GROUND COVER PLANTS AND QUALITY OF PLANT RESIDUE DURING NO-TILL IMPLEMENTATION IN A DRY-WINTER REGION

Under tropical climate , temperature and humidity are high. In the selection of species destined to ground cover plant, under no-till system, the amount and quality of plant residue should be considered. The objective was thus to evaluate the amount and quality of residues of different ground cover plants, produced in a short development period, under no-till system at the implementation stage in a dry-winter region. The experiment was conducted during the 1999/2000 cropping seasons at Experimental Farm of São Paulo State University-Botucatu (SP), on a Red Nitosol. The experimental design was organized as random blocks and four replicates. Plots consisted of : 1- Sorghum bicolor (L.) Moench (Guinea group), cultivars A, 2- Sorghum bicolor (Guinea group), cultivars B, 3- Pennisetum glaucum (L.) R. Br., cultivars BN2, 4- Panicum dichotomiflorum Mix. and 5- spontaneous vegetation. Ground cover plants were desiccated at 53 days after emergence, were evaluated for dry matter production, content and accumulation of macronutrients, and C/N ratio, in addition to chemical composition, sum of cations (Ca, Mg, Mn, K, and Na), and electric conductivity of plant extracts from the aerial part. Pennisetum glaucum in the summer season showed high potential for dry matter production, trash persistence, and nutrient recycling in a short development period. Panicum dichotomiflorum showed the possibility of yielding a grain harvest. Sorghum bicolor (cultivars A and B) was prominent as the most effective residue in neutralizing H+Al and regarding Ca and Mg accumulation in the soil profile