24 results

Morfological and physical transformation in a clayey oxisol under pastures

G. A. F. Fregonezi, M. Brossard, M. F. Guimarães, C. C. Medina

01/Dec/2001

This study was carried out in the Western region of Minas Gerais, Brazil to evaluate the morphological changes in a Yellow-Red Latosol, after a conversion of a 20 year old Brachiaria decumbens pasture, under intensive pasture systems; a pure Brachiaria decumbens and an association of this grass with the legume Stylosanthes guianensis. Through morphological and physical characterization, it could be concluded that: (a) there were structural obstructions to radicular development in the old pasture soil; (b) the soil macrofauna played […]

Alterations of the physical properties of a dark-red latosol (typic Acrustox) under different crops

A. Cavenage, M. L. T. Moraes, M. C. Alves, M. A. C. Carvalho, M. L. M. Freitas, S. Buzetti

01/Dec/1999

The present work had the objective to analyze the alterations of the physical properties of a dark-red Latosol (typic acrustox), under different use systems. In 1996, samples of soils were collected, under corn crop, pinus, eucalyptus, pasture, ciliary forest (after 10 years of cultivation), and native cerrado vegetation, in three depths (0,00-0,10; 0,10-0,20, and 0,20-0,40 m), in the experimental station from Faculdade de Engenharia de Ilha Solteira – UNESP, located in Selvíria county (MS). The experimental design was the totally […]

Characterization of the physical and hydraulic properties of the soil “Terra roxa Estruturada Latossólica” by the instantaneous profile method

A. C. S. da Costa, P. L. Libardi

01/Sep/1999

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 […]

Soil physical properties in no-tillage influenced by liming, previous tillage and traffic

C. A. Tormena, G. Roloff, J. C. M. Sá

01/Jun/1998

In the no-tillage system, the absence of soil revolving, combined with the traffic of machines, promotes excessive soil surface compaction. An experiment was conducted in the county of Ponta Grossa, State of Paraná, Brazil, during the agricultural years of 1989/1990 and 1990/1991, with the objective of studying several factors that intervene in this process. This research compared the effects of three previous soil tillage methods and two liming levels on several physical properties of a clayey Dark Red Latosol under […]

1 2 3