Allaire, S. E., van Bochove, E., Denault, J.-T., Dadfar, H., Thériault, G., Charles, A. and De Jong, R. 2011. Preferential pathways of phosphorus movement from agricultural land to water bodies in the Canadian Great Lakes basin: A predictive tool. Can. J. Soil Sci. 91: 361–374. Preferential flow processes, such as crack flow (CF), burrow flow (BF), finger flow (FF) and lateral flow (LF) are known as factors enhancing phosphorus (P) transport from agricultural soils to water bodies. The objective of this study was to develop a methodology for predicting the likelihood of preferential flow processes in agricultural soils at the landscape scale and their potential occurrence around the Canadian Great Lakes. The methodology considered climate, soil and crop parameters and a water budget that calculated surface runoff and drainage. Crack flow largely depended upon soil clay content, BF on soil texture and climate, FF on layering in sandy soils and LF on the presence of trees, slope and soil restricting layers. Crack flow had a high likelihood to occur southern Lake Ontario and all around Lake Erie. A high likelihood of FF could be found in the area where CF was low (i.e., in the sandy soils north of Lake Huron and Lake Ontario). Burrow flow had a medium likelihood to occur on Manitoulin Island and close to the shoreline north of Lake Ontario. Medium to high likelihood of lateral flow might occur in the area south of Lake Ontario, west of Toronto in a narrow band towards Lake Huron, and to a lesser extend in a large area northeast of Lake Huron. Lateral flow may transport soluble P in areas where P was previously carried downward by FF from inland (in soils) to surface water bodies. In several areas, tile drainage may transport all forms of P carried downward from the soil surface to the subsurface by CF and BF to lake tributaries. Preferential flow distribution maps could be used as tools for supporting the identification of agricultural lands where management might enhance subsurface processes of P transport toward groundwater or surface water bodies.

. 2015. Carbon dynamics in a biochar-amended loamy soil under switchgrass. Can. J. Soil Sci. 95: 1Á13. The environmental impacts of switchgrass production for bioenergy could be reduced through the use of biofertilizers rather than mineral fertilizers and through soil amendment with biochar. The objectives of this study were: (1) to assess the impact of biochar and biofertilizer on switchgrass (Panicum virgatum L.) yield and parameters related to carbon dynamics, (2) to correlate carbon parameters with soil physico-chemical properties over the first two growing seasons, and (3) to develop a C budget. A complete randomized block design was installed in a sandy loam with split plot treatment design, the main plots receiving 0 or 10 t ha(1 of biochar and the sub ( plots receiving no fertilization, mineral N fertilization, or biofertilizers. Biofertilizers had no significant impact on plant and soil. Biochar increased yield relative to the control treatment by about 10% during the first year and root biomass by up to 50% after 2 yr (P0.1). Mineral N fertilization also increased yield resulting in higher plant C sequestration after 2 yr. Biochar increased CO 2 soil concentration (CO 2-soil ) by up to 50% but its impact on CO 2 emission flux (CO 2-flux ) changed over time. The impact of mineral fertilization on CO 2-flux also varied with time. Soil CO 2 dynamics was mostly influenced by temperature, N and water content. Biochar and fertilization treatments showed interactions on some plant and soil parameters. The highest C sequestration budget was obtained with a combination of biochar and mineral N fertilization. The equivalent of about one-third of the increase in soil C content associated with biochar treatments was respired away by soil microorganisms. Nearly one-fourth of C sequestered by plants remained in or at the soil surface (root and crop residues).Key words: Panicum virgatum L., carbon sequestration, CO 2 emissions, soil carbon, soil gas concentration Allaire, S. E., Baril, B., Vanasse, A., Lange, S. F., MacKay, J. et Smith, D. L. 2015. Dynamique du carbone dans une production de panic e´rige´amende´e de biochar sur sol loameux. Can. J. Soil Sci. 95: 1Á13. Le biochar et les bioengrais pourraient aider ar e´duire les impacts environnementaux associe´s a`la production de panic e´rige´pour la bioe´nergie. Cette e´tude vise a`(1) quantifier l'impact du biochar et d'un bioengrais sur le rendement du panic e´rige´(Panicum virgatum L.), la se´questration de carbone, le CO 2 dans le sol (CO 2-soil ) et son e´mission (CO 2-flux ); (2) corre´ler les parame`tres de carbone avec les proprie´te´s du sol et (3) e´valuer le budget de carbone. Un plan expe´rimental en tiroirs a e´te´instaure´sur un loam. Les parcelles principales ont rec¸u 0 ou 10 t ha (1 de biochar, les parcelles secondaires ont rec¸u diffe´rents traitements d'engrais. Les bioengrais n'ont pas influence´les plantes et le sol. Le biochar a favorise´une augmentation de rendement de 10% a`la premie`re saison et la biomasse racinaire de 50% apre`s deux sais...