You searched for subject:(Soil Science).
Showing records 1 – 30 of
2501 total matches.
◁ [1] [2] [3] [4] [5] … [84] ▶
Texas A&M University
1.
Matocha, Christopher John.
Adsorption and transport of pyrithiobac in soils.
Degree: MS, soil science, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-1996-THESIS-M38 
► The fate of agrochemicals in soils is governed by various transport, retention, and transformation processes. The herbicide pyrithiobac (sodium 2-chloro-6(4,6 dimethoxypyrimidin-2-ylthio) benzoate), developed by DuPont,…
(more)
▼ The fate of agrochemicals in soils is governed by various transport, retention, and transformation processes. The herbicide pyrithiobac (sodium 2-chloro-6(4,6 dimethoxypyrimidin-2-ylthio) benzoate), developed by DuPont, has shown excellent promise in controlling several obstinate broadleaf weed species in cotton. However, there is a paucity of information available concerning pyrithiobac activity and behavior in soils. This research was undertaken to investigate the behavior of pyrithiobac on reference adsorbents (Gonzales bentonite, Georgia kaolinite, goethite, and Michigan peat) and four soils (Houston Black c, Hidalgo sl, Orelia scl, and Ships sic) having a wide range of physical and chemical properties. Adsorption isotherms were developed for pyrithiobac adsorption on the reference adsorbents and the soils using the batch-equilibration technique. For the soils, pyrithiobac adsorption ranged from 3.1 to 12.8%, and in the reference adsorbents, from 2.1 to 63.5%. The empirical Freundlich equation adequately described pyrithiobac adsorption on the Michigan peat (C-type isotherm) and Gonzales bentonite (L-type isotherm), but poorly fit the curvilinear (S-type) adsorption isotherms which were observed in the soils and two reference adsorbents (Georgia kaolinite and goethite). However, irrespective of calculation method, the retention of pyrithiobac on the Michigan peat was always greatest, followed in order by Gonzales bentonite, Georgia kaolinite, goethite, and the soils. The affinity of soils for pyrithiobac was low compared to other herbicides based on K[] and K[] values. Differences in adsorption capacity of the four soils varied on the types and amounts of inorganic and organic constituents. Stepwise multiple-regression analyses indicated that free iron oxide content accounted for 45% of the variability (p < 0. 000 1) in pyrithiobac adsorption by the soils. Inclusion of organic carbon content, clay content, cation exchange capacity, and pH into the analyses did not significantly improve the correlations (W=0.48). Transport of pyrithiobac was studied on four soils using intact or undisturbed columns. Based on breakthrough-curves and associated parameters, preferential flow through macropores controlled the movement of pyrithiobac, particularly in the more structured soils (Ships, Houston Black, Orelia).
Subjects/Keywords: soil science.; Major soil science.
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Matocha, C. J. (2012). Adsorption and transport of pyrithiobac in soils. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-1996-THESIS-M38
Chicago Manual of Style (16th Edition):
Matocha, Christopher John. “Adsorption and transport of pyrithiobac in soils.” 2012. Masters Thesis, Texas A&M University. Accessed September 23, 2019.
http://hdl.handle.net/1969.1/ETD-TAMU-1996-THESIS-M38.
MLA Handbook (7th Edition):
Matocha, Christopher John. “Adsorption and transport of pyrithiobac in soils.” 2012. Web. 23 Sep 2019.
Vancouver:
Matocha CJ. Adsorption and transport of pyrithiobac in soils. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2019 Sep 23].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1996-THESIS-M38.
Council of Science Editors:
Matocha CJ. Adsorption and transport of pyrithiobac in soils. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1996-THESIS-M38
Texas A&M University
2.
Swanson, Eric Scott.
Soil microbial biomass: an estimator of soil development in reclaimed lignite mine soil.
Degree: MS, soil science, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-1996-THESIS-S932
► A two-year study was conducted at the Big Brown lignite mine in Fairfield, Texas, to determine the rate and extent of recovery of the soil…
(more)
▼ A two-year study was conducted at the Big Brown lignite mine in Fairfield, Texas, to determine the rate and extent of recovery of the soil microbial biomass (SMB) in mixed overburden. The relationships between SMB carbon (SMBC), basal respiration and soil organic carbon (SOC) accretion was evaluated using the respiratory quotient (qCO2) and the ratio of the SMB to SOC (SMBC:SOC ratio). Newly leveled, 1-, 3-, 5-, 10-, 15-, and 23-year-old reclaimed mixed overburden as well as an unmined soil were sampled bimonthly to measure SMIBC and other parameters. Three methods [chloroform fumigation incubation (FI), chloroform fumigation extraction (FE), and substrate-induced respiration (SIR)] were used to measure SMB and compared as estimators of SMB in reclaimed mine soils. Basal respiration (CO2 evolved from untreated soil), metabolic quotient (i.e. specific respiratory activity; qCO2; C02 produced per unit mass of SMB), and the SMBC:SOC ratio (the abundance of SMB relative to SOC) were used to determine trends in microbial biomass dynamics relative to SOC accumulation. A nearly linear increase in SMB was observed over the chronosequence of mine soils (r – O.98 to 0.99) for each of the three biomass methods. Mean values of SMB from 12 sample dates ranged from 41 pg SMIBC g-1 at the 0-year site to 291 ptg SMBC g-' at the 23-year site. The unmined reference soil averaged 84 jig SMBC g-1 through the period of the study. The qCO2 declined from 0.24 to 0. 12 Mg C02-C Mg SMBC d-' during the first year and tended to stabilize near 0.06 to 0.09 as reclaimed sites matured. The ratios of SMBC:SOC increased linearly with age of site through 23 years (r – O. 97). A substantial amount of seasonal variation in SMB was observed during the two-year study. Older sites (15-and 23-years) showed significant fluctuations of SMB that correlated well with the growing season of Coastal bermudagrass. Microbial biomass peaked during mid to late summer and declined to a minimum during the cold, wet winter months. Younger sites were less affected by seasonal influences, and changes at these sites appeared more related to changes in soil moisture.
Subjects/Keywords: soil science.; Major soil science.
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Swanson, E. S. (2012). Soil microbial biomass: an estimator of soil development in reclaimed lignite mine soil. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-1996-THESIS-S932
Chicago Manual of Style (16th Edition):
Swanson, Eric Scott. “Soil microbial biomass: an estimator of soil development in reclaimed lignite mine soil.” 2012. Masters Thesis, Texas A&M University. Accessed September 23, 2019.
http://hdl.handle.net/1969.1/ETD-TAMU-1996-THESIS-S932.
MLA Handbook (7th Edition):
Swanson, Eric Scott. “Soil microbial biomass: an estimator of soil development in reclaimed lignite mine soil.” 2012. Web. 23 Sep 2019.
Vancouver:
Swanson ES. Soil microbial biomass: an estimator of soil development in reclaimed lignite mine soil. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2019 Sep 23].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1996-THESIS-S932.
Council of Science Editors:
Swanson ES. Soil microbial biomass: an estimator of soil development in reclaimed lignite mine soil. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1996-THESIS-S932
Texas A&M University
3.
Haney, Richard Lee.
Soil carbon and nitrogen dynamics as affected by inputs of dairy manure and poultry litter.
Degree: MS, soil science, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-1997-THESIS-H366
► Due to increased environmental awareness and concern for cleaner drinking water, improved sustainable agricultural practices are becoming more important. Overestimating fertilizer recommendations can potentially lead…
(more)
▼ Due to increased environmental awareness and concern for cleaner drinking water, improved sustainable agricultural practices are becoming more important. Overestimating fertilizer recommendations can potentially lead to nitrate accumulation in surface and groundwater. A rapid soil test based on biological systems which are sensitive to changing soil conditions could help improve fertilizer N recommendations and prevent potential contamination from agricultural inputs. The soil microbial biomass is largely responsible for the transformation of organic matter into inorganic nutrients available for plant uptake and the microbe's pivotal role in agriculture is not completely understood. The need for a better understanding of the seasonal variation in soil microbial biomass and its effects on C and N mineralization would be valuable. The objectives of this study were to: 1) evaluate and optimize parameters for the arginine ammonification procedure to estimate soil microbial biomass C (SMBC) and N mineralization in soils receiving animal manure, 2) evaluate the one-day C02 procedure as a possible routine test for estimating N mineralization in manured soils, 3) determine soil microbial biomass C and N on a monthly basis and correlate with weather trends and animal manure inputs, 4) monitor C and N mineralization in longer term, 24-day incubations as well as initial inorganic N and soil organic carbon on a monthly basis, 5) correlate results of the above procedures with crop yield and N uptake. Arginine ammonification showed strong correlation with SMBC and N mineralization in soil receiving dairy cattle manure-amended plots on 4 of the 8 sample dates. Substrate interference from manure appeared to be a source of interference, and therefore, arginine ammonification was not recommended for estimation of SMBC or N mineralization in soils receiving animal waste. One-day C02 evolution from dairy manure- mineralization in soils receiving animal waste. One-day C02 evolution from dairy manure-amended soils correlated significantly (P<0.05) with SNMC and N mineralization in all eight sampling months. One-day C02 from samples taken prior to the growing season also correlated very strongly with forage N uptake in dairy manure-treated plots (r 2=0. 93). Nitrogen mineralization averaged 40 % from dairy manure in the field across all treatments. The C:N ratio of soil-applied manure or litter should be analyzed to better predict N mineralization potential.
Subjects/Keywords: soil science.; Major soil science.
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Haney, R. L. (2012). Soil carbon and nitrogen dynamics as affected by inputs of dairy manure and poultry litter. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-1997-THESIS-H366
Chicago Manual of Style (16th Edition):
Haney, Richard Lee. “Soil carbon and nitrogen dynamics as affected by inputs of dairy manure and poultry litter.” 2012. Masters Thesis, Texas A&M University. Accessed September 23, 2019.
http://hdl.handle.net/1969.1/ETD-TAMU-1997-THESIS-H366.
MLA Handbook (7th Edition):
Haney, Richard Lee. “Soil carbon and nitrogen dynamics as affected by inputs of dairy manure and poultry litter.” 2012. Web. 23 Sep 2019.
Vancouver:
Haney RL. Soil carbon and nitrogen dynamics as affected by inputs of dairy manure and poultry litter. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2019 Sep 23].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1997-THESIS-H366.
Council of Science Editors:
Haney RL. Soil carbon and nitrogen dynamics as affected by inputs of dairy manure and poultry litter. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1997-THESIS-H366
Texas A&M University
4.
Frybarger, Mary Rita.
A baseline characterization of trace elements in Texas soils.
Degree: MS, soil science, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-1998-THESIS-F79
► A baseline survey of concentrations of Mn, Fe, Zn, Cu, Se, As, Cd, Cr, Co, Pb, Ba, and Ni was performed for 100 soils from…
(more)
▼ A baseline survey of concentrations of Mn, Fe, Zn, Cu, Se, As, Cd, Cr, Co, Pb, Ba, and Ni was performed for 100 soils from seven Land Resource Areas of Texas. Nearly 300 soil samples from the upper, middle, and lower depths of selected pedons were analyzed for trace element concentrations by three extraction methods using inductively coupled plasma-atomic emission spectroscopy. The first method utilized DTPA, which quantities concentrations that are considered ''plant available''. A nitric acid (HNO₃) digestion was used to quantify element concentrations that are acid-extractable while a hydrofluoric acid (HF) digestion gave total element concentrations. Results were compared to the United States Environmental Protection Agency's (USEPA) maximum allowable background concentrations of elements in soils for sewage sludge application. Elements in the study soils were well below USEPA limits. When compared to the median concentration of elements on a worldwide basis, all except Co, As, and Se were found in concentrations lower than the worldwide median but even these elements were well within the published range. Trends in the depth distribution of elements were observed. In general, the surface horizons of the Edwards Plateau/Grand Prairie and Blackland Prairies' soils were higher in trace elements than the middle or lower depths due to the dominance of Mollisols and Vertisols with mollic epipedons. Alfisols and Ultisols of the East Texas Timberlands and Claypan Region lead to trace element concentration in the control section. Concentrations of trace elements were found in the deepest horizons studied for the Central Basin due to the igneous parent materials. No distribution trend was observed for the soils of the Coast Prairie. Soil properties that influence the amount of trace elements in soils as well as their location in the soil profile were investigated by correlation analysis. Sand, clay, and CEC appeared to be the best soil properties correlated to trace element concentrations, while organic C and CaCO₃ equivalent showed fair correlations.
