Soil fertility of cultivated pastures under different managements in the northwest Rio de Janeiro

摘要

Aiming to evaluate the effects of different grass species and management practices on soil fertility, an experiment was conducted in the municipality of Itaperuna, northwest part of Rio de Janeiro State. Three plots of 2 ha were divided in a Red Yellow Ultisol with a strong ondulating relief originally cultivated with Brachiaria brizantha. Besides the maintenance of this specie, the Tifton 85 (Cynodon spp.) and Suázi (Digitaria swazilandensis) were introduced, performing three treatments which received annual fertilization from the beginning of the experiment (2001). Nine soil samplings were done in three thirds of each plot (medium, inferior and superior) between April 2002 and May 2006. Soil samples of 1 dm3 were taken from 0.1 m to 0.7 m depths, with 2 repetitions per trench. Soil fertility attributes were analyzed and interpreted in each sampling time. The data show that, after the introduction of the new species, the rotationed management and the maintenance fertilization, the soil fertility attributes kept very close values without decreasing along time in the experimental area.