Comparative assessment of energy requirement and tillage effectiveness of combined (active-passive) and conventional offset disc harrows

The combination of active and passive tillage tools has been acknowledged as an effective way of dealing with the soil compaction, due to reduced field trips required for preparing seedbed compared to conventional practices. A comparative analysis was carried out between an active-passive configuration of combined offset disc harrow (CODH) and conventional passively-driven mode of offset disc harrow (ODH) in sandy clay loam soil to achieve maximum tillage quality with a minimum expenditure of power. The test parameters consisted of: forward speeds (3.46, 4.55, and 6.82 km h−1), rotational speeds of front gang axle (95, 133, and 150 rpm), and working depths (80, 120, and 145 mm). Better penetration ability and uniformity in tilling depth was observed with CODH compared to passively-driven ODH. The soil pulverizing ability, stubble cutting, and crop residue burial efficiency (CRBE) was observed to be better with CODH compared to passively-driven ODH. The CODH exhibited best tillage performance index at rotational speed of 133 rpm, at which draught requirement and the corresponding driving wheel slip were witnessed to be reduced by 50.73–55.01% and 68.70–79.55%, respectively as compared to free rolling ODH, whereas, fuel consumption per tilled area and specific energy were increased by 0.06–25.53% and 4.07–37.11%, respectively. Furthermore, the soil cone index (CI) and clod size were reduced by 14.29–46.90% and 14.88–43.73%, respectively and the CRBE was increased by 11.36–100%. The results indicate that the active-passive CODH outperformed the conventional passively-driven ODH with respect to both energy consumption and quality of soil tilth.