Volume 23, Number 1, 1999

The variation of bulk density in a vertisol was studied by gamma-ray double bean tomography. Tomographic images of samples deriving from 137Cs and 241Am gamma-radiation were used, providing two attenuation equations which allowed the determination of two variables: bulk density and moisture. The samples, initially with the same bulk density, were submitted to different moistening degrees. The results showed that: (1) the system allowed a satisfactory moisture and bulk density determination; (2) volume of destructured samples varied around 23% from dry to […]

In a trial carried out at Santa Barbara, MG, Brazil, the influence of plant population on throughfall, crop evapotranspiration (ETc) and soil moisture regime of Eucalyptus grandis stands was evaluated. Plant population varied from 500 to 5000 trees ha-1. Soil moisture was measured down to a depth of 285 cm by a neutron probe, every 15 days. Rain water interception increased linearly with increasing plant population, whereas ETc was not significantly influenced. Soil moisture level tended to increase as plant population decreased. During […]

The objectives of this experiment were to identify differences in the total quantity of water stored in soil, storing capacity of water available to the plants and in the water consumption of maize plants cultivated in soils of different textures. The experiment was conducted at the experimental area of the Rural Engineering Department of the Federal University of Santa Maria during the 1995/1996 growing season. A set of 12 drainage lysimeters was used. These were 156 cm long, 100 cm wide and 80 cm […]

The objective of this experiment was to quantify variations in maize canopy of plants submitted to two water managements (irrigated and terminal soil water deficit) in clayey, loamy and sandy soils. The experiment was conducted at the experimental area of the Rural Engineering Department of the Federal University of Santa Maria during the 1995/1996 growing season. A set of 12 drainage lysimeters was used. These were 156 cm long, 100 cm wide and 80 cm deep and were placed under a shelter to avoid […]

Soil water infiltration rate may be the soil property which best reflects the general soil physical conditions, especially the structural quality. A field study was conducted at the Embrapa Trigo, Passo Fundo, Brasil in an Oxisol under long-term soil tillage systems, to evaluate the influence of these systems on soil water infiltration rate as a function of the soil cover and soil physical conditions caused by the different tillage systems. During a corn cropping period, a simulated rainfall with intensity of […]

Soil compaction process studies have more recently involved some soil tests frequently used in soil mechanics. Seeking a better understanding of the application of the Proctor normal test for agricultural purposes, this study aimed to evaluate the soil compaction curve, obtained through this test, and the effect of the degree of compaction on the soil moisture characteristic curves. For the development of this study, a Dusky Red-Latosol (LR), a Red Yellow-Latosol (LV) and a Dark Red-Latosol (LE) submitted to annual […]

Extraction and evaluation of active (AEM) and total (TEM) extraradicular mycelium is the first step in a comprehensive study of the interaction between host plant and arbuscular mycorrhizal fungi (AMF), since these hyphae are responsible for nutrient absorption and translocation from the soil to the host. Extraction methods for extraradicular mycelium in the literature were reviewed and reevaluated, and modifications were made, resulting in a new, simple technique. The evaluation and quantification method of AEM was tested using induced fluorescence […]

Different methods for quantification of active extraradicular mycelium (AEM) and total extraradicular mycelium (TEM) of arbuscular mycorrhizal fungi (AMF) were examined by conducting an experiment under greenhouse conditions, with a completely randomized factorial design and five replicates per treatment. The experiment was arranged in a 4 x 6 x 2 design and the factors were: 3 species of AMF (Glomus intraradices, G. etunicatum and G. clarum) and one control without AMF x 6 levels of P (0, 50, 100, 150, 200 and 250 mg kg-1) x 2 citrus species (Citrus reshni and […]

The aim of this work was to study the influence of residues of five Sorghum bicolor L. (cv CMS XS 376, CMS XS 365, BR 304, BR 700 and CMS XS 755) on soybean growth. These residues were harvested in three different stages during the sorghum cycle (blooming, milking and physiological maturity) and either spread on the soil surface or totally incorporated in soil, in the proportion of 4 g kg-1 of dry matter in the soil (a Dark Red […]

Two field experiments were conducted on a dystrophic Dark Red Latosol (Haplortox) to study the effects of lime, cobalt and molybdenum on chlorophyll contents in the leaves of peanut. Seed treatments (cobalt, molybdenum, cobalt + molybdenum and no treatment) were applied in two peanut cultivars (“Tatu” and “Tupã”) grown in four rates of lime (0, 4, 6 and 8 t ha-1), causing an increase in leaf chlorophyll contents either due to Mo or lime application. Chlorophyll contents in the leaves […]