Summary

Description

The results of the analysis of soil chemical parameters, texture, and color are reported for 185 georeferenced soil profile sample points over four forested headwater catchments near Juruena, Mato Grosso, Brazil (Novaes Filho, et al., 2007a and Novaes Filho, et al., 2007b). Samples were collected from an approximately 20 x 20 m grid over each watershed from 2004/05/01 to 2004/08/18. By sampling each location at depths of 0-20 and 40-60 cm it was possible to distinguish and map the principle soil classes found in the study area to the 2nd category level of the Brazilian System of Soil Classification (Cooper et al., 2005) associated with the topographic relief. The data set contains one comma separated ASCII data file with spatially referenced soil nutrient and organic carbon data from 0-20 cm (A layer, topsoil) and 40-60 cm (B layer, subsoil)depths for the Juruena watersheds study area.A satisfactory relationship between the redness index of the diagnostic horizons and the soil class colors was also found. In spite of the apparent homogeneity of the visible landscape characteristics such as slope, soil color, and vegetation, the carbon and soil clay attributes were found to vary greatly. This variability over small distances demonstrates that extrapolation of soil characteristics and soil carbon stocks to larger areas could produce erroneous results if the spatial variability of the soil attributes is not taken into consideration.