Volume 36, Number 4, 2012

In Brazil, most forest stands have been planted on soils with some degree of physical, chemical or biological degradation. The protection of the trees for the soil, depending on the litter deposition, is a driving force of the restoration process of degraded areas. Since organic matter is related to many of the physical, chemical and biological soil properties, it is characterized as a key factor for the maintenance of the environmental quality of forest systems. The purpose of this study […]

Soil organic matter depletion caused by agricultural management systems have been identified as a critical problem in most tropical soils. The application of organic residues from agro-industrial activities can ameliorate this problem by increasing soil organic matter quality and quantity. Humic substances play an important role in soil conservation but the dynamics of their transformations is still poorly understood. This study evaluated the effect of compost application to two contrasting tropical soils (Inceptisol and Oxisol) for two years. Soil samples […]

Araucaria angustifolia, commonly named Araucaria, is a Brazilian native species that is intensively exploited due to its timber quality. Therefore, Araucaria is on the list of species threatened by extinction. Despite the importance of soil for forest production, little is known about the soil properties of the highly fragmented Araucaria forests. This study was designed to investigate the use of chemical and biological properties as indicators of conservation and anthropogenic disturbance of Araucaria forests in different sampling periods. The research […]

Certain conditions of relief, climate and use can lead to the formation of saline and sodic soils, also called salt-affected soils. With a view to establish guidelines for management practices and land use in the region of Baixo Acaraú, Ceará, the purpose of this work was to generate a map of salinization risk. To classify levels of vulnerability, the pedology, geology, geomorphology and land use/cover were evaluated as well as slope altimetry information, treated in a GIS environment with an […]

In the determination of carbon contents in organic residues, analytical methods for soils are frequently employed without adequate calibration. Thus, methods capable to determine the levels of C and organic matter (OM) in organic residues must be tested and calibrated, using as a reference the dry combustion method. The objectives of this study were to evaluate methods for determining the levels of total carbon (TC), organic carbon (OC) and OM in organic residue samples; to determine mathematical equations for the […]

Urea is the most consumed nitrogen fertilizer in the world. However, its agronomic and economic efficiency is reduced by the volatilization of NH3, which can reach 78 % of the applied nitrogen. The coating of urea granules with acidic compounds obtained by charcoal oxidation has the potential to reduce the volatilization, due to the acidic character, the high buffering capacity and CEC. This work aimed to evaluate the effect of HNO3-oxidized carbon on the control of NH3 volatilization. These compounds […]

Cotton is responsive to boron fertilization, however, results on the mobility of this nutrient in the plant are few and controversial. This study had the objective of evaluating boron translocation and accumulation in cotton cultivars. Four cotton cultivars (FM 993, FM 910, FMT 701, and FMT 523) were grown for six weeks in 8 L pots with washed sand and nutrient solution at two boron concentrations (0 and 4.5 ∝mol L-1). After six weeks, plants were sampled for four more […]

An understanding of the role of organic nitrogen (N) pools in the N supply of eucalyptus plantations is essential for the development of strategies that maximize the efficient use of N for this crop. This study aimed to evaluate the distribution of organic N pools in different compartments of the soil-plant system and their contributions to the N supply in eucalyptus plantations at different ages (1, 3, 5, and 13 years). Three models were used to estimate the contributions of […]

In Brazil, along with the expansion of clonal forestry, the management of more productive and more nutrient-demanding genotypes has led to the appearance of micronutrient deficiency symptoms, mainly of boron (B), and more recently, of copper (Cu) and of zinc (Zn), especially in Cerrado areas. The purpose of this study was to evaluate three extraction solutions to determine Zn availability (Mehlich-1, Mehlich-3 and DTPA pH 7.3) for eucalyptus seedlings grown in a greenhouse, on six Cerrado soil samples, and to […]

The development of water erosion occurs in response to the way water moves through and over a given landscape. The digital elevation model (DEM) must therefore be as accurate as possible, since it is the basis for the analysis of a relief. The objectives of this study were to define a hydrologically consistent digital elevation model (HCDEM) and the most appropriate method to determine the flow direction of the drainage network in the sub-basin of the Terra Dura forest stand, […]