Laboratory tests were performed to investigate the possibilities of using a modified form of Steinbrenner’s apparatus to estimate the intrinsic permeabilities of four different soils. Readings were taken on soils at the same moisture content but different void ratios; and on soils at the same void ratio but different moisture contents. Straight line graphs of positive slopes were obtained when the logarithm of intrinsic permeability was plotted against void ratio for peat, a sandy loam and synthetic soils. Results were extremely variable in the case of a clay soil. An attempt was made to relate the permeability estimated with the apparatus and using air as the permeant to the permeability estimated with water on core samples. Some correlation was observed between the two types of tests on the sandy loam and synthetic soils; but there was no correlation in the case of the peat and clay soils. Results, in general, were variable. / Land and Food Systems, Faculty of / Graduate

Methods of determining the deformation characteristic physical properties and dynamic response of cohesive soils were evaluated in order to obtain design parameters for soil-machine systems. The study was limited to simple scaled soil-machine systems on Haney clay and on mixed Haney clay and Ottawa sand in the semi-solid to plastic range. A special moire method was successfully developed to study large deformation and translation paths of soil as a function of tool shape and position. Compression, direct shear, stress wave and forced vibration methods were used to measure mechanical properties of soils. Advantages and disadvantages of each method were evaluated. Quasi-static stress-strain relationships were established from improved unconfined compression tests to produce unixial compression. Yield stress and strain hardening effects could be observed from these tests. Rate dependency of cohesive soil was verified by observing stress wave propagation in soil. It was observed that stress wave propagation velocity was more sensitive to soil particle size than to soil strength. Forced vibration methods were used to evaluate elastic constants such as Young's modulus and shear modulus which are useful in determining the contribution of elastic strains to the total force required to deform a soil. The theory of plasticity was successfully used in conjunction with experimental observations to establish stress-strain relationships in the soil on the assumption that strain hardening was linear and elastic strains were negligible. The maximum difference between theoretical forces deduced on the above basis and measured forces was less than twenty percent. The use of gelatin as a simulated soil was investigated to determine whether its use could provide a useful qualitative aid to design of soil-machine systems. It was found that the gelatin study gave stress trajectories and slip lines which resembled the results observed by the moire method in actual soil. Results obtained from the application of soil-machine systems on simulated soil and prototype soil were compared. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate

An experimental investigation of the undrained monotonic and cyclic loading behaviour of a saturated angular sand and a rounded sand under triaxial conditions is presented. These studies are aimed at obtaining a unified approach to the undrained behaviour of sand spanning from strain softening (termed liquefaction or limited liquefaction) to strain hardening response and linking the cyclic loading behaviour to the monotonic loading behaviour. It is also aimed at investigating the differences In undrained loading behaviour of sand with different particle angularity. Under monotonic loading, the strain softening response is initiated and terminated at two distinct values of effective stress ratio termed critical effective stress ratio state (CSR) and phase transformation state (PT), regardless of the relative density and consolidation stress conditions. For strain hardening response, the start of dilation also occurs at the same effective stress ratio of PT for strain softening response. It is shown that the unique steady state line concept for liquefaction is also valid for limited liquefaction. The PT states for strain hardening response, however, form a series of lines, which are function of Initial void ratio, merging into the unique steady state line as the consolidation stresses increase. A 3-D effective stress state behavioural model is developed, which enables prediction of the anticipated undrained loading behaviour (strain softening or strain hardening) from the knowledge of the initial state of the sand. It is shown that a complete specifications of initial state of sand, i.e., void ratio, confining pressure and static shear, is required to predict the type of undrained response, especially for angular sand. Under cyclic loading, if liquefaction develops, the CSR, effective stress ratio at PT state and steady state line are the same as those observed under monotonic loading. If cyclic mobility develops, the effective stress ratio at PT state is also the same as that observed under monotonic loading. Thus, the 3-D effective stress state diagram provides a link between monotonic and cyclic loading behaviour, and is used to develop the criteria for the occurrence of liquefaction and cyclic mobility. The influences of void ratio and confining pressure on the cyclic loading behaviour are similar to those for the monotonic loading behaviour. However, the influence of static shear on cyclic loading behaviour can be completely different depending on whether liquefaction or cyclic mobility is developed. The undrained loading behaviour of rounded sand is similar to that of the angular sand. However, for the range of consolidation stresses of interest, the initial relative density alone provides a good single parameter characterizing the initial state of the sand, and hence its anticipated response. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

