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<p dir="ltr">Water scarcity and acute drought continue to be serious concerns, even in humid climates where precipitation normally exceeds evapotranspiration (ET), highlighting the need for improved landscape water conservation practices. Lawns represent the largest area in most managed landscapes and require regular mowing, feeding and sometimes supplemental summer irrigation to persist. A general historical guideline for lawn irrigation is to supply 25-38 mm per growing wk-1 in the absence of rainfall. This fixed volume is often applied on a programmatic “set and forget” three times per week schedule (e.g. M-W-F). This application guideline often results in excess irrigation as it does not take into account plant need or prevailing environmental conditions. Further, in times of acute summer drought policymakers may restrict irrigation to once or twice weekly to conserve water. The effects of these regulations on turf health and potential water savings are unclear. Thus, two multi-year summer field studies were conducted to identify opportunities for improved lawn water conservation. Study one evaluated the effect of varying weekly irrigation volume and frequency on mature Kentucky bluegrass (Poa pratensis L.:KBG) located under a fixed-roof rainout structure. Turfgrass response was measured as visual turf quality (TQ), digital green color (DGC), volumetric soil water content (VWC) and area under the curve for each response variable. In year one, KBG was subject to six irrigation programs and compared to a high deficit control for 49 days. The programs were: 25 mm total water wk-1 applied either three times (M-W-F) or twice (M and F) weekly, 19 mm total wk-1 twice weekly (M and F), 13 mm total wk-1 once weekly and 60 or 80% accumulated ETo three times weekly. Due to poor performance, the high deficit control and 60% ETo were excluded from further evaluation. In year two, seven programs were evaluated: 33 mm total water wk-1 applied once, twice, or three times weekly, or every-other-day, 25 mm total wk-1 applied twice or three times weekly and 80% ETo twice weekly for 63 days. In both years, generally, 25-33 mm wk-1 applied two or three times wk-1 produced the most consistent TQ, DGC and highest VWC. Study two compared three supplemental irrigation programs to a natural rainfall control for six widely planted cool-season lawn grasses for 70 days. The six lawn grasses were: a KBG sod, seeded drought tolerant and susceptible KBG cultivars, a turf-type tall fescue (Schedonorus arundinaceus (Schreb.) Durmort.: TTTF) blend and two KBG and perennial ryegrass (Lolium perenne L.:PRG) mixtures. In Study two, highly significant differences p < .001 occurred for irrigation program and lawn grasses. While supplemental irrigation aided all grasses, rainfall in year one and two measured 119 mm and 343 mm, respectively, affecting data in each study year. Area under the turfgrass quality curve (AUTQC) was lowest for the rainfall control (339 and 425) and highest for 33 mm wk-1 applied three times (507 and 526) and 80% ETo programs (508 and 535) in year one and two, respectively. Annual responses for DGC and VWC generally followed TQ trends. For grasses subject only to natural rainfall, TTTF, and the KBGs were generally superior to the KBG:PRG mixtures, thus emphasizing the importance of species selection. In summary, these studies compared a traditional “set and forget” irrigation program to a range of alternative programs and different lawn grasses. These data provide evidence for irrigation savings by employing a combination of planting drought tolerant lawn species and adopting a more limited irrigation program. Future field studies should include the evaluation of adaptive, data-driven programs based on forecast environmental conditions and threshold responses like DGC or predetermined VWC set points calibrated for varying soil types and growing environments.</p>

Tesis por compendio / [ES] Los cítricos son el cultivo frutícola más importante de Uruguay en términos de producción, superficie y aporte económico. Considerando la gran contribución de los sistemas agroalimentarios a los impactos ambientales, evaluar aquellos asociados a la producción citrícola en el país cobra gran relevancia para transitar hacia sistemas alimentarios sostenibles. En esta línea, el objetivo de la presente tesis es evaluar estos impactos ambientales mediante la utilización del análisis de ciclo de vida (ACV) y estudiar aspectos metodológicos clave de su aplicación a la producción citrícola. Se lleva a cabo una revisón crítica de la literatura de ACV de cítricos y se desarrollan cuatro casos de estudio en establecimientos representativos de la región, en concreto, la producción de limones, mandarinas y naranjas, y la producción de plantones en vivero. Los impactos se evalúan de la cuna hasta la