Browsing by Subject "Soils"
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Item A comparison of vegetation and soils of Flat Top Mountain relict area with an adjacent grazed area in the southern High Plains(1968-06) Brown, Jimmy W.; Schuster, Joseph L.; Meyer, Raymond E.; Leach, T.L.The main purpose of studying the two areas was to determine the influence of long time cattle grazing on both vegetation and soil properties, and to use this information as guidelines for land use planning and treatment on other range areas of the same soils under similar climatic conditions. The objective of the study was to compare vegetation composition, herbage production, woody plant ground cover, and soil properties of the relict area to its adjacent grazed area.Item A genetic and mineralogical study of two soils from the Davis Mountain Region, Texas(Texas Tech University, 1968-06) Ratliff, Larry FelderThe primary purpose of this study was to acquire information concerning the genesis of two soils developed from volcanic materials. Secondary objectives were to establish modal profiles for use in classification of the soils.Item A mineralogical investigation of the Castell soil clay(Texas Tech University, 1966-08) Rogers, James RobertThe purpose of this investigation was to acquire more information about the clay mineralogy of a soil (tentatively named Castell) developed in the Central Basin Land Resource Area of Texas on Valley Springs gneiss. Stahnke (5^) researched the genesis and did preliminary work on the clay mineralogy. He obtained poor X-ray diffraction patterns of the clay fractions studied; therefore, he was not able to draw direct conclusions as to the exact nature of the mineralogy and genesis of the soil. The first step in this study was to confirm the results obtained by Stahnke, proving that his poor results were not due to laboratory technique.Item A re-evaluation of the filter paper method of measuring soil suction(Texas Tech University, 1996-08) Bulut, RifatThe filter paper method is a soil suction measurement technique. Soil suction is one of the most important parameters describing the moisture condition of unsaturated soils. The measurement of soil suction is crucial for applying the theory' behind the unsaturated soils. The filter paper method is a laboratory test method, but it is inexpensive and relatively simple. It is also the only known method that covers the full range of suction. With the filter paper method, both total and matric suction can be measured. If the filter paper is allowed to absorb water through vapor flow (non-contact method), then only total suction is measured. However, if the filter paper is allowed to absorb water through fluid flow (contact method), then only matric suction is measured. In this research, the filter paper method was investigated, especially the lower (wet) part ofthe total suction calibration curve. A total suction calibration curve was constructed using sodium chloride, NaCl, salt solutions and S & S No. 589 White Ribbon filter papers. Salt solutions and filter papers were brought to equilibrium through vapor flow (total suction measurement) at isothermal conditions. Equilibrium time and temperature were two weeks and 25°C , respectively. It was found out that total suction is very sensitive below 2.5 pF and the reason for this sudden change in suction arise from double effect ofthe logarithms (i.e., natural logarithm from Kelvin's equation and base ten logarithm from pF scale) and sensitivity of filter papers to water at low suctions. Filter paper is a poorly graded material, so it has more tendency to absorb water at low suctions. Another conclusion from these experiments and literature review was that the calibration curve is highly salt solution-type dependent because every salt solution has a different chemical activity thus different osmotic potential. The filter paper method needs further investigation in regard to equilibrium time and temperature fluctuations.Item An investigation of the thermal conductivity of a sandy soil as a function of soil moisture content(Texas Tech University, 1986-05) Gupta, SunilEnergy consumption for heating and cooling of residential and non-residential buildings is a significant portion of the total amount of energy used in the United States. Space heating and cooling accounts for almost 25 percent of the total U.S. consumption (as much as is consumed by all of transportation) and the potential for savings is very large indeed (5). For the residential sector alone, space heating accounts for 65 percent of all residential energy with a further 5 percent for space cooling (5). Space heating and cooling is by far the largest