Volume 29, Number 6, 2005

The characterization of several soil phosphorus (P) pools allowed the evaluation of P components not usually monitored in fertilizer soil tests and can help to understand this nutrient’s cycle. The aim of this study was to evaluate the changes in P pools of a Fluventic Eutrochrepts fine clay which had been under long-time sugarcane plantation. In one situation the sugarcane had been cropped for 55 years with and without trash burning prior to harvesting. The other sugarcane plantation, cultivated for 35 years, […]

Crop management systems that favor soil organic matter can improve the available nutrient content for plants and reduce the use of industrial fertilizer. Despite the importance of organic compounds as a P source, little is known about its dynamics in tropical environments. The objective of this study was to identify organic P species present in humic acids by NMR 31P analysis in a fine clay Fluventic Eutrochrepts in Campos dos Goytacazes, in the north of Rio de Janeiro State, Brazil, under […]

Productivity in subsistence or low-input agriculture depends on the release of nutrients through mineralization of soil organic matter (SOM). For this reason, SOM quantity and quality are two important variables related to the sustainability of subsistence family farming. The objective of this work was to study the interrelationships among soil use, texture and relief, at basin scale, on the concentration of total soil C (Ct) and N (Nt), the oxidizable C fraction with 16.5 mol L-1 KMnO4 (Cox) and the amino-sugars fraction […]

The objective of this study was to evaluate the long-term effects of soil tillage systems and methods of lime application on biological, physical and chemical attributes of a clayey aluminic Oxisol, and on soybean yield components. The experiment with tillage systems was installed in 1978 in Guarapuava, PR, southern Brazil, and liming methods began to be tested in 1987. The treatments were: conventional tillage (CT) without liming; CT with liming; no-tillage (NT) without liming; NT with surface liming and NT […]

The final disposal of sewage sludge has become a cause of environmental concern. Because of its high content of both organic matter and plant nutrients, sewage sludge has been used as fertilizer. However, it is important to know the fractions and bioavailability of heavy metals in sludge-amended soils. In the case of zinc, one of the most abundant metals in sewage sludge, knowledge on forms and plant availability are important to predict its behavior in soils. The present experiment was […]

This study aimed to evaluate total N, N-NH4+ and N-NO3– concentrations and pH in columns of alkalinized anaerobic sewage sludge and in percolated liquid, in simulation of real storage conditions. The experiment was conducted in Curitiba – Paraná state, in Cfb climate and rainfall of 197 mm during the incubation period (48 days). The tested factors were: 3 sludge types (covered alkalinized sludge – LCC; uncovered alkalinized sludge – LCD; and uncovered raw sludge – LBD), 4 incubation periods (0; 15; 27; and 48 days) […]

The Integrated Land Use Planning course of the Agronomy School of the Federal University of Rio Grande do Sul State, Porto Alegre, Brazil, associates Soil Science with other courses taught in Agronomy, establishing consistent and meaningful crosslinks. The course uses integrated land use planning to feed the compiled agronomical knowledge into a project of sustainable land use for one or more farms. The following sequence of procedures is used for this purpose: regional characterization, survey of existing natural resources, ascertainment […]

Some of the pedologic alterations resulting from traditional soil management methods were studied in an area cultivated with citrus (Citrus sinensis) in a farm in Bariri County, State of São Paulo, Brazil. A toposequence was established to evaluate the effect of the position in the landscape on changes in soil physical attributes. Field and lab data were taken in vertical profiles of the upper, middle and lower slope levels of a Typic Haplorthox and some parameters were evaluated statistically through […]