An experiment was carried out with crop and cattle rotation in an Oxisoil, in Tupanciretã - RS, which aimed to evaluate the draft effort in fertilizer direct drillings used in direct seeding, working at different depths and intensities of fields under different grazing pressures. Grazing pressure effects on soil compactness were also assessed. The main treatments were grazing maintaining 0.10, 0.20, 0.30, 0.40 m pasture (Lolium multiflorum + Avena strigosa) without grazing, height (adjusting the number of cows on the plots) and two working depths of fertilizer shanks: 0.12 m and 0.15 m. Root dry matter in the superficial layer (0.0 - 0.12 m) was increased when higher grazing pressures were used. Soil resistance to a penetrometer showed increased values at higher grazing pressures; it was detected until 0.12 m depth. Draft requirement of fertilizer shanks increased from 1,900 to 4,300 N (120%) when the working depth changed from 0.12 m to 0.15 m condition. Draft demand by fertilizer shanks was higher on soils under higher pressures as well, but the absolute values showed that only treatments with remaining heights of 0.10 and 0.20 m were different from those found without grazing systems. Soil resistance to penetrometer and power demand by fertilizer shanks was closely related.
no tillage; seed drill; furrow opener
