Spatal distributon of clay, silt and sand contents in the superfcial layer of soil in Santa Catarina State, Southern Brazil

Abstract

The elaboraton of maps with soil atributes is a tool to present soil use and management plans according to agricultural demands. To determine the spatal distributon of clay, silt and sand contents in Santa Catarina State, Southern Brazil, 1,706 soil samples were collected in felds throughout the state. The percentage of each fracton was determined by the
pipete method in soil samples collected at up to 50cm deep. The clay content was determined also by the routne method of chemical soil analysis in samples collected at up to 20cm deep in the same plots. The municipal mean of each atribute was placed at the city geographic coordinates in order to elaborate maps with the spatal distributons of the classes through the ILWIS 3.2 Academic sofware. The spatal distributon of clay and sand contents is associated with the parent material, with an
increase of the clay content from the Coast to the Highlands, remaining high as far as the West and reducing again in the Far West of the state. The sand content followed the opposite patern as compared to clay content, and silt content predominated in the range between 30% and 45%, according to the spatal distributon map.