puerta del establecimiento, usando unidades funcionales tanto de masa como de área y datos primarios correspondientes a varias temporadas de cultivo. Los principales puntos críticos ambientales detectados son las emisiones de campo producto de la aplicación de fertilizantes, la irrigación, y la producción de óxidos de cobre. Desde el punto de vista metodológico, se destaca la importancia de usar distintas unidades funcionales y de abordar la variabilidad temporal y la especificidad según el sitio de los datos de inventario, así como de usar métodos de caracterización de impactos regionalizados. Se observa que la contribución de las primeras etapas del cultivo al impacto ambiental de la producción citrícola es baja. / [CA] Els cítrics són el cultiu de fruita més important de l'Uruguai en termes de producció, superfície i aportació econòmica. Considerant la gran contribució dels sistemes agroalimentaris als impactes ambientals, avaluar aquells associats a la producció citrícola del país cobra gran rellevància per a transitar cap a sistemes alimentaris sostenibles. En aquesta línia, l'objectiu de la present tesi és avaluar aquests impactes ambientals utilitzant l'anàlisi de cicle de vida (ACV) i estudiar aspectes metodològics claus de la seua aplicació a la producció citrícola. Es fa una revisió crítica de la literatura d'ACV de cítrics i es desenvolupen quatre casos d'estudi en explotacions representatives de la regió, en concret, la producció de llimes, mandarines i taronges, i la producció de plançons en viver. Els impactes s'avaluen del bressol fins a la porta de l'establiment, usant unitats funcionals tant de massa com d'àrea i dades primàries corresponents a diverses temporades de cultiu. Els principals punts crítics ambientals detectats són les emissions de camp, producte de l'aplicació de fertilitzants, la irrigació, i la producció d'òxids de coure. Des del punt de vista metodològic, es destaca la importància d'usar diferents unitats funcionals i d'abordar la variabilitat temporal i els aspectes lloc-específics de les dades d'inventari, així com d'usar mètodes de caracterització d'impactes regionalitzats. S'observa que la contribució de les primeres etapes del cultiu a l'impacte ambiental de la producció citrícola és baixa. / [EN] Citrus is the most important fruit crop in Uruguay in terms of production, area, and economy. Considering the great contribution of agri-food systems to environmental impacts, evaluating those associated with citrus production in the country becomes highly relevant to move towards sustainable food systems. In this line, the goal of this dissertation is to evaluate these environmental impacts using life cycle assessment (LCA) and to study key methodological aspects of its application to citrus production. Literature on citrus LCA is critically reviewed and four case studies are developed in representative agricultural holdings of the region, specifically, the production of lemons, mandarins and oranges, and the production of seedlings in nurseries. Impacts are assessed from cradle to gate, using both mass and area functional units and primary data for several growing seasons. The main environmental hotspots detected are on-field emissions from fertiliser application, irrigation, and copper oxides production. As to methodology, the relevance of using different functional units and addressing temporal variability and site-specificity of inventory data is highlighted, as well as using regionalised impact characterisation methods. It is observed that the contribution of the first stages of the crop to the environmental impacts of citrus production is low. / Maria Inés Cabot is the recipient of a PhD scholarship (POS_EXT_2018_1_154319) from the National Agency for Research and Innovation (ANII, Uruguay) and received a support scholarship for the completion of postgraduate studies (BFPD_2023_1#46477920) from the Postgraduate Academic Commission (CAP, University of the Republic). / Cabot Lujambio, MI. (2023). Evaluación de la sostenibilidad ambiental de la producción citrícola en el Uruguay mediante análisis de ciclo de vida [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/199490 / Compendio

