The use of agricultural chemicals, such as nitrogen fertilizers in corn production, often results in water pollution. This research, comprising three parts, was designed to investigate the effects of nitrogen fertilizer application rates, water table management, and corn cropping systems on drainage water quality. The first part was a field study, to investigate the impact of two cropping systems and water table management on nitrate loss through tile drainage. The considered water table treatments were free drainage, and subirrigation with target water table depths at 0.5 m or 0.75 M below the soil surface. Corn (Zea mays L.) monoculture and corn intercropped with annual ryegrass (Lolium multiflorum Lam.) were investigated. The highest annual tile drainage losses of 21.9 kg N/ha were measured in monocropped, freely draining plots. Subirrigation with a water table depth of 0.5 m reduced tile drainage loss of N by over 70%, and intercropping corn with ryegrass under free drainage reduced leaching losses by 50%. / The second part of the research was a simulation study with the water quality model, DRAINMOD-N. The water quality impact of fertilizer application rate under free drainage, subirrigation and controlled drainage was evaluated. Leaching losses, denitrification and N accumulation in the soil profile were investigated. Using data obtained from the field experiment, the performance of DRAINMOD-N was evaluated. DRAINMOD-N assumes that denitrification follows first order kinetics, contrary to field measurements which showed little correlation between denitrification rate and NO$ sb3 sp-$-N concentration. Therefore, DRAINMOD-N was modified by replacing the original denitrification function with the Michaelis-Menten relationship. In so doing, denitrification is expressed as a first order process when NO$ sb3 sp-$-N concentration limits denitrification, and as a zero order process for non-limiting NO$ sb3 sp-$-N concentration. / For denitrification to be a decision making criterion of water table management, inexpensive but reliable measurement techniques are required. Thus, the purpose of the final part of this research was to formulate a technique for measuring real-time denitrification rate. Denitrification rate could be expressed as a function of soil redox potential (Eh) and temperature. Laboratory and field studies showed that factors such as soil nitrate and organic carbon had negligible effect on denitrification rate. Therefore, it can be concluded that for most agricultural soil, Eh and soil temperature will satisfactorily describe denitrification variation.

School vice-principals never aroused so much the interest of educational researchers. The studies done were mostly of a descriptive nature and only a very small number were in a formal, theoretical context. A tendency is emerging in education and consists of recognizing more and more the importance of the vice-principal's role in the schools, specially from the perspective of educational change. / The purpose of the study was to assess the level of internal motivation for a sample of school vice-principals and examine the vice principals job using the Job Characteristic Theory developed by Hackman and Oldham (1980) as a theoretical base, in an effort to identify specific aspects of the job that might be improved. / The Job Diagnostic Survey was used to obtain data from a sample of 131 vice-principals in francophone public schools across the province of Quebec. One way analysis of variance and t-test were used to identify significant differences within groupings and between levels of independent variables: gender, age, years of experiences in education, as vice principals, types of schools, size of schools and willingness to be promoted. / The sample of school vice-principals reported moderately high levels of internal motivation. Examination of the specific job characteristics showed high levels of skill variety and only low to moderate levels of autonomy and job feedback. Finally job incumbents reported moderate levels of satisfaction with conditions of employment, although there were a number of differences within groupings by independent variables indicating low level of general satisfaction and satisfaction with salary.