Medium and short range variability in textural layering in an ochrept developed on an alluvial floodplain

Abstract

The nature and extent of textural layering was investigated in 367 profiles described during a 30 by 30 m grid survey of an area of Ochrepts developed on a Holocene floodplain in the South Island of New Zealand. The typical profile texture form (to 1 m) consists of a uniform textured layer of varying thickness (but less than 60 cm), underlain by a texturally layered portion in the B horizon and below. Textures in the layered portion ranged from heavy silt loams to sands. The number of layers ranged from one to thirteen with six to eight being the most usual. The pattern of textural layering is random and hence unpredictable, and is the result of sedimentary depositional processes forming the parent material of these alluvial soils. Continuous (short range) lateral variability in textural layering was similar to that identified during the 30 by 30 m grid survey.