component of energy use in this sector, and this alone accounts for almost 16 percent of the nation's total raw energy use and is supplied primarily by natural gas and petroleum products (5).Item Classification and characterization of recently buried soils in the southern High Plains(Texas Tech University, 2002-08) Anderson, Joseph GregoryThe Southern High Plains is an extensive plateau, which lacks any major topographic variation. ReUef is provided locally by several types of landforms on the otherwise flat landscape of the Southern High Plains. Dunes, comprised of reworked Holocene eolian sediments, occur in the western and southwestern parts of the area. Thousands of small depressions, or playa lakes, dot the landscape. Some large depressions or basins, most of which are occupied by salinas (ephemeral saline lakes), also occur. In addition, there are several NW-SE trending draws narrow, dry valleys), ancient headwaters of the Red, Brazos, and Colorado Rivers, incised in the surface of the Southern High Plains. This study was focused on soils occurring within the draws and slightly depressed areas in the southwest part of the Southern High Plains. The draws and depressions have been partially filled with aluvial and eolian sediments in Late Pleistocene and Holocene tune (Holliday, 1995). Also, in selected locations, the draws and depressions have up to a meter of sediments deposited since agriculture, including cattle grazing, was initiated in the area.Item Effects of benefin on lettuce grown at varying levels of Nob3s, C1 and SOb4s(Texas Tech University, 1973-08) Christie, Charles JNot availableItem Effects of biosolids and an inorganic mulch on soil-plant relationships in two Chihuahuan Desert grasslands(Texas Tech University, 2000-12) Jurado-Guerra, PedroIn-depth research is needed to understand the effects of biosolids (sewage sludge) application on plant growth in semiarid regions. The objectives of this research were to determine the effects of surface application of biosolids on soil properties and plant growth on two Chihuahuan desert grasslands sites during two years. A tobosagrass (Hilaria mutica) site with a Stellar very fine sandy loam soil and a blue grama (Bouteloua gracilis) site with a Jal fine sandy loam soil were selected on the Sierra Blanca ranch, in Texas. Biosolids at 0,18, and 34 Mg ha^-1 were applied either in the dormant or growing season to experimental plots in 1997 or 1998. An inorganic mulch (synthetic fiber-floor pads, "IM") was applied to simulate ground cover of biosolids rates. Supplemental irrigation was provided to half of the plots throughout the growing season. Afternoon soil temperature, soil-volumetric water content, and soil NO3-N were measured throughout the growing season. Plant tissue nitrogen concentration (TKN) was measured in August and October on both tobosagrass and blue grama in 1998. Standing crop was measured in October for both grasses. In general, soil temperature decreased under application of both mulches at both sites during the two years. Soil-water content was higher under application of both mulches at both sites at most sampling dates. Nitrate-nitrogen in the soil increased with application of biosolids during both seasons of application with a more pronounced effect from biosolids applied during the dormant season during the first year of application on both sites. Nitrate-nitrogen in the soil slightly increased with inorganic mulch application on both sites. The dormant application of biosolids promoted earlier improvement of soil properties compared to growing season application of biosolids during the first year of application at both sites. Tobosagrass TKN remained similar with biosolids application in August and October and decreased with IM application in October. In contrast, blue grama TKN increased with biosolids rates in October and was not affected by mulch application in any date. Standing crop of both grasses increased with application of both mulches and irrigation. Biosolids increased NO3-N in the soil and improved plant forage quality more than the inorganic mulch in both sites and years.Item Effects of particle-size distribution, organic matter and calcium carbonate on water retention of Texas High Plains soils(Texas Tech University, 1985-05) Meng, Tan PiowThe overall objective of the research program was to provide data that will allow the prediction of the probable effectiveness of precipitation when deep plowing has altered the texture of the plow layer.Item Evaluation of groundwater quality in Castro, Dawson, and Terry Counties $c by Ajay Ramachandran.