ABSTRACT The expansion of the sugarcane industry in Brazil has intensified the mechanization of agriculture and caused effects on the soil physical quality. The purpose of this study was to evaluate the limiting water range and soil bearing capacity of a Latossolo Vermelho distroférrico típico (Rhodic Hapludox) under the influence of different tractor-trailers used in mechanical sugarcane harvesting. The experiment was arranged in a randomized block design with five replications. The treatments consisted of green sugarcane harvesting with: harvester without […]

ABSTRACT The interaction of organic compounds with clay minerals can change the size of crystals. However, in soils this effect is still unclear because of limitations in separation of pure mineral phases for conducting dissolution experiments. In this study, the relationship between soil organic matter (SOM) and mean crystallite size (MCS) of clay minerals from surface and subsurface horizons of soils from a toposequence in Southern Brazil was evaluated. Soil C and N contents were determined and the nature of […]

ABSTRACT The expansion of eucalyptus plantations in southern Brazil, especially over regions with natural grasslands, which occurred in the last decade potentially changes total organic carbon and nitrogen in soil. The aim of this study was to test the Century model 4.5 in the simulation of changes in inventories of TOC and TN in the surface layer (0.0-0.2 m) soil in Eucalyptus sp. com different ages in three municipalities in Rio Grande do Sul State, Brazil. Areas adjacent to grasslands […]

ABSTRACT Humic acids (HA) are a component of humic substances (HS), which are found in nearly all soils, sediments, and waters. They play a key role in many, if not most, chemical and physical properties in their environment. Despite the importance of HA, their high complexity makes them a poorly understood system. Therefore, understanding the physicochemical properties and interactions of HA is crucial for determining their fundamental role and obtaining structural details. Cationic surfactants are known to interact electrostatically and […]

ABSTRACT Conversions of plant cover resulting from management practices may alter carbon storage and the natural abundance of 13C. The aim of this study was to evaluate C stocks and natural abundance of C (δ13C) in areas of forest (F) and pasture (P) sequences with different times of usage in an Atlantic Forest area, Santa Catarina, Brazil. Seven usage sequences of forest (F) and pasture (P) were defined through aerial photographs taken in 1957, 1978, and 2008; through interviews with […]

ABSTRACT Soil use can change processes such as soil organic matter decomposition, nutrient cycling, and particle aggregation, which, in turn, influence the occurrence of macrofauna. The objective of this study was to relate land use systems to their effects on the distribution of soil macrofauna groups, as well as their relation to soil physical and chemical properties. The land use systems evaluated were native forest, an Eucalyptus plantation, pasture, a crop-livestock integration area, and a no-tillage crop area. Samples were […]

ABSTRACT Ectomycorrhizal fungi (EMF) may improve the adaptation of eucalypts saplings to field conditions and allow more efficient fertilizer use. The effectiveness of EMF inoculum application in promoting fungal colonization, plant growth, nutrient uptake, and the quality of rooted cuttings was evaluated for Eucalyptus urophylla under commercial nursery conditions. For inoculated treatments, fertilization of the sapling substrate was reduced by 50 %. The experiment was carried out in a completely randomized design in a 4 × 4 factorial arrangement, wherein […]

ABSTRACT Intrinsic equilibrium constants for 22 representative Brazilian Oxisols were estimated from a cadmium adsorption experiment. Equilibrium constants were fitted to two surface complexation models: diffuse layer and constant capacitance. Intrinsic equilibrium constants were optimized by FITEQL and by hand calculation using Visual MINTEQ in sweep mode, and Excel spreadsheets. Data from both models were incorporated into Visual MINTEQ. Constants estimated by FITEQL and incorporated in Visual MINTEQ software failed to predict observed data accurately. However, FITEQL raw output data […]

ABSTRACT Population growth increases the need for food production, coupled in may cases with the indiscriminate use of fertilizers and incorporation of transgenic plants in the production system. The objective of this study was to evaluate the effect of cadmium on the growth of Bt transgenic corn and non-transgenic corn, inoculated with mycorrhizal fungi under controlled conditions. For that purpose, an experiment was set up in a 5 × 4 × 2 factorial arrangement with five Cd rates (0, 28.5, […]

ABSTRACT Cassava (Manihot esculenta Crantz) is a highly mycotrophic crop, and prior soil cover may affect the density of arbuscular mycorrhizal fungi (AMFs), as well as the composition of the AMFs community in the soil. The aim of this study was to evaluate the occurrence and the structure of AMFs communities in cassava grown after different cover crops, and the effect of the cover crop on mineral nutrition and cassava yield under an organic farming system. The occurrence and structure […]