Energy budgeting and carbon footprints of three tillage systems in maize-wheat sequence of north-western Indo-Gangetic Plains

Abstract

Intensive tillage often contributes to yield gains but there is a tradeoff with energy consumption and carbon footprint (CF) challenging agricultural and environmental sustainability. Studies in the past examined the effect of tillage practices on one or two of the metrics viz., crop productivity or energy auditing or CF and a comprehensive evaluation of the three in a single study to identify cleaner and climate-smart production practice is generally lacking. This study quantified the effect of conventional (CT), deep (DT) and no-tillage (NT) with and without straw mulch on energy budgeting, crop productivity, CF and greenhouse gas intensity (GHGI) in maize-wheat sequence in a split plot design field experiment. No-tillage in maize curtailed energy input by 38.4% and 20.1% compared to DT and CT, respectively. Per tonne of maize grain production, NT with mulch (NTM) saved 1044 MJ of energy (41%) and increased grain yield by 35.3% compared with CT without mulch (CTM0). Although grain yield and net energy gain was higher under DT with mulch (DTM) than NTM, yet latter resulted in significantly higher energy productivity and energy use efficiency. Minimum C equivalent emissions and maximum gain in soil organic C in NTM lowered the CF resulting in highest C efficient and sustainable management. Minimal GHGI without yield penalty was achieved by adopting NT with mulching. Energy and C budgeting revealed that NT coupled with mulching is the most energy and C efficient practice followed by DTM; CT without residue retention is the least efficient management practice for intensively cultivated maize-wheat system in north-western Indo-Gangetic Plains.