Factors controlling compressibility of a paleudalf and a haplortox soil. I- initial state of compactness
01/Mar/2002
Knowing the susceptibility of a soil to compaction is important to adjust soil management, tillage practices, and traffic to cause minimal detrimental effects on soil properties. The objective of this study was to determine the preconsolidation pressure (σ’p) and the compression index (Cc) at two depths of two soils under no-tillage and conventional tillage, including a wide variation of the state of compaction. Undisturbed soil samples were collected with rings (5.4cm wide and 2.0cm high), at 0 to 2 and […]
Factors controlling compressibility of a paleudalf and a haplortox soil. II-degree of water saturation
01/Mar/2002
Soil water content is one of the determining factors in controlling compaction caused by animal trampling or machinery traffic.The objective of this study was to evaluate the effect of water content (pore water saturation) on preconsolidation pressure (σ’p) and compression index (Cc) values, for two soils with contrasting textures, at two depths, cultivated under no tillage and conventional tillage.Undisturbed soil samples (5.35cm of diameter for 2cm of height) were collected in the surface layer (0 to 2cm) and in the […]
Quantifying critical pressures for plant growth
01/Mar/2001
Compaction is one of the main causes of degradation of agricultural soils and it has been evaluated through several indicators of: (a) soil structural quality for crop growth, such as the least limiting water range (LLWR), and (b) load support capacity of the soil, i.e., the preconsolidation pressure (σp). This research was carried out with the objective to relate the LLWR and the σp, as well as to determine critical pressures values that can be applied to the soil without […]
Susceptibility to compaction of a haplortox and a paleudalf
01/Jun/2000
Soil compaction of the agricultural soils is a result of soil machine interactions, which influence physical and biological soil properties and their relations with crop growth and yield. The objective of this study was to determine the compression index, the preconsolidation pressure and the soil strain of a Haplortox (LE) and a Paleudalf (PV), with different initial state of compaction and water saturation. Undisturbed soil samples were collected in two soils and at two depths, at no tillage and conventional […]
Estimate of the effect of soil management and moisture content on additional compaction of three latosols
01/Dec/1999
Additional soil compaction occurs when the pressure applied on the soil is greater than the preconsolidation pressure, causing the soil to deform along the virgin compression line. The objectives of this study were: to validate the model proposed by Dias Junior (1994); to propose a model to quantify soil mechanical resistance and; to evaluate the effect of soil use and moisture on the virgin compression line and on the compression index of three Latosols under annual crop, natural forest and […]
Management and moisture effects on the compressive behavior of three latosols (oxisols)
01/Sep/1999
The objective of this work was to analyze the effect of moisture content and soil management on the compressibility behavior of three soils, namely, a Red-Yellow Latosol (LV), Dusky Red Latosol (LR) and Dark-Red Latosol (LE), under annual crop, natural forest and pasture. The soils were located in the region of Lavras and Ijaci (MG). Undisturbed and disturbed soil samples were collected in two depths (0-0,03 and 0,27-0,30 m) with three replicates. The undisturbed soil samples were used in the […]
Soil compressibility of three Latosols (oxisols) as a function of moisture and use
01/Jun/1999
Using the compressibility test, the effect of soil management and moisture content on the preconsolidation pressure (σp) of three soils, a Red-Yellow Latosol (LV), a Dusk Red Latosol (LR) and a Dark-Red Latosol (LE) under annual crop, natural forest and pasture, was studied in the area of Lavras (MG) at two depths (0-0.03 and 0.27-0.30 m). For each condition, five undisturbed soil samples and a disturbed one were collected, with three replications. The undisturbed soil samples with different soil moisture […]