The application of silicates to soils can result in increased soil cation exchange capacity (CEC), displace anions, especially H2PO4– (diacid phosphate), neutralize the pH and Al toxicity and, in general, increase the nutrient availability to plants. However, calcium silicates may be less efficient than calcium carbonates. To evaluate the effect of calcium carbonate substitution by calcium silicate on the soil chemical properties, especially on phosphorus availability, four experiments were conducted in an entirely randomized design with four replications, in a […]

Plant growth-promoting endophytic bacteria can increase plant nutritional efficiency thus favouring its yield. With the purpose of evaluating the influence of 10 previously selected isolates of growth-promoting endophytic bacteria on the uptake, utilization and transport of nutrients by tomato plants, greenhouse experiments were installed. The hypocotyl was cut in order to apply the endophytic bacteria to tomato seedlings cultivar Santa Clara. Fifty five days after transplanting the upper portion of the cut seedlings, the plants were collected to determine the […]

Ammonium and nitrate ions from soil organic N mineralization are the predominant N mineral forms available to plants. The ion ratio and distribution along the soil profile show daily fluctuations and oscillate seasonally. NH4+ and NO3– soil content were evaluated in two adjacent plots, one of them farmed continuously with barley, soybean and barley in a no-tillage system for more than 10 years, with pH 6.0 and fertilized with P and K. A second plot was maintained undisturbed, with native […]

The occurrence of concretionary soils in the Central and Northern Brazil is very common. They are found in low areas and on plateau edges, usually constituting dystrophic soils,poor in nutrients. The finding of an eutrophicc concretionary soil in the edge of a plateau in Ouro Verde de Goiás stimulated this research, which had the purpose of verifying the relationship between the soil eutrophic conditions and the underlying lithologic material, the probable source of the exchangeable bases. The pedologic and geochemical […]

The use of cover crops preceding corn is an alternative to supply nitrogen (N) and to make no-till system viable regions with dry winter such as in the Southeast, Center-West, North, and Northeast of Brazil. The purpose of this study was to evaluate N levels and the effect of cover plants on N supply and corn yield in no-till system. The study was carried out from 2000 to 2003. The experimental design was randomized blocks, with split-split plots and four […]

The basidiospores of Pisolithus sp. contain large amounts of lipids, indicating provision for future germination in the host rhizosphere. However, the accumulation, composition, and mobilization of lipids during formation and germination of these spores are largely unknown. In this study, lipid storage and fatty acid composition during basidiosporogenesis were analyzed in fresh basidiocarps using bright-field microscopy and gas chromatography. Abundant lipid bodies are found in the hyphae, basidia, and basidiospores of fungal basidiocarps. This evidences a considerable C transport in […]

The identification of impacts of mechanized sugarcane harvesting on the structure in different soil classes can be an important strategy to minimize compaction effects. The objective of this study was to evaluate the structural changes, preconsolidation pressure and least limiting water range (LLWR) in a Red-Yellow Latosol (LVA) and a Haplic Cambisol (CX), due to harvest operations at different periods during the sugar cane harvesting season. Undisturbed soil samples were collected in the layer 0 to 0.05 m to determine […]

Water is a critical component of plant metabolism, and a reduction in soil water availability may affect crop growth, development and yield. The objective of this study was to quantify the influence of soil water deficit on transpiration and on some growth (plant height and stem diameter) and development (main stem leaf number) parameters of Eucalyptus grandis (Hill ex Maiden) and E. saligna (Smith) seedlings. For this purpose, a greenhouse experiment was conducted at the Federal University of Santa Maria, […]

The erosivity potential of rainfalls can be estimated by some indexes, among them the EI30, which is given by the product of kinetic energy (E) and rainfall intensity for a 30-minute period (I30). The purpose of this study was to determine rainfall erosivity, hydrological patterns, return period and probability of occurrence of erosive rainfalls in São Borja, RS, Brazil, based on diary rainfall charts of the FEPAGRO meteorological station, from 1956 to 2003. The duration and accumulated amount of each […]

The adaptability of maize genotypes to environments where nutrients are not readily available may be related to an adaptation to the predominance of the soil nitric and ammoniacal forms of N and to the association with beneficial microorganisms such as diazotrohpic bacteria and/or plant growth promoters. The objective of this study was to evaluate the response of two maize intervarietal hybrids to different nitrogen doses and forms as well as the effect of inoculation with A. amazonense. The experiment was […]