湘北地区典型水稻土的发生特性及其在中国土壤系统分类中的归属

选取湘北地区7个发育于2种母质的水稻土剖面样点,通过对其成土环境、剖面形态特征以及土壤理化性质进行野外观测和室内分析,按中国土壤系统分类方案,检索出诊断层和诊断特性,确定其在中国土壤系统分类中的归属,并评述土系的生产性能。结果表明:供试水稻土归属于水耕人为土亚纲下的简育和铁聚水耕人为土2个土类,底潜简育水耕人为土、普通简育水耕人为土、普通铁聚水耕人为土、漂白铁聚水耕人为土4个亚类;进一步按照土族和土系划分标准,划分出7个土族和7个土系。在相同成土环境下,同种母质发育的水耕人为土,土壤系统分类比土壤发生分类具有更强的划分能力。其划分的基层土壤单元(土族和土系),对农业生产、土地资源利用更具有指导意义。     

母质对南方丘陵区水耕人为土理化性质演变的影响

基于时间序列系统分析了我国南方丘陵区三种母质起源的水耕人为土理化性质的演变,结果表明:成土母质可以决定黏粒与土壤有机碳(SOC)对人为水耕成土过程的敏感性,明显影响其演变特征。游离铁(Fed)对人为水耕的成土过程非常敏感,其迁移与转化主要受人为水耕成土过程影响,受成土母质影响很小;硅酸盐铁(Fet-Fed)对人为水耕的成土过程不敏感,但全铁(Fet)含量的分布主要受Fed的影响。黏粒的淋失会对土壤中元素的迁移与分布产生重要影响,造成SiO2相对富集和Al2O3相对亏损,在利用由Al和Si两种元素计算所得到的一些指标指示丘陵区水耕人为土的发育程度时一定要慎重;而TiO2在水耕人为土发育过程中相对稳定,可以作为稳定元素来指示水耕人为土演变过程中其他元素的迁移率。     

南方丘陵区不同母质水耕人为土发育速率的比较

如何度量水耕人为土的发育程度和发育速率是土壤发生学的一个难题。选择南方丘陵区3种常见母质(紫色砂页岩类坡积物PS、第四纪红黏土RC和红砂岩类坡积物RS)发育的水耕人为土时间序列作为研究对象,尝试利用属性距离和土壤发育指数来表征水耕人为土的发育程度,揭示母质对水耕人为土发育速率的影响。结果表明,水耕人为土剖面形态特征经定量后和属性距离一样能够表征水耕人为土发育的时间趋势,在指示水耕人为土的发育程度和估算发育速率上有重要意义。有机碳(SOC)、pH、黏粒含量和磁化率(MS)在计算发生层距离(HD)中贡献很大,而土壤颜色和湿结持性在计算发生层指数(HI)中起着重要作用。RC母质的土壤,土层较厚,颜色红,黏粒含量较高,保肥和保水状况好,土粒的黏结性和可塑性较好,SOC容易累积,发育速率最快。PS母质的土壤,土层较厚,细颗粒(黏粒+细粉粒,0.01mm)含量高,保肥和保水状况好,土粒有一定的黏结性和可塑性,SOC容易累积,发育速率次之。RS母质的土壤,黏粒和细颗粒含量均很低,土层薄,保肥和保水状况以及黏结性和可塑性差,SOC很难累积,发育速率最慢。母质对水耕人为土发育过程的影响可以通过影响其发育速率表现出来。研究同时显示,水耕人为土平均发育速率远较自然土壤快,并在人为培育下快速定向发育。但随着种稻年限的增加,水耕人为土的发育速率普遍下降,水耕人为土发育速率和成土年龄的关系大致符合对数关系。这种定量方法可以提高对水耕人为土形成过程的理解并能实现不同地区水耕人为发育速率的定量比较,有较好的使用前景。但此方法仍处于试验探讨阶段,有待更多的研究来验证和改进。     

