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Este trabalho abordou a utilização de geoestatística para a otimização de esquemas de amostragem, concentrando-se especialmente no impacto da anisotropia na estruturação geométrica do desenho experimental e no processo de geração de imagens contínuas. O atributo estudado foi o teor de argila na camada superficial do solo, levantada em novembro de 1998, em área de Latossolo Vermelho-Escuro, localizada no município de Campos Novos Paulista (SP). A variabilidade espacial e a anisotropia do teor de argila foram determinadas por meio do exame dos semivariogramas obtidos, os quais foram ajustados a modelos teóricos para a obtenção de seus parâmetros (tipo de modelo de semivariograma, pepita, patamar e alcance). O fator de anisotropia observado implicou uma configuração oval, ou anisotrópica, da área de influência dos dados amostrais, em conformidade com a estrutura da variabilidade espacial observada. A anisotropia foi atribuída a fatores intrínsecos do solo, condicionados pela topografia do respectivo processo de formação, e extrínsecos, tais como: a mecanização, divisão de glebas e demais práticas de manejo, feitas no sentido das linhas de plantio, transversalmente ao gradiente topográfico. Considerando essas dimensões, a área de representatividade das amostras (ha/amostra) variou de um esquema a outro, modificando, assim, a densidade de amostras requerida para cada nível de variância. A proporção entre estas áreas mostrou o impacto da anisotropia sobre o número de amostras requerido para cada nível de variância desejável. This study presents the use of geostatistical analyses for the design of sampling schemes, focusing specially on the anisotropy impacts on the dimensioning of sample units and image generation techniques. The attribute studied was the superficial clay content, measured during November 1998 in a Typic Hapludox, in Campos Novos Paulista (SP). Spatial variability and anisotropy of clay content were determined by examining the semivariograms, which were fit to theoretical models to obtain its parameters (variogram model type, nugget, sill and range). The observed anisotropy factor expressed an oval, or anisotropic, configuration of the influence area related to the sampling points, according to the structure detected for the spatial variability. The anisotropy could be explained by soil intrinsic factors, conditioned by the topography in the formation processes, and extrinsic factors, such as mechanization, partitioning terraces and other managing practices, which are applied in plough lines, transverse to topographic gradient. These dimensions caused the variation of the area of samples representativeness (ha/samples) between the sampling designs, modifying the required density for a given variance level. The ratio of these areas showed the impact of anisotropy on the number of samples required for each desirable level of variance.

In the groundwater protection zone around Zagreb, at 14 localities the 1.5 meters thick soil cover were investigated in order to determine the vertical distribution of surface pollutants and mineral composition of soil as possible protective factor for sandy-gravel aquifer situated below it. In the near-surface samples that were taken from the upper part of the A-horizon, increased content of potential pollutants is found. These are the pesticides, total oils and fats, mineral oils, detergents, nitrates, nitrites and trace elements (especially Cu and Pb). A comparison with the more deeply located samples revealed the reduced concentrations, which means that all the potential pollutants are being retarded in the surface horizon. The highest clay content was measured in the surface samples, especially at the locations where either the agricultural or forest soil is developed (45-58%). The principal mineral components of the clay fraction are the smectite, randomly interstratified clay minerals, mica minerals (illite, muscovite), kaolinite and chlorite. The reduction of pollution with depth is explained by the adsorptional-sorptional characteristics of clay minerals (especially of smectite and interstratified clay minerals) and their capability to retain the pollutants by keeping them in the near surface layers. The illegal waste dumps in abandoned gravel pits are the most dangerous source of pollution, since there is only the thin and immature soil cover, unable to prevent the percolation of pollutants directly into the aquifer. Small contents of clay minerals minimize the pollutant retention potential, and penetration of pollutants into the aquifer can be expected.

A geostatistical approach is presented for the inclusion of seismic tomography data and sonic log data into the estimation of hydraulic conductivity. The procedure accounts for the errors in seismic tomography inversion and for the correlation of such errors. The proposed methodology consists of two steps: (1) the cross-variogram inference is carried out using only the data at the wellbore (both hydraulic and seismic); (2) a co-kriging procedure takes the cross-well data into account to interpolate between boreholes. No postulated a- priori relationship is needed. In order to illustrate the methodology a synthetic data set is generated on the basis of evidence from published case studies and simplified physical considerations. The numerical experiments show that the choice of the excitation frequency is critical. A trade-off exists between the need for a high-resolution survey (asking for higher frequencies) and the need for a good correlation between hydraulic conductivity and seismic properties (asking for frequencies below the squirt frequency of the medium). In the simulation using seismic data with the best excitation frequency (1 kHz in this case), the mean squared error of the hydraulic conductivity estimate is two-thirds lower than using hydraulic data alone. It is important to note also that only a part of the interwell region is adequately sampled by the tomographic experiment. Such a region can be readily identified by calculating the energy of the quasi-null space, through singular value decomposition of the tomographic matrix. In planning this type of experiments, it is necessary to carefully verify case by case whether the adopted range of high frequencies does not prevent the seismic energy from propagating effectively from sources to receivers.

