The use of mass (g) or volume (cm3) as a measure of the amount of soil for determination of soil organic matter (SOM), as well as methods of quantitative analysis used for the same purpose, can directly affect the interpretation of results. Therefore, the methods of titulometric and colorimetric determination of organic matter were compared in three soils with different texture, sampling the soil based on mass and on volume. The organic matter content determined for a same soil differed […]

The impact of agro-industrial organic wastes in the environment can be reduced when used in agriculture. From the standpoint of soil fertility, residue applications can increase the organic matter content and provide nutrients for plants. This study evaluated the effect of biological sludge from gelatin industry on the chemical properties of two Ultisols (loamy sand and sandy clay) and an Oxisol (clay). The experiment lasted 120 days and was carried out in laboratory in a completely randomized design with factorial […]

The application of sugarcane residues to the soil may induce changes in soil compressibility parameters. The objective of this study was to investigate the compressibility behavior of a dystrophic cohesive Yellow Latosol in the coastal tablelands of the state of Alagoas, in three different management systems with sugarcane, with different levels of organic residue application. The experiment was conducted in an area of sugarcane production (Usina Santa Clotilde), Alagoas. Three plots were chosen in sugarcane fields: sugarcane under irrigation (SMI), […]

Soils with high levels of toxic Al can cause damage to plants and consequently decrease yields; a proper management is therefore essential to increase yields. Silicon can be a good alternative to reduce the toxicity of Al in the soil. The objective of this study was to evaluate the influence of the interaction between silicon and Al in rice plants grown in naturally aluminous soil. The experiment was arranged in a completely randomized, 2 x 5 factorial design with four […]

Rice in Rio Grande do Sul State is grown mostly under flooding, which induces a series of chemical, physical and biological changes in the root environment. These changes, combined with the presence of rice plants, affect the availability of exchangeable ammonium (NH4+) and pH of soil solution, whereas the dynamics of both variables can be influenced by soil salinity, a common problem in the coastal region. This study was conducted to evaluate the dynamics of exchangeable NH4+ and pH in […]

Soil properties play an important role in spatial variability of crop yield. However, a low spatial correlation has generally been observed between maps of crop yield and of soil properties. The objectives of the present investigation were to assess the spatial pattern variability of soil properties and of corn yield at the same sampling intensity, and evaluate its cause-and-effect relationships. The experimental site was structured in a grid of 100 referenced points, spaced at 10 m intervals along four parallel […]

The compaction of agricultural soils is a phenomenon of great concern in Soil Science. The major goal of research on the mechanical behavior of soil is to identify the least degrading soil management systems. In general, at a same compaction level, the higher content of organic matter, the lower maximum density and higher critical moisture for compaction, which consequently decreases the risk of physical degradation of the soil. The purpose of this study was to study the compressibility of a […]

Tropical landscapes are characterized by complex surface mantles which carry the marks of processes that took place during previous geological periods. However, it is common for vertical layers in the landscape to show morphological characteristics apparently homogeneous, thus hampering the identification of the nature of the source material of their strata. The objective of this study was to analyze the regolith (solum + saprolite) formation from granite of the Xingu Complex in a small watershed covered with Amazonian forest, based […]

The geomorphic surface concept allows interrelationship among various branches of soil sciences, such as geology, geomorphology and pedology. The purpose of this study was to investigate soil-geomorphic surface relations along an upland-downland toposequence in the region of Humaitá, Amazonas State, Brazil. A transect of 4,500 m was studied from the water divide downstream to the flood plain of the Madeira river. The geomorphic surfaces were identified based on the slope rupture, stratigraphic criteria and on other field observations. Trenches were […]

Swine residue (SR) applied as nutrient source of crops such as corn, bean, soybean and wheat, besides representing an environmental-friendly way of disposing of organic waste resulting from swine production, may significantly increase grain yields, replacing mineral fertilizer. The objective was to evaluate the effect of SR rates on corn, common bean, soybean and wheat yields from 2002 to 2007, in comparison with mineral fertilizer. The experiment was carried out at the Instituto Agronômico do Paraná – IAPAR, Pato Branco, […]