ABSTRACT Regosols (Neossolos) are soils with use limitations mainly related to effective depth, abundant presence of rock and saprolite fragments, and frequently high slope gradients; besides that, they represent a new agricultural frontier for grain production in southern Brazil. This study evaluated soil saturated hydraulic conductivity (Ksat) and water retention and availability in Regosols and saprolites derived from volcanic rocks in southern Brazil and the relationship of these variables with porosity in saprolithic horizons characterized by mineralogical weathering. The study […]

A toposequence has soils with distinct structural and morphological properties that may affect soil susceptibility to structural deformation in short spatial distances. The objective of this study was to evaluate soil load-bearing capacity and susceptibility to compaction, and quantify the effects that loads above and below preconsolidation pressure cause on soil permeability to air in a toposequence of the Central Lowlands of Rio Grande do Sul, Brazil. Undisturbed soil samples were collected from horizons of soil profiles of three Alfisols […]

Intensive land use can lead to a loss of soil physical quality with negative impacts on soil aggregates, resistance to root penetration, porosity, and bulk density. Organic and agroforestry management systems can represent sustainable, well-balanced alternatives in the agroecosystem for promoting a greater input of organic matter than the conventional system. Based on the hypothesis that an increased input of organic matter improves soil physical quality, this study aimed to evaluate the impact of coffee production systems on soil physical […]

The S-index was introduced in 2004 in a publication by A.R. Dexter. S was proposed as an indicator of soil physical quality. A critical value delimiting soils with rich and poor physical quality was proposed. At present, Brazil is world leader in citations of Dexter’s publication. In this publication the S-theory is mathematically revisited and extended. It is shown that S is mathematically correlated to bulk density and total porosity. As an absolute indicator, the value of S alone has […]

Although the influence of clay mineralogy on soil physical properties has been widely studied, spatial relationships between these features in Alfisols have rarely been examined. The purpose of this work was to relate the clay minerals and physical properties of an Alfisol of sandstone origin in two slope curvatures. The crystallographic properties such as mean crystallite size (MCS) and width at half height (WHH) of hematite, goethite, kaolinite and gibbsite; contents of hematite and goethite; aluminium substitution (AS) and specific […]

The quality of no-tillage systems depends on an adequate soil management that promotes soil structure improvements. This is associated to the cropping system adopted. This study investigated the effect of long-term no-tillage systems (18 years) on the structural quality of a sandy-clay to clay Oxisol (Latossolo Vermelho) in the region of Campos Gerais, Paraná, Brazil. Five cropping systems were assessed: wheat-soybean [Wt-So], black oat-maize-wheat-soybean [Ot-Mz-Wt-So], vetch-maize-wheat-soybean [Vt-Mz-Wt-So], ryegrass-maize-ryegrass-soybean [Rg-Mz-Rg-So]; and alfalfa-maize [Alf-Mz]. Soil was sampled from the layers 0-5, 5-10 and […]

Understanding and quantifying the impact of land use and soil management on soil organic carbon (SOC) levels and physical properties is essential for the development of a sustainable agriculture. The purpose of this study was to evaluate some physical properties and SOC of an Oxisol in the Northwest of the state of Paraná, under different use and soil management systems, i.e., under native forest, pasture, cassava, and sugarcane. Disturbed soil samples were collected for particle size, particle density, proctor and […]

This study had the purpose of evaluating the effects of two management types of sugarcane: harvesting of burnt cane (BCH) and mechanized harvesting of unburnt green cane (MCH), on some soil physical properties of a dystrophic Rhodic Haplustox. The data were then compared with results for the same soil type under native forest. A completely randomized design was used, with three treatments and 20 replications. The following characteristics were determined: organic matter, aggregate stability, soil bulk density, and porosity at […]

No-tillage associated to cover crops may maintain soil quality, improving or preserving favorable soil physical conditions for plant growth. This study assessed soil bulk density, porosity, penetration resistance, and water infiltration of a PALEUDALF, in the Experimental Area of the Soil Science Department of the Federal University of Santa Maria, in Santa Maria, RS, Brazil, in an experiment started in 1991, with the following crop successions and rotations: (1) Corn/Soybean – Jackbean – MFP; (2) Bare soil – SDES; (3) […]

Soil water properties are related to crop growth and environmental aspects and are influenced by the degree of soil compaction. The objective of this study was to determine the water infiltration and hydraulic conductivity of saturated soil under field conditions in terms of the compaction degree of two Oxisols under a no-tillage (NT). Two commercial fields were studied in the state of Rio Grande do Sul, Brazil: one a Haplortox after 14 years under NT; the other a Hapludox after […]