Estimation of precompression stress in an Ultisol cultivated with sugarcane

Estimativa da tensão de preconsolidação em Argissolo cultivado com cana-de-açúcar

ABSTRACT

Compressive soil properties are typically used for the understanding of compaction process. As an alternative to laboratory tests, pedo-transfer functions have been used to estimate the mechanical behaviour of soil as a function of soil physical parameters. The impact of soil bulk density (BD) and gravimetric water content (w) was examined on soil strength and pedo-transfer functions were proposed to predict the precompression stress (σ_p) in an Ultisol cultivated with sugarcane. Undisturbed soil cores were sampled at the depths of 0-0.20 and 0.20-0.40 m, subjected to different water contents, and subsequently, compression tests were performed to determine σ_p. The data were subjected to analysis of variance and regression analysis. Bulk density and w affected σ_p positively and negatively, respectively. Approximately 70% of the variation of the σ_p could be explained as a function of BD and w through an accessible multiple regression model. Comparisons with other pedo-transfer functions showed that estimates of σ_p may be rather sensitive to soil management and textural classes. Variations imposed by soil management and cohesive character into depth suggest that independent models should be considered to characterise compressive behaviour of soil by horizon or layer.

Key words:
compaction; soil compressibility; coastal tablelands