Volume 23, Number 3, 1999

Irrigation quality has been described by calculated parameters assuming that water storage capacity in soil is a constant. However, this property presents spatial variations. Concern with environmental and economic aspects has led to culture management in specific areas, a fact which requires knowledge of spatial distribution of soil properties. Geostatistics makes possible the identification of the spatial dependence structure and the mapping of a given soil property. The objective of this work was to identify sampling and block kriging intensities, […]

The objective of this work was to analyze the effect of moisture content and soil management on the compressibility behavior of three soils, namely, a Red-Yellow Latosol (LV), Dusky Red Latosol (LR) and Dark-Red Latosol (LE), under annual crop, natural forest and pasture. The soils were located in the region of Lavras and Ijaci (MG). Undisturbed and disturbed soil samples were collected in two depths (0-0,03 and 0,27-0,30 m) with three replicates. The undisturbed soil samples were used in the […]

This study aimed to evaluate the relationship between the mineralogical constituents of clay fraction and the development of micro and macrostructure of Latosols (Oxisols) from southeastern Brazil. For that purpose, samples of oxic horizons were obtained from seven Latosols representative of this group, from Minas Gerais and Espírito Santo states. The different soil samples were submitted to morphological, chemical, physical, mineralogical and micromorphological characterizations. From the different results it was possible to conclude that kaolinite and gibbsite are the main […]

Aiming to evaluate the influence of the clay fraction mineralogy on the physical properties of Latosols (Oxisols) from southeastern Brazil, seven Latosols, representative of this group, were selected from the states of Minas Gerais and Espírito Santo, having distinct morphological features associated with soil structure. The sampling of soils was performed in the latossolic B horizon, with disturbed and undisturbed samples being collected. Chemical, physical and mineralogical characterizations were performed in the laboratory. Regression and correlation analyses taking into account […]

Aggregate stability has been measured by wet sieving, water dropping and sonication. The objective of this study is to propose an index (energy – level based index) to express aggregate stability in A and B horizon aggregates of Dusky Red Latosol and Structured Dusky Red Earth. Aggregates from 4.76 to 7.93 mm were submitted to sonication at increasing energy levels. A dispersion ratio (< 0.053 mm aggregate + particle fraction/total aggregate mass) was plotted against energy levels, for each sample. […]

Understanding the chemistry behavior in acid soils during the decomposition of plant residues is very important for the management of these soils. The effects of incubation (0, 15, 30, 60 and 90 days) of finely ground residues of oil seed radish (Raphanus sativus), soybean (Glycine max) and wheat (Triticum aestivum) (at 2 and 4%) with samples of Bw horizon of three Oxisols of the state of Paraná, Brazil, on the soil pH, dissolved organic carbon (DOC) and soluble and exchangeable […]

The spectroscopic characterization of humic substances in soil has been widely used. However, few studies have been carried out concerning the pedology of tropical soils using such technique. Humic acids (HA) extracted from contrasting horizons of a Red Yellow Latosol and a Podzol, on the highlands of the Serra do Brigadeiro, Araponga, Minas Gerais, were characterized by means of Fourier Transformed Infrared Absorption Spectroscopy (FTIR) and TD analysis. The spectra indicated qualitative differences between the HA extracted from differing soils, […]

The most probable number (MPN) for soil bacteria and fungi was determined using a micro-assay technique, which was more economical and less tedious. This technique was compared with the conventional procedure for counting soil microorganisms in soil samples with different textures. The sensitivity of this method could be also verified when used to evaluate number of microorganisms from different sources of organic matter and chromium added to the soil.

The excess of heavy metals contaminating soils is responsible for a negative impact on microorganisms and toxicity on plants, hence turning revegetation and rehabilitation of areas degraded by these metals very difficult. In the present study, the effects of the isoflavonoid formononetin (7 hydroxy 4’methoxy isoflavona) on growth and metal uptake by corn (Zea mays L.) were studied in soil-mixes with increasing proportions of a contaminated soil with 16.904; 194; 219 and 836 mg dm-3 of soil of Zn, Cd, […]

The adverse effects of the heavy metals on all living forms make rehabilitation of heavy metal-contaminated soils very difficult. In this paper, the effects of seedling inoculation with arbuscular mycorrhizal fungi (AMF) on post-transplant growth and metal uptake of five woody species: (Senna multijuga (L.C. Rich.) Irwin et Barneby (cássia verrugosa), Luehea grandiflora Mart. et Zucc. (açoita-cavalo), Enterolobium contortisiliquum (Vell.) Morong (tamboril), Albizia lebbeck (L.) Benth. (albizia) and Senna macranthera (Collard.) Irwin et Barneby (fedegoso)) in soil mixes containing increasing […]