Subjects/Keywords: soil science.; Major soil science.
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Frybarger, M. R. (2012). A baseline characterization of trace elements in Texas soils. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-1998-THESIS-F79
Chicago Manual of Style (16th Edition):
Frybarger, Mary Rita. “A baseline characterization of trace elements in Texas soils.” 2012. Masters Thesis, Texas A&M University. Accessed September 23, 2019.
http://hdl.handle.net/1969.1/ETD-TAMU-1998-THESIS-F79.
MLA Handbook (7th Edition):
Frybarger, Mary Rita. “A baseline characterization of trace elements in Texas soils.” 2012. Web. 23 Sep 2019.
Vancouver:
Frybarger MR. A baseline characterization of trace elements in Texas soils. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2019 Sep 23].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1998-THESIS-F79.
Council of Science Editors:
Frybarger MR. A baseline characterization of trace elements in Texas soils. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1998-THESIS-F79
Texas A&M University
5.
Campbell, Colin S.
Response of in situ leaf psychrometer to cuticle removal by abrasion.
Degree: MS, soil science, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-1997-THESIS-C353
► In situ measurements of leaf water potential are important for monitoring the energy state of water in plants. Thermocouple psychrometry is an acceptable measurement method,…
(more)
▼ In situ measurements of leaf water potential are important for monitoring the energy state of water in plants. Thermocouple psychrometry is an acceptable measurement method, where leaf water status is inferred by analysis of water vapor pressure adjacent to the leaf surface. Unfortunately, excessive equilibration times, caused by low vapor conductance across the leaf cuticle and vapor sorption in the psychrometer chamber, make in situ sampling difficult. Several methods of removing waxy leaf cuticle have been shown to increase water vapor conductance across the epidermis of the leaf, thus speeding water potential measurement, but have not been compared for relative effectiveness. In addition, mean equilibration time has not been calculated for in situ leaf psychrometers when attached to leaves whose waxy cuticle has been removed. Six waxy cuticle removal treatments were compared to an untreated control to discover which produced a significantly higher conductance of water vapor across the leaf surface. The treatment corresponding to the highest conductance was then used to determine the mean equilibration time of the leaf psychrometer. Six hundred grit sandpaper treatment was found to be the most effective treatment to remove the waxy cuticle. Equilibration was found to be significantly affected by psychrometer cleanliness and plant response to changes in its external environment. By controlling or removing these factors, mean equilibration time for leaves from which the cuticle had been removed was less than 11 min.
Subjects/Keywords: soil science.; Major soil science.
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Campbell, C. S. (2012). Response of in situ leaf psychrometer to cuticle removal by abrasion. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-1997-THESIS-C353
Chicago Manual of Style (16th Edition):
Campbell, Colin S. “Response of in situ leaf psychrometer to cuticle removal by abrasion.” 2012. Masters Thesis, Texas A&M University. Accessed September 23, 2019.
http://hdl.handle.net/1969.1/ETD-TAMU-1997-THESIS-C353.
MLA Handbook (7th Edition):
Campbell, Colin S. “Response of in situ leaf psychrometer to cuticle removal by abrasion.” 2012. Web. 23 Sep 2019.
Vancouver:
Campbell CS. Response of in situ leaf psychrometer to cuticle removal by abrasion. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2019 Sep 23].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1997-THESIS-C353.
Council of Science Editors:
Campbell CS. Response of in situ leaf psychrometer to cuticle removal by abrasion. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1997-THESIS-C353
Texas A&M University
6.
Akin, James Browning.
Attenuation of dilute aromatic hydrocarbon transport by a block copolymer in a compacted vertisol.
Degree: MS, soil science, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-A376
► Municipal solid waste landfills in the United States are built with a composite bottom liner consisting of a flexible membrane liner of high-density polyethylene overlying…
(more)
▼ Municipal solid waste landfills in the United States are built with a composite bottom liner consisting of a flexible membrane liner of high-density polyethylene overlying a compacted soil liner. Hydrocarbons have been shown to pass through the flexible membrane liner by diffusion. Flexible membrane liners often have flaws allowing direct contact between the leachate and the compacted soil liner. The transmission of hydrocarbons to the compacted soil liner presents a threat to groundwater supplies. The study was performed to determine if the modification of a compacted soil liner with a thermoplastic elastomer block copolymer could successfully sequester benzene, toluene, ethylbenzene, and xylenes and meet the United States Environmental Protection Agency's saturated hydraulic conductivity requirement of 1x10⁻⁷ cm sec⁻¹. Compacted Ships clay modified with 0, 1, 3, 5, and 10% weight of a thermoplastic elastomer block copolymer was tested for saturated hydraulic conductivity using 10.2 cm fixed wall permeameters. The compacted Ships clay met the United States Environmental Protection Agency's mandated saturated hydraulic conductivity of 10⁻⁷ cm sec⁻¹ at polymer contents of 3% (wt) polymer or less. The presence of dissolved aromatic hydrocarbons had no effect on the saturated hydraulic conductivity. The ability of the polymer to attenuate the transport of dilute aromatic hydrocarbons was tested by permeating the compacted soil/polymer treatments with a 0.01N CaSO4 solution contaminated with benzene, toluene, ethylbenzene, and xylenes. Leachate from permeameters packed with soil containing more than 1% (wt) polymer had BTEX concentrations below the drinking water standard for 3 or more pore volumes. The findings of this research were applied to a hypothetical compacted soil liner constructed with Ships clay modified to include 3% (wt) polymer and having a saturated hydraulic conductivity of 4.23 x 10⁻⁸ cm sec⁻¹. It was assumed that the soil liner was in direct contact with landfill leachate. The hypothetical liner would protect the groundwater from contamination above the maximum contamination limit for drinking water by benzene for 350 years, toluene for 140 years, and ethylbenzene for 260 years.
Subjects/Keywords: soil science.; Major soil science.
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Akin, J. B. (2012). Attenuation of dilute aromatic hydrocarbon transport by a block copolymer in a compacted vertisol. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-A376
Chicago Manual of Style (16th Edition):
Akin, James Browning. “Attenuation of dilute aromatic hydrocarbon transport by a block copolymer in a compacted vertisol.” 2012. Masters Thesis, Texas A&M University. Accessed September 23, 2019.
http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-A376.
MLA Handbook (7th Edition):
Akin, James Browning. “Attenuation of dilute aromatic hydrocarbon transport by a block copolymer in a compacted vertisol.” 2012. Web. 23 Sep 2019.
Vancouver:
Akin JB. Attenuation of dilute aromatic hydrocarbon transport by a block copolymer in a compacted vertisol. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2019 Sep 23].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-A376.
Council of Science Editors:
Akin JB. Attenuation of dilute aromatic hydrocarbon transport by a block copolymer in a compacted vertisol. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-A376
Texas A&M University
7.
Franti, Jason M.
Movement and treatment of water containing Escherichia coli applied to soil by subsurface drip emitters.
Degree: MS, soil science, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-F73
► Drip tubing as a means of applying domestic wastewater to soil is increasing in use, especially in clayey soils that are unsuitable for traditional disposal…
(more)
▼ Drip tubing as a means of applying domestic wastewater to soil is increasing in use, especially in clayey soils that are unsuitable for traditional disposal systems. Experiments were undertaken to evaluate operational constraints of drip tubing in regards to the reduction of Escherichia coli in wastewater that reaches the soil surface and the number of instances of wastewater surfacing in these clayey soils. Water colored with a dye and inoculated with E. coli was applied to soil through drip emitters at four dosing rates at two sites. Populations of E. coli in water that reached the soil surface were reduced by less than 20%, regardless of the dosing rate. Approximately 50% of emitters produced water on the soil surface at Site 1 and emitters at Site 2 produced few surfacings. Upon excavation, preferential flow was determined to be the mechanism for wastewater reaching the soil surface. Two depths of burial, 15 and 30 cm, were examined to determine depth effects on the frequency of wastewater reaching the soil surface using newly installed drip tubing. Deeper burial inhibited wastewater from reaching the soil surface, but did not eliminate preferential flow. E. coli populations were not reduced in surfacing wastewater when the depth of burial was increased. These same soils were found to remove greater than 99% of the cells when contaminated water was applied in laboratory column studies. However, this soil was free of preferential flow paths. When water was applied to a uniformly disturbed soil, the distribution of water was not uniformly dispersed spherically around the emitter. Instead, water flowed conically toward the microcosm surface when soil water (P[w]) was highest and dispersed into the bottom of the microcosm in drier samples. Some management practices showed potential to disperse domestic wastewater applied through drip emitters in a manner that will limit the instances of poorly treated wastewater reaching the soil surface.
Subjects/Keywords: soil science.; Major soil science.
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Franti, J. M. (2012). Movement and treatment of water containing Escherichia coli applied to soil by subsurface drip emitters. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-F73
Chicago Manual of Style (16th Edition):
Franti, Jason M. “Movement and treatment of water containing Escherichia coli applied to soil by subsurface drip emitters.” 2012. Masters Thesis, Texas A&M University. Accessed September 23, 2019.
http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-F73.
MLA Handbook (7th Edition):
Franti, Jason M. “Movement and treatment of water containing Escherichia coli applied to soil by subsurface drip emitters.” 2012. Web. 23 Sep 2019.
Vancouver:
Franti JM. Movement and treatment of water containing Escherichia coli applied to soil by subsurface drip emitters. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2019 Sep 23].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-F73.
Council of Science Editors:
Franti JM. Movement and treatment of water containing Escherichia coli applied to soil by subsurface drip emitters. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-F73
Texas A&M University
8.
Niemeyer, Patrick G.
Soil phosphorus status and fertilizer use in select agricutural soils in Nicaragua.
Degree: MS, soil science, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-N61
► A survey of small, medium and large Nicaraguan producers indicated a heavy reliance on imported complete fertilizer. Analysis of soils sampled from the large-scale commercial…
(more)
▼ A survey of small, medium and large Nicaraguan producers indicated a heavy reliance on imported complete fertilizer. Analysis of soils sampled from the large-scale commercial producers found low P retention in the lowland heavy clay soils. These soils contained high amounts of plant available P as indicated by four soil P testing methods, Texas A&M, Bray I, Mehlich III and Olsen. These same methods extracted less P from soils from Pacific coast volcanic lowlands and central highland uplands, indicating significant P retention in soils of these two regions. These findings are supported by a greenhouse study in which an indicator crop grown in the lowland clay soils demonstrated no response to added P. A high response in the indicator crop was observed in the volcanic lowland and central highland soils. Correlation between the four P extraction methods and plant response in the volcanic lowland and central highland soils was high, indicating all methods were adequate for these soils. A statistical correlation of the P quantities extracted by the four methods from all soils in the study found that all methods correlated well, indicating that all methods are adequate for the soils in the study. A phosphorus fractionation method found lowland-clay soils were dominated by the Ca-P fraction. The predominant fractions in volcanic lowland and central highland soils were Fe-P and Al-P.
