Volume 32, Number 5, 2008

Knowledge on soil hydraulic properties such as water retention and hydraulic conductivity curves is indispensable for water and pollutant transport modeling of agricultural systems. This soil hydraulic properties are affected by numerous sources of variability, mostly associated with spatial, temporal, and management-related factors. The objective of this study was to analyze the spatial variability of parameters of water retention (van Genuchten) and hydraulic conductivity (Brooks & Corey) curves obtained with the “Beerkan” method based on simple infiltration experiments and soil […]

Soil compaction is a serious problem for the soil quality and development of sustainable agriculture, because compaction affects the flow of soil water and air and reduces crop yields. One of the possibilities to tackle this problem is the use of plants with a deep and vigorous rooting system. The objective of this study was to evaluate the physical quality of a Typic Hapludalf, in a no-tillage system, after the use of cover crops, and to measure the critical limit […]

Soil resistance to root penetration is an important physical characteristic for defining soil management techniques. The purpose of this study was to estimate the mechanical soil penetration resistance of an Oxisol under perennial crop, at three gravimetrical moisture contents, based on bulk density, moisture, and soil clay and organic matter content. The soil penetration resistance was evaluated by an impact penetrometer and the impact data in dm-1 were converted into dynamic resistance (MPa). At the moment of the determination of […]

Soil penetration resistance exercises major influence on crop development, root growth and crop productivity, which is inversely proportional to that soil attribute. In this way, the analysis of spatial variability of soil penetration resistance and crop yield based on geostatistics can indicate alternative management practices, not only to reduce the effects of soil variability on crop yield, but also to improve the estimated crop response under certain management practices. This study aimed to correlate soil penetration resistance (RP) and spatial […]

Considering the importance of understanding the water status of pedological covers for studies of prevention and containment of erosive processes, this study was conducted on a slope with a pedological system composed of Red Latossol (Oxisol)/Red Argisol (Ultisol) derived from Caiuá sandstone, on an experimental farm of the Universidade Estadual de Maringá, Cidade Gaúcha, in Northwestern Paraná State. After a detailed morphologic description of the pedologic system, infiltration experiments were carried out in the main diagnostic horizons and the respective […]

The soil management may influence soil hydro-physical conditions and crop yield. The objective of this study was to determine soil physical properties of an Albaqualf under management systems and to compare them with those under a native pasture. The bulk density, saturated hydraulic conductivity, macroporosity, microporosity, total porosity and aggregation were evaluated in the soil layers 0-0.025; 0.025-0.075; 0.075-0.125; 0.125-0.175; and 0.175-0.275 m. The hydro-physical soil conditions in no-till and conventional systems were similar. The conditions in the soil under native […]

Soil properties and characteristics are related to the quantity and type of minerals in the clay fraction. The objective of this research was to characterize the clay fraction and study the crystallographic characteristics of kaolinites in red and yellow soils, in support of further research on the relationships of this mineral with the characteristics and properties of the dominant soils in coastal tablelands. The following evaluations were performed: determination of the coarse clay/fine clay ratio; mineralogical analyses (qualitative and quantitative) […]

The no-tillage system (NT) affects the rate of soil processes, but little is known about its effect on the mineralogy of tropical and subtropical soils. This study aimed to evaluate the long-term effect of NT system on pedogenetic iron oxides and their relationship with soil organic matter (SOM) fractions. Soil samples were taken at 14 depths within the top 0,20 m soil layer from two clayey Oxisols under NT and conventional tillage (CT) systems of the experimental areas located near the […]

Plant species in sensu stricto Cerrado have adaptive strategies to soil and climatic adversities that require high investment of nutrients, water and photoassimilates. The mutualistic fungi – plant root symbiosis is an important adaptation by which plants can improve soil nutrients and water acquisition and it can be determinant for plant survival in Cerrado conditions. The aim of this study was to establish a method for studying arbuscular mycorrhizal fungi (AMF) and dark septate endophytic fungi (DSEF) in roots of […]

Metabolic activity of microorganisms is one of the main processes of control on the nutrient transformation in soil. However, the activity of the soil microbiota is affected by various factors such as the available nutrients, including phosphorus. The present work had as objective to show an approach of the effect of phosphorus addition (50 to 500 mg kg-1 P of dry soil) on the respiratory response of soil microbiota and the amount of extra and intracellular glucose in typic acrustox of Cerrado.The […]