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The effects of surface-applied poultry manure on top- and subsoil acidity and selected soil fertility characteristics.Judge, Angus. January 2001 (has links)
The effects of surface applications of poultry manure on pH, exchangeable AI, exchangeable
Al saturation and levels of available macronutrients in the surface and subsurface layers were
investigated in some acid soils from the KwaZulu-Natal Midlands. Three field sites with a
history of long-term applications of poultry manure were compared with adjacent fields
where no manure had been applied. Results generally showed an increase in pHwater, pHKCI,
exchangeable Ca, Mg, and K and extractable P and a decrease in exchangeable Al and
exchangeable Al saturation in the surface soil to the depth to which the manure had been
incorporated. Results also provided evidence for substantial downward movement of Ca and
Mg into the subsoil layers (i.e. 30-60 cm) and their accumulation in exchangeable forms.
There was a concomitant general increase in pHKcl and pHwater and decrease in exchangeable
Al and exchangeable AI saturation in the subsoil layers. These results demonstrate that, under
field conditions, surface applications of poultry manure can cause the amelioration of subsoil
acidity. This is an extremely important finding since subsoil acidity is characteristically
extremely difficult and costly to ameliorate.
A leaching column study was subsequently conducted to investigate the mechanisms by
which surface applications of poultry manure ameliorate both top- and subsoil acidity. The
soil used, originating from one of the field sites, had not previously been treated with poultry
manure and had a subsoil pHKCI of 4.25 and an exchangeable acidity concentration of 1.79
cmolJkg. Three forms of poultry manure (layer, broiler and free range) were incorporated
into the surface 5 cm of soil columns at rates equivalent to 5, 10 and 30 Mg/ha. Columns
were maintained in glasshouse conditions for a period of 108 days and over that period they
were leached on four separate occasions (receiving a total of 825 mm of simulated rainfall).
At the conclusion of the experiment, the soil columns were cut into sections for chemical
analysis.
Applications of poultry manure to the surface soil markedly increased pHwater, pHKcl,
exchangeable Ca, Mg, K and Na concentrations and decreased exchangeable Al levels in the
surface 5 cm layer. They also increased the concentrations of soluble C, soluble salts, total Al
and organically-complexed Al in soil solution. These effects were most pronounced with
layer manure and greater at the higher rate of application. The manure-induced decrease in
exchangeable AI, but increase in total AI, in soil solution was attributed to soluble salts,
originating from the manure, displacing exchangeable Al into solution where it was
subsequently complexed by soluble organic matter.
Analysis of subsoil layers (5-15, 15-25, 25-35 and 35-45 cm) at the conclusion of the
experiment showed that surface applications of poultry manure decreased concentrations of
exchangeable Al in the subsoil but had no effect on pHKCl and depressed values for pHwater. It
was suggested that manure-derived urea leached into the subsoil and was then hydrolysed
causing an increase in pH and precipitation of exchangeable Al as insoluble hydroxy-AI
oxides. Towards the conclusion of the experiment nitrification began to proceed, causing
subsoil pHKCl values to decrease back to their original values. Analysis of the inorganic-N
content of leachates and soil layers provided circumstantial evidence for this mechanism.
High concentrations of soluble salts in the subsoil layers (caused by leaching from the
manure) resulted in displacement of exchangeable A13+ and W into soil solution so that the
electrical conductivity and concentrations of total and monomeric Al were elevated and
pHwater was depressed in the subsoil (15-45 cm) of poultry manure-treated columns.
It was concluded that the results underline the opposing effects that poultry manure
applications have on (i) raising soil pH and lowering exchangeable Al but at the same time
(ii) greatly increasing soluble salt concentrations and thus displacing At3+ and H+ back into
soil solution. They also have suggested the importance of the release of N during manure
decomposition in influencing soil pH (through the processes of ammonification, urea
hydrolysis and nitrification) and therefore other soil chemical properties. It is, however, clear
that the long-term effect of surface applications of poultry manure is generally to ameliorate
subsoil acidity by raising subsoil pH and lowering exchangeable Al concentrations. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2001.
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Physical changes in the soil environment due to vehicle traffic.Havard, Peter L. January 1978 (has links)
No description available.
