Comparative analysis of tillage in sandy clay loam soil by free rolling and powered disc harrow

A single-acting (3 × 3) 510 mm powered disc harrow was developed to achieve timeliness in operation in the extensively followed rice-wheat cropping system by reducing tillage passes with the proper incorporation of residues left after rice cultivation. Experiments were carried out at forward speeds of 3.69, 4.67 and 6.55 km h⁻¹ corresponding to speed ratios of 4.74, 3.75 and 2.67, respectively and at 90, 120 and 140 mm operating depths in sandy clay loam soil having an average moisture content of 12 ± 0.75% (db) and cone index of 930 ± 40 kPa. Its comparison was also made with conventional free rolling disc tilling which generally requires more passes. Optimum performance in terms of tillage performance index was achieved at speed ratio of 3.75 with a reduction in draft, slip, and clod size by 30–36%, 53.47–72.25% and 39.20–60.73%, respectively at the cost of 14.28–18.40% increase in fuel consumption (l ha⁻¹) when operated at depth of 120 mm as compared to free rolling mode indicating better energy utilization. Effect of multiple passes of tilling on soil compaction beneath the tillage depth (100–200 mm) was also studied from separate experiments. Soil compaction was observed to be 4.71–7.17% and 5.21–6.86% lesser as compared to that obtained with rotavator after first and second passes of tillage, respectively. However, it was about 0.38–3.00% and 3.00–5.32% more compared to free rolling disc tilling after first and second passes, respectively. Reduced number of passes required for preparing seedbed with powered disc justifies its use for carrying out the tillage.