Crop residues in corn-wheat rotation in a semi-arid region increase CO2 efflux under conventional tillage but not in a no-tillage system

Appropriate management of crop residue plays a key role in mitigating greenhouse gas emissions. However, it has been inadequately implemented in general agricultural management practices. In a field investigation using static chambers, we evaluated the effects of crop residue at three different rates - 100 % (R100), 50 % (R50), and residue removal (R0) - on carbon dioxide (CO2) efflux. The field study was conducted in corn-wheat rotation under conventional (CT) and no-tillage (NT) systems in a semi-arid region. The main results showed that CO2 efflux was positively correlated with higher soil temperature (0.43–0.79) and microbial biomass carbon (0.66–0.89). The crop residue treatments affected these traits. A strong positive relationship between CO2 efflux and the crop residue (R2 = 0.96, CT and R2 = 0.9 for NT) was observed. In the CT system, significant increases were detected among residue rates on cumulative CO2 efflux, where R100 and R50 resulted in 36 % and 25 % higher cumulative CO2 efflux, respectively, than R0. In contrast, there was no significant difference in cumulative CO2 efflux among the crop residue retention (R100 and R50) and removal (R0) treatments under the NT system. Our study revealed that crop residue retention led to increased CO2 efflux under the CT system in semi-arid conditions during the first year of application, while under the NT system, CO2 efflux was not impacted by crop residue. Our results indicate that there is considerable potential for improving soil management practices in the context of soil degradation, climate change, increasing crop productivity, and carbon (C) sequestration.Universidad de Granada/CBUAIran National Science Foundation (INSF