Volume 32, Number 3, 2008

The amendment of agricultural and forest soils with biosolids from sewage treatment plants (STPs) is an alternative to recycle these organic residues. However, biosolids from STPs may contain metals and/or xenobiotics that can affect soil microorganisms. In this study, the impacts of biosolids from the STPs of Barueri and Franca (São Paulo, Brazil), containing high and low metal concentration, respectively, on the microbiota of a Nitisol (clayey) and a Dystric Arenosol (sandy) were determined in microcosm. Immediately after biosolids application […]

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 […]

The objective of this experiment was to compare the ability of soybean (Glycine max), corn (Zea mays), Brachiaria brizantha cv. Marandu and pearl millet (Pennisetum glaucum) for P-uptake, at different levels of the Alvorada natural rock phosphate, under controlled conditions. The soil used was a dystrophic Hapludalf (180 g kg-1 clay), which was limed and fertilized with N, K and micronutrients. The crops were grown in 18 dm3 pots for 50 days in a greenhouse, at different P2O5 rates (0, […]

Common bean is one of the most important staples in Brazil. The objective of this study was to evaluate the common bean cv. Pérola yield and changes in soil chemical attributes as influenced by liming and manganese rates. The experiment was carried out in pots containing dystrophic Red Yellow Latosol (Oxisol). Treatments consisted of a 2 x 6 factorial combination of two limestone (CO3 and MgCO3 in a 3:1 molar ratio) rates, calculated to increase base saturation to 50 and […]

This study aimed to evaluate the differences in carbon and nutrient cycling and balance in two plantation systems of forest species native in the Atlantic Forest. The plantation systems consisted of 22 year-old mixed stand and pure stands of six hardwood species (Peltogyne angustiflora, Centrolobium robustum, Arapatiella psilophylla, Sclerolobium chrysophyllum, Cordia trichotoma, Macrolobium latifolium) native to the southeastern region of Bahia, Brazil, that were evaluated from August 1994 through July 1995. As references, the study included a natural forest and […]

The ion exchange resin method used in some laboratories in Brazil requires soil grinding for the determination of available P. As a consequence of grinding, the extraction of internal labile P in aggregates is expected, increasing the concentration of available-P. On the other hand, finer grinding increases the exposure of soil particle surface, which creates additional sites for further P adsorption. The aim of this study was to evaluate extraction efficiency available-P by Mehlich-1, and anion exchange resin in beads […]

In highly weathered tropical soils phosphorus (P) bioavailability to plants is closely associated with soil organic P forms, which in turn are influenced by the vegetation cover. The aim of this study was to evaluate total organic P (Po), labile P fractions and microbial biomass P in soils under Acacia auriculiformis and Mimosa caesalpiniifolia stands, secondary forest and pasture. The clay-adjusted average content of total Po and labile Po were 375 mg kg-1 P and 40.2 mg kg-1, respectively. The […]

Soil acidity in no-tillage systems can be amended by surface liming. This practice is favored by plant residues on the soil surface, which release water-soluble organic compounds that vary among plant species. The experiment was conducted on a Typic Hapludox (V = 41 %) in Botucatu, São Paulo State, Brazil, to evaluate the effect of surface liming on the concentration of soluble cations in millet, common bean and black-oat crop residues in two growing seasons (2002/03 and 2003/04). For common […]

Basic slag consists of calcium silicate and is an alternative for soil acidity correction. This study evaluated the residual effects of calcium silicate application on the chemical properties of a Rhodic Hapludox in a rotation system with Brachiaria grass under different grazing intensities. The experiment was a complete randomized block design, where the plots consisted of grazing intensities, determined by the forage supply of 50, 100, 150 and 200 kg t-1 of MS/ PV, respectively, and the subplots of surface […]

The recent shift in soil tillage from conventional to no-tillage systems in Brazil alters the soil system dynamics. In soils cultivated under the no-tillage system the relations are established and preserved over the course of time, which increases the functional complexity of the system, while under the conventional system often destroys these relationships. Some questions have risen about the reliability of sampling the so-called “arable soil layer” (0-20 cm) for soil acidity quantification in the no-tillage system due to the […]