Despite the importance of a high white clover (Trifolium repens) content in temperate pastoral systems in terms of livestock performance and nitrogen fixation, the proportion of white clover in grass-clover pastures is often low (<20%). This thesis examined in two experiments whether the white clover content of pastures could be improved by sowing white clover with alternative grass species to diploid perennial ryegrass (Lolium perenne L.). In a pasture experiment, DM production, pasture composition and morphology of grass-clover mixtures was measured over the establishment year (January 2007 to January 2008) where white clover was sown in fine mixtures with diploid perennial ryegrass, tetraploid perennial ryegrass, timothy (Phleum pratense L.) and cocksfoot (Dactylis glomerata L.). Pastures were irrigated and rotationally grazed with on-off grazing with Coopworth ewe hoggets. Total annual DM production of pasture was more than 20% higher in tetraploid (12521 kg DM ha⁻¹) and diploid (11733 kg DM ha⁻¹) perennial ryegrass than timothy (9751 kg DM ha⁻¹) and cocksfoot (9654 kg DM ha⁻¹). However, timothy (5936 kg DM ha⁻¹) and cocksfoot (5311 kg DM ha⁻¹) had more than four times higher white clover annual DM production than tetraploid (1310 kg DM ha⁻¹) and diploid (818 kg DM ha⁻¹) ryegrass. Pasture growth rate at the first three harvests in autumn was significantly greater in tetraploid and diploid ryegrass than timothy and cocksfoot. Timothy and cocksfoot had a higher proportion of white clover than tetraploid and diploid perennial ryegrass throughout the entire year. This was due to more and larger white clover plants in timothy and cocksfoot plots. In a grazing preference experiment, the partial preference of sheep for white clover offered in combination with the same grass species as in the pasture experiment was measured in five grazing tests in May, September, October, November and December 2007. Pastures were sown in January 2007. Paired plots (grass and clover both 4.2 m x 10 m) were grazed by three Coopworth ewe hoggets between 9am and 5pm, and preference was recorded by decline in pasture mass and visual scan sampling for grazing time. Grazing preference for clover was generally low throughout these tests (e.g. average apparent DM intake from clover = 47%; average grazing time from clover = 44%). Several explanations are proposed for this low preference including a high N content and intake rate of the grass relative to the clover. No significant differences were found among the grass treatments in total grass grazing time, total clover grazing time, ruminating time, the proportion of grazing time on clover, selective coefficient for clover and DM intake percentage from clover at any date. There was no significant change in overall sward surface height (SSH) decline among grass treatments throughout all the tests except December 2007 when the overall SSH decline for cocksfoot was significantly lower than the other species. The study indicated that the rapid growth rate of perennial ryegrass in the early phase of pasture establishment, rather than differences in partial preference, was the key factor limiting white clover content in the mixed swards relative to cocksfoot and timothy pastures. It is concluded that high clover-containing pastures capable of delivering high per head performance can be established through the use of slow establishing pasture species such as timothy and cocksfoot.

Text in Afrikaans / Die private persoon het sekere bevoegdhede betreffende die arrestasie en die gebruik van geweld tydens arrestasie van lede van die publiek wat misdade pleeg/gepleeg het. Hierdie bevoegdheid spruit uit sowel die gemenereg as die wettereg. Kragtens die Suid-Afrikaanse Strafproseswet word hierdie bevoegdhede gereel deur aa 42 en 49. Oewerbewoners as eienaars van grand is geregtig op die onverstoorde gebruik en genot van hulle eiendom. Daarteenoor is kanovaarders ook daarop geregtig om op openbare ri vi ere vir wedvaarte te oefen. Di t is egter belangrik om vas te stel of die portage van kano's op die oewer insidenteel is tot die reg om op die rivier te vaar. Ewewig moet bewerkstellig word tussen die botsende belange. Die Waterwet 54 van 1956 behoort gewysig en vereenvoudig te word, aangesien Suid-Afrika nie slegs op die RomeinsHollandse reg kan staatmaak nie - ons waterprobleme staan direk teenoor die van die Nederlande. / The private person has certain powers regarding the arrest and the use of force to effect the arrest of members of the public who have committed/are committing offences. These powers are derived from either common law or statutory law. In terms of the South African Criminal Procedure Act these powers are regulated by ss 42 and 49. Riparian owners are entitled to the undisturbed use and enjoyment of their property. On the other hand, canoeists are also entitled to practise on public rivers. It is important, however, to ascertain whether portage of canoes on the river bank is incidental to the right of canoeing on the river. A balance should be struck between these conflicting interests. The Water Act 54 of 1956 should be amended and simplified, since South Africa cannot rely on Roman Dutch law alone - our water problems are the complete opposite of those in the Netherlands. / Criminal & Procedural Law / LL.M. (Straf- en Strafprosesreg)

