Origins of humus variation

Humus samples derived from peat, moss or ornithogenic sources in the Antarctic continent have been examined by ¹³C nuclear magnetic resonance techniques. The ¹³C spectra show that the humus has undergone very little chemical modification. A fulvic acid fraction from a moss derived soil is almost entirely α- and β-glucose. The results also show that lignin is not a necessary precursor for aromatic components in soils. It is suggested that the aromaticity and carbohydrate content of certain soils is governed by the low temperature which influences the degree of humification.     

Composition,properties and radiocarbon age of humus in paleosols

The paper presents methods for the study of the organic matter content (OM) of Pleistocene and Holocene paleosols. Paleosols of various age from the Russian Plain and Western Siberia were studied for their humus composition and physico-chemical properties. The permanent features of humus in paleosols useful for paleogeographical reconstruction and geoecological monitoring are separated from those criteria which are typical of the natural evolution of OM on the geological timescale.     

A statistical model of proton binding by humus

A model that considers both the carboxyl and weakly acidic groups of humus as continuous binding site distributions in which individual ligand concentrations are normally distributed with respect to the log $\text{K}$ values for proton binding is proposed. The concentration, mean log $\text{K}$ value, and variance for the log $\text{K}$ distribution of each class of functional groups are estimated by nonlinear regression analysis of titration data. The values obtained for those parameters are chemically reasonable and the extent of proton binding between pH 4.0 and pH 10.8 is accurately described by the model.     

Biogeochemical anomalies in fennoscandia: A study of copper, lead and nickel levels in Melandrium dioicum and Viscaria alpina

Herbarium specimens (over 700) of Melandrium dioicum and Viscaria alpina from throughout Fennoscandia were analysed for their Cu, Pb and Ni content. About 80 specimens had anomalous levels of one or more of these elements as determined by cumulative frequency plots. Inspection of collection localities of plants with anomalous heavy metal levels showed that some of the main copper mining districts of Norway and Sweden had been identified as well as several major ultrabasic regions of Fennoscandia. Although over half of the observed anomalies could be explained from previous knowledge of nearby sulphide mineralization, it is suggested that the more promising of the remainder are worthy of follow-up investigations.     

Dispersal of tungsten in glacial drift and humus in Bergslagen, southern central Sweden

Since the late part of the 19th century prospecting for W in the western world has been based mainly on the mechanical concentration of heavy minerals in sediments (panning), followed by visual and chemical analyses of the heavy-mineral fraction. Since the early 1970's, W prospecting in Sweden has been based on the use of heavy-mineral concentrates from till.In tests performed in a scheelite-mineralized area in the Bergslagen area of central Sweden, samples from the A- and C-horizon of the podzolic profile have been collected along grid lines across the ore as well as down-ice along the direction of final glacial transport from the ore. The purpose of the study was to test which sample types should be used in geochemical prospecting for W in the region.The results show that all the sample types studied can be used in geochemical prospecting for W in southern central Sweden. The heavy-mineral concentrate of till is primarily recommended for use at a regional and local scale. Humus is given the lowest priority of the sample types studied because of the poor analytical reproducibility for some samples with high values of W.     

Formation of organic substances of humus nature and their biospheric properties

Hypotheses of humus formation on the basis of polymerization and oxidation reactions were considered. The most popular models of several authors and the general understanding of the structural features of natural polymers were analyzed. Multivariate statistical analysis was performed for zonal factors affecting the formation of humic substances. Evolutionary changes in the understanding of the biospheric functions of humus substances were evaluated. Statistical procedures were proposed for the prediction of the physicochemical behavior of humus substances in environments.     

Major and transition trace element abundances in the khondalite suite of the granulite belt of lapland (fennoscandia): Evidence for an early proterozoic flysch belt

The Granulite belt of Lapland comprises two main units. The more extensive unit, the khondalite suite, is formed of approximately equal proportions of sillimanite-garnet gneisses and garnet gneisses which include impersistent layers of quartz-rich gneisses, calc-silicate rocks and metavolcanics. The less extensive unit, the charnockite complex, corresponds to several tholeiitic and calc-alkaline series, each of them ranging from gabbro to tonalite.An attempt has been made to elucidate the primary features of the khondalite suite and its depositional environment. Major and transition trace element variations suggest that it has an overall sedimentary parentage and that it corresponded to a graywackeshale sequence (turbidites). Original clastic sediments were mainly derived from an eroded continental crust and, in lesser amount, from contemporary volcanism. The geochemical trends for alkalies seem to indicate that this crust was relatively silicic and that it had undergone previous granite-forming events.Taking into consideration the geological setting, the geometry, and the facies of these sedimentary formations, we propose to reinterpret the granulite belt of Lapland as a flysch belt located at a plate junction and pre-dating a continent-continent collision with subducted oceanic crust.     