Subjects/Keywords: soil science.; Major soil science.
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Niemeyer, P. G. (2012). Soil phosphorus status and fertilizer use in select agricutural soils in Nicaragua. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-N61
Chicago Manual of Style (16th Edition):
Niemeyer, Patrick G. “Soil phosphorus status and fertilizer use in select agricutural soils in Nicaragua.” 2012. Masters Thesis, Texas A&M University. Accessed September 23, 2019.
http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-N61.
MLA Handbook (7th Edition):
Niemeyer, Patrick G. “Soil phosphorus status and fertilizer use in select agricutural soils in Nicaragua.” 2012. Web. 23 Sep 2019.
Vancouver:
Niemeyer PG. Soil phosphorus status and fertilizer use in select agricutural soils in Nicaragua. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2019 Sep 23].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-N61.
Council of Science Editors:
Niemeyer PG. Soil phosphorus status and fertilizer use in select agricutural soils in Nicaragua. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-N61
Texas A&M University
9.
Peach, Allen Edward.
Functional and taxonomic diversity of microbial communities in reclaimed East Texas lignite mine soils.
Degree: MS, soil science, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-P395
► A two-year study was conducted at Big Brown lignite mine in Freestone County, Texas, to determine the influence of surface mining and reclamation on the…
(more)
▼ A two-year study was conducted at Big Brown lignite mine in Freestone County, Texas, to determine the influence of surface mining and reclamation on the functional and taxonomic diversity in soil microbial communities. Quarterly soil samples were collected along a chronosequence including sites of 0, 1, 4, 12, and 28 years following mining and reclamation. In addition to these sites, an unmined reference site, and a tree mott (reclamation age of 20 years) were included in the study. The functional diversity of the microbial communities was assessed using the Biolog sole-carbon source utilization (SCSU) assay. Taxonomic diversity was measured using whole-soil fatty acid methyl ester (FAME) analysis. Results indicated that surface mining had a transient influence on both the functional and taxonomic diversity of the soil microbial communities reducing complexity during disturbance and early reclamation. However, the effect was reversed as the reclamation process matured. Principal component analysis (PCA) was able to separate the younger sites from the older sites in both the SCSU profiles and the FAME profiles of the soils. The separation of sites was greater, however, in the analysis of the FAME profiles suggesting a more significant change in the level of taxonomic diversity. Results from the SCSU analysis revealed a return to similarity with the reference site between one and four years. Fatty acid methyl ester profiles indicated a return to similarity with the reference site in approximately 12 years.
Subjects/Keywords: soil science.; Major soil science.
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Peach, A. E. (2012). Functional and taxonomic diversity of microbial communities in reclaimed East Texas lignite mine soils. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-P395
Chicago Manual of Style (16th Edition):
Peach, Allen Edward. “Functional and taxonomic diversity of microbial communities in reclaimed East Texas lignite mine soils.” 2012. Masters Thesis, Texas A&M University. Accessed September 23, 2019.
http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-P395.
MLA Handbook (7th Edition):
Peach, Allen Edward. “Functional and taxonomic diversity of microbial communities in reclaimed East Texas lignite mine soils.” 2012. Web. 23 Sep 2019.
Vancouver:
Peach AE. Functional and taxonomic diversity of microbial communities in reclaimed East Texas lignite mine soils. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2019 Sep 23].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-P395.
Council of Science Editors:
Peach AE. Functional and taxonomic diversity of microbial communities in reclaimed East Texas lignite mine soils. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-P395
Texas A&M University
10.
Porter, Elizabeth Brooke.
Siderite, oxidation, and neutralization potential determination.
Degree: MS, soil science, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-P556
► Due to the nature of native soils overlying lignite seams in Texas, mixed overburden is allowed as a topsoil substitute. Determination of suitable topsoil replacements…
(more)
▼ Due to the nature of native soils overlying lignite seams in Texas, mixed overburden is allowed as a topsoil substitute. Determination of suitable topsoil replacements is based on chemical analysis, including neutralization potential (NP), a component of acid-base accounting (ABA). The presence of siderite (FeCO₃) contributes to an overburdens NP, which may result in false positive ABA values, leading to overestimation of neutralizing minerals and therefore, may result in acid drainage / acid soils. Mineralogy and chemistry of overburden samples from Texas lignite mines were characterized for use in (NP) determination studies. Samples were obtained from the Northwestern Resources (NWR) mine in Jewett, Texas Utilities (TXU) mines at Oak Hill and Big Brown, and Intermountain Laboratories (IML) in College Station. The IML samples all contained FeCO₃ and had high ABA values. The FeCO₃ rock obtained from the NWR mine has cation substitution for Fe in the lattice. The conducted research examined reactions of FeCO₃ under various testing conditions as related to NP determination as well as accuracy of the NP method. The effects of hydrogen peroxide (H₂O₂), potassium persulfate (K₂S₂O₈), and potassium permanganate (KMnO₄) on the NP of mixed overburden containing FeCO₃ were studied. Hydrogen peroxide produced variable results depending upon complete removal of excess oxidant. Oxidation with K₂S₂O₈ produced lower NP values that the standard method. KMnO₄ reduced the NP significantly when FeCO₃ is present in the soil. However, dissolution of minerals other than FeCO₃ may increase NP if 0.5 M HCl is for digestion before oxidation.
Subjects/Keywords: soil science.; Major soil science.
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Porter, E. B. (2012). Siderite, oxidation, and neutralization potential determination. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-P556
Chicago Manual of Style (16th Edition):
Porter, Elizabeth Brooke. “Siderite, oxidation, and neutralization potential determination.” 2012. Masters Thesis, Texas A&M University. Accessed September 23, 2019.
http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-P556.
MLA Handbook (7th Edition):
Porter, Elizabeth Brooke. “Siderite, oxidation, and neutralization potential determination.” 2012. Web. 23 Sep 2019.
Vancouver:
Porter EB. Siderite, oxidation, and neutralization potential determination. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2019 Sep 23].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-P556.
Council of Science Editors:
Porter EB. Siderite, oxidation, and neutralization potential determination. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-P556
Texas A&M University
11.
Shourds, Shalyn Wayne.
Is degradation of the herbicide atrazine enhanced in turfgrass pond sediments.
Degree: MS, soil science, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-S563
► To further understand the fate of atrazine, a herbicide of public concern in the environment, this study was undertaken to determine if atrazine degradation potential…
(more)
▼ To further understand the fate of atrazine, a herbicide of public concern in the environment, this study was undertaken to determine if atrazine degradation potential is increased in turfgrass ponds having a history of repeated exposure to agrichemicals. Two sets of mesocosms (20 L) were established: one containing sediments from a pond at the Turfgrass Research Center on the Texas A&M campus, which had repeated exposure to agrichemicals, the other containing sediments from a pond on a local horse-farm that had no contact with agrichemicals in recent years. These mesocosms were fortified with atrazine (100 [u]g L⁻¹) and incubated under aerobic and hypoxic conditions, and the concentrations of atrazine in the water and sediment were monitored. In addition, dissolved oxygen, phosphate, nitrate, and ammonium levels, and bacterial populations were monitored in the mesocosms. To determine the role of microbes in the degradation of atrazine, sterile controls were developed in a manner similar to the mesocosms. By monitoring the twelve mesocosms, it was possible to determine that the appropriate environments were maintained, and that the water chemistry was consistent with either an aerobic or hypoxic environment, as appropriate. The rates of atrazine degradation in both pond systems were very similar. Atrazine concentrations declined by about 65% in 160 days. Degradation was more rapid under aerobic conditions, but the difference was not statistically significant. Effects of prior exposure to agrichemicals on the rate of atrazine degradation were not detected. The most likely cause is that there was insufficient exposure to atrazine in the turfgrass pond to develop a population of rapid atrazine degraders.
Subjects/Keywords: soil science.; Major soil science.
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Shourds, S. W. (2012). Is degradation of the herbicide atrazine enhanced in turfgrass pond sediments. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-S563
Chicago Manual of Style (16th Edition):
Shourds, Shalyn Wayne. “Is degradation of the herbicide atrazine enhanced in turfgrass pond sediments.” 2012. Masters Thesis, Texas A&M University. Accessed September 23, 2019.
http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-S563.
MLA Handbook (7th Edition):
Shourds, Shalyn Wayne. “Is degradation of the herbicide atrazine enhanced in turfgrass pond sediments.” 2012. Web. 23 Sep 2019.
Vancouver:
Shourds SW. Is degradation of the herbicide atrazine enhanced in turfgrass pond sediments. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2019 Sep 23].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-S563.
Council of Science Editors:
Shourds SW. Is degradation of the herbicide atrazine enhanced in turfgrass pond sediments. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-S563
Texas A&M University
12.
Stecher, Matthew C.
Wastewater treatment and flow patterns in an onsite subsurface flow constructed wetland.
Degree: MS, soil science, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-S72
► Subsurface flow constructed wetlands (SFCWs) are becoming increasingly common as a secondary treatment of onsite domestic wastewater. Even though SFCWs are being used widely, sufficient…
(more)
▼ Subsurface flow constructed wetlands (SFCWs) are becoming increasingly common as a secondary treatment of onsite domestic wastewater. Even though SFCWs are being used widely, sufficient data has not been collected to determine how parameters such as wastewater depth and plants affect treatment. This study was conducted to determine how the sizing of a SFCW and the addition of plants influences the quality of effluent it releases. Data was also collected to determine how wastewater flows in a SFCW at different depths, with and without plants, and in relation to dosing volume. Quality of effluent wastewater was measured for different biological oxygen demand (BOD₅) loading rates, wastewater depths, and with and without Cyperus alternifolius (umbrella palms). Blue dye and bromide tracers were used to determine flow of wastewater through a SFCW at different depths and with plants. Results showed that BOD₅ load reductions were 10% better at a 25 cm vs. a 40 cm wastewater depth when the surface area remained the same. Reductions of influent BOD₅, TSS, and NH₄⁺ concentrations were also 13, 13, and 43% better, respectively, when umbrella palms were growing in the SFCW. It was determined that wastewater mixed with depth as it moved through the SFCW, both when the wastewater inlet pipe was near the wastewater surface, and when it was placed on the bottom of the SFCW having a 17 or 25 cm wastewater depth. Increasing the wastewater depth to 40 cm resulted in less uniform flow of wastewater with depth. More water seemed to move through the middle depths at a 40 cm wastewater depth. Bromide performed better as a tracer to follow water movement than blue dye, since blue dye movement was retarded in the SFCW. Wastewater depth had a significant effect on wastewater treatment, and plants increased wastewater treatment efficiency. This study suggests that the position of the inlet pipe (top or bottom of the gravel bed) is not critical for adequate wastewater treatment. In addition to this, if plants are included, the size of the SFCW could probably be reduced by 10 to 15%. From this research it seems that a small (one family) SFCW for on-site domestic wastewater treatment would have a wastewater depth between 20 and 25 cm.
Subjects/Keywords: soil science.; Major soil science.
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Stecher, M. C. (2012). Wastewater treatment and flow patterns in an onsite subsurface flow constructed wetland. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-S72
Chicago Manual of Style (16th Edition):
Stecher, Matthew C. “Wastewater treatment and flow patterns in an onsite subsurface flow constructed wetland.” 2012. Masters Thesis, Texas A&M University. Accessed September 23, 2019.
http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-S72.
MLA Handbook (7th Edition):
Stecher, Matthew C. “Wastewater treatment and flow patterns in an onsite subsurface flow constructed wetland.” 2012. Web. 23 Sep 2019.
Vancouver:
Stecher MC. Wastewater treatment and flow patterns in an onsite subsurface flow constructed wetland. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2019 Sep 23].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-S72.
