On paddy soils in the southern region of the State of Rio Grande do Sul, Brazil, irrigated (flooded) rice is grown on 1´000´000 ha, under different soil management systems. The influence of poor drainage and alternating oxidation and reduction cycles on the content of soil organic carbon is still poorly understood. This long-term study (21 years) was conducted in Capão do Leão, RS, Brazil, to evaluate the effect of irrigated rice management systems on soil organic carbon stocks and physical […]

Inadequate land use and large buildings in rural areas are causing damages to the soil-climate environment, reducing productivity and thus expanding degraded areas. In view of this problem, this study evaluated the recovery of an Oxisol that had been treated with green manure, soil amendment, gypsum and pasture in the last 17 years. The quality of the structure was used as an indicator of soil recovery. The study was conducted in a completely randomized design with nine treatments and four […]

Studies on sewage sludge (SS) have confirmed the possibilities of using this waste as fertilizer and/or soil conditioner in crop production areas. Despite restrictions with regard to the levels of potentially toxic elements (PTE) and pathogens, it is believed that properly treated SS with low PTE levels, applied to soil at adequate rates, may improve the soil chemical and microbiological properties. This study consisted of a long-term field experiment conducted on a Typic Haplorthox (eutroferric Red Latosol) treated with SS […]

Soil functions and quality are closely linked to soil structure. The effect of management practices on the recovery of the aggregation of a physically degraded soil was studied based on the distribution of water-stable aggregates and single particles (diameter classes 9.51-4.76, 4.76-2.00, 2.00-0.25, 0.25-0.053, < 0.053 mm) and carbon stock (C) in the surface layer (0-7.5 cm) of a Paleudult in the Central Depression region of the state of Rio Grande do Sul, Brazil, under different management systems. The following […]

To analyze the process of degradation caused by natural or anthropogenic influences tools are required, preferentially low-cost, to indicate the degradation stages aiming the selection of techniques to reclaim degraded areas. The purpose of this study was to analyze the variability of microbiological and chemical soil properties as indicators of desertification processes in areas with increasing levels of degradation in the semiarid region of the State of Pernambuco, Brazil. Three environments were sampled: conserved, moderately degraded and heavily degraded in […]

A by-product of Wastewater Treatment Stations is sewage sludge. By treatment and processing, the sludge is made suitable for rational and environmentally safe use in agriculture. The aim of this study was to assess the influence of different doses of limed sewage sludge (50 %) on clay dispersion in soil samples with different textures (clayey and medium). The study was conducted with soil samples collected from native forest, on a Red Latosol (Brazilian classification: Latossolo Vermelho distroférrico) loamy soil in Londrina […]

Biomass and microbial activity have been suggested as appropriate indicators of changes caused by different land use and management systems. The objective of this study was to evaluate alterations in biomass and microbial activity of a typic acric Red-Yellow Latosol (Oxisol), under native Cerrado and different management systems, in the physiographic region Campos das Vertentes, state of Minas Gerais. The evaluated systems were: conventional tillage with potato (CCB); potato followed by oat in rotation with corn (CBAM); conventional tillage with […]

Nitrogen (N) is required in large quantities by corn and its supply causes technical concerns related to crop performance and profitability, and environmental concerns in view of the high risk of nitrate leaching. Results of 61 field experiments conducted through 13 years, in a cooperative effort of the Fundação Agrária de Pesquisa Agropecuária (FAPA) and the Universidade Federal do Rio Grande do Sul (UFRGS), were analyzed and interpreted aiming at establishing a N fertilizer indication for high corn yields, adjusted […]

Several studies have shown the satisfactory performance of the Century Model to study soil organic matter (SOM) for the climatic and edaphic conditions of Rio Grande do Sul. However, soil N stocks were usually overestimated in these simulations. The objective of this study was to parameterize the N cycle submodel of Century for a successful use in N dynamic studies in Southern Brazil. For the simulations, data from a long-term study site established in an Acrisol (Argissolo Vermelho distrófico) at […]

This study was carried out to characterize the possible changes in the chemical nature of humic acids extracted from an Oxisol (0-10 cm) by Fourier transform infrared spectroscopy (FTIR), in the experimental area of Embrapa Meio Ambiente, in Jaguariúna (SP), Brazil. The data were obtained after six corn cultivations, and application of variable doses of sewage sludge (dry basis) from Barueri (BSS), in the treatments: BSS0 – control without sewage sludge application; NPK – mineral fertilization as required by corn; application […]