Impact of conservation tillage on soil health and maize-wheat cropping system productivity

Abstract:

Leading soil scientists have long argued that the plough is both agriculture's oldest tool and its greatest threat to long-term soil productivity. This research evaluated four tillage systems, Conventional Tillage (CT), Minimum Tillage (MT), Zero Tillage (ZT), and Zero Tillage with Residue retention (ZT+R), over three consecutive years (2020-2023) in a maize-wheat rotation at the Institut Pertanian Sumatera research farm, Medan, North Sumatra. A randomised complete block design with four replications was used. After three years, ZT+R raised soil organic carbon from 0.68% to 1.04%, increased aggregate stability by 47%, and improved water-holding capacity by 22% relative to CT. System productivity (maize + wheat yield) under ZT+R was 10.90 t/ha in year three, compared with 8.55 t/ha under CT, a 27.5% gain. CT showed a declining yield trend, while ZT+R showed steady improvement. These results indicate that retaining crop residues under zero tillage can reverse soil degradation and lift productivity in tropical maize-wheat systems.