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Three sugarbushes were selected for the study of root distribution. Saint-Hippolyte was the best site for the distribution and production of fine roots. A high water-table and an abrupt change in texture limited the extension of the root system to the top 40 cm at the Vaudreuil site. In Tingwick, an acid mineral B horizon with a low Ca saturation restricted the production of fine roots in that horizon. / A sugarbush in Norbertville was used as a replacement for the Vaudreuil site for the study on root chemistry. The Saint-Hippolyte site had the best overall nutrient status. The molar ratio Ca/inorganic Al and Mg/inorganic Al in solution never reached values low enough to be considered toxic for the growth of fine roots. However, Al seems to increase the imbalance between Ca and K and may be responsible for the low foliar P found at Norbertville. Aluminium may also inhibit Ca uptake by roots due to very low Ca content in Tingwick.

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Extreme rainfall events may have catastrophic impacts on the population and infrastructures, therefore it is essential to have accurate knowledge of extreme rainfall characteristics. Moreover, both the scientific community and policymakers have recently shown a growing interest in the potential impacts of climate change on water resources management. Indeed, changes in the intensity and frequency of occurrence of extreme rainfall events may have serious impacts. As such, it is important to understand not only the current patterns of extreme rainfalls but also how they are likely to change in the future. / The objective of the present research is therefore to find the best method for estimating accurately extreme rainfalls for the current time period and future periods in the context of climate change. The analysis of extreme rainfall data from the province of Quebec (Canada) revealed that, according to L-moment ratio diagrams, the data may be well described by the Generalized-Extreme-Value (GEV) distribution. Results also showed that a simple scaling relationship between non-central moments (NCM) and duration can be established and that a scaling method based on NCMs and scaling exponents can be used to generate accurate estimates of extreme rainfalls at Dorval station (Quebec, Canada). Other results demonstrated that the method of NCMs can accurately estimate distribution parameters and can be used to construct accurate Intensity-Duration-Frequency (IDF) curves. / Furthermore, a regional analysis was performed and homogenous regions of weather stations within Quebec were identified. A method for the estimation of missing data at ungauged sites based on regional NCMs was found to yield good estimates. / In addition, the potential impacts of climate change on extreme rainfalls were assessed. Changes in the distribution of annual maximum (AM) precipitations were evaluated using simulations from two Global Climate Models (GCMs) under the A2 greenhouse gas emission scenario: the Coupled Global Climate Model version 2 (CGCM2A2) of the Canadian Centre for Climate Modelling and Analysis, and the Hadley Centre's Model version 3 (HadCM3A2). Simulations from these two models were downscaled spatially using the Statistical DownScaling Model (SDSM). A bias-correction method to adjust the downscaled AM daily precipitations for Dorval station was tested and results showed that after adjustments, the values fit the observed AM daily precipitations well. The analysis of future AM precipitations revealed that, after adjustments, AM precipitations downscaled from CGCM2A2 increase from current to future periods, while AM precipitations downscaled from HadCM3A2 show a mild decrease from current to future periods, for daily and sub-daily scales.

Public concern for the intergenerational transfer of natural resources has generated an interest in sustainable development and sustainable agriculture. Policy makers have a new mandate to insure the promotion of sustainable agriculture. At the same time these policy makers must also reduce public expenditures in agriculture. These two conflicting mandates can only be accomplished when private market values for various soil conservation investments are known. Once this market information is known, policy makers can formulate appropriate policies to achieve both goals. / The focus of this research is to measure the significant factors affecting land values in the study area. The sample farm sales data used were drawn from four of Quebec's twelve agricultural regions. Two of these regions are among Quebec's most productive. These data were used in conjunction with a Hedonic Pricing Model for the analysis. / This research seeks to quantify the implied price paid for land characteristics, soil conservation and capital improvement investments. The research should determine whether the studied land market provides adequate price incentives for private market implementation of soil conservation and capital improvement investments. These investments are necessary to achieve a sustainable agriculture scheme.

Potato requires high levels of nitrogen fertilizer. Up to now in Quebec, no nitrogen fertilizer recommendation has been based on nitrogen availability in the soil, even those soil nitrogen testing is available. The objectives of this study were: (1) to determine the relation between soil nitrate-N content, nitrogen fertilization and potato yield; and (2) to determine the time and the sampling depth of soil most appropriate to predict potato yields and response to nitrogen fertilizer under Quebec conditions. Soil samples were taken at two depths at planting and at hilling time in 28 sites fertilized at four levels of nitrogen. Laboratory measures of nitrate-N were carried out on those samples. A combination of nitrate-N and nitrogen fertilisation gave the best explanation of the variation potato yields. A maximum of 46% of yield variation was attributed to the combination of those two factors in general. Best coefficients of determination were obtained when the sampling of nitrate-N was done at planting time compared to time. Regression models predicted nitrogen fertilizer needs of 89 to 200 kg ha$ sp{-1}.$ The same conclusions were found in the case of the variety Superior alone. The variation of yield explained was up to 62%. Regression models predicted nitrogen fertilizer needs of 77 to 224 kg ha$ sp{-1}$ for Superior. It was concluded that the analysis of soil nitrate-N can improve the prediction of nitrogen fertilizer needs for an optimum potato production.

This thesis examines how cultural understandings are generated and transmitted in a Canadian multicultural teaching hospital. It explores how issues of 'culture' are addressed formally and informally in the experiences of patients and practitioners. Using the approach of an institutional ethnography, emphasis is placed upon informal strategies of cultural care as a taken-for-granted practice in clinical life. It illuminates how pressure to learn culturally sensitive care seeps into the fabric of daily clinical life, and how cultural practices are constructed within a complex set of organized social practices. / The study concludes that advocacy of multicultural policies, must consider the dominance of existing western health care paradigms. It advocates culturally responsive care as a parallel force that can collaborate with the regimes of formal health practices. It argues that providing effective health care to all segments of Canadian society requires structural changes in health education which need to address existing disjunctures between 'effective ideals' and ideological knowledge, in order that all are ensured optimum health care.