer illite/vermiculite, in addition to the same minerals found at the surface. Deep soils (13.0-27.0 cm) show disappearance of mixed-layer illite/smectite and illite/vermiculite and show evidence of the presence of mixed-layer chlorite. Comparisons between recently and historically burned soils and unburned soils showed slight trends in alterations of clay mineral structures in the surface soil, including alteration of the 001 illite peak, the 001 kaolin peak, and a decrease in the swelling component of mixed-layer illite/smectite. These trends indicate fire impacts the structure of soil clay minerals. 相似文献