Volume 28, Number 3, 2004

The heterogeneity in soil compaction induced by different traffic intensities can reduce the productivity of citrus trees. The objective of this research was to quantify the compression index (CI) and the preconsolidation pressure (sp) in different sampling positions (row, between wheel track, wheel track, and canopy projection) to evaluate the compaction heterogeneity in a Haplustox under an orange orchard. The sampling was carried out at forty randomly distributed sites (ten samples in each position). The samples were water saturated and […]

Soil physical quality in continuous and short-duration rotational cattle grazing systems was evaluated using the Least Limiting Water Range (LLWR) approach. Soil samples were collected on an experimental site at the Embrapa – Beef Cattle Research Center (Campo Grande, MS, Brazil). The studied soil was a Typic Acrudox. Four sampling sites were selected: two under a short-duration continuous grazing system and two under intensive short-duration rotational grazing system. Thirty soil cores were collected in each site under the continuous grazing […]

Iron deficiency in coffee plants cultivated in ferric Latosols may be induced by conditions that affect the transport of this nutrient in soils, such as P concentration, high pH values and low soil moisture content. The iron diffusive flux (FeF) in soils was evaluated as a function of P rates and levels of acidity and moisture. Surface soil samples of a clayey dystroferric Red Latosol and a loamy-sand dystroferric Yellow Red Latosol were supplied with 20 mg dm-3 Fe as […]

The alluvial soil of the Assunção Island, in the São Francisco River, Cabrobó, State of Pernambuco, Brazil, has been intensively cultivated with annual crops under irrigation. The present yields are unsatisfactory due to the use of inadequate agricultural practices that are not sustainable. This study aimed to survey the soil chemical properties in an area of 1,131 ha by collecting 1,053 samples in the 0-0.30 m surface soil layer. The samples were analyzed for chemical properties and the data were […]

Late season potassium (K) deficiency has been observed quite frequently for cotton crops in the Brazilian cerrado region. One possible reason for such a problem could be the low water availability at this period of the season. Thus, an experiment was conducted in order to quantify the relative contribution of mass flow and diffusion in supplying K to cotton roots, as affected by soil water and K availability. The arable layer of a typic Red Latosol (Haplortox), with 630 mg […]

A field trial was carried out to evaluate the effects of nitrogen and potassium top dressing on upland rice. The treatments consisted of a 5 x 3 factorial design (five nitrogen doses – 0, 25, 50, 75, and 100 kg ha– and three potassium doses – 0, 25 and 50 kg ha-1), arranged in a complete randomized design, with three replicates. The results showed that several yield characteristics were positively influenced by nitrogen and potassium fertilization. The best combination of […]

The diversity of ecosystems in southeastern Brazil can not always be related to edaphic, geomorphologic, or hydrologic factors. Mountain summits, where soils are characterized by common parent material, offer a special environment for studies of soil genesis and dating of cyclic events related to regional climate dynamics. After a detailed investigation of soils from the São José Hills (Prados – Minas Gerais State, Brazil), two soil profiles (P1 and P2) originated from arenite of the Tiradentes Formation were studied. They […]

Given the importance of cohesive soils derived from sediments of the Barreiras Formation, and the extensive area occupied by them in northeastern Brazil, the objective of this study was to identify and characterize the occurrence of cohesive soils in Coastal Plains of Ceara State. Three soil profiles were studied: two cohesive Argisols and one non-cohesive Argisol. Their morphological characteristics and physical, chemical, and mineralogical properties were assessed to confirm the presence of cohesive horizons. The results validated the hypothesis of […]

Root growth is affected by mechanical soil resistance and affects the crop yield potential. This study evaluated the soil penetration resistance on a clayey Oxisol under distinct no-tillage cropping systems. The experiment was carried out at the technological field of Cotrijui in southern Brazil. The soil was a Haplorthox with a clay content of 0.68 kg kg-1 and it has been under four no-tillage cropping systems: succession soybean/wheat; corn/black oat/corn + velvet bean/wheat/soybean/wheat; velvet bean/wheat/soybean/ wheat/soybean/black oat; and crotalaria/wheat/soybean/black oat/corn/wheat. […]

Inadequate soil management systems can lead to water erosion, nutrient losses and superficial water pollution, accelerating environmental degradation. The P and K losses caused by water erosion were evaluated from November 1999 to October 2001 in an Inceptisol with 0.102 m m-1 slope, in Lages, Santa Catarina State, Brazil, under natural rainfall conditions. The evaluated soil management systems were: no-tillage for six years (NT6), no-tillage for nine years (NT9), chiseling plus one disking for nine years (C + D9), and […]