(Texas Tech University, 2004-08) Ramachandran, AjayNot availableItem Fine particulate matter generation under controlled laboratory and wind tunnel conditions(Texas Tech University, 2000-12) Amante-Orozco, AlejandroEvaluation of the propensity of soils for PMio (particulate matter < 10 //m in diameter) emission and identification of the causes for variations in PMio production are critical to improve the estimation of airborne PMio emission by wind erosion. Development of equipment and techniques to satisfactorily generate and analyze dust aerosols in the laboratory would greatly facilitate PM10 studies. Preliminary studies were conducted using the Lubbock dust generation, analysis and sampling system (LDGASS) to determine the appropriate operation and set of conditions which would generate reproducible and reliable results of dust analysis. Results indicated that the effect of the soil sample mass used in the LDGASS on PM10 emission was significant (P < 0.05) and the emission of PMio was proportional to the sample mass. Airflow rate through the system significantly affected PMio production. Particle size distributions of generated dust plumes were also affected by the airflow rate. Similar experiments were then conducted separately using the LDGASS and a wind tunnel to evaluate the comparability of PMio emissions produced by the kinetic energy applied by the LDGASS with those obtained by reproducing the wind erosion process in a wind tunnel. The effect of soil clay and calcium carbonate (CaCOa) content on PMio emission from eight agricultural soils near Lubbock, Texas, was evaluated. Aerodynamic roughness of a highly erodible agricultural field near Lubbock, Texas, was simulated in the wind tunnel. Sand abrader was fed into the wind tunnel to abrade soil aggregates and to generate PM10 aerosol. Wind tunnel results showed that PMio emissions significantly (P < 0.05) increased as soil CaCOa content increased and as clay content decreased. Average PM10 concentrations of 69.1 and 127.1 /ug/m^ were observed for low and high CaCOs levels, respectively. Average PMio concentrations for low and high day levels were 118.9 and 91.2 lug/m^, respectively. Accordingly, the soil with high CaCOs and the lowest clay content among soils high in CaCOa produced more PMio (174 fig/m3) than the remainder soils, and the soil with low CaCOs and the highest day content generated less PMio (42.6 /dg/m^) than the other soils. From 96 to 99 % of the total variation in PMio concentrations was accounted for selected soil properties. Analysis of LDGASS and wind tunnel results and estimates of kinetic energy suggested that the LDGASS imparted much more kinetic energy to a dust source than the wind tunnel. The LDGASS was modified and the new results were in agreement with the results obtained for the wind tunnel. The correlation coefficients (r) between PMio measured in the wind tunnel by a DataRAM and PMio measured by the modified LDGASS by a DataRAM and by a MiniVOL were .62 (P = 0.002) and 0.66 (P = 0.001), respectively. Functional equations to estimate PMio emissions in the wind tunnel from PMio generated by the modified LDGASS produced determination coefficients (r^) of 0.60 and 0.61 for DataRAM and MiniVOL data, respectively.Item Fungal functional diversity: exploring patterns and processes associated with soil fungal assemblages along an altitudinal gradient in the Chihuahuan Desert(Texas Tech University, 2002-05) Sobek, Edward AndrewSoil fungi are intimately associated with the maintenance and stability of terrestrial ecosystems through their involvement in the decomposition process. During decomposition, organic carbon is mineralized to CO2 and bound nutrients are returned to the labile soil nutrient pool for subsequent growth of plants and soil microbes. To better understand the relationship between soil fungal diversity, and factors influencing their functional ability in the decomposition of soil organic matter, this dissertation examined, (1) development of methods to determine soil fungal functional diversity, (2) seasonal trends in fungal function al diversity, and (3) the relation between soil fungal functional abilities and a suite of environmental variables that are important in ecosystem nutrient cycles. The context of this research endeavor focused on assemblages of soil fungi associated with an environmental gradient in the Chihuahuan Desert, specifically, the Pine Canyon Watershed in Big Bend National Park. The Pine Canyon Watershed contains five distinct vegetation zones along an altitudinal gradient and contains the majority of vegetation types that are found in the Chihuahuan Desert. Soil samples were collected within each of these zones over a three-year period. Sampling coincided with seasonal changes in