L’humanité fait face aux défis urgents de réduire l’impact environnemental de l’agriculture, de changer les régimes alimentaires et d’accroître la production alimentaire. Le palmier à huile est une plante pérenne tropicale emblématique de ces défis. Alors que sa culture peut être à l’origine d’impacts environnementaux, le palmier à huile peut produire, en conditions optimales, 7 à 10 fois plus d’huile alimentaire que les cultures oléagineuses annuelles. Dans ce contexte, améliorer la durabilité de la production d’huile de palme est crucial, tant pour réduire les impacts environnementaux négatifs que pour garantir la sécurité alimentaire. L’application de fertilisants azotés (N) a été identifiée comme une source majeure d’impacts environnementaux dus à la culture du palmier. Des analyses de cycle de vie de l’huile de palme ont été réalisées pour quantifier les impacts et identifier des améliorations de pratiques agricoles. Cependant, les seuls modèles d’émissions disponibles pour estimer les pertes de N dans l’environnement sont généralement valides pour les cultures annuelles et en climat tempéré. L’utilisation de tels modèles dans l’analyse de cycle de vie peut mener à des résultats très incertains ou à une faible sensibilité aux pratiques. L’objectif global de ce travail de recherche était d’aider à l’identification de pratiques pour réduire les pertes de N dans l’environnement. Le cœur du travail était le développement d’un modèle estimant toutes les pertes de N dans les plantations, tout en étant sensible aux pratiques. L’étude s’est concentrée sur les flux de N dans les plantations de palmiers sur sols minéraux. Nous avons réalisé quatre étapes pour mener à bien cette recherche. Premièrement, nous avons mené une revue de littérature de tout le savoir existant concernant les flux et pertes de N dans les plantations. Deuxièmement, nous avons comparé 11 modèles existants, pouvant être utilisés pour prédire les pertes de N dans les plantations. Troisièmement, nous avons réalisé une analyse de sensibilité de Morris approfondie du modèle mécaniste APSIM-Oil palm. Quatrièmement, nous avons construit IN-Palm, un indicateur agri-environnemental pour les pertes de N dans les plantations. Nous avons utilisé la méthode INDIGO® et l’approche de modélisation par arbres de décisions flous pour développer IN-Palm, et nous avons validé cet indicateur en utilisant des mesures de lixiviation de N d’une plantation à Sumatra, Indonésie. Notre revue de littérature et notre comparaison de modèles ont montré que les particularités du palmier à huile peuvent affecter significativement les dynamiques et pertes de N. Nous avons identifié des manques de recherche et des incertitudes sur les pertes de N, leurs déterminants et la modélisation des particularités du palmier. Nous avons identifié les déterminants des pertes de N et du rendement dans le modèle mécaniste APSIM-Oil palm. Nous avons développé IN-Palm, qui utilise 21 variables d’entré facilement accessibles pour estimer chaque voie de perte de N. Les prédictions de lixiviation de N par IN-Palm étaient acceptables, et IN-Palm s’est montré efficace pour tester des changements de pratiques agricoles. Cette recherche constitue une synthèse exhaustive des connaissances et modèles disponibles pour les flux et pertes de N dans les plantations. L’un des principaux résultats est un nouvel indicateur agri-environnemental, IN-Palm, sensible aux pratiques et conditions locales, de même qu’utilisable en tant que modèle d’émission dans des approches holistiques. Cet indicateur peut être une base utile pour de futures recherches sur l’utilisation d’indicateurs agri-environnementaux pour réduire l’incertitude des analyses cycle de vie, et pour de futures adaptations à d’autres plantes pérennes tropicales. / Humanity faces the challenges of urgently decreasing the environmental impact of agriculture, shifting diets and increasing food production. Oil palm is a tropical perennial crop emblematic of these challenges. While its cultivation can be associated with environmental impacts, oil palm can produce 3 to 7 t of edible oil ha-1 in optimal conditions, which is 7 to 10 fold higher than in annual oil crops. In this context, improving palm oil production sustainability is crucial for both reducing negative environmental impacts and ensuring food security. Application of synthetic nitrogen (N) fertilisers was identified as a major source of environmental impacts associated with the cultivation of oil palm. Life cycle assessments of palm oil have already been performed to help quantify impacts and identify potential improvements of management practices. However, the only available emission models to estimate N losses to environment are generally valid for annual crops and temperate climate conditions. The use of such general models in life cycle assessment may lead to very uncertain results or to low sensitivity of assessments to management practices. The overall objective of this research work was to help identify management practices to reduce N losses in the environment. The core of the work was hence to develop a model that