Crop residue in direct contact with the soil surface is very effective in dissipating the energy of raindrop impact on soil, being also a physical barrier against interrill overland flow. The presence of these residues may strongly affect the interrill soil erosion process. A study was carried out with the objective of evaluating the relationship between interrill erosion and amounts of crop residue in direct contact with soil surface and to verify the differences in this relationship for corn and […]

The objective of this study was to evaluate the relation between the chemical composition of litter accumulation and its effect on the physics and fertility of soil in two plantation systems of native forest species. 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, evaluated from August 1994 through November 1996. As a […]

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 […]

Three series of experiments were carried out. In the first, the effects of N, Mo, and rhizobium were studied at two municipalities; in the second, conducted at another municipality, a factorial with four rates of N (0, 30, 60, and 90 kg ha-1) and four rates of Mo (0, 40, 80, and 120 g ha-1) was studied; and in the third, at six municipalities, the following combinations of N at planting time (kg ha-1), N as side dressing (kg ha-1) […]

This work aimed to measure and analyze total rainfall (P), rainfall intensity and five-day antecedent rainfall effects on runoff (R); to compare measured and simulated R values using the Soil Conservation Service Curve Number method (CN) for each rainfall event; and to establish average R/P ratios for observed R values. A one-year (07/01/96 to 06/30/97) rainfall-runoff data study was carried out in the Capetinga watershed (962.4 ha), located at the Federal District of Brazil, 47° 52′ longitude West and 15° […]

A greenhouse experiment was carried out to evaluate the effect of urban waste compost on soil fertility and on total and extracted contents (DTPA 0.005 mol L-1 pH 7.3) of the elements Fe, Mn, Zn and Ni in a sandy Red-Yellow Podzolic soil (Ultisol). The yield of dry matter of Sorghum bicolor plants and the content of P, K, Ca, Mg, Fe, Mn, Zn and Ni were evaluated in plant tops as a function of compost rates of 0, 12.5, […]

Tensiometers were installed in a 25 m2 area plot, every 15 cm, at depths varying from 30 to 240 cm, with three repetitions, to determine the matric potential (φm) of a “Terra Roxa Estruturada Latossólica” soil. Its volumetric water content was also indirectly measured by using the soil water retention curve. The θ-method (Libardi et al., 1980) fitted the soil redistribution profiles (θ vs t) with determination coefficients (R2) greater than 0.98. The hyphotesis of a unit hydraulic gradient was […]

The diffusive flux (diffusion) is the main form of zinc transport in soil, due to its low concentration in solution. This work aimed to evaluate the diffusion of Zn in samples of three soil types: a loamy texture Dark-Red Latosol (LE), a medium texture Red-Yellow Podzolic (PV), and a sandy texture Red-Yellow Latosol (LV). The diffusion was assessed in samples with the natural pH for the three soil samples and at pH 5.40 for the LE and 6.00 for the […]

This paper describes a technique that retrieves soil moisture from monopolarized SAR data. The technique uses SAR data obtained by the Japanese Earth Resources Satellite (JERS-1) and two empirical models. One relates the backscatter coefficient with the complex permitivity (Dubois’s model), and the other relates the complex permitivity with soil parameters such as soil moisture (Hallikainen’s model). First, the SAR data were calibrated to obtain the backscatter coefficient and the Dubois’s model was inverted to achieve the complex permitivity. The […]

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. […]