Les propriétés hydrodynamiques des sols, représentées par les fonctions de rétention en eau et de conductivité hydraulique, régissent les écoulements d'eau et de solutés de puis la surface jusqu'aux nappes souterraines. La caractérisation et la compréhension de cette dynamique des fluides ont énormément d’importance pour la détermination des ressources en eau disponibles, la pollution des sols et des eaux souterraines. Le radar de sol est une méthode d'imagerie géophysique particulièrement adaptée pour détecter les contrastes de paramètres électromagnétiques tels que ceux engendrés par des gradients de teneur en eau. La problématique à laquelle répond cette thèse est de savoir si le suivi temporel par radar de sol de phénomènes de dynamique des fluides en proche surface, tels que des infiltrations, est suffisant pour retrouver les paramètres hydrodynamiques du sol considéré, de manière plus efficace que les procédés d'estimation classiques.Nous avons développé des algorithmes couplant des modèles hydrodynamique et électromagnétique, afin d'obtenir les propriétés hydrodynamiques de sols, en inversant les temps aller-retour des ondes électromagnétiques correspondant à des réflexions sur des contrastes de permittivité forts comme ceux rencontrés sur des fronts ou bulbes d'infiltration.Nous avons développé le suivi radar de deux techniques d'infiltration, en simple anneau et en forage de faible profondeur. La première permet une modélisation unidimensionnelle alors que la seconde utilise une modélisation 2D-axisymétrique. Dans chaque cas, nos méthodes originales ont été testées numériquement, puis appliquées à différentes expériences de terrain, principalement sur des sols sableux. Les paramètres des fonctions de rétention en eau et de conductivité hydraulique retrouvés sont en accord avec ceux obtenus classiquement par des méthodes telles que des mesures sur échantillons en colonne suspendue et in situ par infiltromètrie à disque. Au-delà de l'aspect quantitatif des processus hydrodynamiques, l'interaction de ces derniers avec les champs électromagnétiques conduit à l'observation de phénomènes atypiques, comme des guides d'ondes créés par des bulbes d'infiltration.De plus, nous avons montré que le radar de sol est assez précis pour détecter des différences dans les profils de teneur en eau selon le cycle drainage-imbibition, causées par l'hystérèse sur les fonctions de rétention en eau et de conductivité hydraulique. Les paramètres de ces fonctions ont été obtenus par inversion de données radar lors de suivis de battements de nappe au sein de réservoirs, de l'ordre du mètre cube, en laboratoire. / Soil hydraulic properties, represented by the soil water retention and hydraulic conductivity functions, dictate water flow in the vadose zone, from surface to aquifers. Understanding the water flow dynamic has important implications for estimating available water resources and flood forecasting. It is also crucial in evaluating the dynamicsof chemical pollutants in soil and in assessing the risks of groundwater pollution. Ground Penetrating Radar is a geophysical method particularly suited to measure contrasts of electromagnetic parameters such as those created by water content variations in soils.In this manuscript, we focus on Ground Penetrating Radar temporal monitoring of fluid flows in the near surface, such as infiltration in soil. We were initially curious to know to know if Ground-Penetrating Radar could be used to estimate soil hydraulic properties, more efficiently than classical soil characterization methods such as disk infiltrometer and water hanging column. We developed coupled hydrodynamic and electromagnetic numerical modeling to invert the two way travel times associated with reflections corresponding to strong dielectric permittivity contrasts, such as these involved on infiltration bulbs or fronts orwater tables.We designed two types of Ground Penetrating Radar infiltration monitoring techniques: one using a single ring infiltrometer and the other using shallow boreholes. The first type of infiltration experiment relied on uni-dimensional numerical modeling whereas the second one used a 2D-axi-symmetrical hypothesis. In each of these cases, our original methods have been numerically tested and applied to sandy soils. Beyond quantitative soil hydraulic parameter estimations, electromagnetic wave interactions with hydrodynamicprocesses lead to peculiar phenomena such as waveguide creation by infiltration bulbs.In addition, we showed that Ground Penetrating Radar monitoring was accurate enough to detect the hysteresis of the water retention function during successive drainage and wetting cycles, in a laboratory experiment using a sub-metric tank filled with Fontainebleau sand. The parameters characterizing the hysteresis of this function have been quantified through two-way travel time inversions of the bottom tank reflection during one-step and multi-step hydraulic head experiments.

