Volume 24, Number 3, 2000

Morphological, physical and chemical data of 58 soil profiles of Ferralsols and low activity clay Cambisols, Lixisols, Acrisols and Nitisols and of Alisols of the International Soil Reference and Information Centre (ISRIC) collection, described and sampled in eighteen different countries of tropical and subtropical regions, were selected to analyse their consistency and, or, variability and to search for properties to better describe and differentiate them. The soil profile descriptions were based on the guidelines of FAO and the FAO endorsed […]

Microbial biomass plays an important role in phosphorus cycling in tropical and subtropical soils. The purpose of this research is to quantify the content of phosphorus stored in the microbial biomass in soils under different tillage and cropping systems. Four long term experiments were then used, involving no-tillage and conventional tillage and different crop rotations, installed in different soils (Heavy clay Rhodic Hapludox, Clay Rhodic Hapludox and fine-loamy Rhodic Paleudult) in the state of Rio Grande do Sul – Brazil. […]

In this study, a first order exponential model was adjusted to the experimental data of soil organic carbon (OC) and total nitrogen (TN) of a 9-year-old experiment in southern Brazil. Parameters of soil organic matter dynamics were determined and the soil OC and TN stocks simulated in a Paleudult soil under three tillage systems (conventional tillage: CT, reduced tillage:RT, and no-tillage:NT) and three cropping systems (oat/maize-O/M, oat + vetch/maize-O + V/M and oat + vetch/maize + cowpea-O + V/M + […]

This study was carried out to assess the influence of winter plant cover on the chemical soil properties in a Structured Terra Roxa soil in Santa Catarina, Brazil. The plant cover consisted of an association of black oats (Avena stirgosa Schreb) with pasture turnip (Raphanus sativus L.) and organic fertilization using poultry manure and mineral fertilization. Soil samples collected in August 1994 and January 1995, at depths of 0-10, 10-20 and 20-30 cm, were analyzed for an experiment initiated in […]

Root system growth of the common bean, variety IAC-Carioca, under center pivot irrigation in rotation with fallow; corn; black oat; sunn hemp (Crotalaria juncea L.); pigeon pea [Cajanus cajan (L.) Millsp.] and velvet bean (Mucuna aterrima) was evaluated during a non-conventional (Autumn – Winter) cultivation period, from 1993 to 1995, on a typic Haplorthox soil, at an experimental area of the Instituto Agronômico, in Ribeirão Preto, São Paulo, Brazil. The crop sequences of common bean with corn and green manure […]

This paper reports the effects of applying solid urban waste compost to 21 acid soils and five alkaline soils on the electrical conductivity (EC), pH (both in CaCl2 0.01 mol L-1 and in water), and potential acidity (H + Al). The compost was collected at São Matheus Treatment Plant, São Paulo. In acid soils, the compost was applied with and without mineral fertilizers and dolomitic lime (to reach 70% of base saturation). Lime was substituted by gypsum in alkaline soils. […]

Imazaquin herbicide is an organic molecule presenting ionizable functional groups, with its sorption depending on soil pH and electrical charges. In this research, sorption of imazaquin was evaluated on an Anionic Acrudox at different soil depths and pH values. Radiolabelled (14C) molecules were employed to study imazaquin sorption, which was estimated by the difference between applied concentration and that remaining in solution. The sorption data were fitted to Freundlich equation to determine the sorption coefficient values (Kf), which were, overall, […]

Soil loss tolerance refers to the maximum rate of annual soil loss that will permit crop productivity to be obtained economically and indefinitely. Besides the usual form, it can also be used in the Universal Soil Loss Equation as a criteria to better define terrace spacing on croplands. This research work was developed during 1998, at the Agroveterinary Center/UDESC, in Lages, Santa Catarina, Brazil, to establish soil loss tolerance values by water erosion for 73 soil profiles of Santa Catarina, […]

Microorganisms were isolated from phenolic sands resulting from metallurgic activities, using Minimal Medium for fungi containing pentachlorophenol (PCP) as the only carbon source. After four successive subcultures every 15 incubation days, the final culture was plated on Martin Medium Agar. Three different fungi were isolated and subsequently identified as Acremonium sp., Paecilomyces sp. and Penicillium sp.; which were tested for their ability to degrade: PCP, indigo dye and Remazol Brilliant Blue R (RBBR). The decolouration of indigo dye was 99% […]

An empirical equation to represent the analytical soil particle-size curve is proposed. Based on this equation, a new expression was obtained to calculate the predominant mean diameter of soil particles, which represents the mean size of these particles. The equations can be applied, advantageously, in soil physics as well as in geological, geomorphological and sedimentological studies.