Determination of support in soil sampling

Short-range variation of measurements of a soil characteristic is a function of the support (i.e., size, shape, and orientation of the physical sample taken at a sample point) of the soil samples. This short-range variance often shows up as a substantial component of the nugget effect in experimental semivariograms or estimated generalized covariance functions. Proper choice of support may substantially reduce short-range variance (or nugget) of measurements made at sample points and thereby reduce estimation variance in point or block kriging based on these measurements. Appropriate variance formulas and an example are given for determination of support when support is an array of vertical cores (or bucket auger samples) of equal depth and diameter.     

Multivariate oceanographic sampling

Increasing attention in recent years has been devoted to the application of statistical techniques in the analysis and interpretation of geologic and oceanographic data. Equally important, but less well explored, are methods for efficient experimental design. The theory of linear programming provides plans for optimal sampling of geologic and oceanographic phenomena. Of particular significance are solutions to problems of multivariate sampling. Often, a single field sample may be analyzed for a number of oxides, or a number of minerals, or a number of textural parameters. In general, these variables differ in the degree to which they are diagnostic of changes in the phenomenon of interest, and thus they must be known with different levels of precision if they are to be useful. Similarly, the variables differ in the ease with which they may be measured. If a sampling plan is to be most efficient, it must provide the requisite levels of precision for the minimum expenditure of time and effort. Sampling for a single variable may be optimized directly. Sampling for several variables simultaneously usually introduces special difficulties, but if the objective function can be generalized to hold for all variables, solutions can be determined even in this situation.     

Estimation of non-ergodic variograms and their sampling variance by design-based sampling strategies

Design-based sampling strategies based on classical sampling theory offer unprecedented potentials for estimation of non-ergodic variograms. Unbiased and uncorrelated estimates of the semivariance at the selected lags and of its sampling variance can be simply obtained. These estimates are robust against deviations from an assumed spatial autocorrelation model. The same holds for the variogram model parameters and their sampling (co)variances. Moreover, an objective measure for lack of fit of the fitted model can simply be derived. The estimators for two basic sampling designs, simple random sampling and stratified simple random sampling of pairs of points, are presented. The first has been tested in real world for estimating the non-ergodic variograms of three soil properties. The parameters of variogram models and their sampling (co)variances were estimated with 72 pairs of points distributed over six lags.     

Effects of humus on the environmental activity of mineral-bound Hg: Influence on Hg volatility

The effects of three humus fractions (fulvic acid, brown humic acid and grey humic acid) on the volatility of five types of mineral-bound Hg were investigated. Fulvic acid was found to strongly promote the volatilization of Hg bound by Fe₂O₃, MnO₂ and kaolinite, but suppressed the volatilization of Hg bound by bentonite and CaCO₃. Brown humic acid was found to enhance the volatilization of Hg bound from all the tested minerals, except for Fe₂O₃. Grey humic acid had the weakest effect in promoting or suppressing Hg volatilization. The influence of the various humus fractions on the volatilization of mineral-bound Hg is closely related to the complexing capacity and complex stability of the particular humus material. The higher the complexing capacity and the lower the complex stability, the more prominent is the humus material in promoting Hg volatility. The Hg sorption capacity and sorption strength of the minerals, as well as their Hg speciation characteristics, limit the effect that humus has to volatilize Hg.     

石灰土发育过程中土壤腐殖质组成及其与土壤钙赋存形态关系

选取桂林典型石灰土不同发育阶段土样(黑色石灰土、棕色石灰土、黄色石灰土),对土壤中腐殖质组成、土壤钙的形态及其含量进行测定。结果显示:(1)石灰土发育过程中,黑色石灰土、棕色石灰土、黄色石灰土总碳量分别为230.15mg/g、37.49mg/g、17.94mg/g,胡敏酸所占比例分别为31.94%、9.44%、7.25%,富啡酸所占比例为1.04%、36.14%、66.16%,胡敏素为67.02%、54.41%、26.59%;(2)黑色石灰土、棕色石灰土、黄色石灰土中土壤钙全量分别为21486.66mg/kg、6913.33mg/kg、5540.17mg/kg,且三种土壤中均是酸溶态所占比例最高,分别为57.58%、74.69%、80.83%,其次为可还原态、残渣态和可氧化态;(3)相关性分析表明,土壤钙及其各形态均与土壤有机碳总量、胡敏酸、胡敏素成正相关关系,与富啡酸成负相关关系,土壤腐殖质组成及其含量在很大程度上影响着土壤钙含量及赋存形态。      

