Prediction of soil shear strength in agricultural and natural environments of the Brazilian Cerrado

Abstract

The objective of this work was to develop uni‑ and multivariate models to predict maximum soil shear strength (t_max) under different normal stresses (σ_n), water contents (U), and soil managements. The study was carried out in a Rhodic Haplustox under Cerrado (control area) and under no‑tillage and conventional tillage systems. Undisturbed soil samples were taken in the 0.00–0.05 m layer and subjected to increasing U and σ_n, in shear strength tests. The uni‑ and multivariate models – respectively t_max=10^(a+bU) and t_max=10^(a+bU+csn) – were significant in all three soil management systems evaluated and they satisfactorily explain the relationship between U, σ_n, and t_max. The soil under Cerrado has the highest shear strength (t) estimated with the univariate model, regardless of the soil water content, whereas the soil under conventional tillage shows the highest values with the multivariate model, which were associated to the lowest water contents at the soil consistency limits in this management system.