Identificação do limite entre solo e saprolito em argissolos bruno-acinzentados derivados de rochas sedimentares

Abstract

The Argissolos (Ultisols and Alfisols) derived from sedimentary rocks occur in the region of Central Depression of the Rio Grande do Sul state, over siltstones and sandstones in the soft wavy reliefs. These soils are predominantly shallow, which gives greater importance to its deep layers. These layers have often been inadequately described in the fields due to the difficulty in interpreting the contact between the soil and saprolite. Moreover, the horizon/layer C has been the subject of disagreement among researchers as yet be considered either saprolite and soil. In this sense, the objective of this study was to analyze different profiles of Argissolos derived from sedimentary material of the the Sanga do Cabral and Santa Maria - Member Alemoa formations, located between the Santa Maria and Sao Pedro do Sul town. This research focused on a morphological, a physical and chemical characteristics of the soils profiles. The results showed two situations: the C is a horizon that has a development showing strong evidence of pedogenesis, with morphology, physical and chemical behavior similar to the Bt horizon, and C is a transition layer between the saprolite (Cr) and soil (Bt), independent of both, but with the possibility of interconnections with them.