Micromorphological evidence of pedogenetic pathway of a Podzolic Gray Luvisol (Falmouth series) in Nova Scotia

Abstract

A catena of Podzolic Gray Luvisols (Falmouth series) – Gleyed Gray Luvisols (Queens series) – Orthic Gleysols (Kingsville series) is commonly found on fine loamy, weakly calcareous parent materials in Nova Scotia, with Podzolic Gray Luvisols occupying the best drained landscape positions. The hypothesis that podzolic B horizons of Podzolic Gray Luvisols were developed on degraded Bt horizons was investigated by micromorphological characterization of one Podzolic Gray Luvisol pedon. Although not visible in field examinations, argillans were common in thin sections of the Bf and Bm horizons. These argillans were not associated with the walls of voids or the surface of grains. Argillans of the Bt horizons, however, were associated with features such as cracks, vughs, and channels. The upper Bt horizon (i.e., Bt1gj) showed signs of degradation. The pale brown matrix color was more like the Bm horizon above than the dark brown Bt2gj horizon below. The strongly acidic nature of the Bt1gj horizon may have triggered degradation. It is concluded that the Bf and Bm horizons were developed on degraded Bt horizons through the translocation of amorphous Fe and Al and organic matter. Key words: Pedogenesis, micromorphology, Luvisols, bisequal soils