Volume 36, Number 2, 2012

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 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), […]

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 […]

Mechanical chiseling has been used to alleviate the effects of compaction in soils under no-tillage (NT). However, its effect on the soil physical properties does not seem to have a defined duration period. The purpose of this study was to evaluate the behavior of the bulk density (BD) and degree of compaction (DC) at different soil depths, after chiseling in no-tillage, for one year. The experiment was performed in Ponta Grossa, Paraná State, Brazil, using an Oxisol (Rhodic Hapludox). Bulk […]

Mathematical models have great potential to support land use planning, with the goal of improving water and land quality. Before using a model, however, the model must demonstrate that it can correctly simulate the hydrological and erosive processes of a given site. The SWAT model (Soil and Water Assessment Tool) was developed in the United States to evaluate the effects of conservation agriculture on hydrological processes and water quality at the watershed scale. This model was initially proposed for use […]

Surface roughness is a relevant soil property in terms of its influence on soil water infiltration and storage, sediment retention on the soil surface, and water erosion. In turn, surface roughness is influenced by soil tillage, moisture, compaction, crop residues, residual effects of land use, and by rainfall erosivity. The purpose of this study was to quantify the effect of soil tillage type, soil compaction and rainfall erosivity on surface roughness. The experiment assessed an Inceptsol with a relatively flat […]

Due to losses caused by water erosion, the development of techniques that increase the efficiency of soil conservation practices is fundamental. Terracing of agricultural lands is an important conservation practice. Bearing in mind that improperly built terraces may negatively affect the landscape, the purpose of this work was to evaluate the efficiency as well as the adequacy of retention terraces. Assessments were performed in four terraces implanted in different states, all located in the mideastern region of the state of […]

The maintenance of a good soil physical quality is essential to preserve the environment and maximize crop yields. A compacted soil can affect soil density, porosity and penetration resistance, influencing root growth. The purpose of this study was to evaluate the physical quality of an Oxisol, clay texture, with the soybean cultivar CAC-1, at four compaction and three irrigation levels, using the soil physical properties, as well as the relationship of root system with the crop yield. The experiment had […]

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 purpose of this study was to assess the relationship between dissolved organic carbon (DOC) and physics properties of soil under different land use systems in central Amazonia. The DOC concentrations of primary forest soil were measured in three topographical positions, and in areas of pasture, secondary forest and an agroforestry system (AFs) down to a depth of 2 m. The soil solution was collected and analyzed for the organic C phase during a hydrological cycle. The average dissolved organic […]