Volume 34, Number 2, 2010

Soil is an important pool for C stocks and plays a fundamental role in greenhouse gas emissions and consequently in climatic changes. Land use change can cause either a negative or a positive effect in terms of greenhouse gas emissions to the atmosphere. However, the intensification of global warming has been confirmed, related mainly to the increase of greenhouse gas emissions from burning of fossil fuel, deforestation, and adoption of inadequate agricultural land management practices. An inadequate soil use does […]

The GPR uses indirect technique for investigation of subsurface structures, characterized as non-invasive method, which allows to extract information throughout the soil profile without drilling, probing or digging. This study aimed to evaluate the use of GPR in the establishment of soil physical properties in a area under sugar cane, and its correlation with the volumetric cylinder method. The study area in Bom Sucesso, State of Paraná (Brazil), had been used for sugar cane cultivation for over 20 years. Undisturbed […]

The technique of TDR (time-domain reflectometry) is an important tool for the study of soil water content. For a correct use of this technique, models that relate the volumetric water content in soil with the soil dielectric constant must be calibrated, considering the characteristics of each soil. The purpose of this study was to evaluate the influence of soil type and sampling form (disturbed and undisturbed samples) on the dielectric constant (Ka) of the soil and the performance of models […]

The potential yield of sugarcane depends on factors related to climate, soil and the plant variety. Management systems that provide the addition of organic waste to the soil can cause changes in physical attributes of the soil, enhancing the growth of the root system and sugarcane yield. The objective of this study was to evaluate the effects of different management systems at several levels of organic residue addition on the distribution and indices of aggregate stability of dystrophic cohesive Yellow […]

Nutrients are basically transported to the roots by mass flow and diffusion. The aim of this study was to quantify the contribution of these two mechanisms to the acquisition of macronutrients (N, P, K, Ca, Mg, and S) and cationic micronutrients (Fe, Mn, Zn, and Cu) by maize plants as well as xylem exudate volume and composition in response to soil aggregate size and water availability. The experiment was conducted in a greenhouse with samples of an Oxisol, from under […]

The ferrimagnetic minerals maghemite (γFe2O3) are closely related with metal availability and P adsorption capacity. Magnetization is spontaneous in a significant percentage of Brazilian soils. In the State of Paraná (Brazil) this area represents up to 50 %. The determination of the mass-specific magnetic susceptibility (ΧBF) is the simplest method of identification and quantification of ferrimagnetic minerals in soils. The ΧLF is a quick, cheap, non-destructive technique, with satisfactory reproducibility, and can be used as a criterion in pedogenetic studies […]

Soil organic matter (SOM) contents and characteristics are results of production, incorporation, decomposition, alteration, and mineralization rates, according to environmental conditions. In hydromorphic soils, SOM dynamics are regulated by O2 deficit, lowering the decomposition rates and producing substances different from those in well-drained soils. This article aimed to determine SOM contents and characteristics at three locations in the State of Espirito Santo, Brazil. Total organic carbon (TOC) was quantified by three methods, besides partitioning humic substances (HS) and determining the […]

Pineapple (Ananas comosus L. Merrill) in vitro propagation results in the production of a large quantity of healthy and homogeneous plantlets. Despite these advantages, the long time required for acclimatization makes this agricultural practice too costly. Growth acceleration of plantlets by inoculation with endophytic and epiphytic diazotrophic bacteria may be useful to reduce this period. The objectives of this study were to evaluate the potential of 20 diazotrophic bacteria strains in synthesizing indole, solubilizing Ca phosphate and Zn oxide and […]

Two bacterial strains that amplified part of the nifH gene, RP1p and RP2p, belonging to the genus Enterobacter and Serratia, were isolated from the rhizoplane of Lupinus albescens. These bacteria are Gram-negative, rod-shaped, motile, facultative anaerobic, and fast-growing; the colonies reach diameters of 3-4 mm within 24 h of incubation at 28 ºC. The bacteria were also able to grow at temperatures as high as 40 ºC, in the presence of high (2-3 % w/v) NaCl concentrations and pH 4 […]

Of all nutrients, N has the strongest effect on grass growth and an adequate N fertilization can reduce the time required for the formation of high-quality mats. This study aimed to evaluate the influence of N fertilization on Bermuda grass sod production and quality. The experiment was conducted in an area of commercial sod production, in Capela do Alto, state of São Paulo. Cynodon dactylon (Pers) L., known as Bermuda grass, was evaluated in a randomized complete block design with […]