Volume 32, Number 1, 2008

Pedotransfer functions (PTFs) are useful tools to obtain estimates of soil physical properties such as the soil water retention curve (SWRC) and the soil resistance to penetration curve (SRPC), which are important inherent soil properties and difficult to measure. Most of the studies in the literature report PTFs only in relation to SWRC estimates. An important and necessary advance in this research area would be the development of PTFs for a simultaneous estimation of the SWRC and SRPC, which is […]

Soil management systems, with crops under no-tillage (NT), crops (soybean) in rotation with pastures under NT and permanent pastures (Brachiaria sp.), were evaluated for soil aggregation and aggregate stability. Three long-term experiments (9 and 11 years) in the state of Mato Grosso do Sul were sampled in the layers 0-5, 5-10 and 10-20 cm for determination of the aggregate stability in wet and dry sieving. The mean weight diameter (MWD) and the aggregate stability index (IAS) were calculated. In all experiments, the […]

The knowledge of the pressure levels that can be applied to the soil under different weed management system (WMS) is importante for coffee plantations management. The objective of this study was to evaluate the influence of different weed management systems on the susceptibility to compaction of a Red-Yellow Latossol (Oxisol) (LVA) using soil support capacity (CSC) models. This study was carried out at the Epamig Research Farm in Patrocínio, state of Minas Gerais, Brazil, in a coffee plantation using Ruby […]

Different physical properties are used to evaluate the soil physical quality. In this context, soil tensile strength and friability are indicators of the soil physical and structural quality. The objective of this study was to quantify the tensile strength and friability of an Oxisol under different soil use systems: forest, fallow and cultivated. Soil samples were collected from three contiguous areas of an Experimental Farm of the State University of Maringá. Two areas were cultivated: one with annual crops under […]

In agricultural areas irrigated with water of unsatisfactory quality, plants that are tolerant to the salinity in water and soil are needed. The purpose of this work was to evaluate the influence of the salinity of irrigation water and soil mulch on the vegetative development of amaranth (Amaranthus spp) in a greenhouse. The experiment was carried out from March to May 2006 in PVC columns with 30 kg of soil with silt loam texture. The non-use of mulch and four salinity […]

This study had the objective of characterizing the main soil types cultivated with melon, based on physical features, in the Apodi Tableland, state of Rio Grande do Norte, to provide basic information for an adequate soil and crop management. Three soil types were studied, in September 2003: Cambissolo Háplico Ta eutrófico típico – CXve (Typic Haplocambids), Latossolo Vermelho-Amarelo eutrófico típico – LVAe (Typic Eutrotorrox) e Argissolo Vermelho distrófico arênico – PVd (Arenic Kandiustults). A general analysis of the soil physical […]

The field capacity, or its equivalent for soils in pots, the “pot capacity”, is an important parameter for irrigation management. We aimed to determine both water content and water loss as a function of time in pots filled with material of a clayey and a medium-textured soil. From these data the pot capacity water content was estimated using different criteria. It was concluded that the final water content extrapolated from the observed q-t curve is a good estimator of the […]

The content and shap of clay minerals are important in the definition of soil structure morphology. To evaluate the clay mineralogy and chemical properties of different aggregate size-classes of Latosols (Red-Yellow – LBd and Dusky Red – LVdf) derived from basalt in the state of Paraná, Brazil, soil samples of the Bw1 and Bw2 horizons were collected in four LBd and three LVdf profiles, distributed across two distinct toposequences. Dried and undisturbed soil samples were separated into six size-classes (2-4; […]

The shape and size of aggregates define most soil characteristics, mainly the total porosity and macro and micropore distribution. This study aimed to investigate the morphology of soil aggregates of different size classes of a Red-Yellow (LBd) and a Dusky Red Latosol (LVdf) located in two respective natural toposequences, in Paraná State, Brazil, using scanner images. Undisturbed soil samples of the Bw1 and Bw2 horizons were collected in four LBd profiles and three profiles of the LVdf toposequence. After drying, […]

The humification degree and the chemical nature of organic residues are essential factors controlling their degradation and nutrient release. To characterize the organic matrix, samples of sewage sludge, poultry, pig, cattle and quail manure, besides commercial compost, organic substrate and humic material were analyzed for: pH, electric conductivity, cation exchange capacity (CEC), water retention capacity, concentration of total N and mineral N, organic matter, total organic carbon (TOC) and the TOC fractions: humic acid C-fraction; fulvic acid C-fraction, water soluble […]