Some chemical, physical and micropedological studies of Vancouver Island shot soils

A study was undertaken to determine some of the chemical, physical and pedological factors affecting the genesis of shot formations in the Fairbridge and Alberni shot soils series of Vancouver Island, British Columbia. On the basis of hardness, color and texture, Fairbridge and Alberni shot formations were separated into two groups, one of which was classified as true shot and the other as pseudoshot. Chemical analyses showed that the two forms contained different amounts of aluminum, iron, manganese, phosphorus and silica, and that both forms acted as accumulation centres for aluminum, iron, manganese and phosphorus when their totals of these elements were compared with those present in the shot formation matrix ('B' horizons) and parent material ('C' horizons). Physical analyses of shot formations showed diversity in the percentages of sand, silt and clay contained in shot and pseudoshot, and the particle size distribution of these components also differed in both forms. Shot formations were found to be concentrated in the surface ('B') horizons of each series studied, and the 'C' horizon of each soil type was found to be impermeable to water. This latter condition, coupled with the seasonal fluctuation in temperature and precipitation in the respective areas, produced alternate wetting and drying cycles similar to those observed by other investigators of shot soils. Micropedological studies involving the preparation, examination and photographing of shot formation and soil horizon thin sections showed that the degree of weathering of clay minerals in shot and pseudoshot was not comparative, and that similar differences existed between shot formations and the 'B' and 'C' horizons of each soil series. It is postulated that shot genesis might begin with parent material which, after passing through a pseudoshot stage, develops into the true shot form.Land and Food Systems, Faculty ofGraduat