Volume 26, Number 2, 2002

Nine profiles were studied along a toposequence developed on Barreiras Group sediments, in Fazenda Rio Negro, Entre Rios, Bahia, Brazil. Besides conventional analysis, an electromagnetic probe through GPR – Ground-Penetrating Radar was employed. The objective of this study was to analyze the use of this tool in the acquisition of information on features occurring underground, by comparing the radargrams and pedologic descriptions obtained in the area. The equipment used was a Geophysical Survey model, with an 80 MHz antenna. The […]

This paper deals with the genesis of hydromorphic sandy soils with spodosol morphology found in extensive flat surfaces, in which isolated zones with undulating relief emerge, containing well drained oxisols. The objective of this study was to explain the existence of pedogenetic relationship in an oxisol-spodosol system, and to verify the possible development of the sandy materials as a consequence of oxisol transformation. For this purpose, we characterized the morphology of the soils and their physical, chemical and mineralogical attributes. […]

Soil or land leveling, a process of adequation of land surface, is being practiced in many rice-growing farms in the state of Rio Grande do Sul, Brazil. This process produces profound changes in the morphological, physical, chemical, and biological properties of the soil. To study these changes, test areas were selected with homogeneous surfaces where Planosols occur and on which land leveling was performed for eight years, one year, and one month and with original soil, at São João do […]

The Guaratuba watershed is located at the “Parque Estadual da Serra do Mar” and has its headwaters in the Atlantic plateau. The area has a gneissic bedrock in a parallel hilly relief with high slope gradient, covered by the Atlantic forest consisting mostly of low size trees. The climate is humid tropical with rainfall of 2,000 mm year-1, with no dry season. The predominant soils are Red Yellow Argisol (Typic Kandiudults or Paleudults and Typic or Lithic Hapludults) and Haplic […]

The use of legume cover crops contributes to soil conservation and would be an economical N source to maize. Since only winter legumes were evaluated in southern Brazil, this study was carried out to assess the effect of four intercropped summer species (Canavalia ensiformis, Cajanus cajan, Stizolobium niveum and Glycine sp.) on N supply and maize yield increase, in comparison with a control treatment, without legume cover crops. Cropping system effects on maize crop were evaluated under three mineral N […]

This study was carried out to evaluate the effect of cultivation systems on soil carbon and nitrogen contents and on the distribution of light and heavy fractions of soil organic matter (SOM). Density and particle-size fractionations were used to isolate free light fraction (FLF), intra-aggregate light fraction (ILF) and heavy fractions (HF) of a Red-Yellow Latosol from a field experiment at Embrapa Rice and Beans in Goiás, Brazil. Treatments consisted of a combination of soil tillage and crop rotation. Soil […]

The objective of this work was to present the Analysis of Correspondence as a multivariate statistical method that can help with yield mapping interpretation. There is a concern about its indiscriminated use as a tool of predictive information, without taking into account the spatial and temporal variability of the yield. The hypothesis that the use of yield mapping is strictly related to the variability of the components was studied. Four yield maps were used corresponding to collected yield samples for […]

The objective of this study was to investigate the chemical nature of free (FLF) and intra-aggregate (ILF) light fraction of soil organic matter, using infrared spectroscopy as well as to determine whether these fractions are compositionally distinct pools of soil organic matter. Both FLF and ILF were isolated by flotation on NaI solution at a specific gravity of 1.8; for ILF extraction, the soil sample was sonicated after FLF isolation. Samples were collected from two Oxisols from contrasting regions of […]

Water/Hydro-erosion comes as a result of rain erosivity and soil erodibility. Knowledge on erosivity is therefore useful as a guide for recommendations on management practices and soil conservation which have the aim to reduce hydro- erosion. Objectives of this study were the factor identification and quantification of natural rain erosivity in Lages, Santa Catarina, as well as knowledge on its temporary distribution. The study was carried out in 2000, using data on rainfall and soil loss of the period from […]

The soil erodibility factor (K factor) of the Universal Soil Loss Equation (USLE) refers to the natural soil susceptibility to erosion and represents the quantity of lost soil per rain erosivity unit (R factor), a factor, which is of great importance in conservation management. Using data of soil loss, measured under natural rainfall conditions in collector ponds of superficial runoff, and of natural rainfall erosivity (EI30) in the period from 1989 to 1998 in Lages (SC), the soil erodibility factor […]