The present study aimed to evaluate the effect of the vegetation type and the sampling time on urease activity in two different tropical soils (Rhodic Oxisols). The experiment was installed in a typic alumino-ferric Red Latossol and a typic distrophic Red Latosol under five different vegetations: pinus, eucalypt, citrus, soybean and corn. The soil samples were collected from April 1990 to March 1991 and the urease activity, total nitrogen and organic carbon were determined. The urease activity changed according to […]

Nitrogen (N) is the nutrient taken up in the largest quantity by corn and it has the greatest effect on grain yield. Its dynamics in the soil-plant system is influenced by the management. The aim of this study was to evaluate nitrogen rates and application times in corn in a recently implanted no-tillage system. This study was conducted at the Experimental Station of UNESP/FEIS – Ilha Solteira campus in Selvíria, State of Mato Grosso do Sul, Brazil, during the growth […]

This study was carried out to evaluate chemical changes and corn growth in an Albaqualf soil.The tannery wastes used were primary sludge with Cr at the rates of 13.8 and 27.6Mgha-1 corresponding to 250 and 500mgkg-1 of Cr soil, respectively, and the sludge from liming, at the rates of 10.25 and 20.50Mgha-1. The experiment was conducted in a greenhouse during 108days.The liming sludge increased pH (4.9 to 5.8), soil Ca (0.5 to 3.2cmolcdm-3) and resulted in corn yields similar to […]

The aim of this work was to evaluate the effects of human intervention, i. e., jungle clearing and introduction of pasture (Brachiaria sp), on the total-N and organic-C contents and humic acids, fulvic acids and humina fractions. This research was carried out in a forest near Porto Velho – Rondônia (Amazo Forest) and Senador Canedo – Goiás (“cerrado”). The soil samples were collected in 1995, from areas of primary vegetation and planted pasture, obeying a line with 24 points every […]