Impact of conservation agriculture and weed management on carbon footprint, energy efficiency, and sustainability in maize-wheat cropping systems

This study assesses the impact of conservation agriculture (CA) and weed management practices on the productivity, profitability, energy use, and carbon sustainability of a maize-wheat cropping system. Fifteen treatment combinations, incorporating five tillage methods (conventional-till maize and wheat [CT-CT], conventional-till maize and zero-till wheat [CT-ZT], zero-till maize and zero-till wheat [ZT-ZT], zero-till maize and zero-till plus residue in wheat [ZT-ZTR], and zero-till plus residue maize and wheat [ZTR-ZTR]) and three weed management practices (recommended herbicide [H-H], integrated weed management [IWM-IWM], and hand weeding [HW-HW]), were tested in a strip plot design. The results showed that ZTR-ZTR significantly increased system productivity (6.90 Mg ha(-1)), net returns, and benefit-cost ratio (BCR; 2.69), compared to CT. However, CT systems had 173 % higher energy use efficiency (EUE) and 170 % higher energy intensity (EI) than CA systems. CA-based treatments used about 15 % direct renewable energy and 85 % indirect renewable energy, while CT systems used 15-20 % direct non-renewable energy and 85-86 % indirect non-renewable energy. Among weed management practices, recommended herbicides (H-H) led to the highest productivity (6.71 Mg ha(-1)), EUE (9.80), net returns (3003 US$ ha(-1)), and BCR (3.08), but also higher carbon footprints. This underscores the balance between productivity, energy efficiency, and carbon in agriculture.