Soil Fragmentation, Surface Roughness and Draft Force in Chisel Tillage with a Toothed Roller: Experimental and Analytical Study

Efficient seedbed preparation under conservation-oriented tillage requires balanced aggregate fragmentation, surface microrelief and energy demand. This study investigated the influence of passive toothed roller parameters on soil fragmentation, surface roughness, draft force and fuel consumption during chisel tillage under medium-loam Calcisol conditions. Three configurations were compared: a chisel plow without a roller, with a slat roller and with a toothed roller. An analytical framework describing aggregate capture, tooth–soil contact frequency and resistance formation was combined with field experiments and regression-based response surface analysis. The toothed roller improved measured soil treatment indicators compared with the no-roller and slat-roller configurations due to discrete tooth–soil interaction, localized stress concentration and repeated loading of loosened aggregates. Rational parameter ranges were identified: a roller diameter of 0.45–0.46 m, 13–15 teeth, transverse spacing of 8.0–8.6 cm, a tooth height of 7.5–8.5 cm and specific load of 0.9–1.1 kN m−1. Under the selected configuration, aggregates smaller than 50 mm increased from 76.1% to 88.0%, surface roughness decreased from 6.8 to 3.7 cm and residue retention remained above 60%. Fuel consumption increased to 28.4–28.5 L ha−1, reflecting the additional energetic cost of fragmentation and levelling. The approach supports rational selection of passive toothed roller parameters under the tested conditions.