重庆市更新统沉积物发育土壤的特性及分类

选取重庆市境内分别由夹卵石黄色黏土(PC)、黄色黏土(YC)、红色黏土(RC)等更新统沉积物发育的6个典型旱地和水田土壤剖面为研究对象,探讨其土壤特性及系统分类归属。结果表明,PC发育的旱地土壤富含砾石且无铁锰斑纹,YC发育的旱地土壤不含砾石但有铁锰斑纹,RC发育的旱地土壤耕作层以下黏粒淀积明显。在PC和YC发育的水田土体内,上部土层的有机质累积明显且彩度较下部低,游离铁在下部土层有明显聚积,而母质为RC的水田土体内游离铁则迁移不明显。3个旱地土壤分别被划归为普通简育湿润雏形土、普通铁质湿润雏形土和红色铁质湿润淋溶土3个亚类,3个水田土壤则分别被划归为普通铁聚水耕人为土和普通简育水耕人为土2个亚类,共可建立6个土族和6个土系。YC发育的普通铁质湿润雏形土有铁锰斑纹存在,这是古水文条件的反映,现已完全脱离地下水的影响,故不再具有潮湿土壤水分状况;沉积物特征、区域气候等会影响旱地土体内黏粒的淋溶淀积,进而影响其土纲划分;水耕活动使更新统沉积物发育的雏形土和淋溶土演变为水耕人为土;地块筛选、坡改梯、拣拾等人为活动会显著减少PC发育的水田土体内砾石含量,影响其土族控制层段的颗粒大小级别判定。     

闽北地区水耕人为土的发生与系统分类研究

水耕人为土是在水耕条件下形成的具有人为诊断层的独特土壤类型。对采自福建省北部的13个水耕人为土典型剖面进行了土壤形成条件调查和土壤理化性状鉴定,明确了其发生学特性,并依据《中国土壤系统分类检索(第三版)》,鉴定了其诊断层和诊断特性,确定了研究土壤剖面在中国土壤系统分类中的归属。鉴定出的诊断层主要有水耕表层、水耕氧化还原层、漂白层、黏化层;诊断特性主要有人为滞水土壤水分状况、潜育特征、盐积现象、氧化还原特性。13个剖面可分别归属为弱盐潜育水耕人为土、普通潜育水耕人为土、漂白铁聚水耕人为土、普通铁聚水耕人为土、普通简育水耕人为土5个亚类。     

广西水耕人为土黏粒矿物组成及其空间分布特征

黏粒矿物影响着土壤理化性质，可指示成土因素特征和土壤发生发育过程/强度，也是中国土壤系统分类的基层单元土族矿物学类型划分的重要依据。本研究选择了广西不同纬度和成土母质的18个代表性水耕人为土的剖面，应用X射线衍射（XRD）方法分析了其典型水耕氧化还原层（Br层）的黏粒矿物组成及其空间分布特征，并确定了其中“黏质”剖面的土族控制层段矿物学类型。结果表明：（1）供试土壤的黏粒矿物主要包括高岭石、伊利石、三水铝石、1.42 nm过渡矿物、蒙脱石和蛭石等，依次分别出现在100%、88.9%、72.2%、61.1%、44.4%和38.9%的剖面中。（2）黏粒矿物组成在纬度空间分布上具有明显规律性特征。随着纬度降低，土壤黏粒中的高岭石增加，伊利石、蒙脱石、1.42nm过渡矿物逐渐减少；纬度＞23°N区域内，成土母质对黏粒矿物组成影响明显。（3）纬度23°N是黏粒矿物组成和土族矿物学类型分界线，＜23°N区域，黏粒矿物均以高岭石为主，是“黏质”剖面的土族控制层段的主要矿物学类型；＞23°N区域，黏粒矿物组成以高岭石、蒙脱石、伊利石或1.42 nm过渡矿物为主，因成土母质不同而异，“黏质”剖面的土族控制层段矿物学类型包括高岭石混合型、混合型和伊利石型。     

辽宁省白浆化土壤中白土层的特征及其形成

本文以辽宁省浑河在不同历史时期形成的阶地上的黄土状物质发育的土壤为研究对象,通过对剖面形态学特征、基本理化性质和母质均一性判定等研究,探讨了浑河三级阶地白浆化土壤的白土层特征及其形成机制。结果显示:(1)土壤粉粒中的稳定元素钛与锆分析结果表明在三级阶地上的21-003、21-009、07和21-076剖面和二级阶地上的21-001、21-200、03和04剖面的母质均一;(2)由于土体发育程度不同,一级阶地土体中无淀积层;二级阶地土体中有淀积层且无白土层,尚未出现白浆化现象;三级阶地土体中淀积层和白浆化现象明显,出现了白土层,其形成以黏粒的机械淋溶和潴育淋溶为主;三级阶地上土壤比二级阶地和一级阶地发育时间长,但尚未达到漂白层的标准。     

