Cracking Depths in Indian Vertisols: Evidence of Holocene Climate Change

Abstract

In Indian sub-continent, Vertisols in humid tropical (HT), sub-humid moist (SHM), sub-humid dry (SHD), semi-arid moist (SAM), semi-arid dry (SAD) and arid dry (AD) climatic environments indicate their occurrence in a climosequence. The soils show a change in their morphological, physical, chemical and micromorphological properties due to change of climate from humid to arid during the Holocene period. Formation of pedogenic CaCO₃ (PC), illuviation of clay and the development of subsoil sodicity are concurrent, contemporary and active pedogenetic processes operating during the climate change of the Holocene period. These processes impaired the hydraulic properties of soils in general, and in soils of drier climates in particular. As a result, cracking pattern, chemical composition and plasmic fabric were more modified in soils of the drier climates. Such modifications in soil properties have a place in the rationale of Vertisol order of the US Soil Taxonomy. The soils of wetter climates (HT, SHM and SHD) are grouped in Typic Haplusterts whereas the soils of drier climates (SAM, SAD and AD) are classified as Aridic Haplusterts, Sodic Haplusterts and Sodic Calciusterts. Such pedological study demonstrates how the depth of cracking in Vertisols in a climosequence can be used as simple analytical tools in inferring the change in climate in a geologic period.