Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Includes bibliographical references (p. 129-145).

The building blocks of a sedimentary system are essential inputs into studies of reservoir character and comparisons with other sedimentary systems. Yet, our current knowledge of the building blocks of deep water slope channel deposits is still largely speculative. A quantitative approach has been utilised in order to analyse a host of lithological data and objectively identify these sedimentary components. The laterally-extensive and gently-dipping continental slope deposits of the San Fernando Channel System, Baja California, provide the required control on sub-seismic-scale temporal and lateral variations of lithofacies and 3D architecture. High resolution photo-panoramas (with better than 2mm accuracy) of the prominent conglomeratic component of the succession were collected from various key parts of the outcrop. Image analysis of segments extracted from the photo-panoramas generates key parameters for comparison of texture and fabric of conglomerates, such as clast to matrix ratio, major axis length and relative orientation. Statistical analysis of these data enabled the erection of an objective lithofacies scheme for the gravel fraction, the grouping of lithofacies into objectively-defined assemblages, and the establishment of models for the lateral and stratigraphic distributions of these assemblages. 12 lithofacies were objectively identified through hierarchical cluster analysis of 4 quantitative lithological parameters. Statistical analyses indicate significant differences in diversity in the lithofacies assemblages between the early and later parts (termed Stage 1 and Stage 2) of a channel complex set (sensu Sprague, et al., 2002), and to a lesser extent between marginal and axial parts of the system. These can be related to spatial differences and temporal changes in the nature of the turbidity currents flowing through the channel system. Gravelly units become more organised and less diverse with time in one CCS, and each successive CCS more organised at earlier stratigraphic levels than the next, except for the last CCS which is interpreted as influenced by a tectonic paroxysm. These seemingly autocyclic changes in organisation are interpreted as process-responses to changes in equilibrium profile as the nature of confinement changes with the infilling of an initial erosional confinement, to confinement by a master levee and gradual infilling through the evolution of each CCS.

Characterization of heterogeneous soil hydraulic parameters of deep vadose zones is often difficult and expensive, making it necessary to rely on other sources of information. Pedotransfer functions (PTFs) based on soil texture data constitute a simple alternative to inverse hydraulic parameter estimation, but their accuracy is often modest. Inverse modeling entails a compromise between detailed description of subsurface heterogeneity and the need to restrict the number of parameters. We propose two methods of parameterizing vadose zone hydraulic properties using a combination of k-means clustering of kriged soil texture data, PTFs, and model inversion. One approach entails homogeneous and the other heterogeneous clusters. Clusters may include subdomains of the computational grid that need not be contiguous in space. The first approach homogenizes within-cluster variability into initial hydraulic parameter estimates that are subsequently optimized by inversion. The second approach maintains heterogeneity through multiplication of each spatially varying initial hydraulic parameter by a scale factor, estimated a posteriori through inversion. This allows preserving heterogeneity without introducing a large number of adjustable parameters. We use each approach to simulate a 95 day infiltration experiment in unsaturated layered sediments at a semiarid site near Phoenix, Arizona, over an area of 50 x 50 m(2) down to a depth of 14.5 m. Results show that both clustering approaches improve simulated moisture contents considerably in comparison to those based solely on PTF estimates. Our calibrated models are validated against data from a subsequent 295 day infiltration experiment at the site.