西南山区采煤塌陷对水田土壤物理性质的影响

为探讨西南山区采煤塌陷对水田土壤物理性质的影响及受损水田复垦途径,通过野外试验与室内测定方法分析了水田受损前后土壤物理性质的变化,结果表明:1)0~40 cm受损水田土壤容重显著增加,含水率、孔隙度(0~20 cm旱地1、2除外)显著下降;0~60 cm土壤垂直剖面除含水量干化趋同外,构型及演替规律未发生变化;2)水田受损后黏粒含量与成土母质密切相关:0~20 cm土层中0.005 mm黏粒含量高低呈现旱地3(泥页岩风化物)旱地1(泥页岩+灰岩风化物)旱地2(泥页岩+灰岩+砂岩风化物)变化,水耕历史较长、受损漏失严重的水田土壤黏粒(0.005 mm)质量分数均值分布自上而下累积增加;3)试验点土壤剖面构型、成土母质是造成渗透流量和渗透速度随累计时间增加呈减小趋势和波动与趋稳现象的主要原因,采煤塌陷并未对土壤包气带层渗水性产生严重影响;4)根据试验数据分析结果,研究区受损水田复垦可优先选择泥页岩、灰岩风化物沉积区、水耕历史较长、渗透系数小于3 m/d的沟谷区进行。该研究可为研究区采煤塌陷对水田土壤物理性质的影响提供系统诊断依据,并为受损水田复垦提供有效途径。     

南方丘陵区三种母质水耕人为土有机碳的累积特征与影响因素分析

本研究分析了南方丘陵区3种母质水耕人为土有机碳的累积特征与影响因素。结果表明：紫色砂页岩和第四纪红黏土母质的水耕人为土在发育过程中有机碳较易累积,在种稻初期土壤有机碳的增加主要集中在耕作层,到一定阶段后下层(耕作层以下)也明显增加;相比之下,红砂岩母质的水耕人为土在发育过程中有机碳较难累积。利用逐步回归方法得到的丘陵区水耕人为土耕作层有机碳动态变化模型表明丘陵区水耕人为土有机碳的动态变化主要受细颗粒(黏粒+细粉粒)的影响。     

新疆米泉的灌淤亚类水耕人为土

新疆米泉地区起源于原灰漠土或灌耕土的水稻土，成土过程中水耕熟化和灌淤、淋溶与淀积并行，形成独特的灌淤－水耕表层（耕作层＋犁底层）和灌淤－水耕氧化还原层，总厚度〉５０ｃｍ。基于研究，将供试土壤划分为铁聚水耕人为土和铁渗水耕人为土两个土类，并建议在水耕人为土系统分类中增设灌淤亚类。     

我国北亚热带白浆化土壤矿物学特性的研究

本文对北亚热带地区七个白浆化土壤的原生矿物和次生矿物的特性进行了研究。重，轻矿物含量表明土壤继承了母质的特性，粘淀层与漂白层的母质沉积是间断的，前者风化强度大于后者。石英颗粒表现特征显示漂白层物来来源于黄土物质再堆积，粘土矿物以水云母为主，其结晶度较差，氧化铁类型以针铁矿和赤铁矿为主，也有非晶质氧化铁和硅酸盐中的Ｆｅ＾２＋，其形成条件与现代化成土条件一致。     

重庆市潜育水稻土发育特性和系统分类研究

以重庆市境内7个发生分类的潜育水稻土典型剖面作为研究对象,通过剖面形态特征观测和理化性质测定分析,探讨其发育特性和在中国土壤系统分类(CST)中的归属。结果表明,7个供试剖面主要位于丘陵山地下坡、坡麓以及江河沿岸一级阶地,质地多为粉壤土或粉质黏壤土,不同土壤剖面中游离铁分布有较大差异,潜育特征受到人为滞水和地下水的影响,主要出现在耕作表层和受地下水位影响的深度范围内。依据CST,7个典型剖面均具有水耕表层、人为滞水土壤水分状况、潜育特征和氧化还原特征,但1个剖面虽有水耕表层但无水耕氧化还原层而隶属潜育土土纲中的石灰简育正常潜育土亚类;其余6个剖面具有水耕表层和水耕氧化还原层而分别隶属于水耕人为土亚纲中的复钙潜育水耕人为土、铁聚潜育水耕人为土和普通潜育水耕人为土亚类,依据土族和土系划分标准,建立了5个土族和7个土系。值得注意的是,目前CST中简育正常潜育土尚没有反映人为水耕活动影响(即水耕现象)的亚类,因此可以考虑新增水耕简育正常潜育土亚类。     

