The microenvironment near the seed is directly affected by the type of mechanism of furrow opening and the soil compacting element. This study was therefore carried out to evaluate the soil density close to the seed in a no-till system using computerized tomography. The experiment was set up in a split-plot design in which the plots consisted of three soil water contents (0.22; 0.28; and 0.34 kg kg-1), and the subplots of two mechanisms for furrow opening (stub runner and double disk-type). […]

Chisel plowing in-between rows of sugar cane ratoon, associated with fertilizer and harrowing (triple cultivation) is a common practice to reduce soil compaction, but little is known about its effects on ratoon rooting. The purpose of this study was to evaluate the effects of post-harvest chisel plowing on the physical properties of an Oxisol, root distribution, and yield. The experiment was set up in an Arenito Caiuá Soil and used the third ratoon of RB72454 sugar cane variety. The treatments […]

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. […]

This study aimed to evaluate physical and chemical alterations in a distrophyc Yellow Argisol (Ultisol) presenting loamy to clayey texture and a smooth relief, under different use at the “Favo de Mel” settlement, Sena Madureira county, Acre State, Brazil. At the beginning of the rainy season (October 1999), soil material was collected in the following land use: native forest (control), recently deforested (slash and burn); a two-year old crop of palm tree (Bactris gassipae); and a four-year old Brachiaria (Brachiaria […]

The soil bulk density of undisturbed samples was evaluated using computed tomography and paraffin-sealed soil clod techniques, with the objective of identifying soil compaction processes and to compare the applied methodologies. Data were also used to complement a soil classification survey for irrigation purposes. Samples were collected from soil profiles of the semi-arid region of Petrolina (PE), Brazil, from the soil surface down to a depth of 1 m, in 10 cm layers. Two distinct areas were chosen: (1) native […]

Acid drainage, resulting from sulfide oxidation, is an environmental problem which may impair soil and water sources quality. Such impact may occur in several environments, but it is commonly related to coal mining. This work was carried out to study the kinetics of pyrite oxidation in coal mining spoil from Candiota (RS) Brazil, under different conditions of atmospheric O2 access and pH. The study aimed to evaluate the possibility of adjusting carbonate dissolution rate to the sulfide oxidation rate in […]

Undisturbed samples of representative horizons of soils from Jaíba Project, northern Minas Gerais, Brazil, and compacted and non-compacted layers of soils under intensive use were collected and micromorphologically analyzed to obtain more information on their evolution degree and also to evaluate the soil alterations caused by agricultural use. Four soils derived from limestone (P1 to P4) and one originated from detritic sediments (P5) were studied, as well as layers with and without indication of compaction. The micromorphological study revelead that […]

A soybean crop experiment using samples from a sandy Dark Red Latosol was conducted in a greenhouse at the Universidade Federal de Uberlândia, Minas Gerais, Brazil from July/1996 to February/1997, to evaluate the effects of inoculation and subsoil compaction on the shoot dry matter production (ADMP), root dry matter production in the superior ring of the column, and nitrogen absorption and concentration in soybean shoots.. The treatments were set in a 2 x 3 x 4 factorial design and corresponded […]

Soil pans caused by tillage operation may restrict root growth thus reducing yield. Physical properties of soil such as bulk density and soil strength have been used as parameters for management decision in order to promote root growth. This work was carried out to evaluate the relationship among these soil parameters and root growth, in a 7 year field experiment with five soil tillage systems and soybean (Glycine Max L.). The tillage systems combined summer and autumn tillage with disk […]

High phosphate adsorption in oxidic tropical soils changes the charge balance on the surface of particles and can increase dispersion. Consequently, it can affect pore size distribution, aggregate stability and susceptibility to compaction. In order to measure the effect of phosphate sorption on compression curves and consistence limits, a Dark-Red Latosol (LE) (very fine, allitic, isothermic Typic Hapludox) and a Cambisol (C) (very fine, isothermic Oxic Distropept) were sampled at 0-3 and 27-30 cm depth, at Campos da Mantiqueira, Minas […]