The importance of rare‐earth elements (REEs) in the global economy is booming as they are used in numerous advanced technologies. Industrially, the extraction and purification of REEs involve multiple liquid–liquid extraction (LLE) steps as they exhibit very similar complexation properties with most common ligands. In order to substantially improve this process and provide a greener alternative to LLE, functional porous hybrid materials, demonstrating enhanced selectivity towards heavier REEs compared to commercially‐available products, are proposed. In addition, because of the grafting procedure used in the synthesis, the proposed materials demonstrate a higher degree of reusability, increasing their marketable potential.

R. 2006. Winter damage to perennial forage crops in eastern Canada: Causes, mitigation, and prediction. Can. J. Plant Sci. 86: 33-47. Harsh winter climate results in frequent losses of stands and yield reduction in many forage-growing areas of Canada and other parts of the world. Climatic conditions and crop management both affect the winter survival of perennial forage crops. In this review, we present the main causes of winter damage in eastern Canada and we discuss crop management practices that help mitigate the risks of losses. Predictive tools available to assess the risks of winter damage both spatially and temporally are also presented. Our understanding of the causes of winter damage and of the plant adaptation mechanisms to winter stresses, particularly the role of N and C organic reserves, has improved. Forage species commonly grown in eastern Canada differ in their tolerance to subfreezing temperatures and to anoxia caused by the presence of ice on fields. Some improvement in winter hardiness of forage legume species has been achieved through breeding in eastern Canada but new technologies based on laboratory freezing tests and the identification of molecular markers may facilitate the future development of winter-hardy cultivars. Crop management practices required for good winter survival are now better defined, particularly those involving cutting management and the interval between harvests. Simulation models and climatic indices derived from our current knowledge of the causes of winter damage provide general indications on the risk of winter damage but their degree of precision and accuracy is still not satisfactory. Further improvements in winter survival require a more thorough understanding of the different causes of winter damage and, primarily, of their complex interactions with genetic, climatic, and management factors.

Understanding the mechanisms controlling crop effects on soil aggregation is necessary to develop sustainable soil management practices. Changes in soil aggregation, carbohydrates, and fungal vs. bacterial biomass were monitored following a shift from fallow (bare soil) to various cropping systems. Faba bean (Vicia faba L.) and wheat (Triticum aestivum L.) were used as annual cropping systems, while alfalfa (Medicago sativa L.), timothy (Phleum pratense L.), bromegrass (Bromus inermis L.), and reed canarygrass (Phalaris arundinacea L.) were used as perennial cropping systems. Crops were established in spring 1989, on a silty clay loam (fine, mixed, frigid Typic Dystro‐chrept) and a clay loam (fine‐loamy, mixed, frigid Typic Humaquept) near Québec City (Canada). After three growing seasons, the mean‐weight diameter of water‐stable aggregates (MWD) was higher under reed canarygrass (2.26 mm in the clay loam and 2.45 mm in the silty clay loam) and timothy (2.13 and 2.26 mm) than under faba bean (1.92 and 1.89 mm) or wheat (2.06 and 1.57 mm). Intermediate values were found under alfalfa and bromegrass. Changes in MWD were not correlated with microbial biomass C. Acid‐hydrolyzable carbohydrates correlated with MWD in the silty clay loam (r2 = 0.42**) but the relationship decreased with higher carbohydrate levels in the clay loam (r2 = 0.05). Close correlations were found between MWD and both fungal glucosamine (r2 = 0.68***, soils combined) and bacterial muramic acid (r2 = 0.48***). Changes in MWD were mostly reflected in aggregates >2 mm, and the close relationship with fungal glucosamine suggests that fungi played a dominant role in soil macroaggregation. Measurement of muramic acid and glucosamine is proposed as a potential approach to compare bacterial vs. fungal contributions to soil aggregation.

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