The freeze-thaw process controls several hydrologic processes including infiltration, runoff, and soil erosion. Simulating this process is important particularly in cold and mountainous regions. The Soil and Cold Regions Model (SCRM) was used to simulate, study, and understand the behavior of 12 homogenous soils, subject to a freeze-thaw process based on meteorological data at a snow dominated forest site in Laramie, WY, from 2010 and 2012. To complete a simulation, which accounts for all three phases of water (liquid, vapor, and ice), the model requires meteorological data, canopy characteristics, soil physical properties including the van Genuchten-Mualem parameters, and the initial state of the soil profile. Different model conditions were applied included the relationship between soil pore size, soil particle contact, soil thermal conductivities, soil ice/water content, snow cover, and meteorological data. Analysis of the simulations used metrics such as soil frost depth, days with ice, and maximum ice content. The results showed a threshold in snow depth ranging from 20 to 40 cm to fully insulate the soil from the atmosphere. Additionally, the model showed that the freeze-thaw process was strongest in the period with a shallow snow pack and that particle packing within the soil profile was an important factor in this process. Soil texture and water content controlled soil thermal properties. Water movement towards the freezing front was especially important in fine textured soils, where water and ice was concentrated in the upper layers. In coarser textured soil, frost also occurs, but not to the same extent. Based on these results, future research that combines a broader set of soil conditions with an extended set of field meteorology data could elucidate how soil texture controls thermal properties related to soil frost.

Thesis (M.S.) in Earth Sciences--University of Maine, 2007. / Includes vita. Includes bibliographical references (leaves 86-93).

The application of the crop water stress index (CWSI) method to irrigation scheduling is enhanced by knowledge of the relationship between CWSI and soil water potential (SWP) and how this relationship is affected by soil texture. A study using the same cultivar of cotton on three different soils was conducted in southern Arizona over a single growing season. Detailed data were collected of CWSI and soil moisture content for several treatments that scheduled irrigations at threshold CWSI values. CWSI was correlated with soil water potential values calculated from pressure plate determined moisture release curves. Spatial variability of soil characteristics necessitated use of average rather than plot specific moisture release curves. Analysis showed a linear CWSI-SWP relationship that varied greatly with soil depth and study site. The study concluded that soil profile average SWP alone does not normalize the CWSI between sites with different soil textures.

Call number: LD2668 .T4 1986 L39 / Master of Science / Agronomy

O aumento das doses de potássio (K) para atender a demanda nutricional desse nutriente em cafezais produtivos induz a deficiência de Mg. Esta pesquisa foi realizada com o objetivo de compreender como a classe de solo interfere na interação entre esses nutrientes (K e Mg), de maneira que a aplicação de alta dose de K não afete a nutrição da planta em relação ao Mg. Dois experimentos foram conduzidos em duas classes de solo: Latossolo, com textura muito argilosa, em Machado-MG, e Argissolo, com textura media sobre argilosa, em Monte Santo de Minas-MG. Adotou-se delineamento fatorial com três doses de K (110, 260 e 390 kg ha-1 K2O) x cinco doses de Mg (0, 81, 162, 324 e 405 kg ha-1 MgO), com três repetições. No Argissolo, a lixiviação de K impediu a redução da concentração foliar de Mg, independentemente da dose de K. No Latossolo, a concentração de Mg foliar variou com a dose de K, e apresentou ajuste quadrático. A concentração foliar de Mg aumentou linearmente com a dose desse nutriente, independentemente da classe de solo e da dose de K. / The increasing levels of potassium (K) applied to attend coffee nutritional demand has induced a widespread of Magnesium (Mg) deficiency. The purpose of this research is to understand how the soil features interfere on the interaction between these nutrients (K and Mg) in the coffee, to guide the management of potassium fertilizer, where the application of high doses of K does not interfere with nutritional status the coffee with respect to Mg. Two experiments were conducted in contrasting soil classes at two sites: Oxisol, with a clay textured soil at Machado-MG, and an Ultisol, with medium texture at Monte Santo de Minas, in a factorial design with three rates of K (110, 260 and 390 kg ha-1 K2O) x 5 rates of Mg (without Mg, 81, 162, 324 and 405 kg ha-1 MgO) with three replications. On the Ultisol, K leaching prevented the reduction of leaf Mg content, independently of the application rate of K. On Oxisol, leaf Mg content was modified according to K rate, and presented quadratic adjust. Mg leaf content was enhanced linearly with the application of this nutrient, independently of the soil class and the K rate.