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The influence of soil particle surfaces and soil porosity on the biodegradation of key refuse leachate organic molecules.Du Plessis, Chris Andre. January 1995 (has links)
Many studies have been undertaken to determine the effects of soil and soil properties on
migrating metal pollutants. Organic pollutants, however, in addition to their interactions with
soil components , are also susceptible to degradation (catabolism) by microorganisms.
Soil-microorganism-pollutant interactions have, traditionally, been studied in soil columns
(microcosms). One of the shortcomings of column and in situ studies is that the identity and
specific effect(s) of the soil component(s) affecting or influencing attenuation are not known
and cannot readily be determined. Attenuation effects of the soil components are, therefore,
difficult to interpret. ("Attenuation" in this context is the combined effects of both soil
adsorption and microbial catabolism). Attenuation studies often only consider the physical
conditions such as aeration, permeability, flow rate, temperature, etc. This approach assumes
the soil to be a homogeneous matrix with no specific physico-chemical properties attributable
to different components within the matrix. Soil physical factors suspected of influencing
pollutant attenuation could be misleading without consideration of the physico-chemical
interactions between soil components, microorganisms and pollutants. Adhesion of pollutants
and microorganisms seems to be most important in this regard.
The initial phase of this study was undertaken to examine the effects of three different soil
materials on attenuation of key landfill leachate molecules. Examination of the effects of soil
surface type on attenuation focused on adsorption / desorption of the pollutant molecules and
microorganisms. These experiments sought to investigate the physico-chemical effects of soil,
microorganism, pollutant interactions and were done as batch slurry experiments as well as in
soil columns. Two soil horizons from the Inanda soil form (humic A and red apedal B) and
the topsoil (vertic A) from a Rensburg soil form were used. The Inanda topsoil had a high
organic matter content and both the topsoil and subsoil had a kaolinitic clay mineralogy; the
Rensburg topsoil clay mineralogy was predominantly smectitic with a relatively low organic
matter content.
From the batch experiments, the adsorption of a hydrophobic molecule (naphthalene) and a heavy metal (cadmium) were found to be influenced to a significant extent by soil characteristics.
Adsorption of naphthalene was due to the soil organic matter (SOM) content whereas cadmium
adsorption was due to the cation exchange capacity (CEC) of the soil. Soil characteristics did
not seem to have a significant influence on the adsorption of a water soluble compound such
as phenol at the concentrations used. Attenuation of naphthalene was found to be affected by
adsorption of the pollutant molecule (related to SOM) as well as the CEC of the soil. The
attenuation of hydrophobic molecules can possibly be ascribed to the influence of CEC on the
microbial population responsible for attenuation. This would seem to indicate interaction
between the soil surfaces and the catabolizing microbial population. Desorption of the
pollutant (and possibly also of the microbial population) was achieved by the addition of
acetonitrile and methanol both of which reduced the polarity of the water. These solvents were
also found to be toxic to the catabolizing microbial population at high concentrations. The
toxicity thresholds of both solvents for catabolizing microorganisms differed significantly
between soil- (> 15 %, v/v) and soil free (< 5 %, v/v) treatments. This discrepancy cannot
be accounted for by adsorption and is ascribed to physico-chemical interaction between
microorganisms and the soil surfaces. This interaction probably affords protection from,
otherwise, toxic concentrations of solvents or metals. The important effects of soil surfaces
on attenuation processes were thought to be due to the strong adsorption of naphthalene.
Surface attachment of microorganisms was, however, also inferred from results obtained with
phenol. This seemed to indicate that microbial attachment to soil surfaces was an important
aspect in attenuation and did not occur only because of pollutant adsorption.
Soil column experiments were made with both naphthalene and phenol. The naphthalene,
which was adsorbed to the soil, did not leach from the columns to any appreciable extent.
This was despite the addition of acetonitrile to some columns. This was probably due to
greater microbial catabolism caused by desorption and, subsequent, increased soluble
concentrations of the molecule. After extraction from the soil at the end of the experiment it
was clear that the sterile controls held much higher concentrations of naphthalene than the
experimental columns. The soil type and treatments showed little difference in the naphthalen concentration extracted from the soil columns. This did not reflect the differences found
between soil materials in the batch experiments and was probably due to the masking effect
of the soil physical factors on attenuation processes. Unlike naphthalene, phenol, because of
its high solubility, was detected in the column leachates at relatively high concentrations. The
phenol concentrations were much higher for the Inanda subsoil (approximately 4 mM) than the
Inanda topsoil (approximately 2 mM) and Rensburg topsoil (< 1 mM). The Rensburg topsoil
produced the lowest phenol concentrations in the leachate and this can probably be ascribed
to the larger quantity of micropores in this soil. Thus, it seems that the soil physical features
had a pronounced influence on attenuation. Whether this effect was directly on the studied
molecule or indirectly, because of the effects on the microbial population, is not known.