Digitized by Kansas Correctional Industries

Infections of the cow udder leading to mastitis and lower milk quality are a critical challenge facing northeast organic dairy farmers. Limited mastitis treatment options are available to organic producers and bedding systems impact cow health, including mastitis risk. Composted bedded pack, a system touted for increased cow comfort and well-being, allows stratified accumulation of bedding and manure in the barn. This method is gaining popularity among organic producers, yet little is known about the microbiota of the accumulated pack and its interaction with the cow mammary gland. An in-depth single farm study was conducted that surveyed bedded pack (microbiome and microarthropod community), dipteran vectors of bacterial mastitis pathogens, and the teat skin and teat cistern milk microbiomes. Comparisons were made with four additional farms utilizing bedded packs to test generality of results. Few fly pests were observed in the bedded pack. However, bedding on all farms was found to harbor the mesostigmatid mite genus Glyptholaspis, a well-established predator of nematodes and muscid fly larvae, suggesting that predators may suppress populations of biting flies in bedded pack barns. Additionally, the fungivorous genus Rhizoglyphus was commonly abundant in all farms, suggesting that the mite community regulates microbial activity at multiple trophic levels. High-throughput sequencing of universal marker genes for bacterial and fungal communities was used to characterize the skin and milk microbiome of cows with both a healthy and infected quarter on the case study farm, and the composted bedded pack of all five farms. The bedded pack microbiome varied with bedding material and management style; fungal taxa were primarily yeasts of the Ascomycota; all farms additionally contained anaerobic fungi associated with the bovine rumen. Common bacterial genera included Acinetobacter and Pseudomonas, both of which were also commonly observed on teat skin and in milk. The udder microbiome varied through time and between skin and milk. Both healthy and infected milk microbiomes reflected a diverse group of microbial DNA sequences. Health status of the quarter changed whether taxa were shared between the teat skin, milk, and bedding. Proportion of taxa shared between healthy milk and skin was stable while taxa shared in infected quarters varied widely. Taxa shared among all habitats included yeast genus Debaryomyces and bacteria Acinetobacter guillouiaea. Results support an ecological interpretation of both the udder and the bedded pack environment and support the notion that mastitis can be described as an imbalance of the healthy mammary gland microbiome. Future work might compare udder health between common bedding practices, investigating the impact of bedding on the microbiota of the mammary gland in the healthy and diseased state.

Normal healthy growth and development of plants is controlled by certain factors known as factors of plant growth. They are soil, climate, and plant inheritance. The soil contains many nutrient elements needed by plants both in macro and micro quantities. Iron is one of the essential elements required by plants in small amounts. When plants are starving for any of the essential nutrients, characteristic symptoms usually appear as certain abnormalities, discoloration and deformation of leaves, fruits, and other parts. The deficiency symptoms, though not easily recognizable in some cases at the beginning, are quite apparent in advanced stages of plant growth. The characteristic symptom of iron deficiency in plant nutrition is chlorosis. Chlorosis is a general term which denotes a lack of chlorophyll in leaves and replacement of the normal green color either wholly or in part by yellow color. In most cases the chlorosis is characterized by a distribution of the yellow color throughout the green in patterns. The more specific term, iron chlorosis, refers to chlorosis due to iron deficiency in the plant and which can be alleviated by providing the plant with suitable iron compounds.

Evaporation and transpiration from the soil and plant, respectively, have received increasing attention from those who work with water supply, irrigation, and drainage.

Water requirement was defined by Briggs and Shantz in 1911 as the ratio of the weight of water absorbed by a plant during its growth to the weight of dry matter produced. Ballard (1933) and Williams (1935) defined water requirement as the ratio of the amount of water transpired to the amount of dry matter produced. Ballard (1933) and Williams (1935) defined water requirement as the ratio of the amount of water transpired to the amount of dry matter formed during the whole or any part of the life cycle of the plant. Miller (1938) and Kramer (1959) postulated that the water requirement is the ratio of water used to the dry matter produced, and therefore could more accurately be termed transpiration ratio because it is largely controlled by transpiration. Regardless of specific definition, the dry matter considered in such ratios is generally the amount harvested, including the entire plant except the roots. The amount of water measured is the amount lost during growth since the amount of water retained within the plant is insignificant when compared with either total water intake or the amount transpired. The water requirement thus constitutes a useful way to characterize the plant and soil-water conditions and plant growth. The availability of soil water to a plant is one of the factors that vitally affects its water requirements. In turn, the availability of soil water is affected by soil moisture tension and the salt content of the soil. Thus it seems likely that a significant relationship may exist between a plant's water requirement and its degree of salt tolerance. The relation between water requirement and salt tolerance could not be established based on the information found in the literature at this time. the study reported here was undertaken in an attempt to determine the effect of salt on the water requirement of plant species known to have different degrees of salt tolerance.

