The soil parent material

Abstract

Since primitive times, communities acknowledged the importance of the substratum that supports the plants and, therefore, this knowledge precedes the creation of Pedology. The concept of parent rock was after replaced by the concept of parent material. In temperate climate regions, it is easy to see the connection between this material and the soil above, since its formation was restricted to the post-glaciation Quaternary period, whereas, in regions of the humid tropics, this connection is more complex, since climatic changes promote the formation of overlapping pedogenic cycles, making it difficult to identify the nature of the material that formed the soils. According to the focus of the study, the contacts between the geological substratum and soil have different names and conceptions depending on the parent material: regolith, alterite, saprolite, C horizon and D layer. Regardless of the applications, the objective of this study is to evaluate researchers’ diferente understanding of these terms. Soil genesis is a very complex subject, particularly regarding the distinction between in-situ parent material and transported material. In this case, sedimentological methods, absolute dating, and geostatistical analysis are important tools to investigate the soil parent material.