Soil organic matter (SOM) plays an essential role in agriculture and environments. Humic substance (HS) is a major component of SOM. This research was to investigate HS using solid state nuclear magnetic resonance (NMR). Several experiments were concluded, and their results and conclusions are reported below. 13C direct-polarization magic-angle-spinning (DP/MAS) corrected by cross-polarization spin-lattice relaxation time (CP/T1) experiments with total sideband suppression (TOSS) were found to be quantitative. None of eight models proposed in the literature totally match compositions determined with this technique. Qualitative and quantitative analyses of HAs with five different 13C solid-state NMR techniques were assessed using different HAs. The techniques compared are: (1) DP/MAS at 13 kHz, (2) conventional CP/MAS at 5 kHz, (3) ramp-CP/MAS at 8 kHz, (4) CP/TOSS at 4.5 kHz, and (5) DP/MAS corrected by CP/T1-TOSS. DP/MAS or DP/MAS corrected by CP/T1-TOSS was used as a quantitative reference. Ramp-CP/MAS and CP/TOSS gave acceptable qualitative results. Conventional CP/MAS spectra at 13C frequency of 75 MHz was neither qualitatively nor quantitatively. Crystalline poly(methylene) exists in an untreated peat, soil humin and HAs but little or none is present in fulvic acids (FAs). The similar characteristics of crystallites in tree leaves and SOM indicate that crystallites in SOM might be from the biopolymers of the protective parts of higher terrestrial plants. New information on the chemical and physical structures of a peat HA was obtained using a series of two-dimensional 1H-13 C heteronuclear correlation solid-state NMR (HETCOR) experiments. COO carbons appeared to be prominently in OCHn-COO environments, but some were also bonded to aromatic rings and aliphatic chains. Compositional heterogeneity was also studied by introducing 1H spin diffusion into the HETCOR experiment. The chain mobility of different HAs was investigated with 1D proton and 2D WISE (wideline separation) solid-state NMR techniques. 1D proton spectra only gave an overall estimate of the mobility of HAs. 2D WISE showed that HS mobility difference may arise from bound water.

According to the report of th« Land Utilisation Committee (18) appointed by the Secretary of Agriculture in 1921 there are approximately 231,000,000 acres of humid grassland pasture in the United States* This area has an average carrying capacity of about one animal unit per five acres. (An animal unit may be defined as the equivalent of a mature horee, cow er steer, five hogs, or seven sheep* ) In addition to the above it is estimated that there are 587,000,000 acres of arid and ee»iarid pasture and range, practically all of which ie located in the fleet* The productiveness of this area is low, however, about twenty- four acres being required for one animal unit. Considering the potential acreage of agricultural land in the United States as 1,734,000,000 acres (18), it thus becomes apparent that nearly one half of that area is new devoted to pasturage*

Soil moisture and nitrogen are often the primary controlling factors of crop production . Production functions are valuable in describing crop responses to such controlling factors. Such functions are al so needed for determining the economic reliability of crop production. Soil moisture and nitrogen fertilizer were maintained at various levels to determine the response of field corn to these controlling factors. A conventional split plot design, a continuous function experimental design, and a confined barrel plot design were used to obtain data for determining production functions. The complete factorial, conventional split plot data was successfully used to generate reliable production functions in two locations. The multiple correlation coefficient was approximately 0. 68. The continuous function design consisted of a large number of treatment combinations with only small sequential increments in treatment levels , from plot to plot. This made it possible to eliminate border rows and use a much smaller plot size. The design was tested in two locations, using 10 soil moisture levels and 22 nitrogen fertilizer levels. The multiple correlation coefficients were about 0.33 and 0.49. Using this design, it was necessary to replicate entire blocks. The production functions from the conventional split plot design and continuous variable plot design compared favorably within locations, but not between locations. Production functions were also determined for relative yields and treatments . The inputs were expressed as fractions relative to both the maximum and optimum levels. The relative production functions were similar for both locations. The production functions were tested for transferability by making adjustments in the input data to account for site specific controlling factors. No definite conclusions were possible although the results suggest that transferability is possible. Several reduced field designs were also tested using the data obtained. Three different incomplete factorial, split plot designs appear to be suitable for generating production functions. Grouping of the continuous function plots to as few as four soil moisture levels by four fertilizer levels also gave reliable production functions. Several suggestions regarding the use of reduced field designs are presented along with suggested future research needs in this area . The data indicate that the continuous variable design is quite useful for determining production function s. The barrel plots consisted of field corn grown under various treatment combinations on undisturbed soil cores. The data obtained from these barrel plots (210 liters) were too variable to generate a reliable production function.

The study was designed to test the genetic theory of soil development of two soils derived from different geological material , but developed under conditions of similar climate, topography, biological activity, and age. An attempt was made to relate the soils characteristics to their present classification. Parleys and Mendon series which developed from Bonneville and Salt Lake Formation, respectively, were selected for that purpose. Along the east side of Cache valley , two pedons representing each of the studied series were selected to have similar soil formers except for their parent material. Evidently , these studied soils have been developed (rom different heterogenous sediments. Mendon soils have been developed from Salt Lake Formation to at least 51 cm depth, whereas, the solum horizons are attributed to the Bonneville Formation. The Parleys soil seems to be mainly developed from Bonneville formation. But the upper solum horizons are probably interlayered with fine deposits of Holocene age. Those soils which derived from different geological deposits show a high degree of similarity between them. Heterogeneity and the nature of the soil parent material, and similarity of their climatic and developmental conditions are believed to be the major causes to inhibit many genetic variables between them. In northern Utah, the Hendon soils are classified as Calcic Pachic Argixerolls, at the subgroup level. This study has shown that most of the Mendon pedons do not have a Pachic epipedon. Therefore, these studied soils could be grouped together in one subgroup. The result is Calcic Argixerolls in ftne-silty, mixed, mesic family. Re-examining Mendon series in Cache valley and reclassifying them on the basis of Pachic epipedon would be an interesting subject for further study.

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