Agricultural soils under no tillage systems are affected by soil compaction caused by machinery traffic, which can restrict root growth and reduce crop yields. The purpose of this study was to evaluate the effect of different compaction levels on the physical quality of a Red Latosol (Oxisol), sandy-loam, in the Jaboticabal county, São Paulo state, Brazil, under corn, using multivariate analysis. The experimental design was completely randomized with six compaction levels and four repetitions. Undisturbed soil samples were collected in […]

Electrochemistry and organic matter concentrations in the surface horizons of Oxisols are closely related. This study evaluated the electrochemical properties in the surface horizon of seven Brazilian Oxisols after the removal of humic substances by alkaline extraction. Based on their mineralogy the soils were grouped as kaolinitic or oxidic. Less than 3 % of the total organic matter were soluble humic substances extractable by NaOH 0.1 mol L-1, indicating their strong specific adsorption to the inorganic mineral sites. The removal […]

Besides the direct nutritional effect of mineralization of organic matter or by biological nitrogen fixation activity, the humic substances and endophytic diazotrophic bacteria can directly influence plant metabolism, modifying plant growth and development patterns. The purpose of this study was to evaluate the effect of the combined use of humic acid (HA) and Herbaspirillum seropedicae, an endophytic nitrogen-fixing bacteria, on the root growth of seed pieces – heat-treated or not – of the sugarcane variety RB 72 454. After hot […]

Due to the building of the Hydroelectric Power Plant of Ilha Solteira, in the late 60s, some areas have been deforested and were used as “loan areas”. Thus, the soils belonging to these locations were subtracted and these areas’ physical, chemical and biological properties became inappropriate. This work aimed at evaluating the use of chemical and organic fertilization to improve the degraded subsoil and replanting with mycorrhizal Stryphnodendron polyphyllum (“barbatimão”). The area is located at the Experimental Station (FEPE), UNESP/Ilha […]

The recent shift in soil tillage from conventional to no-tillage systems in Brazil alters the soil system dynamics. In soils cultivated under the no-tillage system the relations are established and preserved over the course of time, which increases the functional complexity of the system, while under the conventional system often destroys these relationships. Some questions have risen about the reliability of sampling the so-called “arable soil layer” (0-20 cm) for soil acidity quantification in the no-tillage system due to the […]

Land degradation in semiarid regions is a result of natural processes that can be induced or intensified by man through the inadequate use of natural resources, resulting in the degradation of vegetation, soil and water resources. Aiming to relate vegetation and soil degradation processes in the Agreste region of Pernambuco State, soil and vegetation in twelve representative plots were characterized as preserved, moderately degraded and degraded environments in the municipality of Jataúba. To study the vegetation, plants were stratified in […]

Selenium (Se) retention by soil colloids is an important process to maintain the environmental quality. Little information is available on Se adsorption in highly weathered tropical soils, and there are few numerical parameters that can be used as references to aid on adoption management strategies in contaminated areas. Increasing amounts of Se (5, 10, 25, 50, 100 and 250 mg L-1), added as Na2SeO3, were equilibrated with samples of ten Brazilian Oxisols [three Typic Hapludoxes (TH-1, TH-2 and TH-3), two […]

The presence of a groundcover in-between tree rows in orange orchards can affect the water uptake and physiology of the orange trees. The objective of this study was to characterize the relationships between the physiological variables of orange leaf and soil water content in a Paleudults in groundcover management systems with bahiagrass (Paspalum notatum), leguminous perennial peanut (Arachis pintoi) and spontaneous vegetation. The study was performed in in an experimental “Pêra” orange orchard established in 1993 in Alto Paraná, northwestern […]

In the soil, forms and content of water-soluble carbon (WSC) are influenced by factors such as organic matter quality and content, soil acidity, nutrient availability, mineralogy, and aspects related to the microbial community. This study aimed to evaluate forms and quantities of carbon (C) in leachates from Latosols (Oxisols) with different Fe contents, amended with lime and/or phosphorus. Samples of mesoferric Red Latosol (LV1) and hypoferric Red Latosol (LV2) were collected in the Rio das Mortes wathershed, state of Minas […]

The new techniques proposed for agriculture in the Amazon region include rotational fallow systems enriched with leguminous trees and the replacement of biomass burning by mulching. Decomposition and nutrient release from mulch were studied using fine-mesh litterbags with five different leguminous species and the natural fallow vegetation as control. Samples from each treatment were analyzed for total C, N, P, K, Ca, Mg, lignin, cellulose content and soluble polyphenol at different sampling times over the course of one year. The […]