Council of Science Editors:
Stecher MC. Wastewater treatment and flow patterns in an onsite subsurface flow constructed wetland. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2001-THESIS-S72
Texas A&M University
13.
Baker, Andrew Dwight.
Bioavailable organic carbon in wetland soils across a broad climogeographic area.
Degree: MS, soil science, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-2002-THESIS-B353
► Soils from a broad climogeographic region of the U.S., ranging from Alaska to Louisiana and Texas, were obtained from the NRCS National Soils Laboratory in…
(more)
▼ Soils from a broad climogeographic region of the U.S., ranging from Alaska to Louisiana and Texas, were obtained from the NRCS National Soils Laboratory in Lincoln, Nebraska. Soils were also collected in the summer of 1996 from upland and poorly drained areas in northern Alaska for comparison of biological properties and to determine the effects of drying on estimation of microbial biomass and activity. Air-dried soils were moistened and incubated 48 h, during which time CO₂ evolution was measured. Following the preincubation, microbial biomass was determined using a modification of the chloroform-fumigation-incubation method to accommodate limited sample quantity. Carbohydrates were determined using bicinchoninic acid reagent and total extractable carbon was determined by analysis of 0.5-M K₂SO₄ extracts with a total carbon analyzer. The objectives of this study were to elucidate geographical trends and meaningful relationships between the bioavailable C parameters. Soil microbial biomass, determined by chloroform fumigation incubation, correlated best with organic C and basal respiration with subtraction of unfumigated controls. Extraction of C with hot water was a rapid, simple procedure that provided the best predictor of soil respiration. Potassium sulfate-extractable carbon was consistently lower than hot water extractable C. Soils from northern states tended to contain more organic carbon than soils in southern states, however, not necessarily more bioavailable C. Detecting geographical trends for bioavailable C proved more difficult due to numerous factors such as topographic position, surface vegetation, climate, and land use.
Subjects/Keywords: soil science.; Major soil science.
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Baker, A. D. (2012). Bioavailable organic carbon in wetland soils across a broad climogeographic area. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2002-THESIS-B353
Chicago Manual of Style (16th Edition):
Baker, Andrew Dwight. “Bioavailable organic carbon in wetland soils across a broad climogeographic area.” 2012. Masters Thesis, Texas A&M University. Accessed September 23, 2019.
http://hdl.handle.net/1969.1/ETD-TAMU-2002-THESIS-B353.
MLA Handbook (7th Edition):
Baker, Andrew Dwight. “Bioavailable organic carbon in wetland soils across a broad climogeographic area.” 2012. Web. 23 Sep 2019.
Vancouver:
Baker AD. Bioavailable organic carbon in wetland soils across a broad climogeographic area. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2019 Sep 23].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2002-THESIS-B353.
Council of Science Editors:
Baker AD. Bioavailable organic carbon in wetland soils across a broad climogeographic area. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2002-THESIS-B353
Texas A&M University
14.
Barth, Amy Kristen.
Land capability classification of minesoils in East Texas.
Degree: MS, soil science, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-2002-THESIS-B385
► Surface mining regulations require successful reclamation of areas disturbed by mining processes to a condition comparable to or better than the pre-mine soil. The regulations…
(more)
▼ Surface mining regulations require successful reclamation of areas disturbed by mining processes to a condition comparable to or better than the pre-mine soil. The regulations also require a plan for reclamation in which proposed uses must be set for the post-mine land. A land capability classification specific to minesoils will facilitate the design of appropriate land uses or alternative uses for reclaimed mine areas based on observed limitations. The proposed system is similar to the Land Capability Classification System (LCCS) used by the United States Department of Agriculture (USDA), National Resources Conservation Service (NRCS). Soil chemical and physical characteristics were measured to determine what limitations occur in minesoils; measurements included soil pH, potential acidity, exchangeable acidity, acid-base account, particle size distribution, available nutrients (N, P, K), amounts of basic cations, electrical conductivity, cation exchange capacity, permeability, cone index, moisture content, and available water-holding capacity. Comparisons were made between pre-mine soils and minesoils from the dragline and cross-pit spreader methods of overburden removal. Segments of the study site from the dragline minesoil were limited by slope, texture extremes, low pH, and salinity. Based on averages across the entire study site, the capability class of the dragline soil is IIIe. Segments of the study site from the cross-pit spreader minesoil were limited by slope. Based on averages across the entire study site, the capability class of the cross-pit spreader soil is IIe. The land capability classes were improved in most cases compared to pre-mine soils due to less extreme slopes and decreased root-zone limitations by means of improved permeability, effective depth of rooting, and available water capacity. The problems presented by some areas of the minesoil (low pH, salinity, texture extremes) can be managed by future land owners if they are aware of the severity and scope of the problem in association with their intended land use. Application of the LCCS can be useful to predict suitable land uses for minesoils. Allowances for variability of the soils and potential yield should be considered as part of the criteria for classification. Choosing an appropriate scale for classification is equally important, depending on the intended land use.
Subjects/Keywords: soil science.; Major soil science.
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Barth, A. K. (2012). Land capability classification of minesoils in East Texas. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2002-THESIS-B385
Chicago Manual of Style (16th Edition):
Barth, Amy Kristen. “Land capability classification of minesoils in East Texas.” 2012. Masters Thesis, Texas A&M University. Accessed September 23, 2019.
http://hdl.handle.net/1969.1/ETD-TAMU-2002-THESIS-B385.
MLA Handbook (7th Edition):
Barth, Amy Kristen. “Land capability classification of minesoils in East Texas.” 2012. Web. 23 Sep 2019.
Vancouver:
Barth AK. Land capability classification of minesoils in East Texas. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2019 Sep 23].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2002-THESIS-B385.
Council of Science Editors:
Barth AK. Land capability classification of minesoils in East Texas. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2002-THESIS-B385
Texas A&M University
15.
Huebner, Henry Joseph.
The evaluation of two extraction procedures for the recovery of organic chemicals from spiked soils.
Degree: MS, soil science, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-1993-THESIS-H887
► Hazardous waste site assessments are based on the results of analytical procedures used to identify and quantify chemicals contaminating the soil. The accuracy of these…
(more)
▼ Hazardous waste site assessments are based on the results of analytical procedures used to identify and quantify chemicals contaminating the soil. The accuracy of these results is fundamentally linked to the ability of a solvent extraction procedure to desorb and remove contaminants from a sample matrix prior to analysis. The recovery efficiency of an extraction procedure will indeed affect the quality of analytical data and may influence waste site assessments. The objective of this study was to compare the extraction efficiencies of the automatic Soxtec and U. S. EPA SW846 Soxhlet methods. In phases one and two of the experiment, extractions were performed on silicon dioxide matrices and silt-loam soils spiked with benz(a)pyrene, pentachlorophenol, and naphthalene at three concentration levels. Each test sample contained either an individual chemical or a 1: 1: I mixture of all three chemicals. Phase three consisted of extractions performed on a silt-loam soil spiked with a coal tar complex mixture. Soxtec samples were sequentially extracted with dichloromethane and methanol while Soxhlet samples were extracted with dichloromethane., Gas chromatographic results obtained from sample extract analysis were used to calculate percent recoveries of the chemicals. The recoveries of benz(a)pyrene and pentachlorophenol in the Soxtec procedure ranged from 55-88% and 49-88% respectively, For the Soxhlet method, the recoveries ranged from 4673% and 52-87% respectively, Complex mixture recoveries ranged from 50-60% for both procedures. The mutagenic potentials of the solvent extracts were evaluated using Salrnonella typhimtii- ium strain TA98 with and without metabolic activation. Assay results indicated a positive correlation between mutagenic response, assay controls, and the chemical concentrations derived from GC analysis. The data indicate that the Soxtec method which requires 2 hours, is as effective as the traditional 16 hour Soxhlet extraction procedure for recovering organic chemicals from contaminated matrices. The Soxtec method, thus, offered substantial time and cost savings.
Subjects/Keywords: soil science.; Major soil science.
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Huebner, H. J. (2012). The evaluation of two extraction procedures for the recovery of organic chemicals from spiked soils. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-1993-THESIS-H887
Chicago Manual of Style (16th Edition):
Huebner, Henry Joseph. “The evaluation of two extraction procedures for the recovery of organic chemicals from spiked soils.” 2012. Masters Thesis, Texas A&M University. Accessed September 23, 2019.
http://hdl.handle.net/1969.1/ETD-TAMU-1993-THESIS-H887.
MLA Handbook (7th Edition):
Huebner, Henry Joseph. “The evaluation of two extraction procedures for the recovery of organic chemicals from spiked soils.” 2012. Web. 23 Sep 2019.
Vancouver:
Huebner HJ. The evaluation of two extraction procedures for the recovery of organic chemicals from spiked soils. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2019 Sep 23].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1993-THESIS-H887.
Council of Science Editors:
Huebner HJ. The evaluation of two extraction procedures for the recovery of organic chemicals from spiked soils. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1993-THESIS-H887
Texas A&M University
16.
Ramsey, Ronald Roland.
The atmospheric release of benzene, toluene, ethylbenzene, and xylene from contaminated soils.
Degree: MS, soil science, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-1993-THESIS-R183
► Chemicals may enter the environment in a number of ways accidents, spills during transport, leakage from waste disposal or storage sites, or discharge from industrial…
(more)
▼ Chemicals may enter the environment in a number of ways accidents, spills during transport, leakage from waste disposal or storage sites, or discharge from industrial facilities. Hydrocarbons usually enter the environment through accidental spills or the leaking of storage tanks and their piping. The number of leaking underground storage tanks (LUST) that are reported to government agencies has dramatically increased in the past several years. It is estimated that of 2.1 million buried fuel tanks, 360,000 sites will be reported leaking by 1997. The Environmental Protection Agency (EPA) estimates that it will take 20 to 30 years and an average of 1 00, 000 to 400, 000 per site to remediate all sites. Many techniques have been developed for the remediation of gasoline contaminated soils. Excavation and removal of soils containing hydrocarbons is the most widely used remediation technique because of immediate and total site cleanup. Benzene, toluene, ethylbenzene, and xylene (BTEX) combined are from 10 to 40 percent of unleaded gasoline. During the excavation of LUST and the storage of the contaminated soils, many of the lighter compounds in gasoline (including BTEX) volatilized into the atmosphere. The objectives of this study were to: evaluate the impact of soil type on the volatilization of BTEX from excavated soil-, evaluate the impact of the thickness of the layer of excavated soil on the volatilization of BTEX; and evaluate the impact of a layer of sewage sludge placed over the excavated soil on the volatilization of BTEX from the soil. In the studies, BTEX exhibited a two phase vaporization process. During the first phase (24 to 72 hours) of vaporization, free product is the source of BTEX released into the atmosphere. Sixty to ninety percent of the BTEX applied to the soil was vaporized during the first phase of volatilization. During the second phase of release, the vaporization of BTEX occurred slowly as the smaller fractions of BTEX volatilized from the other phases of the soil system. Ninety to one hundred percent of the BTEX applied was vaporized during the experiments. The rate of volatilization from a Brackett clay soil was approximately IO% less than the rate from a Weswood silt loam soil. The lower amount of BTEX volatilized was attributed to the higher organic carbon content and higher clay content in the Brackett clay soil. There was no significant observed effect on the rate and amount of volatilization from different depths of excavated soil. Increasing the amount of organic matter in a soil, such as adding a layer of sewage sludge, decreased the rate and amount of BTEX volatilization.
Subjects/Keywords: soil science.; Major soil science.