estimates all N losses in oil palm plantations, while being sensitive to management practices. The study focused on N fluxes in industrial oil palm plantations on mineral soils. We performed four steps in order to complete the objectives of this research work. First, we conducted a literature review of all the existing knowledge about N fluxes and losses in plantations. Second, we compared 11 existing models that may be used to predict N losses in plantations. Third, we performed an in-depth Morris’s sensitivity analysis of one of the models, the APSIM-Oil palm process-based model. Fourth, we used all the information identified in the previous chapters, together with expert knowledge, to build IN-Palm, an agri-environmental indicator for N losses in oil palm plantations. We used the INDIGO® method and the fuzzy decision tree modelling approach to develop IN-Palm, and we validated this indicator using a field dataset of N leaching from a plantation in Sumatra, Indonesia. Our literature review and model comparison showed that oil palm peculiarities may impact significantly N dynamics and losses. We identified research gaps and uncertainties about N losses, their drivers and the modelling of oil palm peculiarities. We identified the main drivers of N losses and yield in the APSIM-Oil palm processbased model. We built IN-Palm, which uses 21 readily available input variables to estimate each N loss pathway. IN-Palm predictions of N leaching were acceptable, and IN-Palm has shown efficient to help testing management changes. This research constitutes a comprehensive synthesis of the available knowledge and models for N fluxes and losses in oil palm plantations. One of the main results is a novel agri-environmental indicator, IN-Palm, operationally-oriented, sensitive to local practices and environmental conditions, as well as potentially useable as an emission model for holistic approaches such as life cycle assessment. The INDIGO® method and fuzzy decision tree modelling approach were shown to be very well adapted for building agri-environmental indicators in contexts of knowledge scarcity. This indicator can be a useful base for further research about using agrienvironmental indicators to reduce uncertainty in life cycle assessment, and for future adaptations for other tropical perennial crops.

Over the past thirty years, price relativities and technological development have motivated an increase in the area of land allocated to cropping, as opposed to pasture production, throughout the central wheat belt of Western Australia. Nevertheless, reducing the proportion of pasture in these rotations has challenged the future productivity of farming systems in this area. First, the frequent application of selective herbicides for weed control in extended cropping rotations has promoted the development of herbicide resistance in a number of major agricultural weeds. Second, the primary use of annual plants has promoted the development of soil salinisation by allowing a significant proportion of rainfall to recharge saline water tables. The inclusion of perennial pasture phases between extended periods of cropping may mitigate or delay these constraints to production through (a) allowing the use of costeffective forms of non-selective weed control, and (b) through creating a buffer of dry soil that absorbs leakage occurring beneath subsequent crops. This study consequently explores the value of including perennial pasture phases in dryland agricultural systems in the eastern-central wheat belt of Western Australia, accounting for benefits related to herbicide resistance and water table management. A novel computational algorithm for the solution of multiple-phase optimal control problems is developed and used to conduct a conceptual analysis of the value of lucerne (Medicago sativa L.) pasture for managing annual ryegrass (Lolium rigidum Gaudin), the primary weed in wheat belt cropping systems. The competitiveness and fecundity of annual ryegrass provide strong economic incentives to maintain a low weed population, irrespective of herbicide-resistance status. Consequently, the ineffectiveness of selective herbicides primarily reduces the profitability of cropping by motivating the adoption of more costly non-selective forms of weed control. The inclusion of lucerne in land-use rotations is only optimal in the presence of severe herbicide resistance given (a) the low efficiency of alternative weed-management practices available during the pasture phase, relative to selective-herbicide application; (b) the significant cost of establishing this perennial pasture; and (c) the high relative profitability of cereal production in the absence of resistance. The value of lucerne, relative to annual pastures, for weed management is explored in greater detail through the use of compressed annealing to optimise a sophisticated simulation