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 agronomic use of biosolid is considered an adequate alternative to its disposal and, although a technical knowledge about its fertilizing properties is already available, information on its qualitative, economical and practical aspects for its use on the field is also needed. The biosolid produced by the “Companhia de Saneamento de Brasília” (CAESB) showed an appreciable variability in nutrient concentration among each monthly sampling from August, 1995 to July, 1996 and among the sludge treatment plants (ETEs) where the biosolid […]

The accumulation of herbicides in the environment as a consequence of their intensive usage associated to their high persistance is a matter of principal concern due to their harmful effects on the fauna and flora. Atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) is one of the worldwide mostly used herbicides, and is being detected in considerable amounts in aquatic and soil ecosystems. The goal of this study was to evaluate the sorptive behaviour of atrazine in a Humic Cambisol under its natural form and in […]

The structural features of humic acids (HA) after addition of organic matter from urban residues were evaluated. The HAs were extracted from the surface (0-20 cm) of an ultisol (Seropédica, RJ) and oxisol (Piraí, RJ) which had been treated with the equivalent of 80 t ha-1 (dry material) of compost from urban waste and also sewage sludge. The incubation time in the laboratory was 24 weeks under room temperature and humidity at field capacity. Tha HAs were characterized by elemental […]

Potential acidity is of great importance for the base saturation determination and for the recommendation of liming. The objective of this study was to evaluate the relationship between pH SMP and H + Al contents, in order to establish an equation for the potential acidity estimation of soils from Northern Minas Gerais, Brazil. The H + Al concentration (0.5 mol L-1 calcium acetate pH 7.0) and pH SMP were analysed at EPAMIG/CTNM soil fertility laboratory, in 50 soil samples. The […]

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 […]

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 […]

Independent of the runoff capacity to transport mineral and organic particles of soil, the assessment of rainfall erosive action, during its initial phase, would not be complete if the mechanisms of soil detachment and splash by raindrop impact were not appraised. Considering the lack of data on these mechanisms in soils of Ceará State, Brazil, the objectives of this work were: to compare collection methods of detached and splashed soil and to evaluate the correlations between rainfall erosivity and splash […]

The aim of this study was to verify the influence of mineralogy and former soil use on adsorption and forms of P in Latosols. The following five soils were used to include a wide range of contents of hematite, goethite, kaolinite (Ka) and gibbsite (Gi): (cohesive Yellow Latosol, dystrophic Yellow Latosol, acric Red Latosol, and two dystropherric Red Latosols, one developed from gabbro and one from tuffite), collected from non-cultivated areas and adjacent areas cultivated for long periods, receiving liming […]

Repeated sewage sludge application to soils can cause changes in some soil chemical properties. The goal of this paper was to evaluate changes in soil organic carbon content, electric conductivity, pH and CEC after sewage sludge application during two years in a row. The soil used was as a Typic Hapludox and, after the sludge application, was planted with sugarcane. The experiment had five treatments: lime + inorganic fertilization, control and sewage sludge in three levels: 33, 66 and 99 […]