桂林毛村岩溶区自然植被土壤团聚体中腐殖质组成初步研究

探索土壤有机碳物理保护与化学保护的关系,有助于揭示土壤固碳和培肥机理,明确不同粒级团聚体和不同腐殖物质组分对土壤固碳和肥力的贡献。本研究对岩溶区自然植被土壤团聚体中腐殖质含量进行了研究,结果表明:(1)灌丛和林地土壤团聚体中有机碳含量总体上均表现为随着土层深度的增加逐渐下降,而在不同土层深度随着团聚体粒径范围的变化则有机碳含量的变化规律则不同,无明显一致的规律;(2)两种土地利用方式各粒径团聚体中胡敏酸和富里酸均比全土小。这可能是由于在湿筛分离团聚体的过程中溶于水的那部分胡敏酸和富里酸成分被损失掉;(3)各腐殖质组分随着团聚体粒径范围的减小在两种自然植被上均无明显一致的规律,但胡敏酸和富里酸总量则基本表现为随着团聚体粒径范围的减小而逐渐升高,即在0.25mm和0.5~0.25mm粒径范围团聚体中最大;(4)两种自然植被土壤各土层中和各团聚体中胡敏酸/富里酸(HA/FA)基本上表现为小于1,这主要是因为研究区温度相对较高,湿度较大,植被覆盖度大,微生物降解作用强所致。     

Numerical analysis of sampling disturbances in clay soils

In this paper, an insight is provided into the quality of soil samples during the penetration of soil samplers. An updated Lagrangian finite element formulation with the second Piola–Kirchhoff stress rate (the Truesdell stress increment) to account for the large deformation behaviour near the sampling tube is used to determine the mechanical disturbances to a soft clay. The penetration of the sampler is simulated by splitting a group of nodes ahead of the penetration route up to a sufficient depth and applying incremental displacements to match the geometric configuration of the sampling tube. Consolidation effect is included to account for the rate of penetration. Thin-layer elements are added at the inside wall of the sampling tube to model the soil–sampler interface. The numerical results show that the central core of the sample is subjected to three distinct stages of vertical strain history, compression–extension–recompression, with the primary irrecoverable disturbances due to the compression stage ahead of the sampler. The degree of disturbance for a frictionless sampler was found to be constant after a penetration depth of 75 per cent of the sample tube diameter, while for a frictional sampler the degree of disturbances keeps increasing as the penetration proceeds. The results of a parametric study to determine the influence on sampling disturbances due to the rate of penetration, the thickness and the tip angle of the sample tube and sampler type are also presented.     

半干旱草原浅覆盖区手持钻机化探取样技术的应用及探索

浅层钻探技术是覆盖区化探取样技术研究的新方向。手持钻机是轻便钻机的一种。为了探索手持钻机的化探取样效果,以内蒙古拜仁达坝银铅锌矿区为代表的大兴安岭南部半干旱草原浅覆盖区作为研究区,采用回转式和冲击式手持钻机开展浅钻化探取样试验,分析该方法相对于常规化探方法的优势。结果表明,浅钻化探取样具有方便快捷、效率较高、成本较低等优点。通过对比两类钻机的钻进、取样工艺及效果,分析总结两类钻机对于草原覆盖区不同覆盖物的适用性及存在问题,为覆盖区浅钻化探技术和取样钻机的发展和推广提供借鉴和参考。     

Geochemistry of till and humus in the Kotkajärvi Cu---Co---Au prospect, Kalvola, southern Finland

A small Cu---Co---Au occurrence was found by means of till geochemistry. The metal anomalies in the till are highly local and the fineness of the gold grains and their association with goethite suggest that Au may first have been dissolved and then reprecipitated. The till very probably contains remnants of an older preglacial weathering crust. There are also high concentrations of Cu, Co, As, Mo and Zn in the humus horizon. Only one humus sample had a Au content above the detection limit, 0.02 ppm. The heavy-mineral samples from the near-surface part of the till proved useful in the regional prospecting phase.     

“Discovery” sampling in geological research

“Discovery” sampling is a simple sampling inspection technique which has been used by internal auditors during the last 30 years. Occasionally it has found application in agricultural research. It will be shown that an amended version of this technique can be used in the sampling of orebodies for the presence of particles of a mineral such as gold, silver, uranite, and so forth. While with the classical Discovery sampling a simple discrete distribution (Multinomial, Poisson, etc.)is involved, in our case convolutions of a discrete (Poisson)and continuous distributions (gamma, lognormal)occur, because of the indirect procedure used in detecting the presence of the mineral in the orebody. Illustrative examples using two distributions of gold particles are given.     

Mechanistic roles of soil humus and minerals in the sorption of nonionic organic compounds from aqueous and organic solutions

Mechanistic roles of soil humus and soil minerals and their contributions to soil sorption of nonionic organic compounds from aqueous and organic solutions are illustrated. Parathion and lindane are used as model solutes on two soils that differ greatly in their humic and mineral contents. In aqueous systems, observed sorptive characteristics suggest that solute partitioning into the soil-humic phase is the primary mechanism of soil uptake. By contrast, data obtained from organic solutions on dehydrated soil partitioning into humic phase and adsorption by soil minerals is influenced by the soil-moisture content and by the solvent medium from which the solute is sorbed.