Inoculation of the columns with a phenol catabolizing population had only a slight increased
effect on leachate phenol concentrations from all columns. This increased effect was,
however, only prolonged in the case of the Inanda subsoil. The flow rate through the columns
affected leachate phenol concentration which was lower with a slower flow rate and, thus,
longer retention time.
From the column experiments soil physical parameters were suspected of influencing, and
possibly overriding, the soil surface effects on microbial activity (capacity to catabolize a
organic molecule of interest). Soil porosity, as caused by different soil materials, was
suspected of being the most important soil physical parameter influencing microbial activity.
To investigate the potential effect of soil porosity, relatively homogeneous porous media i.e.
chromatography packing material and acid washed sand were used. These materials had more
defined and distinct porosities and were considered to be suitable for investigating the
fundamental influence of porosity on microbial activity. Saturated continuous flow columns
were used and three types of packing configurations were tested: chromatography packing
(CHROM) material (porous particles); acid washed sand (non-porous) (AWS); and a 1: 1 (w/w)
mixture of chromatography packing and acid washed sand (MIX). Only a single water soluble
molecule, phenol, was used in this phase of the investigation.
Bacterial filtration ("filtration" as a component of "attenuation'') was found to be highest for
the CHROM and lowest for the AWS materials. This difference in microbial retention affected the phenol catabolism in response to increased column dilution rates. The CHROM
and MIX materials had distinctly different porosities than that of the AWS, due to the internal
porosity of the chromatography packing. This greater pore size distribution in the MIX and
CHROM packing materials created pores with different effective pore dilution rates within the
microcosms at similar overall flow rates. The greater pore size distribution in the MIX and
CHROM packing materials facilitated pore colonization since some pores did not participate,
or conduct, mass flow as occurred in macropores. This led to different microcolonization
effects in the macro- vs micropores. Since the MIX and CHROM packing materials had more
micropore colonization sites these packing materials showed a greater range of substrate
affinities (i.e. Ks values) for the phenol substrate.
The extent to which micropore colonization occurred could be detected by the effect it had on
phenol breakthrough curves. In the MIX and CHROM materials, microbial colonization
caused blocking of micropores with a subsequent effect on the phenol breakthrough curves.
The AWS material, however, which had a low inherent microporosity, showed microbially
induced microporosity probably due to biofilm development. The fact that the MIX and
CHROM packing materials facilitated micropore colonization was also responsible for the
greater resistance to, and the recovery from , potentially inhibitory cadmium concentrations.
This effect was also apparent in the presence of acetonitrile, although this effect was not
identical to that observed with cadmium. Finally, column pressure build up as a function of
pore clogging was determined and was found to occur in the order AWS > MIX > CHROM.
This was most likely due to fewer potential liquid flow paths with a higher blocking potential
in the AWS.
Extrapolation of the fundamentals of the above findings led to the conclusion that soil surface- and
soil porosity effects are extremely important factors in determining the behavior of soils
as bioreactors. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1995.
