Comparison of the variability in a soil taxonomic unit with that of the associated soil mapping unit

Abstract

The variation in morphological and chemical properties within the Westmere silt loam mapping unit mapped at the soil type level in the Wanganui district of New Zealand is compared with the variation in the same properties in the Westmere silt loam taxonomic unit. Nearly half of the measured morphological properties are similarly distributed in both the taxonomic and mapping unit, while approximately equal proportions of the remaining properties show either leptokurtic (more peaked) distributions or platykurtic (broader) distribution in the taxonomic unit. Chemical properties generally show slightly less variance (as shown by cv values) in the taxonomic unit. Considered overall, a similar degree of variation exists in both the taxonomic and mapping units. This can be explained by the main inclusions within the Westmere silt loam mapping unit being characterized by a range of morphological and chemical properties similar to the Westmere silt loam taxonomic unit and with a similar (or possible lesser) degree of variability.