O aumento das doses de potássio (K) para atender a demanda nutricional desse nutriente em cafezais produtivos induz a deficiência de Mg. Esta pesquisa foi realizada com o objetivo de compreender como a classe de solo interfere na interação entre esses nutrientes (K e Mg), de maneira que a aplicação de alta dose de K não afete a nutrição da planta em relação ao Mg. Dois experimentos foram conduzidos em duas classes de solo: Latossolo, com textura muito argilosa, em Machado-MG, e Argissolo, com textura media sobre argilosa, em Monte Santo de Minas-MG. Adotou-se delineamento fatorial com três doses de K (110, 260 e 390 kg ha-1 K2O) x cinco doses de Mg (0, 81, 162, 324 e 405 kg ha-1 MgO), com três repetições. No Argissolo, a lixiviação de K impediu a redução da concentração foliar de Mg, independentemente da dose de K. No Latossolo, a concentração de Mg foliar variou com a dose de K, e apresentou ajuste quadrático. A concentração foliar de Mg aumentou linearmente com a dose desse nutriente, independentemente da classe de solo e da dose de K. / The increasing levels of potassium (K) applied to attend coffee nutritional demand has induced a widespread of Magnesium (Mg) deficiency. The purpose of this research is to understand how the soil features interfere on the interaction between these nutrients (K and Mg) in the coffee, to guide the management of potassium fertilizer, where the application of high doses of K does not interfere with nutritional status the coffee with respect to Mg. Two experiments were conducted in contrasting soil classes at two sites: Oxisol, with a clay textured soil at Machado-MG, and an Ultisol, with medium texture at Monte Santo de Minas, in a factorial design with three rates of K (110, 260 and 390 kg ha-1 K2O) x 5 rates of Mg (without Mg, 81, 162, 324 and 405 kg ha-1 MgO) with three replications. On the Ultisol, K leaching prevented the reduction of leaf Mg content, independently of the application rate of K. On Oxisol, leaf Mg content was modified according to K rate, and presented quadratic adjust. Mg leaf content was enhanced linearly with the application of this nutrient, independently of the soil class and the K rate.

Knowledge of the spatial distribution of soil textural properties at the watershed scale is important for understanding spatial patterns of water movement, and in determining soil moisture storage and soil hydraulic transport properties. Capturing the heterogeneous nature of the subsurface without exhaustive and costly sampling presents a significant challenge. Soil scientists and geologists have adapted geophysical methods that measure a surrogate property related to the vital underlying process. Apparent electrical conductivity (ECa) is such a proxy, providing a measure of charge mobility due to application of an electric field, and is highly correlated to the electrical conductivity of the soil solution, clay percentage, and water content. Electromagnetic induction (EMI) provides the possibility of obtaining high resolution images of ECa across a landscape to identify subtle changes in subsurface properties. The aim of this study was to better characterize subsurface textural properties using EMI mapping and geostatistical analysis techniques. The effect of variable temperature environments on EMI instrumental response, and ECa - depth relationship were first determined. Then a procedure of repeated EMI mapping at varying soil water content was developed and integrated with temporal stability analysis to capture the time invariant properties of spatial soil texture on an agricultural field. In addition, an EMI imaging approach of densely sampling the subsurface of the Reynolds Mountain East watershed was presented using kriging to interpolate, and Sequential Gaussian Simulation to estimate the uncertainty in the maps. Due to the relative time-invariant characteristics of textural properties, it was possible to correlate clay samples collected over three seasons to ECa data of one mapping event. Kriging methods [ordinary kriging (OK), cokriging (CK), and regression kriging (RK)] were then used to integrate various levels of information (clay percentage, ECa, and spatial location) to produce clay percentage prediction maps. Leave-one-out cross-validation showed that the multivariate estimation methods CK and RK, incorporating the better sampled surrogate ECa, were able to improve the RMSE by 7% and 28%, respectively, relative to OK. Electromagnetic induction measurements provide an important exhaustive layer of information that can improve the quality and resolution of soil property maps used in hydrological and environmental research.