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Effectiveness of a soil inoculant for improving crop yield on two Indiana soilsSiefert, William A. January 1992 (has links)
Biological soil inoculants are products that contain beneficial microorganisms with the ability to increase plant-available nutrients. Soil inoculants are claimed to serve as a supplement for fertilizer N, improve germination and tilth, improve root systems, and increase crop quality and yield. The inoculant evaluated in this study was Effective Microorganisms (EM) produced by Nature Farm Foundation of Lompoc, California. A field trial with corn (Zea mays, L.) was conducted at Oakwood Organic Farm in East Central Indiana in 1992. Two soil types were used in the study, a Genesee silt loam (Fluventic Eutorchrept) and a Sloan silt loam (Fluventic Haplaquoll). Soil nitrate level measured through the growing season was not significantly affected by the addition of EM. Neither foliar nutrient content nor grain dry matter yield were significantly greater with use of EM compared to the control. / Department of Natural Resources
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Återfyllnadsmassor vid sanering : Materialkrav med avseende på markmiljö och marklevande organismerLehman, Hanna January 2014 (has links)
The purpose of this study was to determinate what requirements there should be on refilling material used as soil remediation based on the soil environment, i.e. soil processes and factors important to soil-dwelling organisms. The study was conducted by investigating which parameters that is important for the soil environment and by comparing them with each other. To exemplify how the parameters may change in different locations, data for total organic carbon, dry matter (i.e. water content), and pH were analyzed from different locations before and after soil remediation. Dry matter, organic matter, pH, compaction, grain size, porosity and soil composition were found to have a significant impact on various soil processes and soil organisms. Field investigations were made to examine dry- and organic matter and pH. The results were indicating that dry matter increased and that the organic matter decreased when the area was refilled with a coarse material. This study showed that there should be requirements on the characteristics of refilling material such as; organic matter content, good water holding capacity, a pH that is as neutral as possible and that the soil should not be too compact. A conclusion from this study was that crushed rock may not be the optimal refilling material after soil remediation.
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Peatmoss influence on strength, hydraulic characteristics and crop production of compacted soilsOhu, John Olutunde. January 1985 (has links)
The quantitative effects of increasing the organic matter contents of three soils upon their susceptibility to compaction, the recovery of tilth after compaction and the fertility of the soils were investigated. These effects were further studied on the production of bush bean (Phaseolus vulgaris). / Soil consistency limits, soil water status, applied pressure and organic matter contents were used to predict shear strength, penetration resistance and water retention characteristics of compacted soils, with the aim of meeting the widespread demand for possible techniques of soil compaction prediction. / Soil compaction increased the ability of the soils to retain moisture, increased penetration resistance, shear strength and decreased the available water capacity of soils. On the other hand, organic matter increased the ability of the soils to retain moisture, expanded the available water capacity and decreased the penetration resistance and shear strength of compacted soils. / Although soil compaction increased the stem diameter of bush bean; the height, yields and root dry matter of the crop decreased with higher compaction levels. On the contrary, higher organic matter levels increased the plant and yield parameters of the crop.
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Erosion modelling under different land use management practicesPudasaini, Madhu S., University of Western Sydney, College of Science, Technology and Environment, School of Engineering and Industrial Design January 2003 (has links)
Soil erosion has been recognised as a global threat against the sustainability of natural ecosystem. The work in this thesis has been undertaken to assist in combating this threat, and addresses the soil erosion issues associated with urban construction activities. The Revised Universal Soil Loss Equation (RUSLE) was employed in this research work and the parameters associated with the model were calibrated. This model was chosen for calibration, as it has been proven to be an easy to use tool yet providing reasonable results. Large scale rainfall simulators developed at UWS were used for rainfall simulation at two sites with diverse soil types: dispersive clayey soils at Penrith and highly permeable sandy soil at Somersby (Both in New South Wales, Australia). It is concluded that RUSLE can be successfully used in single storms for erosion prediction. Calibrated values of RUSLE parameters are useful in predicting soil erosion from the construction sites in NSW. It is also identified that in rolled smooth land condition, clayey soils are more erodible than sandy soil. Specific support practices such as short grass strips, gravel bags and silt fences are identified as very effective erosion control measures in reducing soil erosion from 45% to 85%. These results will be very useful in soil erosion prediction planning and conservation management in NSW. / Master of Engineering (Hons)
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Development of a geographic information system-based virtual geotechnical database and assessment of liquefaction potential for the St. Louis Metropolitan areaChung, Jae-Won, January 2007 (has links) (PDF)
Thesis (Ph. D.)--University of Missouri--Rolla, 2007. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed March 24, 2008) Includes bibliographical references (p. 145-155).
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An investigation of the role of soil micro-organisms in phosphorus mobilisation : a report submitted to fulfil the requrements of the degree of Doctor of Philosophy /Coyle, Kieran. January 2001 (has links) (PDF)
Thesis (Ph.D.) -- University of Adelaide, Dept. of Agronomy and Farming Systems, 2002. / "September 2001" Includes bibliographical references (leaves 206-230).
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Numerical analysis of shallow circular foundations on sands /Yamamoto, Nobutaka. January 2006 (has links)
Thesis (Ph.D.)--University of Western Australia, 2006.
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