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Ramsey, R. R. (2012). The atmospheric release of benzene, toluene, ethylbenzene, and xylene from contaminated soils. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-1993-THESIS-R183
Chicago Manual of Style (16th Edition):
Ramsey, Ronald Roland. “The atmospheric release of benzene, toluene, ethylbenzene, and xylene from contaminated soils.” 2012. Masters Thesis, Texas A&M University. Accessed September 23, 2019.
http://hdl.handle.net/1969.1/ETD-TAMU-1993-THESIS-R183.
MLA Handbook (7th Edition):
Ramsey, Ronald Roland. “The atmospheric release of benzene, toluene, ethylbenzene, and xylene from contaminated soils.” 2012. Web. 23 Sep 2019.
Vancouver:
Ramsey RR. The atmospheric release of benzene, toluene, ethylbenzene, and xylene from contaminated soils. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2019 Sep 23].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1993-THESIS-R183.
Council of Science Editors:
Ramsey RR. The atmospheric release of benzene, toluene, ethylbenzene, and xylene from contaminated soils. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1993-THESIS-R183
Texas A&M University
17.
Trostle, Calvin Lewie.
The behavior of soil-applied cyclotri- and cyclotetraphosphate in Texas soils.
Degree: MS, soil science, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-1993-THESIS-T857
► Cyclotriphosphate (C3P) is of interest to soil scientists because it demonstrates little or no retention by soil constituents. Non-sorption is desirable in the development of…
(more)
▼ Cyclotriphosphate (C3P) is of interest to soil scientists because it demonstrates little or no retention by soil constituents. Non-sorption is desirable in the development of mobile P fertilizers. Work was expanded to include cyclotetraphosphate (C4P), a larger but commercially unavailable cyclic P compound that is more stable than C3P in solution. High-purity C4P was prepared by ethanol precipitation of the hydrolysis products Of P4010. Improved methods of ion chromatography were applied to the analysis of cyclic P and all hydrolysis products extracted from soil using a water/0-5 M H2SO4/1 .0 M NAOH extraction procedure developed for this work. Separation and direct quantitative analysis of linear and cyclic polyphosphates were accomplished in less than 15 minutes. The rapidity and ease of these analyses represent a vast improvement over previous methods of polyphosphate analysis. Four diverse Texas soils received 1 00 and 400 gg cyclic P g-1 soil as either C3P or C4P and were incubated under different water, temperature, biological activity, and time regimes. The larger C4P was not appreciably sorbed in soil and was more stable than C3P under all conditions. Rate constants and the time to one half of initial P concentration were determined for each P. Kinetic data suggested that the hydrolysis of cyclic P in soils is complex, but cyclic P hydrolysis most likely follows first-order kinetics. The mechanism of C4P hydrolysis- particularly at low P application rates-may involve direct conversion of C4P to diphosphate and triphosphate (in addition to tetraphosphate), possibly due to phosphatase action in C4P hydrolysis. Temperature dependency of C3P and C4P hydrolysis was examined. All treatments showed Qlo < 2.0, indicating the prominence of biological hydrolysis in cyclic P decomposition in soils. Energy of activation (EA) was 45.8 and 61.1 kJ mol-1, respectively, for C3P and C4P on Falba sandy loam at the low P rate (38.6 and 51.2 kJ mol-I for the same treatments on Branyon clay). Nineteen soil parameters were examined for correlation with C3P and C4P hydrolysis. Numerous significant correlations (P < 0.05) were reported, but high intercorrelation among related soil factors was suspected, thus reducing the value of correlation analysis.
Subjects/Keywords: soil science.; Major soil science.
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Trostle, C. L. (2012). The behavior of soil-applied cyclotri- and cyclotetraphosphate in Texas soils. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-1993-THESIS-T857
Chicago Manual of Style (16th Edition):
Trostle, Calvin Lewie. “The behavior of soil-applied cyclotri- and cyclotetraphosphate in Texas soils.” 2012. Masters Thesis, Texas A&M University. Accessed September 23, 2019.
http://hdl.handle.net/1969.1/ETD-TAMU-1993-THESIS-T857.
MLA Handbook (7th Edition):
Trostle, Calvin Lewie. “The behavior of soil-applied cyclotri- and cyclotetraphosphate in Texas soils.” 2012. Web. 23 Sep 2019.
Vancouver:
Trostle CL. The behavior of soil-applied cyclotri- and cyclotetraphosphate in Texas soils. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2019 Sep 23].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1993-THESIS-T857.
Council of Science Editors:
Trostle CL. The behavior of soil-applied cyclotri- and cyclotetraphosphate in Texas soils. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1993-THESIS-T857
Texas A&M University
18.
Waggoner, Paul James.
Microbial hydrolysis of urea and its subsequent nitrification in East Texas lignite mine spoil.
Degree: MS, soil science, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-1993-THESIS-W1314
► A functional nitrogen (N) cycle within mine spoils is necessary for successful long-term revegetation. To initiate successful revegetation of mined lands, large inputs of N…
(more)
▼ A functional nitrogen (N) cycle within mine spoils is necessary for successful long-term revegetation. To initiate successful revegetation of mined lands, large inputs of N fertilizers are required. Urea is gaining worldwide popularity as an N source due to its high N content (47.0 %) and economical price. Since little is known about the behavior of urea in the mixed overburden mine spoils of east Texas, a two-year study was conducted to determine rates of urea hydrolysis, and its subsequent nitrification and effects on microbial activity, at reclaimed sites of varied ages. Newly-leveled, I-, 4-, and 8-year-old spoil and an unmined soil at the Big Brown Mine in Fairfield, TX, were fertilized with 244 kg N ha-' of (NH4)2SO4 or urea. After fertilization, soils were periodically analyzed for microbial activity (arginine ammonification, AA; substrate induced respiration, SIR), ability to hydrolyze urea (UH), numbers of nitrifying bacteria, and nitrification potentials (Nps). Only soils from the unmined and newly- leveled sites failed to show increased AA rates. Vegetated mine spoils showed AA rates ranging from 1.2 to 2.3 mg NH 4 N kg-I soil h-1 within seven days. Rates of AA were similar in soils fertilized with (NH4)2SO4 or urea. Rates of SIR showed a similar pattern, being maximal in the 8-yr spoil and rates were similar in soils fertilized with (NH4)2SOl or urea. Rates of AA and SIR were highly correlated (r = 0.59 to 0.93). Revegetated mine spoils (4 to 8 yrs) showed UH rates as high, or higher than those of the unmined soil. Rates of UH were greatest at the 8-yr site (ranging from 3.0 to 3.5 mg urea-N hydrolyzed kg-' soil h-1) and lowest at the newly-leveled site (maxi-mum rate of 0.5 mg urea-N kg-' soil h-'). Rates of UH were similar in soils fertilized with (NH4)2SO4 or urea. Nitrification potentials in vegetated spoil (I to 8 yrs) were similar to, or greater than those of the unmined soil (ranging from 2.4 to 5.2 mg N03 – N kg-' soil d-1). The newly-leveled site showed NPs below 2 mg N03 – N kg-' soil d-1. Peak NPs were observed two weeks after fertilization and the (NH4)2SO4 and urea treatments showed similar rates. Nitrifying bacteria regained pre-mining levels within one year in revegetated mine spoil. Numbers ranged from loglo MPN 3 to 6. Soils from the I-, 4-, and 8-yr sites showed numbers similar to, or greater than, numbers in the unmined soil. Numbers of NH 4 +- and N02 – oxidizing bacteria were similar in soils fertilized with either N source. Bacterial numbers increased one order of magnitude after the newly-leveled site was sprigged, suggesting an inoculation effect. Numbers of nitrifying bacteria and nitrification potentials were highly correlated (r = 0.75 to 0.94). This study demonstrated the rapid recovery, to pre-mining levels, of selected soil microbial activities and populations of nitrifying bacteria in mixed overburden. Ammonium sulfate and urea produced very similar responses for the parameters measured. Urea appears to be as suitable an N source as (NH 4)2SO4 in the…
Subjects/Keywords: soil science.; Major soil science.
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Waggoner, P. J. (2012). Microbial hydrolysis of urea and its subsequent nitrification in East Texas lignite mine spoil. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-1993-THESIS-W1314
Chicago Manual of Style (16th Edition):
Waggoner, Paul James. “Microbial hydrolysis of urea and its subsequent nitrification in East Texas lignite mine spoil.” 2012. Masters Thesis, Texas A&M University. Accessed September 23, 2019.
http://hdl.handle.net/1969.1/ETD-TAMU-1993-THESIS-W1314.
MLA Handbook (7th Edition):
Waggoner, Paul James. “Microbial hydrolysis of urea and its subsequent nitrification in East Texas lignite mine spoil.” 2012. Web. 23 Sep 2019.
Vancouver:
Waggoner PJ. Microbial hydrolysis of urea and its subsequent nitrification in East Texas lignite mine spoil. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2019 Sep 23].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1993-THESIS-W1314.
Council of Science Editors:
Waggoner PJ. Microbial hydrolysis of urea and its subsequent nitrification in East Texas lignite mine spoil. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1993-THESIS-W1314
Texas A&M University
19.
Greenberg, Wendy Avra.
Hydrology and morphology of a toposequence of three Claypan soils in Central Texas.
Degree: MS, soil science, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-1994-THESIS-G7986
► Aquic conditions are defined in terms of saturation and reduction, but they are often evaluated based on soil redoximorphic features. Interpretations of redoximorphic features are…
(more)
▼ Aquic conditions are defined in terms of saturation and reduction, but they are often evaluated based on soil redoximorphic features. Interpretations of redoximorphic features are complicated by the presence of relict features in some areas. In this study three Alfisols forming a toposequence in the Claypan Major Land Resource Area were evaluated for redoximorphic features and actual current moisture conditions. The purpose of this study was to analyze the Silawa-Rader-Edge toposequence to determine which redoximorphic fealures in these soils are associated with contemporary aquic conditions and which are relict features. Saturation, matric potential, and redox potential were measured at several depths with piezometers, tensiometers, and permanently installed Eli electrodes. Redoximorphic and other features were described in the field and from thin sections. Supporting laboratory analyses included physical and chemical characterization, x-ray diffraction, and elemental analysis. None of the three soils studied had a Ground water table within 5 meters of the surface. The high chroma colors in Silawa reflected current well drained conditions which were confirmed by field monitoring. The Fe-Mn nodules and concretions in Silawa were relict features either transported with the terrace deposit or formed in place during a previous wetter moisture regime. The low chroma colors and few nodules in Edge were also relict features from previous wetter environments and did not reflect current well drained conditions. in Rader there was a perched water table at I meter for 6 to 7 months each year during the study period. Thus, Rader met the requirements for episaturation. Water also perched above 60 cm for shorter periods immediately following rainfall events. From Eh readings, Rader appeared to have sufficient periods of reduction in some microsites to mobilize Fe. Therefore, redoximorphic features within perched water tables reflected current as well as previous aquic conditions, while features below BC horizon upper boundary, at 153 cm, were relicts. Taxonomic classifications of the three pedons representing Silawa, Rader, and Edge series were evaluated. All three pedons studied had good evidence for argillic horizons, but each pedon had a few characteristics outside the range of the established series taxonomic placement. The Rader site appeared to be borderline between aquic (as classified) and oxyaquic sub-groups. There were significant microsite variations indicated by replicate readinos for piezometers in Rader and tensionieters and Eh electrodes as in all three soils. Replicates often indicated similar trends but different degrees of saturation and reduction. The designation of aquic or oxyaquic subgroup for Rader hinges on whether reduction is required throughout most of the soil mass to meet aquic condition requirements or reduction in only some microsites is sufficient. The aquic conditions section of the most recent Key to taxonomy (Soil Survey Staff, 1992) does not address this issue.
Subjects/Keywords: soil science.; Major soil science.
