Volume 36, Number 5, 2012

Nutrients accumulated in dry crop residues and released in the decomposition process return to the soil and may become available to subsequent crops. The objective of this study was to evaluate the decomposition and nutrient release of plant residues of different no-tillage crop sequences in the second growing season. A field experiment was carried out on a Rhodic Eutrudox in Jaboticabal, SP, Brazil (48°18’W and 21°15’S), arranged in a randomized split-block design with three replications. The treatments consisted of combinations […]

The adoption of no-tillage systems (NT) and the maintenance of crop residues on the soil surface result in the long-term increase of carbon (C) in the system, promoting C sequestration and reducing C-CO2 emissions to the atmosphere. The purpose of this study was to evaluate the C sequestration rate and the minimum amount of crop residues required to maintain the dynamic C equilibrium (dC/dt = 0) of two soils (Typic Hapludox) with different textural classes. The experiment was arranged in […]

The Cerrado is being increasingly exploited in production systems characterized by intensive land use, without due concern for the preservation of natural resources. The objective of this research was to evaluate the effect of no-tillage soybean on the physical properties of Oxisols. The study was carried out in the region of “Serra do Quilombo”, located in the Cerrado region of the State of Piauí.  To assess changes in soil properties caused by agricultural use, soil samples were collected from conventional […]

The State of Rio Grande do Sul is the greatest producer of flooded rice of Brazil, concentrated mostly along the western border. The objective was to evaluate soil physical properties and flooded rice yield in no-till and conventional tillage systems and rice straw levels in no-till system. The study consisted of four experiments (E), laid out in experimental design was completely randomized blocks, with four experiments (E) and 10 repetitions in experiment 1, 2 and 3 and 6 in experiment […]

In the last years, soil quality indexes for analyses of the environmental sustainability and agricultural production have been proposed in increasing numbers. However, none of these indexes is related to the groundwater recharge soil quality index for conditions in Brazil. The objective of this study was to generate a soil quality index related to the groundwater recharge (SQIGR) of the physiographical conditions of the Upper Rio Grande Basin and to draw a map of SQIGR using geostatistical procedures. The proposed […]

Successive applications of liquid swine waste to the soil can increase the contents of total organic carbon and nutrients and change acidity-related soil chemical properties. However, little information is available on the effects of swine waste application in solid form, as of swine deep-litter. The objective of this study was to evaluate alterations of organic carbon and acidity-related properties of a soil after eight years of pig slurry and deep-litter application. In the eighth year of a field experiment established […]

Microbial processes have been used as indicators of soil quality, due to the high sensitivity to small changes in management to evaluate, e.g., the impact of applying organic residues to the soil. In an experiment in a completely randomized factorial design 6 x 13 + 4, (pot without soil and residue or absolute control) the effect of following organic wastes was evaluated: pulp mill sludge, petrochemical complex sludge, municipal sewage sludge, dairy factory sewage sludge, waste from pulp industry and […]

The recovery of degraded areas is a slow process and requires the addition of organic residues to improve the soil physical properties. It is known that sewage sludge has a high content of organic matter and nutrients, acting as soil conditioner and supplying nutrients to soil and plants. In a degraded Entisol (typic Quartzipsamment) area, on the Fazenda Entre Rios of the company Suzano Bahia Sul Pulp and Paper, in Itatinga-SP, native Atlantic Forest species were planted. The area was […]

The application of sewage sludge is a concern because it may affect the quality of organic matter and microbiological and biochemical soil properties. The effects of surface application of sewage sludge to an agricultural soil (at 18 and 36 t ha-1 dry basis) were assessed in one maize (Zea mays L.) growing season. The study evaluated microbial biomass, basal respiration and selected enzymatic activities (catalase, urease, acid and alkaline phosphatase, and β-glucosidase) 230 days after sewage sludge application and infrared […]

The possibilities of remediation of a Latossolo Vermelho Amarelo artificially contaminated with oil (5,000 mg kg-1) were investigated. Different remediation methods with chemical oxidants were compared: KMnO4 0.10 mol L-1; K2S2O8 0.10 mol L-1; H2O2 0.10 mol L-1; H2O2/Fe2+ 0.10/0.08 mol L-1 (Fenton’s reaction) and H2O2/Fe2+/UV 0.10/0.08 mol L 1 (photo-Fenton reaction). The remediation was practically complete (99 %) after 30 min of the photo-Fenton process. No other oxidant reached this dissipation rate after 180 min. The remediation was least […]