model. The profitability of candidate rotations is also manipulated to account for the long-term production losses accruing to the recharge of saline groundwaters that occurs beneath them. Sequences incorporating lucerne are only more profitable than those that include annual pasture at the standard set of parameter values if (a) annual ryegrass is resistant to all selective herbicides, (b) the water table is so shallow (approximately less than 3.5 m deep) that frequent rotation with perennials is required to avert soil salinisation, or (c) sheep production is highly profitable. The value of perennial pasture is sufficient under these circumstances to overcome its high establishment cost. Consistent with intuition, these benefits are reinforced by lower discount rates and higher rates of leakage occurring beneath annual-based systems. Formulation of an effective communication strategy to report these results to producers is justified given the complexity involved in determining the true magnitude of these intertemporal benefits through alternative means, such as field trials.

The hypothesis for this study was that phenanthrene degrading bacterial inoculants, in combination with grass species able to tolerate petroleum hydrocarbon contamination, will result in increased degradation, as compared to natural rates of hydrocarbon degradation, or to rates of degradation attributed to bacteria or plants alone. Three experiments were performed to examine this hypothesis: i) assessment of the effect of phenanthrene degrading bacteria (<i>Sphingomonas yanoikuyae</i>, <i>Rahnella aquatilis</i>, and <i>Arthrobacter globiformis</i>) on seed germination, location of attachment on seeds and roots, and inoculant survival on selected grass species, ii) determination of the inoculant survival in contaminated soil in the absence of plants and the ability to degrade target compounds, and iii) degradation potential and survival of selected grass species and bacterial inoculants in soil. In general, all applied inoculants were able to effectively colonize the seeds and had a neutral or positive effect on seed germination and seedling growth. Possible plant and bacteria pairs were chosen based on positive influence of the inoculant and are as follows: perennial ryegrass (<i>Lolium perenne</i>) or creeping red fescue (<i>Festuca rubra</i>) with <i>A. globiformis</i> or <i>S. yanoikuyae</i>, or slender wheatgrass (<i>Elymus trachycaulus</i>) with <i>A. globiformis</i> or <i>R. aquatilis</i>. Soil-based assessment of the survival and degradation of hydrocarbons by the selected inoculants was examined with or without a manure nutrient amendment. The addition of the inoculants had a positive impact on the efficacy of hydrocarbon removal in the soil. The manure-amended soil, or <i>A. globiformis</i> inoculated non-amended soil treatments reduced total petroleum hydrocarbon concentration by ~45%, whereas the non-amended control only resulted in a ~20% reduction. When soils were amended with manure and inoculated with any of the phenanthrene degrading bacteria, contaminant concentration decreased in soil by ~33%. <i>Sphingomonas yanoikuyae</i> survived the longest in soil in the absence of plants. A growth chamber experiment was conducted to determine the efficacy of plant and bacteria pairs for hydrocarbon removal in recalcitrant contamination found in soil from Bruderheim, Alberta. Additional replicates containing this soil were spiked with hexadecane, phenanthrene, and pyrene so the effectiveness of the plant and bacteria pairs at higher levels of fresh contamination could be assessed. In the spiked treatment, inoculation with <i>S. yanoikuyae</i> increased creeping red fescue root biomass. In the non-spiked treatment, <i>S. yanoikuyae</i> application increased creeping red fescue root and shoot biomass. Perennial ryegrass root and shoot biomass did not increase when inoculated with <i>S. yanoikuyae</i>, although root biomass values were observably higher in non-spiked soils. Creeping red fescue inoculated with <i>S. yanoikuyae</i> resulted in the greatest decrease in hydrocarbon concentration as compared to other treatments (~61%). The perennial ryegrass treatment, when inoculated with <i>S. yanoikuyae</i> increased percent hydrocarbon removal (~10%) above that obtained with perennial ryegrass alone. The addition of plants and <i>S. yanoikuyae</i> increased hydrocarbon degradation relative to control soils, although the addition of vegetation alone had a comparable effect. A critical benefit of inoculation was the increase in creeping red fescue root biomass at higher concentrations of contamination. This is important because the larger the root biomass the larger the volume of soil that can be remediated. The results indicate that the use of specific plant-bacterial inoculants can enhance remediation of hydrocarbon contaminated soils.

