Effect of climate on morphological features of soils from loess in the southern part of South Island, New Zealand

Abstract

Soils developed in thick loess deposits in subhumid and humid climatic zones in the southern part of the South Island, New Zealand, form a continuum in which the morphological features occur in sequential order. The sequence consists mainly of soils belonging to the Fragiochrept and Dystrochrept great groups. The climatic factor, particularly the moisture regime, is considered to be largely responsible for the differing morphological features. The principal morphological features are fragipans and stratigraphically equivalent horizons that are not 'fragic'; gammate colour patterns; and mottling and gleying above the fragipan. These features show an interrelationship that is explained by the progressive modification and destruction of the fragipan due to the impress of the moisture regime.