Genesis of a Xeralf on feldspathic sandstone, South Australia

A Xeralf on feldspathic sandstone was sampled from a hillslope in the Mount Lofty Ranges in order to study its genesis and, in particular, the origin of the strong texture contrast. Micromorphological study demonstrated that the clay present in void argillans and papules in the B2 horizon accounted for only a small amount of the clay present. Elemental analysis of the whole soil (< 2 mm) and sand, silt and clay fractions showed that there had been considerable weathering of both quartz and microcline, which were the dominant minerals present. Kaolinite is the dominant clay mineral weathering product. Illite appears to be forming from vermiculite in the A horizon. Using zircon as an internal standard, it was shown that elemental losses of SiO₂ and reductions in weight and volume were similar in A and B horizons. Losses of aluminium and potassium were greatest in the A horizon, least in the B3. There has been an absolute increase in the amount of iron. A possible source is iron from heavy mineral bands upslope. It was concluded from the similarity of the quartz particle-size distributions of the A2, B2 and B3 horizons that the intensity of weathering of quartz was the same in A and B horizons. In the case of feldspar (mostly microcline), there is a greater proportion of feldspar in the fine sand and silt fractions of the A2 horizon than in the B horizon. Weathering of feldspar is greatest in the A horizon. The texture profile is principally a function of greater lateral loss of clay from the A horizons compared to the B horizons.     

长江三角洲水稻土主要土种在中国土壤系统分类中的归属

本文概述了长江三角洲水稻土的形成背景,说明了我国水稻土与水耕人为土分类上的区别.在此基础上,将长江三角洲水稻土主要土种按中国土壤系统分类的严格定量指标,分别阐明其在系统分类中的归属.     

江淮流域白浆化土壤的矿物组成与化学特性的研究

对采自江淮流域的7个典型白浆化工土壤剖面不同粒级的矿物特性与化学组成进行了研究。结果表明：该区域白浆化土壤的质地为粉砂质壤土及粘壤土，粉粒含量为45%～76%。粘粒矿物以水云母为主，含量为60%～80%，继承了黄土母质的特性，土体硅铝率（Sa)与硅铁铝率（Saf）分别为7.70～14.05与6.43～10.24，而粘粒的分别为3.53～4.22和2.40～3.35。各剖面土体Sa与Saf以表层较高或最高，有明显富硅现象；而粘粒的Sa和Saf及矿物组成，颗粒组成的层次差异则表现出母质层次上的不连续性，白土层与粘化层的显著分异是由于全新世黄土性沉积物，经过冲积淤积交替更迭，加上后期淋溶淀积而成；脱硅、脱盐基和富铝化及氧化还原淋溶淀积是其重要成土过程，后一过程不同的利用方式，强度有所差别，以水稻土较强。     

Podzolization as a deferralitization process: a study of an Acrisol–Podzol sequence derived from Palaeozoic sandstones in the northern upper Amazon Basin

Morphological, geochemical and mineralogical studies were carried out in a representative soil catena of the low‐elevation plateaux of the upper Amazon Basin to interpret the steps and mechanisms involved in the podzolization of low‐activity clay soils. The soils are derived from Palaeozoic sandstones. They consist of Hydromorphic Podzols under tree savannah in the depressions of the plateaux and predominantly of Acrisols covered by evergreen forest elsewhere. Incipient podzolization in the uppermost Acrisols is related to the formation of organic‐rich A and Bhs horizons slightly depleted in fine‐size particles by both mechanical particle transfer and weathering. Weathering of secondary minerals by organic acids and formation of organo‐metallic complexes act simultaneously over short distances. Their vertical transfer is limited. Selective dissolution of aluminous goethite, then gibbsite and finally kaolinite favour the preferential cheluviation of first Fe and secondly Al. The relatively small amount of organo‐metallic complexes produced is related to the quartzitic parent materials, and the predominance of Al over Fe in the spodic horizons is due to the importance of gibbsite in these low‐activity clay soils. Morphologically well‐expressed podzols occur in strongly iron‐depleted topsoils of the depression. Mechanical transfer and weathering of gibbsite and kaolinite by organic acids is enhanced and leads to residual accumulation of sands. Organo‐metallic complexes are translocated in strongly permeable sandy horizons and impregnate at depth the macro‐voids of embedded soil and saprolite materials to form the spodic Bs and 2BCs horizons. Mechanical transfer of black particulate organic compounds devoid of metals has occurred later within the sandy horizons of the podzols. Their vertical transfer has formed well‐differentiated A and Bh horizons. Their lateral removal by groundwater favours the development of an albic E horizon. In an open and waterlogged environment, the general trend is therefore towards the removal of all the metals that have initially accumulated as a response to the ferralitization process and have temporarily been sequestrated in organic complexes in previous stages of soil podzolization.     

