Volume 22, Number 4, 1998

The aim of this study was to test the effect of three methods of estimating the DRIS indices on the nutritional status of eucalipt plantations, based on the grouping of these indices by the Nutrient Application Potential Response Method. Nutrient concentrations of tree leaf, branch, stembark and stemwood, determined in 1986 trees of Eucalyptus grandis x E. urophylla hybrids growing in the States of Espírito Santo and Bahia, Brazil, were evalued by the methods of Jones, Elwali and Gascho, and […]

With the objective of evaluating the effect of exclusive supply of ammonium or nitrate, or both, on the growth of eucalypt seedlings, two experiments were carried out under greenhouse conditions. Eucalyptus urophylla and E. camaldulensis were cultivated in the first experiment and Eucalyptus pellita, E. grandis and E. cloeziana in the second. Initial growth (32 days) was carried out on washed sand bed. Then the seedlings were transferred to nutrient solution with three ammonium/nitrate ratios (100-0, 50-50 e 0-100%) where […]

Alternative methods to correct soil acidity are needed because farmers who adopted no-tillage no longer want to plow soils to incorporate lime. Two experiments were carried out during the years 1993-1996 under no-tillage to evaluate the response of soybean, wheat, corn, oat and barley to lime applied on the surface of soils with 380 g kg-1 clay (LEd-Haplorthox) and with 580 g kg-1 clay (LRd-Haplorthox). A completely randomized block design, with three replications and seven treatments, was used. The treatments […]

Data from 1.213 trees of Eucalyptus grandis x E. urophylla hybrids were collected between 1988 and 1994 from the Aracruz Celulose S.A. commercial plantation in the State of Espírito Santo, Brazil. Data on stand productivity and macronutrient concentration in four tree components (leaf, branch, stembark and stemwood) were used to determine the reference values of nutrient concentration by the methods of Mathematical Chance and DRIS. The formula of Jones and the population distribution based on age and selection of the […]

Six calcareous soil profiles (P1, P2, P3, P4, P5 and P6) were investigated with regard to their main characteristics of soil organic matter related to structural organization. The effect of degrading processes on these soils was also considered, mainly under intensive cultivation. Based on morphological in situ observation and analytical data, the profiles P1 e P2 showed organic matter with an advanced level of evolution presenting reasonable amounts of low polymerized materials (fulvic acids). Conversely, profiles P3, P4, P5 e […]

The success of soil conservation tillage systems to control water erosion is related to the amount of crop residue and percentage of soil surface coverage. Residue persistence after harvesting is important to maintain soil coverage, which affects soil physical-hydric properties and runoff. The study was conducted in Santa Catarina State, Brazil, with the purpose of evaluating oat and corn residue persistence on soil surface under no-tillage system. The trial was carried out from October of 1995 to December, 1996, using […]

No-tillage soil management does not permit incorporation of crop residues and requires surface application of fertilizers and corrective agents, thereby affecting nutrient availability and distribution. This study was carried out to evaluate the chemical changes in no-tillage system compared to conventional tillage and native grass field. Samples from a sandy/clay Red-Yellow Podzolic (Typic Hapludalf), taken at 0-5, 5-10, 10-20 and 20-40 cm depth, were used to determine zero point of salt effect (ZPSE), humic substances, permanent charge, soil pH, exchangeable […]

The effect of topdressed N on the dry matter production of no-till oat (Avena strigosa Schreb) planted onto native pasture, without desiccation with herbicides, in soil classified as Dark-Red Latosol (Haplorthox), was studied in three experiments. Experiment 1 was carried out in 1994 to evaluate the effect of rates of nitrogen (0, 20, 40, 80, 160, and 320 kg ha-1 ), split into three applications (1/3, 30 days after emergence of plants-DAE, 1/3 after the first cutting, and 1/3 after […]

In the tropical soil environment, raindrop impact is capable of disrupting natural soil aggregation and porosity, thus influencing the amount of infiltrated water and its redistribution. Under such conditions, a vegetation cover of weeds cannot be viewed simply as a crop competitor. This research project was designed to examine, under field conditions, the changes of soil properties, namely soil water content, structure and sealing, resulting from different types of weed management, with the aim of contributing to the establishment of […]

Simple linear correlations among runoff and rainfall erosivity parameters and soil losses caused by erosivity rainfall in Haplargids were studied. Data related to 1986-1990 were obtained in the Experimental Station at Sumé-Brazil. The rainfall erosivity parameters were the following: a) total height of the rainfall (P) in mm; b) maximum intensity (In): I5; I10; I15; I20; I25; I30; I35; I40; I45; I50; I55; I60 and I120 minutes in mm h-1, respectively; c) total kinetic energy by the Wischmeier & Smith’s […]