Physico-hydrical mapping of the soils of the Santa Maria and Cambiocó Basin, Rio de Janeiro State

Abstract

The physico-hydrical classification system (PHCS) proposed by Ottoni Filho (Ottoni Filho 2003) categorizes soil profiles according to their aeration and water capacities based on in situ tests to determine field capacity and steady state infiltration rate, and systematically adds this information to the pedological survey. However, this system still lacks a systematic procedure of classification of pedological mapping unities in terms of physico-hydrical characteristics. Thus, the use of pedological mapping would have its potential enhanced if such characteristics were included. This study defined the physico-hydrical mapping methodology of soils based on pedological mapping units; the method has been applied to a 13-km2 watershed in the state of Rio de Janeiro. A direct correspondence was not found between the physicohydrical and pedological classifications. The main physico-hydrical limitations of the soils of the studied basin were related to the low aeration capacity of Haplic Gleisols and Red-Yellow Argisols, the low water availability of Gleic Haplic Cambisols and Litholic Neosols, as well as the small depth of Litholic Neosols. In conclusion, the physico-hydrical mapping was both satisfactory and advantageous, and its application to other soils from diverse pedoenvironments is recommended.