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Greenberg, W. A. (2012). Hydrology and morphology of a toposequence of three Claypan soils in Central Texas. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-1994-THESIS-G7986
Chicago Manual of Style (16th Edition):
Greenberg, Wendy Avra. “Hydrology and morphology of a toposequence of three Claypan soils in Central Texas.” 2012. Masters Thesis, Texas A&M University. Accessed September 23, 2019.
http://hdl.handle.net/1969.1/ETD-TAMU-1994-THESIS-G7986.
MLA Handbook (7th Edition):
Greenberg, Wendy Avra. “Hydrology and morphology of a toposequence of three Claypan soils in Central Texas.” 2012. Web. 23 Sep 2019.
Vancouver:
Greenberg WA. Hydrology and morphology of a toposequence of three Claypan soils in Central Texas. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2019 Sep 23].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1994-THESIS-G7986.
Council of Science Editors:
Greenberg WA. Hydrology and morphology of a toposequence of three Claypan soils in Central Texas. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1994-THESIS-G7986
Texas A&M University
20.
Starowitz, Susan Marie.
A study of aquic conditions in a microtoposequence of seasonally wet soils on the Texas Coast Prairie.
Degree: MS, soil science, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-1994-THESIS-S795
► The purpose of this study was to investigate the aquic conditions of three soils with different wetness characteristics based on microtopographic landform positions. The landform…
(more)
▼ The purpose of this study was to investigate the aquic conditions of three soils with different wetness characteristics based on microtopographic landform positions. The landform positions included a closed, seasonally ponded depression, an intermound, and a pimple mound. The proposed criteria for aquic conditions as defined by the International Committee on Aquic Moisture Regimes (ICOMAQ) were to be identified by 1) redoximorphic features and 2) measurement of saturation and reduction to locally verify morphological inferences used to predict these conditions. Interpretations of redoximorphic features are complicated by the presence of relict features in some areas. Morphological properties and laboratory analyses were used to establish a relationship between the redoximorphic features and the frequency and direction of saturation and reduction. The criteria of aquic conditions were evaluated for three pedons and related to morphological properties in order to draw inferences regarding wetness conditions. Taxonomic classification of the three pedons representing the toposequence of mound (Oxyaquic Paleudalf), intermound (Typic Natraqualf), and depression (Typic Endoaqualf), were evaluated in the central Texas Gulf Coast Prairie, northwest of Houston, from the upper to the lower topographic positions. During a 19-month period, each of the different landform positions were seasonally saturated and exhibited different perched and groundwater tables within the upper 2 m. During periods of saturation, low oxidation reduction potentials suggested Fe reduction was occurring in each soil. The mound site exhibited a continuous groundwater table with saturation below 50 cm and reduction below 100 cm. Therefore the Fe-Mn nodules and concretions of the mound site above 50 cm were relict features either transported or formed in place during a previous wetter moisture regime. The presence of a natric horizon and intensive crayfish activity at the intermound site caused the more hydrologically restrictive physical characteristics of the subsoil. Saturation at the intermound occurred at the surface and below 100 cm. This corresponds with decreased water movement within the portion of the profile where a natric horizon occurred between 26 and 136 cm. At the intermound site a confined water table evident from a hydrostatic head was exhibited by the piezometer at 497 cm. The depression site exhibited seasonal saturation and reduction throughout the profile with a confined water table evident from a hydrostatic head occurring in the piezometer at 433 cm. Therefore, redoximorphic features in the depression are associated with current as well as perhaps previous aquic conditions. Redoximorphic features generally supported observed saturation and reduction in the upper soil profiles, but features were observed in portions of the unsaturated profile where neither saturation nor reduction was observed. Positive correlation of redoximorphic features with aquic conditions will require longer periods of monitoring with meteorological data…
Subjects/Keywords: soil science.; Major soil science.
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Starowitz, S. M. (2012). A study of aquic conditions in a microtoposequence of seasonally wet soils on the Texas Coast Prairie. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-1994-THESIS-S795
Chicago Manual of Style (16th Edition):
Starowitz, Susan Marie. “A study of aquic conditions in a microtoposequence of seasonally wet soils on the Texas Coast Prairie.” 2012. Masters Thesis, Texas A&M University. Accessed September 23, 2019.
http://hdl.handle.net/1969.1/ETD-TAMU-1994-THESIS-S795.
MLA Handbook (7th Edition):
Starowitz, Susan Marie. “A study of aquic conditions in a microtoposequence of seasonally wet soils on the Texas Coast Prairie.” 2012. Web. 23 Sep 2019.
Vancouver:
Starowitz SM. A study of aquic conditions in a microtoposequence of seasonally wet soils on the Texas Coast Prairie. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2019 Sep 23].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1994-THESIS-S795.
Council of Science Editors:
Starowitz SM. A study of aquic conditions in a microtoposequence of seasonally wet soils on the Texas Coast Prairie. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1994-THESIS-S795
Texas A&M University
21.
Zeng, Wen.
Effects of climatic chance on surface water and energy balances of sorghum and cotton in West Texas.
Degree: MS, soil science, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-1994-THESIS-Z54
► Global climatic change may be occurring due to the increase of carbon dioxide and other "greenhouse" gases in the atmosphere. Effects of climatic change on…
(more)
▼ Global climatic change may be occurring due to the increase of carbon dioxide and other "greenhouse" gases in the atmosphere. Effects of climatic change on surface water and energy balances of sorghum (Sorghum bicolor L. Moench) were evaluated by the dynamic simulation model ENWATBAL. Daily temperature was varied ︢30C from the control case, while global irradiance (Rs), vapor pressure (VP), wind speed (U) and leaf area index (LAI) were altered ︢20% individually, and in combination. Evaporation (E) and transpiration (T) were calculated separately. One degree incremental changes in temperature resulted in an average increase of 2.9% (6 mm) in E and 3.0% (11 mm) in T. The inputs that affected T (from greatest to least influence) were Rs, LAI, U, and VP, while E was affected most by LAI, followed by VP, U, and Rs. When the inputs were integrated, temperature and VP were the most important factors affecting ET. Warmer and drier weather (+20C,-20% VP) caused a 9% increase in ET. Effects of gradual climate change on water balance of sorghum and cotton (Gossypium hirsutum L.) were assessed by using the WXGEN climate generator model to create weather data for several scenarios in Bushiand and Lubbock, TX, that were used in the ENWATBAL. A gradual 0.50C increase in air temperature over 25 years, in combination with gradual ︢15% changes in VP, a 10% decrease in Rs, increases in LAI of 8.5% for cotton and 3.5% for sorghum, and reductions in stomatal conductance by 3.75% for cotton and 6.75% for sorghum from the control case were studied. ENWARTBAL simulations over a 25-year period predicted that climate change and CO2 induced changes in plant growth and stomatal response had little effect on ET. The changes in ET from the control case over 25 years on all scenarios on both sorghum and cotton ranged 0.2% to 1.1%. Limited rainfall was main reason for the small differences among scenarios.
Subjects/Keywords: soil science.; Major soil science.
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Zeng, W. (2012). Effects of climatic chance on surface water and energy balances of sorghum and cotton in West Texas. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-1994-THESIS-Z54
Chicago Manual of Style (16th Edition):
Zeng, Wen. “Effects of climatic chance on surface water and energy balances of sorghum and cotton in West Texas.” 2012. Masters Thesis, Texas A&M University. Accessed September 23, 2019.
http://hdl.handle.net/1969.1/ETD-TAMU-1994-THESIS-Z54.
MLA Handbook (7th Edition):
Zeng, Wen. “Effects of climatic chance on surface water and energy balances of sorghum and cotton in West Texas.” 2012. Web. 23 Sep 2019.
Vancouver:
Zeng W. Effects of climatic chance on surface water and energy balances of sorghum and cotton in West Texas. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2019 Sep 23].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1994-THESIS-Z54.
Council of Science Editors:
Zeng W. Effects of climatic chance on surface water and energy balances of sorghum and cotton in West Texas. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1994-THESIS-Z54
Texas A&M University
22.
Barghassa, Peyam.
Ammonia volatilization from soils with surface rice straw residue.
Degree: MS, soil science, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-B37
► Reduced tillage rice production can result in rice straw and other residue on the soil surface which may enhance NH, volatilization of surface-applied N. Laboratory,…
(more)
▼ Reduced tillage rice production can result in rice straw and other residue on the soil surface which may enhance NH, volatilization of surface-applied N. Laboratory, greenhouse, and field experiments were conducted to determine the effect of surface rice residue and related factors on NH3 volatilization from an acid Beaumont clay (pH 5.4) and an alkaline Lake Charles clay (pH 7.4). The treatments in the greenhouse and lab consisted of all possible combinations of the following variables: surface rice straw vs. no straw, (NH4)2SO4 VS-urea, surface broadcast vs. deep placement of N, immediate flooding vs. delayed flooding. The treatments in the field consisted of all possible combinations of the following variables: surface rice straw vs. no straw, (NH4)2SO4 VS-urea, and single vs. two equal split applications of the N. The presence of surface straw increased NH3 loss in all studies on both soils. Urea tended to volatilize more than (NH4)2SO4 due to greater straw urease activity. Subsurface application of N virtually eliminated NH3 1oss. Generally,a delayed flood increased NH3 loss- Subsurface N application increased N uptake in the greenhouse. No variable affected N uptake in the field, possibly due to low NH3 losses in the field (O to 6% of applied N). The only variable to affect grain yield was the N application method. Split-applied N increased yield in the Beaumont field study, but decreased it in the Lake Charles study. Reduction in grain yield was not related to increase in NH3 loss. Factors specific to each field may have affected grain yield. A high urease activity (1 980 mg urea kg-' hr'), pH (7.2), and H-ion buffering capacity (73 mmol kg-' (pH unit)-') of rice straw created a conducive environment for NH3 volatilization of surface-applied N, particularly urea. Soil CEC's of over 50 cmol kg-' bound NH4+ from deep-applied N before volatilization could occur.
Subjects/Keywords: soil science.; Major soil science.
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Barghassa, P. (2012). Ammonia volatilization from soils with surface rice straw residue. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-B37
Chicago Manual of Style (16th Edition):
Barghassa, Peyam. “Ammonia volatilization from soils with surface rice straw residue.” 2012. Masters Thesis, Texas A&M University. Accessed September 23, 2019.
http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-B37.
MLA Handbook (7th Edition):
Barghassa, Peyam. “Ammonia volatilization from soils with surface rice straw residue.” 2012. Web. 23 Sep 2019.
Vancouver:
Barghassa P. Ammonia volatilization from soils with surface rice straw residue. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2019 Sep 23].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-B37.
Council of Science Editors:
Barghassa P. Ammonia volatilization from soils with surface rice straw residue. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-B37
Texas A&M University
23.
Kan, Weiqun.
Properties and potential uses of water treatment sludge from the Neches River of southeast Texas.
