ABSTRACT Soil temperature is a physical property of great agricultural importance in the soil-plant relationship and in energy exchange with the atmosphere. This study was conducted in a degraded Cambissolo Háplico Ta Eutrófíco (Cambisol; Inceptisol) in the Irecê Identity Territory, Bahia, Brazil, aiming to evaluate the hourly, daily, and monthly fluctuations of soil temperature at depth, and soil thermal diffusivity in the castor bean crop. Hourly soil temperature data from February 4, 2014, to September 30, 2015, were obtained by […]

ABSTRACT The CO2 emission from the soil surface, commonly referred to as soil CO2 efflux (ECO2) or soil respiration, is the sum of processes that include root respiration and microbial activity. Measuring this evolution is important to establish sustainable land use models and to estimate global fluxes of carbon, which affect climate change. Despite its importance, few measurements have been made in areas of the semiarid Brazilian Northeast region, and most of them were made using the alkali absorption method […]

ABSTRACT Measurements of the soil cone index are widely used to assess soil resistance to root penetration (SR) and to monitor the soil compaction status of agricultural fields. However, soil sampling for SR estimation is a rather challenging task in view of the high spatial and temporal variability of the soil. This study proposed a bootstrapping method to determine the minimum sample size required to estimate the vertical profile of mean soil cone index (CI) values at different levels of […]

ABSTRACT Residue management in cropping systems may improve soil quality. However, there are few studies on the effects of residue management on soil aggregation and carbon content in the humin (C-HUM), humic acid (C-HAF) and fulvic acid (C-FAF) fractions in South China. Therefore, the effects on soil aggregation and on the C-HUM, C-HAF, C-FAF from incorporating winter cover crop residues in a double-cropped rice (Oryza sativa L.) system in South China fields were studied. The experiment has been conducted since […]

ABSTRACT Establishing the number of samples required to determine values of soil physical properties ultimately results in optimization of labor and allows better representation of such attributes. The objective of this study was to analyze the spatial variability of soil physical properties in a Conilon coffee field and propose a soil sampling method better attuned to conditions of the management system. The experiment was performed in a Conilon coffee field in Espírito Santo state, Brazil, under a 3.0 × 2.0 […]

ABSTRACT Solute transport parameters can be determined in miscible displacement experiments, usually performed in columns with disturbed (sieved) soil samples. Experiments with undisturbed samples are uncommon, due to the difficulty of taking undisturbed samples at the size required for these experiments. Structural alteration of the disturbed material implies modifications in the pore geometry that determines hydraulic properties, including hydraulic conductivity and retention and properties related to miscible displacement. An existing model for prediction of breakthrough curves based on retention properties […]

ABSTRACT Soils with an A horizon formed by human activity, an anthropogenic A horizon, are found in the Amazon Region. Few studies have examined the spatial distribution of the properties of these soils. We mapped the spatial variability of some soil properties in an area of Archaeological Dark Earth (ADE) in the Brazilian Amazon. A sampling grid was defined over an area of 42 × 88 m under cacao cultivation in which sampling points were established at a spacing of […]

ABSTRACT The soil porous space is where processes related to gases and soil solution occur, and provides an adequate guide for agricultural practices. This study aimed to evaluate the integrated effects of cultivation and the application of liquid bovine biofertilizer on the porous network of a Typic Haplocambids (Cambissolo Háplico Ta Eutrófico) cultivated with figs (Ficus carica L.). Four treatments were evaluated (under fig cultivation with the application of 20, 40 and 60 % of biofertilizer through irrigation, a control […]

ABSTRACT Root growth can be limited by physical and chemical conditions of the soil. Compacted and acidic soils, where there is an occurrence of exchangeable Al, constitute barriers to use of the soil by plant roots. The hypothesis of this study was that physical and chemical properties of the inter-row soil of a peach orchard influence the root distribution of different rootstocks. The aim of this study was to describe and register the soil physical and chemical properties and root […]

ABSTRACT There are many methods for determining precompression stress (σp), whose value is affected by the slope of the soil compression curve. This study was designed to evaluate the hypothesis that for a certain compression curve all methods used to determine σp present the same value and accuracy. The aim of this study was to compare the accuracy and the relationship among seven of these methods by computational simulation of soil compression curves under nine scenarios. The following methods were […]