temperature and precipitation. Functional diversity was determined for fungal assemblages from each vegetation zone, using the Soil FungiLog procedure developed from this research.Item Laboratory study for adsorption of selected pesticides on two types of playa basin soils(Texas Tech University, 1991-05) Chen, Yu-ChiThe mobility of pesticides through soil following agricultural application is of concern due to the potential threat of groundwater contamination by leaching. The pesticide transport down through the soil into groundwater is affected by many processes taking place in the soil profile. These processes include convection, dispersion, diffusion, adsorption, degradation, volatilization, and plant uptake (Cheng and Koaklnen, 1986). As the understanding of these processes increases, better control of pesticide fates should be expected. This study considers the effects of adsorption of four typical pesticides on two High Plains soils by means of laboratory experiments and mathematical models. Column experiments described by the one-dimensional convective-dlspersive transport equation are used to quantitatively determine the adsorption parameters for the selected pesticides. Batch experiments for adsorption isotherms are also conducted for the comparison with results of the column experiments.Item Mineralogy of the playa clays at the Pantex plant, Amarillo, Texas(Texas Tech University, 1996-08) Mars, Kenneth R.The Southem High Plains of Texas contains approximately 20,000 small ephemeral lake basins called playas. Recentiy, these playas have received considerable attention due to the realization that focused recharge to the Ogallala Aquifer can occur through these basins (Wood and Osterkamp, 1984, 1987; Scanlon et al., 1994; Wood et al., 1996). The Pantex Plant, located 16 miles northeast of Amarillo, Texas, in Carson County, has five playa lakes on property owned or leased by the Department of Energy. Potential contamination of the Ogallala Aquifer from Pantex has created much concern. Measurable contamination has been detected in the soils underlying the Plant (Laun, 1995). A sufficient knowledge of soil properties in playa basins is necessary to properly characterize the potential of contamination. Playa basins are a major focus of surface mnoff on the Southem High Plains. Playa basins have a distinctive surface soil, termed the Randall soil series (USDA-SCS unpublished material, 1978). Randall soils are defined as fine, montmorillonitic, thermic typic Halplustert. Playa basins collect mn-off from agricultural fields, roads, pavement and other man-made stmctures that can be sources of contamination. Mineralogy influences factors such as recharge and contaminant attenuation through these basins.Item Modeling wind erosion: detachment and maximum transport rate(Texas Tech University, 1994-12) Wilson, Gregory R.In 1941, R.A. Bagnold published the basic laws goveming the detachment and transport of dune sand. Smce then, researchers modeling the sediment transport phenomenon have chosen to take a more empirical approach, especially when describing erosion processes on soils. Empirical modeling is accepted in many scientific circles. However, researchers seekmg extensive knowledge of wind erosion problems must understand and explain the fundamental processes of sediment transport, and not merely predict the magnitude of the sediment load carried by a particular wind energy. Modeling and understanding wind erosion is essential to address present air quality concems. Dust generation, a byproduct of the saltation component of wind erosion, is explained by the physics of detachment and transport of particles from the action of wind forces and abrasion. The Agricultural Research Service of the United States Department of Agriculture has developed several models to predict soil loss by wind on farm fields. These models, although of great mathematical and computational elegance, do not include key variables identified by Bagnold as early as 1941 and, therefore, are limited in value and applicability because the basic equations describmg the physical processes are incomplete. A need exists to clarify the processes of wind erosion and apply sensible understanding through modelmg to better predict and control wind erosion. This study explores the basic erosion processes of soil and sand by wind, models the detachment process in terms of physical and temporal soil properties, describes the transition from aggregated soil particles to loose, noncohesive particles by the kinetics of abrasion down-wind with field length, and describes the maximum transport rate of this loose, noncohesive material as a function of particle size, particle