Degree: MS, soil science, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-K36
► Land application of water treatment plant (WTP) sludge has been an unsolved problem. The objectives of this study were (1) to investigate characteristics of organic…
(more)
▼ Land application of water treatment plant (WTP) sludge has been an unsolved problem. The objectives of this study were (1) to investigate characteristics of organic polymer sludge, and (2) to determine the effects of the sludge on soil properties that influence utilization of the sludge as a soil amendment. Water treatment sludges were obtained from water utilities along the Neches Rivet-near Beaumont, Texas. They were mostly coagulated with organic polymers. Mineralogical composition, cation exchange capacity (CEC), scanning and transmission electron microscopy (SEM and TEM), aggregate stability, Atterberg limits, hydraulic conductivity, dispersion, crust strength, adsorption characteristics, nitrogen content and mineralization potential of the sludge or sludge-amended soil were determined in this study. Mineralogical composition of organic polymer sludge was similar to local Beaumont clay soil. The major fraction of the sludge, the coarse clay, was estimated to be 40% kaolinite, 32% smectite, 20% quartz and 8% mica. However, XRD patterns of the sludge indicated that expansion of the smectite was inhibited by organic polymer coagulant added during water clarification, which also was confirmed by aggregate stability of the sludge. Cation exchange capacity of the bulk sludge samples ranged from 8 to 28 cmol kg-1. Quantitative mineralogical analyses showed that CEC of the sludge was reduced by blockage of cation exchange sites with organic polymers. SEM and TEM results indicated that the sludge was mostly fine aggregates of clay particles. Dried sludge aggregates were not prone to swell, due to their resistance to rewetting. The aggregate stability of dried sludge was above 90% after a 24 hours soaking period in water, compared to 7% aggregate stability of local Beaumont clay soil. Addition of 0 to 10% sludge to Boonville sandy loam soil increased the aggregate stability of the soil from 4 to 13%. Atterberg limit showed that wet sludge had wide ranges of moisture contents in semi-solid and plastic states, and shrunk greatly during drying. Shrinkage limit of the sludges ranged from 16 to 66%; plastic limit from 111 to 138%; and liquid limit from 208 to 320%, which suggested that the sludge was highly plastic and compressible. Addition of 0 to 10% sludge into Boonville sandy loam soil increased the infiltration rate of the soil two orders of magnitudes from 1.4 x 10-4 to 1. I X 10-2 CM / S, and reduced the dispersion of the soil significantly. Moreover, addition of from 0 to 10% sludge into Boonville sandy loam soil greatly reduced the crusting produced by rainfall, and the penetration resistance of the crust decreased from 53.1 to 14.4 kg / cm. Metal adsorbing ability of the Boonville sandy loam soil was reduced by addition of the sludge. Adsorption of Zn+2 decreased from 19.7 to 17.7 ug / g when the sludge was amended from 0 to 10%. Total nitrogen and exchangeable ammonium nitrogen (NH4+) contents of the sludge were four times and twenty times as high, respectively, as those of local Beaumont clay and Lake Charles…
Subjects/Keywords: soil science.; Major soil science.
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Kan, W. (2012). Properties and potential uses of water treatment sludge from the Neches River of southeast Texas. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-K36
Chicago Manual of Style (16th Edition):
Kan, Weiqun. “Properties and potential uses of water treatment sludge from the Neches River of southeast Texas.” 2012. Masters Thesis, Texas A&M University. Accessed September 23, 2019.
http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-K36.
MLA Handbook (7th Edition):
Kan, Weiqun. “Properties and potential uses of water treatment sludge from the Neches River of southeast Texas.” 2012. Web. 23 Sep 2019.
Vancouver:
Kan W. Properties and potential uses of water treatment sludge from the Neches River of southeast Texas. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2019 Sep 23].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-K36.
Council of Science Editors:
Kan W. Properties and potential uses of water treatment sludge from the Neches River of southeast Texas. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-K36
Texas A&M University
24.
Marquart, Darren Keith.
Chemical stabilization of three Texas Vertisols with sulfonated naphthalene.
Degree: MS, soil science, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-M376
► Vertisols shrink and swell with changes in the moisture content of the soil. The volume changes that occur in Vertisols cause destructive forces that can…
(more)
▼ Vertisols shrink and swell with changes in the moisture content of the soil. The volume changes that occur in Vertisols cause destructive forces that can damage a structure built on these soils. This damage is a serious consideration in the management and design of roadways, foundations, and runways. Therefore, there is a need to find solutions to this problem. Condor SS is a stabilization agent that has been marketed with little to no data on its effectiveness. It is marketed as a sulfonated naphthalene "ionizer" that "releases" water from the clays in the soil and reduces shrink/swell. A sulfonated naphthalene standard was tested on three Texas Vertisols to determine its effect on soils with similar mineralogy that represent a range of pH values found in Texas Vertisols. Changes in the mineralogy, in the cation exchange capacity, and in the fabric of the soil were examined to determine how changes may affect the swelling of the three test soils. Tests indicated that a new mineral phase identified as basaluminite, or an intermediate hydroxy aluminum phase, has an effect on the physical characteristics of the soils tested. Basaluminite was evident in the mineralogical analysis of the three soils after treatment. Hydroxy aluminum groups evidently reduced the cation exchange capacity of each of the soil clays. Each soil showed a decrease in permeability and a decrease in swell after treatment with a standard sulfonated naphthalene mixture. Electron microscopy indicated that the interaction of the soil particles was altered due to treatment with the sulfonated naphthalene standard and changed the fabric of the soil due to increased aggregation of particles. This research shows there is a positive effect against the volume changes caused by the shrinking and swelling of Vertisols due to the addition of sulfonated naphthalene to the soil. It also indicates that laboratory testing is essential before adding the stabilizer to the soil because of differences in soil properties.
Subjects/Keywords: soil science.; Major soil science.
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Marquart, D. K. (2012). Chemical stabilization of three Texas Vertisols with sulfonated naphthalene. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-M376
Chicago Manual of Style (16th Edition):
Marquart, Darren Keith. “Chemical stabilization of three Texas Vertisols with sulfonated naphthalene.” 2012. Masters Thesis, Texas A&M University. Accessed September 23, 2019.
http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-M376.
MLA Handbook (7th Edition):
Marquart, Darren Keith. “Chemical stabilization of three Texas Vertisols with sulfonated naphthalene.” 2012. Web. 23 Sep 2019.
Vancouver:
Marquart DK. Chemical stabilization of three Texas Vertisols with sulfonated naphthalene. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2019 Sep 23].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-M376.
Council of Science Editors:
Marquart DK. Chemical stabilization of three Texas Vertisols with sulfonated naphthalene. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-M376
Texas A&M University
25.
Najjar, Namir Fouad.
Exchangeable sodium accumulation and replacement in Southeast Texas soils under turfgrass.
Degree: MS, soil science, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-N346
► Many municipal water supplies in Southeast Texas have a relatively high level of Na+ and low total dissolved solids. Most soils of this area are…
(more)
▼ Many municipal water supplies in Southeast Texas have a relatively high level of Na+ and low total dissolved solids. Most soils of this area are dominated by smectitic clays that respond to wetting by swelling, especially when wetted with high Na waters of low salinity. This study assessed the degree of Na accumulation in Southeast Texas soils under irrigated turfgrass, tested models predicting Na accumulation, and evaluated response of sodic soil to amendments. The Ap, E, and Bt horizons of 18 turf soils in 10 municipal water districts were studied. Irrigation water sodicity (SARiw) and salinity (ECiw) were strongly correlated with soil sodicity (SARE) and salinity (ECe). The SAR,W was found to be the best single variable to model soil Na accumulation but exchangeable Na also increased as a function of years of irrigation. The multiple regression equation: SARE =-5.16 + 0.53 SARiw + 4.04 In (yr) (R2 = 0.86) best predicted SARE to a depth of 30 cm. This study also compared gypsum, a common amendment for sodic soil reclamation, to langbeinite. A column leaching experiment using sodic water was conducted on a sodic, non-saline Boonville soil (fine, montmorillonitic, thermic Ruptic Vertic Albaqualf) amended with gypsum and langbeinite at rates equivalent to exchangeable Na in soil depths of 15 and 30 cm. The soil water at depths of 7.5, 15 and 22.5 cm and the effluent from each column were collected at intervals of 12 h and analyzed for sodium adsorption ratio (SAR) and soluble bases. Saturated hydraulic conductivity (Ksat) was calculated. At the end of the experiment, soil samples were removed from each column in four depth increments. Significantly less exchangeable Na and lower SAR of the soil waters were found in the lower sections of the soil columns, and Ksat was greater for the amended treatments than for the control.
Subjects/Keywords: soil science.; Major soil science.
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Najjar, N. F. (2012). Exchangeable sodium accumulation and replacement in Southeast Texas soils under turfgrass. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-N346
Chicago Manual of Style (16th Edition):
Najjar, Namir Fouad. “Exchangeable sodium accumulation and replacement in Southeast Texas soils under turfgrass.” 2012. Masters Thesis, Texas A&M University. Accessed September 23, 2019.
http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-N346.
MLA Handbook (7th Edition):
Najjar, Namir Fouad. “Exchangeable sodium accumulation and replacement in Southeast Texas soils under turfgrass.” 2012. Web. 23 Sep 2019.
Vancouver:
Najjar NF. Exchangeable sodium accumulation and replacement in Southeast Texas soils under turfgrass. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2019 Sep 23].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-N346.
Council of Science Editors:
Najjar NF. Exchangeable sodium accumulation and replacement in Southeast Texas soils under turfgrass. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-N346
Texas A&M University
26.
Reeder, Geoffrey Benton.
Emergency response planning for railroad transportation related spills of oil or other hazardous materials.
Degree: MS, soil science, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-R438
► In December 1984 an unintentional release of poison gas from a chemical plant in Bhopal, India killed over 2,500 people. Thousands of others were injured.…
(more)
▼ In December 1984 an unintentional release of poison gas from a chemical plant in Bhopal, India killed over 2,500 people. Thousands of others were injured. Although this material was not in transportation at the time, this accident raised public awareness. Americans began to ask, "What if something similar happened here?" Chemicals with hazardous properties have become part of daily life. Industry, government, and the public have become aware of the need to respond to problems involving hazardous materials. Safe transportation of hazardous materials is very important. Union Pacific Railroad transports more hazardous material shipments than any other carrier. Early on they realized the benefits to having a dedicated team of personnel to respond to incidents involving hazardous materials. In order to remain the safest carrier of these commodities, an emergency response plan utilizing in house response personnel was needed. This document describes how that plan was created and includes a copy of the plan for the Union Pacific Railroad's Settegast Yard in Houston, Texas. Other carriers may use this as a template to establish their own in house response teams or emergency response plans.
Subjects/Keywords: soil science.; Major soil science.
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Reeder, G. B. (2012). Emergency response planning for railroad transportation related spills of oil or other hazardous materials. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-R438
Chicago Manual of Style (16th Edition):
Reeder, Geoffrey Benton. “Emergency response planning for railroad transportation related spills of oil or other hazardous materials.” 2012. Masters Thesis, Texas A&M University. Accessed September 23, 2019.
http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-R438.
MLA Handbook (7th Edition):
Reeder, Geoffrey Benton. “Emergency response planning for railroad transportation related spills of oil or other hazardous materials.” 2012. Web. 23 Sep 2019.
Vancouver:
Reeder GB. Emergency response planning for railroad transportation related spills of oil or other hazardous materials. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2019 Sep 23].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-R438.
Council of Science Editors:
Reeder GB. Emergency response planning for railroad transportation related spills of oil or other hazardous materials. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-R438
Texas A&M University
27.
Rooney, Daniel James.
A method to hydrologically isolate water soluble wastes.
