Resistência mecânica à penetração de um argissolo amarelo distrófico típico sob diferentes sistemas de produção em plantio direto

The determination of the penetration resistance (RP) of a typical Hapludalf was accomplished in 1997, in Pelotas (RS), Brazil (31o49'S and 52o30'W). The study consisted of eight treatments with different cover crops, under rotation and succession under no-tillage. The samplings were accomplished up to the depth of 0.60 m and soil water content were accomplished in the layers of 0.00-0.10; 0.10-0.20; 0.20-0.40 and 0.40-0.60m. Starting from the obtained results it was concluded that the production systems presented values of RP more elevated until to 0.20m; the treatment rye-grass/common bean, oat/soybean, vetch/corn presented the largest values of RP along the soil profile.