It is estimated that 22 000 contaminated areas exist in Sweden today. In order to classify the risk of contaminant migration from these areas and to prioritize which of these contaminated areas should first be treated, the Swedish Environmental Protection Agency (EPA) has designed a method, for the investigation of contaminated areas (MIFO). One of these contaminated areas is the landfill Gräsötippen outside Köping. The landfill has been used by both Yara AB and the Köping municipality between the years 1945 and 1975, and both industrial and household waste have been deposited there. The aim of this report is to survey which contaminants that can be found in the soil and water in the landfill Gräsötippen and to evaluate the migration of these contaminants. With help of this information, the landfill will then be risk classified according to MIFO. The goal is that this report will provide a basis for future studies and remedial measures at the landfill. To get a picture of what has been deposited at the landfill Gräsötippen, employees and former employees at Yara and others with connection to the landfill have been interviewed. Piezometers have been installed in and around the landfill so as to provide information on groundwater levels and movement, and for the collection of groundwater samples. Soils samples were collected as well. The water and soil samples were analyzed with regard to metals, organic compounds and nutrients. Furthermore, groundwater flow has been modeled using VS2DI, in order to get a picture of the groundwater’s flow direction and velocity under the landfill. In the water samples, only lead was detected with levels over the Maximum Contaminant Level (MCL) from the EPA. Relatively high levels of nutrients were also detected. In the soil, carcinogenic PAH, PCB, aliphatic hydrocarbons, aromatic hydrocarbons, arsenic, lead, cadmium, mercury and zinc were detected over the EPA MCL. The landfill Gräsötippen has a good location in an area with deep clay, which prevents rapid spreading of contaminants. No high levels of contaminants are leaching out today. The spreading of the contaminants is minor; most of the contaminants are fixed in the soil and do not spread to the surroundings. The water flow’s primary direction from the landfill is south but there are also flows to the west and east. Today, there are a number of proposals with regard to decreasing the risk for future contaminant dispersal from the landfill and to keep control of the water that is used in the area. A few of these proposals are to finally cover the landfill, to analyze the grass and plants in the enclosed pasture on the landfill, and to continuously analyze the water in the installed piezometers and drinking water wells on and around the landfill. The landfill Gräsötippen is classified to risk class 3, moderate risk, according to MIFO. / Det uppskattas idag finnas 22 000 förorenade områden i Sverige. För att kunna riskklassa dessa förorenade områden och prioritera vilka som först bör efterbehandlas har Naturvårdsverket utarbetat en Metodik för Inventering av Förorenade Områden (MIFO). Gräsötippen utanför Köping är ett av dessa förorenade områden. Deponin har använts av både Yara AB och Köpings kommun mellan åren 1945-1975 och fungerat som deponi för både industri- och hushållsavfall. Syftet med denna rapport är att kartlägga vilka föroreningar som finns i mark och vatten i Gräsötippen och tolka föroreningarnas spridning. Utifrån den informationen ska deponin sedan riskklassas enligt MIFO. Målet är att rapporten ska kunna fungera som underlag för framtida åtgärdsplaner för Gräsötippen. För att få en bild över vad som har deponerats på Gräsötippen har anställda och före detta anställda vid Yara samt andra som har haft anknytning till Gräsötippen intervjuats. Grundvattenrör har installerats i och runtom deponin för att det skulle kunna tolkas hur grundvattnet rör sig under deponin och för att det skulle kunna tas prover på grundvattnet och jorden. De vatten- och jordprover som togs, analyserades med avseende på metaller, organiska föreningar och närsalter. Dessutom har en modellering utförts i VS2DI för att få en bild över grundvattnets flödesriktning och hastighet under deponin. I vattenproven detekterades endast bly över Naturvårdsverkets riktvärde samt relativt höga halter av närsalter. I jorden detekterades cancerogena PAHer, PCB, alifater, aromater, arsenik, bly, kadmium, kvicksilver och zink över Naturvårdsverkets riktvärden. Gräsötippen är bra placerad i ett område med tjock lera som förhindrar snabb spridning och idag lakas inga höga halter av föroreningar ut. Spridningen av föroreningar är liten, istället ligger de flesta föroreningarna fast i marken och sprids därmed inte till omgivningen. Vattenflödets huvudriktning från deponin är söderut, men det sker även flöden åt både väster och öster. Det finns i dagens läge en del förslag på åtgärder som bör utföras på Gräsötippen för att minska risken för framtida spridning och upprätthålla kontroll på det vatten som används i närområdet. Några av dessa åtgärder är att sluttäcka deponin, att analysera gräs och växter i hagen på deponin samt att kontinuerligt analysera vattnet i grundvattenrören och brunnarna på och runt Gräsötippen. Vid riskklassningen av Gräsötippen enligt MIFO, klassas den till riskklass 3, måttlig risk.

No description available.

Thesis (Ph. D.)--School of Civil and Environmental Engineering, Georgia Institute of Technology, 2004. Directed by J. Carlos Santamarina. / Includes bibliographical references (leaves 266-279).

Thesis (M. Phil.)--University of Hong Kong, 2002. / Includes bibliographical references (leaves.