Degree: MS, soil science, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-R66
► A natural cover system with gravel used as a capillary barrier was designed and evaluated as a method to hydrologically isolate buried water soluble oil…
(more)
▼ A natural cover system with gravel used as a capillary barrier was designed and evaluated as a method to hydrologically isolate buried water soluble oil and gas wastes. Simulated cover systems were installed in 200 liter barrels and tested in a greenhouse. The treatments contained gravel barrier thicknesses of 0, 8, 15, 23, and 30 cm. Gravel was placed over a salt contaminated soil and was covered with 30 cm of a sandy clay topsoil. Drains were installed in the bottom of the barrels to collect drainage from the gravel layer and below the buried saline waste. Treatments were tested for effectiveness in both a wet and dry moisture regime using simulated monthly rainfall applications. Upward migration of soluble salts was monitored by measuring the electrical resistance of the soil by means of salinity sensors at the base of the topsoil. Electrical conductivity (EC) measurements of the leachate were used to determine the downward movement of soluble salts. Total volume of leachate from each drain was also monitored for each simulated month. Core samples were taken to determine the EC of the topsoil at the conclusion of the experiment. Electrical resistance values indicated that upward soluble salt migration occurred immediately on treatments which did not include a capillary barrier. EC values for all gravel barrier treatments indicated no upward migration of the buried saline waste. Values for EC at the base of the topsoil ranged from 10 to 20 dS M-1 in the treatments with no capillary barrier to 0.1 to 1.0 dS M-1 in treatments containing a capillary barrier. Effluent EC was significantly higher (29-56 dS M-1 ) from below the saline soil than from the gravel drain (2-9 dS M-1 ). In addition, 93 % of the leachate from both moisture regimes that permeated the cover system was collected from the gravel drain. These results indicate that a cover system which includes a capillary barrier would protect groundwater by greatly decreasing downward movement of water soluble constituents. Upward migration of buried water soluble wastes would also be prevented which would in turn protect the topsoil and surface waters.
Subjects/Keywords: soil science.; Major soil science.
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Rooney, D. J. (2012). A method to hydrologically isolate water soluble wastes. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-R66
Chicago Manual of Style (16th Edition):
Rooney, Daniel James. “A method to hydrologically isolate water soluble wastes.” 2012. Masters Thesis, Texas A&M University. Accessed September 23, 2019.
http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-R66.
MLA Handbook (7th Edition):
Rooney, Daniel James. “A method to hydrologically isolate water soluble wastes.” 2012. Web. 23 Sep 2019.
Vancouver:
Rooney DJ. A method to hydrologically isolate water soluble wastes. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2019 Sep 23].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-R66.
Council of Science Editors:
Rooney DJ. A method to hydrologically isolate water soluble wastes. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-R66
Texas A&M University
28.
Sutter, Brad.
Phosphorus adsorption and desorption properties of lunar simulants.
Degree: MS, soil science, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-S88
► To reduce resupply costs of a permanently inhabited lunar base, astronauts will grow crops to supply food, regenerate suitable levels of oxygen, remove carbon dioxide…
(more)
▼ To reduce resupply costs of a permanently inhabited lunar base, astronauts will grow crops to supply food, regenerate suitable levels of oxygen, remove carbon dioxide and recycle water (transpiration). To obtain efficient crop growth, nutrient interactions in lunar soil must be understood. However, due to the high value and limited amounts of lunar soil, lunar simulants were used to approximate nutrient interactions in lunar soil. The primary objective of this research was to determine the most efficient phosphorus (P) fertilizer rate that would provide optimal crop growth in Minnesota Basalt Lunar Simulant (MBLS) and Lunar Glass Simulant (LGS). To achieve this objective, simulant P adsorption, desorption and kinetic desorption Q/I relationships coupled with a wheat growth study were used to determine optimal P requirements for wheat. Phosphorus adsorption Q/I relationships were obtained by incubating simulants with P and analyzing for adsorbed P(QA) and solution P (IA)' Simulant desorption samples were incubated with P. Subsequently, anion-exchange resin was added to the simulants and the amount of P adsorbed by the resin (QD) and solution P (ID) were determined. Kinetic desorption curves (QDT versus time) were obtained using the desorption procedure; however, the resin was removed at intervals from 0 to 70 hours. Wheat was grown in MBLS for 50 days under controlled conditions. After harvest, fresh leaf, dry leaf and root weights were measured. Phosphorus concentrations were determined in leaves, roots and the MBLS solution. Laboratory studies indicated that both simulants did not tightly adsorb P, and any P that was adsorbed was readily released to the resin. The wheat growth study showed that an initial P application of 20 mg P/kg was adequate for wheat. Because most of the applied P remained in solution, it was recommended that, initially, a small P application (10-20 mg P/kg) be applied to the simulants. Additionally, small applications should continue to be added to maintain adequate solution P levels. Larger applications would only introduce more P in solution than required, promoting inefficient use of P fertilizer.
Subjects/Keywords: soil science.; Major soil science.
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Sutter, B. (2012). Phosphorus adsorption and desorption properties of lunar simulants. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-S88
Chicago Manual of Style (16th Edition):
Sutter, Brad. “Phosphorus adsorption and desorption properties of lunar simulants.” 2012. Masters Thesis, Texas A&M University. Accessed September 23, 2019.
http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-S88.
MLA Handbook (7th Edition):
Sutter, Brad. “Phosphorus adsorption and desorption properties of lunar simulants.” 2012. Web. 23 Sep 2019.
Vancouver:
Sutter B. Phosphorus adsorption and desorption properties of lunar simulants. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2019 Sep 23].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-S88.
Council of Science Editors:
Sutter B. Phosphorus adsorption and desorption properties of lunar simulants. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-S88
Texas A&M University
29.
Tavaria, Freni Kekhasharu.
Effect of low pO2 and host plant on colonization of roots by Pseudomonas putida PH6 (L1019).
Degree: MS, soil science, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-T38
► Effective use of genetically altered microorganisms to enhance growth requires a full understanding of the factors governing their colonization potential, as well as survival in…
(more)
▼ Effective use of genetically altered microorganisms to enhance growth requires a full understanding of the factors governing their colonization potential, as well as survival in soil. A low oxygen concentration is known to increase leakage of substrates from roots, therefore affecting the rhizosphere bacterial population. In this study, I have evaluated the effects of low oxygen partial pressure on "total" numbers of bacteria, numbers of Pseudomonas putida PH6(L1019) associated with maize roots, and the amount of soluble carbon exuded or stored in roots. Low pO2 experiments were conducted by exposing roots of maize plants (grown in Weswood silt loam) to low pO2 in solution (hydroponic experiments), or by growing maize plants in fritted clay, and inoculating with L1019. Root and solution (from hydroponics only) samples were collected at selected time intervals, for enumeration of bacteria and determinations of total organic carbon (TOC) and hexose carbon analysis. In the hydroponic experiments, roots tended to accumulate 1.3-fold more carbon, and "total" bacterial numbers were 1.8 to 2.4-fold higher in the low pO2 treatments than under aerated conditions. However, numbers of L1019 were 1.2 to 5.4-fold higher under aerated conditions, suggesting that substrate availability was not the only factor affecting establishment of L1019. However, when similar experiments were conducted using fritted clay or with individual plants in smaller volumes of nutrient solution, results showed that low P02 conditions favored establishment of L1019, and this was related to greater carbon availability. Rhizosphere survival experiments were conducted using maize, sorghum, oat, cotton, and soybean plants grown in Weswood soil and inoculated with L1019. L1019 successfully colonized and persisted (up to 49 days) in the rhizosphere of these plants at densities of log 4.65.6 cfu/gram root dry weight. L1019 increased plant growth parameters of C3 but not of C4 plants. Selection of pseudomonads using apomictic hosts was done by growing apomictic grasses in diverse soils and identifying the isolates using fatty acid profiles. Different microbial biotypes tended to be isolated from the rhizosphere of different host plants when planted in the same soils, suggesting that the host plant was an important factor influencing the microflora present in the rhizosphere.
Subjects/Keywords: soil science.; Major soil science.
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Tavaria, F. K. (2012). Effect of low pO2 and host plant on colonization of roots by Pseudomonas putida PH6 (L1019). (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-T38
Chicago Manual of Style (16th Edition):
Tavaria, Freni Kekhasharu. “Effect of low pO2 and host plant on colonization of roots by Pseudomonas putida PH6 (L1019).” 2012. Masters Thesis, Texas A&M University. Accessed September 23, 2019.
http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-T38.
MLA Handbook (7th Edition):
Tavaria, Freni Kekhasharu. “Effect of low pO2 and host plant on colonization of roots by Pseudomonas putida PH6 (L1019).” 2012. Web. 23 Sep 2019.
Vancouver:
Tavaria FK. Effect of low pO2 and host plant on colonization of roots by Pseudomonas putida PH6 (L1019). [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2019 Sep 23].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-T38.
Council of Science Editors:
Tavaria FK. Effect of low pO2 and host plant on colonization of roots by Pseudomonas putida PH6 (L1019). [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-T38
Texas A&M University
30.
Wright, Alan Lee.
Oil bioremediation in salt marsh mesocosms as influenced by nitrogen, phosphorus, and bacterial seeding.
Degree: MS, soil science, 2012, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-W75
► Glasshouse experiments were conducted to determine the effects of N and P fertilization and bacterial seeding on crude oil degradation in salt marsh mesocosms containing…
(more)
▼ Glasshouse experiments were conducted to determine the effects of N and P fertilization and bacterial seeding on crude oil degradation in salt marsh mesocosms containing marsh soil and Spartina alterniflora. Fertilization with urea, NH4, and N03 applied at 75 or 150 kg N ha-1 did not enhance oil degradation during 82 d of experimentation in continuously flooded mesocosms during winter (temperature range of 17-30'C). Phosphorus applied at 40 kg P ha-' with or without N significantly enhanced oil degradation during winter. Phosphorus applied alone led to 46% of the applied total petroleum hydrocarbons (TPH) remaining in mesocosms while 57% of the applied TPH remained in the treatment not receiving P. Two slow-release fertilizers containing N and P, Max Bac and Inipol, enhanced oil degradation more than other N fertilizers applied with P. During summer (temperature range of 27-42'C), Max Bac and P applied at 100 kg N ha-' and 40 kg P ha-' did not enhance oil degradation in continuously or alternately flooded mesocosms during the 40 d of experimentation. Continuously flooded mesocosms averaged 28% TPH remaining while alternately flooded mesocosms averaged 49%. Bacterial seeding proved ineffective in enhancing oil degradation. Five commercial bioremediation products did not enhance oil degradation compared to uninoculated controls in continuously flooded mesocosms during 33 d of experimentation during spring (temperature range of 27 42'C) or in alternately flooded mesocosms during 41 d of experimentation during summer. Max Bac and P applied at 100 kg N ha-] and 40 kg P ha-I enhanced oil degradation during spring but not during summer. The use of 15 N techniques during winter revealed that approximately 23% of the applied urea-N and NH4-N was taken up by S. alterniflora compared to 8% of the applied N03-N. Further studies may be needed to assess the effectiveness of N and P fertilization in natural field conditions.
Subjects/Keywords: soil science.; Major soil science.
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Wright, A. L. (2012). Oil bioremediation in salt marsh mesocosms as influenced by nitrogen, phosphorus, and bacterial seeding. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-W75
Chicago Manual of Style (16th Edition):
Wright, Alan Lee. “Oil bioremediation in salt marsh mesocosms as influenced by nitrogen, phosphorus, and bacterial seeding.” 2012. Masters Thesis, Texas A&M University. Accessed September 23, 2019.
http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-W75.
MLA Handbook (7th Edition):
Wright, Alan Lee. “Oil bioremediation in salt marsh mesocosms as influenced by nitrogen, phosphorus, and bacterial seeding.” 2012. Web. 23 Sep 2019.
Vancouver:
Wright AL. Oil bioremediation in salt marsh mesocosms as influenced by nitrogen, phosphorus, and bacterial seeding. [Internet] [Masters thesis]. Texas A&M University; 2012. [cited 2019 Sep 23].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-W75.
Council of Science Editors:
Wright AL. Oil bioremediation in salt marsh mesocosms as influenced by nitrogen, phosphorus, and bacterial seeding. [Masters Thesis]. Texas A&M University; 2012. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-W75
◁ [1] [2] [3] [4] [5] … [84] ▶
. 
Open Access Theses and Dissertations