MERCURY QUANTIFICATION IN SOILS USING THERMAL DESORPTION AND ATOMIC ABSORPTION SPECTROMETRY: PROPOSAL FOR AN ALTERNATIVE METHOD OF ANALYSIS
01/Jul/2015
Despite the considerable environmental importance of mercury (Hg), given its high toxicity and ability to contaminate large areas via atmospheric deposition, little is known about its activity in soils, especially tropical soils, in comparison with other heavy metals. This lack of information about Hg arises because analytical methods for determination of Hg are more laborious and expensive compared to methods for other heavy metals. The situation is even more precarious regarding speciation of Hg in soils since sequential extraction methods […]
SPATIAL UNCERTAINTY OF NUTRIENT LOSS BY EROSION IN SUGARCANE HARVESTING SCENARIOS
01/Jul/2015
The assessment of spatial uncertainty in the prediction of nutrient losses by erosion associated with landscape models is an important tool for soil conservation planning. The purpose of this study was to evaluate the spatial and local uncertainty in predicting depletion rates of soil nutrients (P, K, Ca, and Mg) by soil erosion from green and burnt sugarcane harvesting scenarios, using sequential Gaussian simulation (SGS). A regular grid with equidistant intervals of 50 m (626 points) was established in the […]
Methods to Quantify Nickel in Soils and Plant Tissues
01/May/2015
In comparison with other micronutrients, the levels of nickel (Ni) available in soils and plant tissues are very low, making quantification very difficult. The objective of this paper is to present optimized determination methods of Ni availability in soils by extractants and total content in plant tissues for routine commercial laboratory analyses. Samples of natural and agricultural soils were processed and analyzed by Mehlich-1 extraction and by DTPA. To quantify Ni in the plant tissues, samples were digested with nitric […]
Potential Phosphate Solubilization Mediated by Rhizospheric Microbiota of Eucalyptus Cultivated in a Typical Toposequence of the Zona da Mata, Minas Gerais, Brazil
01/May/2015
The use of rock phosphates, combined with proper management of soil microorganisms able to solubilize phosphate, is an alternative for reducing the costs of P fertilization. However, both practices require prior assessment of the potential of the rhizospheric microbiota in solubilizing P sources with low reactivity under field conditions. The objective of this study was to evaluate the potential of soil microbes to solubilize Ca, Fe, and Al phosphates, as well as Araxá and Catalão rock phosphates, in rhizospheric and […]
Early Changes in Soil Metabolic Diversity and Bacterial Community Structure in Sugarcane under Two Harvest Management Systems
01/May/2015
Preharvest burning is widely used in Brazil for sugarcane cropping. However, due to environmental restrictions, harvest without burning is becoming the predominant option. Consequently, changes in the microbial community are expected from crop residue accumulation on the soil surface, as well as alterations in soil metabolic diversity as of the first harvest. Because biological properties respond quickly and can be used to monitor environmental changes, we evaluated soil metabolic diversity and bacterial community structure after the first harvest under sugarcane […]
Chemical and Biochemical Properties of Soils Degraded by tin Mining and in a Rehabilitation Phase in the Amazon Basin
01/May/2015
Tin mining in the Serra da Onça in the Jamari National Forest, State of Rondônia, Brazil, caused severe chemical, physical, and biological changes in the soil. In 1997, the area was divided into plots and a rehabilitation program was begun, which consisted of land surface modeling, construction of terraces, liming, fertilization, and planting of leguminous crops and native plants. In subsequent years, new plots were set up in the rehabilitation program so that at the time of sampling the different […]
Modeling Bulk Density of Subsoil under Native Vegetation in Minas Gerais, Brazil
01/May/2015
Bulk density (ρb) is an important indicator of soil physical quality, but it is seldom assessed at greater depths due to sampling difficulties. Pedotransfer functions have been relatively successful in estimating ρb, but specific functions for most Brazilian biomes are not available. The aim of this study was to develop mathematical functions to describe ρb to a depth of 1 m in areas of native vegetation in central and southern Minas Gerais, Brazil. For determination of ρb, soil core samples […]
Physical Properties of a Cultivated Cambisol Treated with Biofertilizer in the Apodi Plateau, Ceará, Brazil
01/May/2015
Knowledge of soil physical changes and soil quality is important for creating adequate management strategies to be adopted for soil under crop production. The aim of this study was to evaluate the effects of cultivation and application of biofertilizer (obtained from cattle manure) on the physical quality of a Cambisol planted to Ficus carica L. with a drip irrigation system and to verify the efficiency of indicators in assessing changes in its physical properties. In order to evaluate physical quality, […]
Contribution of Topography and Incident Solar Radiation to Variation of Soil and Plant Litter at an Area with Heterogeneous Terrain
01/May/2015
Natural processes that determine soil and plant litter properties are controlled by multiple factors. However, little attention has been given to distinguishing the effects of environmental factors from the effects of spatial structure of the area on the distribution of soil and litter properties in tropical ecosystems covering heterogeneous topographies. The aim of this study was to assess patterns of soil and litter variation in a tropical area that intercepts different levels of solar radiation throughout the year since its […]
Toxic Effects of Arsenic on Eisenia Andrei Exposed to Soils Surrounding Gold Mining Operations
01/May/2015
Products from mining operations are of great economic importance to the state of Minas Gerais, Brazil. However, due to the extensive damage they may cause to biota, including soil fauna, recovery and biomonitoring of these areas and their surroundings are necessary. Considering the ecological importance of earthworms and their potential as bioindicators, the aim of this study was to evaluate the toxicity of arsenic to earthworms of the species Eisenia andrei Bouché in soils around gold mining operations in the […]