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Maintaining the future sustainability of agriculture and ensuring soil security is of primary concern across Canada. Understanding the state of soil erosion and determining the vulnerable areas are essential measures in combatting future soil erosion and avoiding soil degradation. Therefore, the general goal of this thesis was to quantify soil erosion rates and develop an improved understanding of erosion processes within the Canadian Prairies. To fulfill the aim of the research project, typical agricultural and native prairie landscapes of the region were studied within three watersheds including the Red River Valley and the Broughton’s Creek watershed in Manitoba, and the Bigstone Creek watershed in Alberta. Initially, passive uni-directional wind erosion sediment samplers were employed to assess wind-eroded soil movement in agricultural lands of the Red River Valley. Cesium-137 (137Cs) measurements were conducted to quantify total soil loss and deposition rates within the wetland landscapes in the Broughton’s Creek and Bigstone Creek watersheds. In addition, soil and sediment properties were characterized to understand tillage-, water- and wind-induced sediment transport dynamics and distinguish between eroded and depositional zones. Landform classification maps of the studied wetland catchments were also created to assist developing sediment budgets of soil loss and accumulation, and quantify sediment flux rates from agricultural fields to wetland environments. Furthermore, soil erosion models were used to characterize spatial patterns of soil loss by tillage, water, and wind erosion and assess relative contribution of these processes towards total soil erosion. This study found that: i) Measured soil loss and sedimentation caused by wind erosion are very small in the Red River Valley. Moreover, abrasion of crops by wind-transported sediment was not observed in this study; ii) Using the measurements of 137Cs, average annual soil losses in cultivated fields were

Maintaining the future sustainability of agriculture and ensuring soil security is of primary concern across Canada. Understanding the state of soil erosion and determining the vulnerable areas are essential measures in combatting future soil erosion and avoiding soil degradation. Therefore, the general goal of this thesis was to quantify soil erosion rates and develop an improved understanding of erosion processes within the Canadian Prairies. To fulfill the aim of the research project, typical agricultural and native prairie landscapes of the region were studied within three watersheds including the Red River Valley and the Broughton’s Creek watershed in Manitoba, and the Bigstone Creek watershed in Alberta. Initially, passive uni-directional wind erosion sediment samplers were employed to assess wind-eroded soil movement in agricultural lands of the Red River Valley. Cesium-137 (137Cs) measurements were conducted to quantify total soil loss and deposition rates within the wetland landscapes in the Broughton’s Creek and Bigstone Creek watersheds. In addition, soil and sediment properties were characterized to understand tillage-, water- and wind-induced sediment transport dynamics and distinguish between eroded and depositional zones. Landform classification maps of the studied wetland catchments were also created to assist developing sediment budgets of soil loss and accumulation, and quantify sediment flux rates from agricultural fields to wetland environments. Furthermore, soil erosion models were used to characterize spatial patterns of soil loss by tillage, water, and wind erosion and assess relative contribution of these processes towards total soil erosion. This study found that: i) Measured soil loss and sedimentation caused by wind erosion are very small in the Red River Valley. Moreover, abrasion of crops by wind-transported sediment was not observed in this study; ii) Using the measurements of 137Cs, average annual soil losses in cultivated fields were

Knowledge of nutrient accumulation and partitioning in plants is important to determine the optimum timing of harvesting during phytoremediation of biosolids. This research showed that a greater proportion of nitrogen (N) and phosphorus (P) absorbed by cattail and switchgrass was partitioned to the aboveground biomass (AGB), but this partition decreased after the onset of nutrient retranslocation to roots. Therefore, AGB should be harvested prior to retranslocation in order to optimize nutrient phytoextraction. Trace elements partitioned preferentially to the root biomass, indicating that AGB harvesting will have little impact on their phytoextraction. Net mineralized N concentration (Nmin) in biosolids from the primary lagoon cell was optimized near field capacity [60% water filled pore space (WFPS) but changed little under drier conditions (30% WFPS). Under near-saturation conditions (90% WFPS), net Nmin decreased with incubation time, likely due to reduced mineralization and denitrification. Available (Olsen) P concentration was not affected by moisture content.

Growth room experiments were conducted to examine terrestrial and wetland-based phytoremediation approaches as alternatives to biosolids management. Results from both experiments show that biosolids do not need to be amended with soil to encourage plant growth and optimize biomass yields. In the terrestrial phytoremediation approach, two harvests per growth cycle produced greater switchgrass biomass yield than a single harvest but had no significant effect on cattail biomass yield during the first cycle. Repeated harvesting also significantly increased mean nutrient uptake in Cycle 1, reflecting the greater biomass yield from two harvests compared with a single harvest. In the wetland experiment, nutrient phytoextraction under two harvests was 4.25% of initial N content and 2.28% of initial P content compared with 2.9% and 1.58%, respectively, under a single harvest. Terrestrial phytoremediation could be beneficial to small communities that cannot afford the costly excavation, trucking, and eventual spreading of biosolids on agricultural land.

Growth room experiments were conducted to examine terrestrial and wetland-based phytoremediation approaches as alternatives to biosolids management. Results from both experiments show that biosolids do not need to be amended with soil to encourage plant growth and optimize biomass yields. In the terrestrial phytoremediation approach, two harvests per growth cycle produced greater switchgrass biomass yield than a single harvest but had no significant effect on cattail biomass yield during the first cycle. Repeated harvesting also significantly increased mean nutrient uptake in Cycle 1, reflecting the greater biomass yield from two harvests compared with a single harvest. In the wetland experiment, nutrient phytoextraction under two harvests was 4.25% of initial N content and 2.28% of initial P content compared with 2.9% and 1.58%, respectively, under a single harvest. Terrestrial phytoremediation could be beneficial to small communities that cannot afford the costly excavation, trucking, and eventual spreading of biosolids on agricultural land.

Growth room experiments were conducted to examine terrestrial and wetland-based phytoremediation approaches as alternatives to biosolids management. Results from both experiments show that biosolids do not need to be amended with soil to encourage plant growth and optimize biomass yields. In the terrestrial phytoremediation approach, two harvests per growth cycle produced greater switchgrass biomass yield than a single harvest but had no significant effect on cattail biomass yield during the first cycle. Repeated harvesting also significantly increased mean nutrient uptake in Cycle 1, reflecting the greater biomass yield from two harvests compared with a single harvest. In the wetland experiment, nutrient phytoextraction under two harvests was 4.25% of initial N content and 2.28% of initial P content compared with 2.9% and 1.58%, respectively, under a single harvest. Terrestrial phytoremediation could be beneficial to small communities that cannot afford the costly excavation, trucking, and eventual spreading of biosolids on agricultural land.

Growth room experiments were conducted to examine terrestrial and wetland-based phytoremediation approaches as alternatives to biosolids management. Results from both experiments show that biosolids do not need to be amended with soil to encourage plant growth and optimize biomass yields. In the terrestrial phytoremediation approach, two harvests per growth cycle produced greater switchgrass biomass yield than a single harvest but had no significant effect on cattail biomass yield during the first cycle. Repeated harvesting also significantly increased mean nutrient uptake in Cycle 1, reflecting the greater biomass yield from two harvests compared with a single harvest. In the wetland experiment, nutrient phytoextraction under two harvests was 4.25% of initial N content and 2.28% of initial P content compared with 2.9% and 1.58%, respectively, under a single harvest. Terrestrial phytoremediation could be beneficial to small communities that cannot afford the costly excavation, trucking, and eventual spreading of biosolids on agricultural land.