The town of Umuarama, Northwest of Paraná, presents sandy and medium-textured soil, derived from Cretaceous Caiuá Formation Sandstone. Besides the natural fragility of these soils, deforestation, use and generalized occupation have contributed to the identification of erosive processes. A slope next to the urban area was selected for a toposequence study aiming at a macro and micromorphological pedologic characterization followed by a physico-hydric characterization of the pedologic horizons. The data allowed to reach some important conclusions concerning material behavior, hydric […]

The objectives of this study were to determine the influence of different soil tillage methods on the loss of heavy metals by erosion, and to evaluate the level of contamination in sediments and water from the main stream in Caetés watershed, Paty do Alferes County, Rio de Janeiro. The experiment was conducted from December 1996 to March 1997, and cucumber (Cucumis sativus L.) was the cultivated crop. Four Wichmeier plots were installed, with an area of 22 x 4 m. […]

The cessation of growth of native forage during winter has encouraged the improvement of native grasslands. Aiming to study water intake rates and soil and water losses by erosion as affected by different methods of native grassland improvement, an experiment was conducted at the Agronomic Experimental Station of the Federal University of Rio Grande do Sul, in Eldorado do Sul, Brazil, on a Paleudult soil under extensive native grassland use. A mixture of winter species of forage, specifically oat (Avena […]

A field experiment of soil and water losses by erosion was carried out during six consecutive agricultural years (1973/74 to 1978/79) at the Experimental Center of Campinas, Instituto Agronomico of São Paulo, Brazil, in a Typic Haplorthox, to evaluate soil loss ratio (SLR) for three green manures: Crotalaria juncea L., Stizolobium aterrinum Piper et Tracy and Dolichos lablab L. Four cropstage periods were defined as isolated periods (0-30, 30-60, 60-90, and 60-120 days after planting), and as accumulated cropstage period (0-30, […]

Simple linear correlations among runoff and rainfall erosivity parameters and soil losses caused by erosivity rainfall in Haplargids were studied. Data related to 1986-1990 were obtained in the Experimental Station at Sumé-Brazil. The rainfall erosivity parameters were the following: a) total height of the rainfall (P) in mm; b) maximum intensity (In): I5; I10; I15; I20; I25; I30; I35; I40; I45; I50; I55; I60 and I120 minutes in mm h-1, respectively; c) total kinetic energy by the Wischmeier & Smith’s […]

The determination of land degradation risk in a watershed is an important factor in environmental and agricultural land-use planning. The current trend is to analyze the necessary information for land evaluation in a less subjective way and compatible with geoprocessing techniques. However, criteria and parameters used to quantitatively evaluate the land degradation risk at the watershed scale and based on Geographic Information Systems (GIS) still need to be better defined. The objective of this study, conducted in the second semester […]

A field experiment, located on a private farm close to Piracicaba, State of São Paulo, Brazil, was conducted on a severely eroded soil (Ultisol-Entisol association), which has been planted with sugar cane for the last 30 years. The objective was to characterize the spatial variability of soil and plant attributes. An area of 50 by 70 m was divided into 10 columns and 14 rows in a grid of 5 m, resulting in 140 sampling points. Soil samples were collected […]

The objectives of this paper were: to verify the adequacy of different rainfall erosivity indices, to compare two equations to calculate the rainfall kinetic energy and to estimate the USLE K-factor (soil erodibility) of two soils (Dark – Red Latosol and Red – Yellow Podzolic soil) from the Sete Lagoas (MG) region. There was not a significant difference between the studied equations to calculate rainfall kinetic energy. The EI30 index showed to be a good rainfall erosivity predictor and can […]

The assessment of the soil erodibility (K-factor) is essential for using the universal soil loss equation. The objective of this paper was to verify the adequacy of different indirect methods to estimate the K-factors of soils with argillic horizon from diverse geographic regions of Brazil. Superficial samples of 22 soils bearing argillic horizon were collected. The K-factors measured directly in the field of all these soils are already known. Several chemical and physical analyses were performed in order to calculate […]

Previous studies showed the effectiveness of stone barrier contours on reducing slope lengths, retaining sediment and nutrients, and decreasing runoff, erosion rate and siltation of reservoirs. The extent of these benefits regarding to soil productivity in semiarid regions, however remained unknown. The aim of this study was to determine the effects of stone barrier contours on the productivity of a lithosol thirteen years after its construction. Experiments were carried out in areas of retained sediment and in areas where the […]