size distribution, friction velocity, threshold friction velocity, and surface cover. Derived equations work equally well for sand and soil at different moisture conditions. A wind tunnel study was conducted to veriíy the maximum transport rate equation, and the study provided msight into the contradictory findings of published results. The derived model, with assumptions and simplifications duly noted, provides the analytical framework from which wind erosion and dust generation models can be developed on the basis of physics, rather than statistical correlation.Item Salinity Effects on Growth and Fine Structure of Atriplex Halimus 1(Texas Tech University, 1974-05) Kelley, David BryanAtriplex halimus L. plants were grown in nutrient culture solutions of full-strength Hoagland's, and fullstrength Hoagland's supplemented with either 0.174 M NaCl or 0.345 M NaCl. Observations were made on growth habit, net growth, and leaf cell ultrastructure of plants from the various treatments. Plants grown under control conditions (full-strength Hoagland's with no supplemental salt) had an erect habit with no lateral branching, but had a reduced net growth in comparison to plants in either of the salt treatments. Plants in the 0.174 M NaCl treatment were relatively erect (some recumbency was noted) and exhibited much better growth than either the control treatment or the high-salt (0.345 M NaCl) treatment. This is an indication of the plant's need for sodium chloride in the medium as either a nutrient or an osmoticum, and leads to the classification of A. halimus as a halophyte. Plants grown in the high-salt treatment showed a marked recumbency and a reduction in growth, but nevertheless showed a better net growth than plants in the control treatment. The fine structure of the leaf cells is correlated to salinity treatments. Plants grown in high-salt treatments showed swelling of organelles (chloroplasts and mitochondria) and other structural differences. The hair cells, which showed little ultrastructural response to high-salinity treatments, were characterized by unique ultrastructural features directly related to salinity tolerance.Item Salinity effects on growth, PEP carboxylase, and photosynthesis in three ploidy levels of Atriplex canescens (Pursh) Nutt.(Texas Tech University, 1983-05) Hamilton, Gary JohnNot availableItem Soil amendments and seed treatments to improve germination of chile pepper(Texas Tech University, 1997-05) Attebury, Jim KellyFarmers in eastem New Mexico and in the southera High Plains of Texas have to contend with problems that growers in other areas do not (ViUalon, 1992). Due to the elevation, topography, and latitude of this agricultural area, early spring soil conditions provide a host of obstacles to crop establishment. This is particularly tme of chile peppers. Adverse environmental conditions, such as wide diuraal temperature differences, high winds, moisture variability, irrigation induced salinity, and soil cmsting, as well as pathogens and insects, or biological features, are also present. Planting is a critical time in chili production (Carter, 1994). Transplants offer one method of crop establishment, however, beyond a certain scale of production this becomes impractical. Cost of hybrid seed is also an economic factor since planting seed cost can range from $15-$700 per pound (Carter, 1995, personal communication ). The most serious problems faced by pepper producers in New Mexico and on the southera High Plains of west Texas is the difficulty of establishment of suitable stands when planted directly into field seedbeds. Direct-seeding into the soil is widely used but suitable stands are difficult to achieve. Peppers are planted very shallow, and seeds are susceptible to desiccation and chiUing injury, thereby intermpting the germination process. Root system development and anchorage of the plant is influenced by the method of plant establishment (Leskovar and Stoffella, 1995). This can have an impact on yield and quality of pepper pods. Attempted mitigating efforts have included seed pretreatments (soaking, hardening, priming, polymer treatments) to speed the germination process and soil treatments or conditioners (polymer treatments, phosphoms, anti-cmstant) to alter the soil conditions (Heydecker and Coolbear, 1977).Item The correlation of soil test values with cotton and grain sorghum yield response to nitrogen and phosphorus on the southern High Plains of Texas(Texas Tech University, 1961-08) Ritchie, Joe TackettNot availableItem The effect of soil type on stolon number, tuber initiation, and tuber volume in Irish potatoes(Texas Tech University, 1977-05) Hickey, Michael G.Not available