不同改土物料对白浆土磷吸附解吸的影响

向白浆土各层次土壤施入不同改土物料,比较不同处理土壤对 P 的吸附解吸情况.结果表明:各土层土壤对 P的吸附量均随着平衡液浓度的增加而增加;不同土层间土壤吸附 P 量大小顺序为淀积层＞混拌层＞白浆层＞黑土层;随着平衡液浓度的增大,P 吸附的增加率递减;施 Ca 加大了土壤对 P 的吸附,其中黑土层增加220.16%,白浆层增加54.50%,淀积层增加 52.36%;而施有机肥减弱了土壤对 P 的吸附,其中黑土层降低70.16%,白浆层降低45.50%,淀积层降低55.27%.Ca 有降低土壤 P 解吸率的趋势,有机肥能大幅度地提高其解吸率.     

Soil altitudinal sequence on base-poor parent material in a montane cloud forest in Sierra Juárez, Southern Mexico

The soils of montane cloud forests (MCF) are still insufficiently studied. A number of researchers report Podzols to be the main soil group for MCF ecosystems; however, a great deal of contradictory data exists. We studied an altitudinal sequence of soils formed on ferrous chlorite shale under natural MCF vegetation in Sierra Juárez, Southern Mexico, from 1500 to 2500 m asl. The soils of the upper part of the toposequence were Folic Stagnic Podzols, with inclusions of Folic Stagnosols in local depressions, while the soils of the lower part of the toposequence were Folic Cambisols (Humic, Hyperdystric). All the soils in the toposequence were extremely acid, and had thick organic surface horizon. Mineral horizons of all soils were poor both in exchangeable and total reserves of bases; the bases were concentrated mainly in organic topsoil. With decreasing altitude both the thickness of albic horizons, the depth of the maximum acid oxalate-extractable Fe and Al concentrations, and the difference in clay content between the eluvial and illuvial horizons decreased. In the upper part of the toposequence the composition of soil clays was similar to that of parent material (chlorite and mica), with some mixed-layered 2:1 minerals. However, gibbsite and kaolinite were also present in the soils of the other site within the same upper MCF belt. The phenomenon was ascribed to parent material heterogenity. In the medium and lower parts of the toposequence gibbsite and kaolinite were the dominant minerals. We consider that the main pedogenic processes in the study area are raw humus accumulation, weathering in situ, podzolization, and iron reduction due to water stagnation in mineral topsoil. The intensity of weathering decreases, while the extent of water stagnation increases with altitude. To a great extent the genesis and altitudinal distribution of the soils in the MCF depends on parent material.     

Particle size and free iron oxide distribution in some latosols and groundwater laterites of Ghana

The distribution of particle size and Na-dithionite-extractable (di-Fe₂ O₃) and NH₄-oxalate-extractable (ox-Fe₂O₃) iron oxides were investigated in twelve soil profiles representing latosols and groundwater laterites. Soil profiles studied were selected from the major ecological zones of Ghana. The pattern of distribution of free Fe₂O₃ was closely related to that of clay (< 2μ) in soil profiles of the humid forest zones where clay content was more than 40% in the B horizons. In soil profiles of the relatively dry savannah zones with less than 40% clay in the B horizon, the pattern of distribution of free Fe₂O₃ was closely related to that of silt (2–20 μ). The amount of free Fe₂O₃ in the soils appeared to be related to kind of parent rock or parent material and to climatic factors operating in the various ecological zones. Using the amount of di-Fe₂O₃ in the B horizon as a basis for assessing the relative degrees of pedogenesis in soil profiles developed from the same kind of parent material, it was concluded that soil profile development had progressed most in the rain forest zone. Free Fe₂O₃ was considered as having reached an advanced stage of crystallinity or aging in most of the soils because of the low ox-Fe₂O₃/di-Fe₂O₃ ratios in the solums of most of the soil profiles. Soils studied were placed in the ferrallitic and ferruginous soil classes of D'Hoore. The great soil groups could not be characterized by depth function curves of free Fe₂O₃. However, it was proposed that the relative amounts of di-Fe₂O₃ in the B horizons of the soil profiles could be used as a basis for classifying these soils at the family level.