13 páginas, 6 figuras, 4 tablas., [ES] Se estudia una cronosecuencia en el sistema de terrazas fluviales del río Tajo, en el sector comprendido entre Aranjuez y Toledo (España Central) con el fin de establecer la variación de las propiedades de los suelos con el tiempo. La cronología relativa del sistema de terrazas se establece según dataciones por faunas de vertebrados, industrias líticas, criterios cartográficos y geomorfológicos relativos y por correlación con otros sistemas de terrazas de la Cuenca del Tajo. Se establecen unos índices como criterios de la evolución del suelo: CA, porcentaje de arcilla en el horizonte argílico (Bt); COA, contenido global de arcilla, que corresponde al producto del contenido de arcilla por el espesor del horizonte argílico en cm; ILU, índice de iluviación, relación entre el porcentaje de arcilla en el horizonte Bt/porcentaje de arcilla en el horizonte A; y, AC/L, índice de vejez, relación entre el porcentaje de arcilla/porcentaje de limo en el horizonte Bt. Se realiza el estudio estadístico de las correlaciones lineales entre estos índices y la edad relativa de los suelos estimada a través de la cota relativa de los niveles de terrazas correspondientes. El índice de vejez (AC/L) es el que muestra los mejores resultados como criterio cronológico de evolución edáfica en la cronosecuencia estudiada. La aplicación de estos índices cronológicos a otras cronosecuencias de terrazas fluviales (río Henares y río Esla) confirma la utilidad de estos criterios de la evolución del suelo. Los mejores resultados se obtienen para el índice de vejez, y en segundo lugar el contenido de arcilla, y el contenido global de arcilla. El índice de iluviación presenta una mayor variabilidad, y su uso como criterio cronológico de evolución es menos preciso, debido a que resulta más afectado por la conservación total o el truncamiento parcial del perfil original., [EN] A soil chronosequence on fluvial terraces of the Tajo river (Aranjuez-Toledo sector, Central Spain) is studied in order to establish the variation of soil properties with time. Relative chronology of terraces has been established based on vertebrates fauna, lithic industry, geomorphic criteria, and by correlation with other terrace systems of the Tajo basin. Sorne indices have been established as estimators of soil evolution degree: CC: clay content (%) in Bt horizon; OCC: global clay content, obtained by the product of thickness and clay percentage of Bt; CS: clay/silt ratio, which results from the division of clay percentage and silt percentage in Bt horizon, and constitutes an estimation of the soil ageing; ILL: illuviation index, or ratio between clay content in Bt horizon and clay content in the overlying horizon. The study of correlations among the properties of argillic horizons and the aforementioned indices and the relative age of the soils have been carried out. The application of these indices to other similar chronosequences confirm their validity. The best results have been obtained for the CS index (ageing index), OCC and CC. Illuviation index shows a great variability, so its use as an evolution criterion is less precise, because it is affected by the total preservation or truncation of the upper part of the original profile., DGICYT Proyectos PB95-0946-PB95-0109 y Junta de Castilla- León Proyecto SAG4/94.

The objective of this work was to study the degradation kinetics of a nitrification inhibitor (NI), dicyandiamide (DCD), and evaluate its effectiveness in reducing nitrous oxide (N2O) emissions in different types of soils. Three soils contrasting in texture, mineralogy, and organic carbon (C) content were incubated alone (control) or with urine at 600 mg N/kg soil with 3 levels of DCD (0, 10, and 20 mg/kg). Emissions of N2O and carbon dioxide (CO2) were measured during the 58-day incubation. Simultaneously, subsamples were collected periodically from the incubating soils (40-day incubation) and the amounts of DCD, NH4+, and NO3− were determined. Our results showed that the half-life of DCD in these laboratory incubating soils at 25°C was 6–15 days and was longer at the higher rate of DCD application. Of the 3 soils studied, DCD degradation was fastest in the brown loam allophanic soil (Typic orthic allophanic) and slowest in the silt loam non-allophanic soil (Argillic-fragic Perch-gley Pallic). The differences in DCD degradation among these soils can be attributed to the differences in the adsorption of DCD and in the microbial activities of the soils. Among the 3 soils the highest reduction in N2O emissions with DCD from the urine application was measured in the non-allophanic silt loam soil followed by non-allophanic sandy loam soil and allophanic brown loam soil. There was no adverse impact of DCD application on soil respiratory activity or microbial biomass.

When input patterns are recognized, the recognized results are classfied into three groups. These are rejected group, error recognition group and correct recognition group. Chow has been studied the relation of these groups. However, in this paper, the author investigates about the case of normal distribution with different mean and variance which are not considered.

DFI Deep Mixing Conference 2015, SAN FRANCISCO, FRANCE, 02-/06/2015 - 05/06/2015; Because of its economical as well as its sustainable advantages, this deep mixing method, so far confined to the improvement of compressible or high organic content soils has become an attractive alternative to traditional methods for soil reinforcement, retaining walls (temporary or final), foundations and cutoff walls. But these new applications imply new requirements on the method as well as on the material.While numerous researches on the hardened material have been carried out, no widely applicable formula or nomograms are available yet, mainly due to the lack of international standard and practice, and because they often focuses on a particular soil. This paper deals with the mechanical behavior of the Deep Mixing material. It presents an extensive laboratory experimental program carried out to determine the influenceof the different constituents of the Deep Mixing material on its mechanical properties evolution, for any given soil. The analysis is conducted to study the influence of soil nature, water and cement contents on Deep Mixing strength, deformability and workability. Relations and nomograms linking those parameters are proposed, making the results presented directly usable for design methods and on site applications.