Chemical and Morphological Soil Characteristics in a New England Drainage‐toposequence

Chemical, physical, and morphological properties of soils in a representative drainage‐toposequence in central Massachusetts were determined. The soils reflect the acid character of the glacial till derived from granitic materials by the low cation exchange capacity (CEC) and base saturation values, although some effect of past liming is evident. Within a depth of 70 cm most catena members are underlain by a hardpan. This appears to be mainly of geogenetic origin but also exhibits pedogenetic influences in the occurrence of free grain and channel argillans in the upper 25 cm of the pan, especially in well‐ and moderately well‐drained profiles. Depth to the hardpan varies between 45 and 120 cm and in general is somewhat less in soils on the steeper slopes than those on the more level areas. The slowly permeable pan severely restricts vertical drainage of excess soil water and causes increased lateral flow. This results in wetter soil conditions downslope as is evident from the presence of mottling in B horizons. The hardpan is characterized by low chroma ped interiors and bright, high chroma ped ferrans indicative of prolonged wet, but unsaturated, soil conditions. The somewhat poorly and poorly drained catena members have B horizons with relatively low chroma matrix colors and high chroma channel neoferrans which reflect a generally wet soil environment with relatively short, drier periods. Dithionite‐citrate and sodium pyrophosphate‐extractable iron and aluminum contents were determined in B horizons of selected profiles along the catena to evaluate the performance of present U.S. soil taxonomic criteria for spodic horizons since the well‐ and moderately well‐drained soils were classified as Brown Podzolic soils until the 1975 revision. Current chemical criteria effectively exclude these soils from spodic horizon qualification.