Volume 25, Number 2, 2001

Soil and water loss under natural rainfall in Lages (SC – Brazil), from November 1992 to October 1998, were used to calculate soil loss ratio (SLR) and C factor for the Universal Soil Loss Equation (USLE) under three soil tillage systems and two crops. Treatments studied were plowing followed by two disking (P+D), chiseling plus disking (C+D) and no-tillage (NT), cultivated in succession with soybean (Glycine max) and wheat (Triticum aestivum L.), compared to a check plot: plowing followed by […]

The objectives of this work were to assess soil and water losses and determine interrill erodibility (Ki) of three soils with clayey texture: Typic Rhodudult (PE), a Typic Hapludult (PV) and a Rhodic Hapludox (LR) for the application of the WEPP (Water Erosion Prediction Project) model in Lavras, Minas Gerais, Brazil and to evaluate the relationship between Ki and some physical, chemical and mineralogical soil properties and surface characteristics. The experiment was set in a completely randomized block design, consisting […]

Rainfall characteristics may determine most of the harmful effects of soil erosion. Intensity variation during a rainfall is one of these important rainfall characteristics. However, there is a lack of information about rainfall patterns that occur in Brazil. This research had as objectives the determination of natural erosive rainfalls patterns verified in Santa Maria (RS), and the estimation of rainfall return period for the three patterns proposed. Daily rainfall charts were obtained from the Research Center of Forestry and Soil […]

Erosion is largely affected by rainfall intensity. However, few studies in Brazil have been dedicated to evaluate this effect. This research aimed to determine soil and water losses on a Typic Hapludalf soil, submitted to four different rainfall patterns, under the following treatments: rainfall simulation of variable intensity in advanced, intermediary, delayed and constant patterns. Rainfall duration was one hour, with a peak of 120 mm h-1 during 5 min for patterns with variable intensity and 35 mm h-1 for uniform intensity, applied over soil […]

Procedures based on modifications of chemical properties are potentially useful for mitigating phytotoxicity of heavy metals in soils. However, it is difficult to predict the effects of different ameliorating agents on the bioavailability of heavy metals in soil simultaneously contaminated with several metals. This study was developed in a soil from a dumping site of a zinc extraction and manufacturing industry-Companhia Mineira de Metais-CMM, located at Três Marias (MG), to assess content, fractioning and bioavailability of Zn, Cd, Cu and […]

A laboratory experiment was carried out to evaluate the hexavalent chromium reduction as affected by organic carbon amendment, Mn2+ and microbial activity. Samples of a Hapludult soil (50 g) were placed in plastic bags (50 g) and incubated during 42 days with lime (2.0 Mg ha-1), Cr6+, cattle manure(organic carbon) and Mn2+ in the doses of 20, 50 and 40 mg kg-1, respectively. Half the samples were sterilized by autoclaving to eliminate biological activity. Cattle manure and Mn sulfate amendment promoted a total soil hexavalent chromium […]

Most of the silicon absorbeb by plants remains deposited on the external part of the cell walls as a layer of amorphous silica (SiO2.nH2O), probably affecting straw mineralization in soils. An experiment was performed with the aerial part of oat plants, cultivated in nutrient solution with and without silicon addition, to evaluate this hypothesis. Dried aerial parts of oat plants tissue was mixed with soil or washed quartz sand and placed in PVC tubes. Distilled water was percolated through the […]