The hypothesis for this study was that phenanthrene degrading bacterial inoculants, in combination with grass species able to tolerate petroleum hydrocarbon contamination, will result in increased degradation, as compared to natural rates of hydrocarbon degradation, or to rates of degradation attributed to bacteria or plants alone. Three experiments were performed to examine this hypothesis: i) assessment of the effect of phenanthrene degrading bacteria (<i>Sphingomonas yanoikuyae</i>, <i>Rahnella aquatilis</i>, and <i>Arthrobacter globiformis</i>) on seed germination, location of attachment on seeds and roots, and inoculant survival on selected grass species, ii) determination of the inoculant survival in contaminated soil in the absence of plants and the ability to degrade target compounds, and iii) degradation potential and survival of selected grass species and bacterial inoculants in soil. In general, all applied inoculants were able to effectively colonize the seeds and had a neutral or positive effect on seed germination and seedling growth. Possible plant and bacteria pairs were chosen based on positive influence of the inoculant and are as follows: perennial ryegrass (<i>Lolium perenne</i>) or creeping red fescue (<i>Festuca rubra</i>) with <i>A. globiformis</i> or <i>S. yanoikuyae</i>, or slender wheatgrass (<i>Elymus trachycaulus</i>) with <i>A. globiformis</i> or <i>R. aquatilis</i>. Soil-based assessment of the survival and degradation of hydrocarbons by the selected inoculants was examined with or without a manure nutrient amendment. The addition of the inoculants had a positive impact on the efficacy of hydrocarbon removal in the soil. The manure-amended soil, or <i>A. globiformis</i> inoculated non-amended soil treatments reduced total petroleum hydrocarbon concentration by ~45%, whereas the non-amended control only resulted in a ~20% reduction. When soils were amended with manure and inoculated with any of the phenanthrene degrading bacteria, contaminant concentration decreased in soil by ~33%. <i>Sphingomonas yanoikuyae</i> survived the longest in soil in the absence of plants. A growth chamber experiment was conducted to determine the efficacy of plant and bacteria pairs for hydrocarbon removal in recalcitrant contamination found in soil from Bruderheim, Alberta. Additional replicates containing this soil were spiked with hexadecane, phenanthrene, and pyrene so the effectiveness of the plant and bacteria pairs at higher levels of fresh contamination could be assessed. In the spiked treatment, inoculation with <i>S. yanoikuyae</i> increased creeping red fescue root biomass. In the non-spiked treatment, <i>S. yanoikuyae</i> application increased creeping red fescue root and shoot biomass. Perennial ryegrass root and shoot biomass did not increase when inoculated with <i>S. yanoikuyae</i>, although root biomass values were observably higher in non-spiked soils. Creeping red fescue inoculated with <i>S. yanoikuyae</i> resulted in the greatest decrease in hydrocarbon concentration as compared to other treatments (~61%). The perennial ryegrass treatment, when inoculated with <i>S. yanoikuyae</i> increased percent hydrocarbon removal (~10%) above that obtained with perennial ryegrass alone. The addition of plants and <i>S. yanoikuyae</i> increased hydrocarbon degradation relative to control soils, although the addition of vegetation alone had a comparable effect. A critical benefit of inoculation was the increase in creeping red fescue root biomass at higher concentrations of contamination. This is important because the larger the root biomass the larger the volume of soil that can be remediated. The results indicate that the use of specific plant-bacterial inoculants can enhance remediation of hydrocarbon contaminated soils.