Susceptibility to Compaction, Load Support Capacity, and Soil Compressibility of Hapludox

Abstract

Models that integrate the influence of soil intrinsic attributes on the estimation of soil compaction are scarce for Hapludox. The present study tested the hypothesis that the compressive behavior of Hapludox with wide variations in intrinsic soil attributes can be estimated based on pedotransfer functions (PTFs). The general goal of this research was to determine the effect of intrinsic soil attributes on the susceptibility to compaction, preconsolidation pressure and compression curve of Hapludox, and to develop PTFs that allow the estimation of these parameters based on easily measurable soil attributes. The study was conducted on a soil toposequence that includes a sandy Typic Hapludox, a loamy Typic Hapludox, and a clayey Rhodic Hapludox. The uniaxial compression test was applied to 50 undisturbed soil samples at matric potential values of −10 and −100 kPa. After load withdrawal, soil bulk density, void ratio, gravimetric soil water content, particle‐size distribution, particle density, and organic matter were determined. The compression curves, the compression index, and the preconsolidation pressure were obtained. The relationship between the compression index, soil bulk density, and clay content was statistically significant with R2 = 0.77. Organic matter and soil water content did not affect the compression index. The preconsolidation pressure was significantly related with soil bulk density, soil water content, and clay content (R2 = 0.70), but was unaffected by organic matter. Soil compressibility was dependent on soil bulk density. A nonlinear model fitted the data with R2 = 0.90 allowing to predict the compressibility of soils for a wide range of stresses and inherent soil properties.

Soil and macro-pores under uniaxial compression. I. Mechanical stability of repacked soil and deformation of different types of macro-pores

“…This was expected and is in good agreement with other studies (e.g. Imhoff et al, 2004). This highlights the crucial role of soil moisture for soil compaction.…”

Soil Compressibility under Irrigated Perennial and Annual Crops in a Semi-Arid Environment

“…These values for σ p are close to those found in other studies for soils under different agricultural systems, such as no-tillage (55 to 196 kPa, Suzuki et al, 2008), sugarcane (22 to 305 kPa, Imhoff et al, 2004), orange orchards (170 kPa in the crop rows and 305 kPa for the inter-row spaces and canopy projection, Lima et al, 2004). Values were influenced by the equilibration matric potential of the soils, ranging from -10 to -100 kPa, including the matric potential adopted in this study.…”

“…The compression index (Cc) was calculated from the adjusted coefficients using the model of Gregory et al (2006), which estimates the slope of the virgin compression line, with the modulus of the slope at the inflection point (m) estimated by the equation Cc = lk/exp(1) in which Cc is the compression index, l and k are coefficients obtained when adjusting the Gompertz model (Gregory et al, 2006), and exp (1) is the exponential function of the number one. The preconsolidation pressure (σ p ) was determined from the compaction curve adjusted by the Gompertz equation (Gregory et al, 2006) using the algorithm proposed by Imhoff et al (2004) with the Mathcad® software. This method results in slightly lower values of σ p than Casagrande (1936), but better describes the soil curve because the rate of decrease of the void ratio is lower after the inflection point.…”

“…Other studies have focused on investigating the methods applied in determination of σ p and pedotransfer functions (Dias Junior and Pierce, 1996;Imhoff et al, 2004;Cavalieri et al, 2008;Suzuki et al, 2008;Severiano et al, 2011;Silva and Lima, 2016).…”

Comparison of Methods for Determining Precompression Stress Based on Computational Simulation

“…The curves simulated cover a wide range of soil compression curves, such as those obtained for soil samples in compression tests under different soil bulk densities, textures, and moisture contents (Arvidsson and Keller, 2004;Imhoff et al, 2004;Gregory et al, 2006;Cavalieri et al, 2008;Ajayi et al, 2009;Saffih-Hdadi et al, 2009;Ajayi et al, 2013;An et al, 2015).…”