Soils chemical fertility in pastures formed by native species and Brachiaria decumbens managed with annual fire

Abstract

The aim of this paper was to study the chemical fertility of soils under pastures submitted to more than 10 years to different managements with different levels of technology. The study was conducted in four areas: 1) area with 12 years of native pasture with burning every three or four years, 2) area with 12 years of native and Brachiaria decumbens pasture with burning every two or three years, 3) area with 13 years of native pasture managed with annual burning and 4) area with 10 years of Brachiaria decumbens pasture, fertilizing and liming every 4 years, without burning. These areas were collected 10 soil samples from completely random, at depths 0-5, 50-10, 10-15, 15 - 20 and 20 to 30 cm for determination of pHH2O, CTCpH7,0, V%, m% , the P, K, Ca+Mg and organic matter. The comparison among treatments was done by Student-t test (p = 0.05). The results showed that the Brachiaria decumbens management showed the best results regarding the analyzed soil attributes. The managements native burned every two years, and a mixture of native and Brachiaria decumbens and burned every three years, showed no differences in the soil analyzed attributes. Native pasture management with annual burning caused the lowest values of organic matter.