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Agricultural activity is the major anthropogenic source of nitrous oxide (N2O) emissions from terrestrial ecosystems. Conservation agriculture including crop residue management can play a key role in enhancing soil resilience to climate change and mitigating N2O emissions. We investigated the effects of crop residue rates, including 100 % (R100), 50 % (R50), and residue removal (R0), on N2O emissions in corn-wheat rotation under conventional (CT) and no-tillage (NT) systems. The key factors evaluated affecting N2O emissions included soil temperature, soil moisture, soil ammonium, and soil nitrate concentrations. Results showed that the N2O emissions increased with the increasing rate of residue under both CT and NT systems. Both R100 and R50 significantly (p <.05) increased the N2O emissions compared to R0 during the annual rotation cycle. Soil moisture and mineral nitrogen (ammonium and nitrate) were the main driving factors that stimulated N2O emission in both CT and NT systems. In the NT and CT systems, cumulative N2O emissions showed a significant increase with R50 (+75.5 % in NT, +36.5 % in CT) and R100 (+134 % in NT, +40 % in CT) as compared to R0. Furthermore, no significant differences were found between R100 and R50 in the CT system, while in the NT system significant increases were observed for R100 compared to R50. Overall, our study justified as a first approach only during the first year that crop residue removal led to decreased N2O emissions under semi-arid conditions. However, due to the deteriorating impact of crop residue removal on crop productivity and soil C sequestration, this management method cannot be considered a sustainable agronomic practice. We suggest long-term studies to determine the appropriate rate of postharvest crop residue to achieve less N2O emissions and climate-friendly agricultural practices. [ABSTRACT FROM AUTHOR]

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 % (R 100), 50 % (R 50), and residue removal (R 0) - on carbon dioxide (CO 2) 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 CO 2 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 CO 2 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 CO 2 efflux, where R 100 and R 50 resulted in 36 % and 25 % higher cumulative CO 2 efflux, respectively, than R 0. In contrast, there was no significant difference in cumulative CO 2 efflux among the crop residue retention (R 100 and R 50) and removal (R 0) treatments under the NT system. Our study revealed that crop residue retention led to increased CO 2 efflux under the CT system in semi-arid conditions during the first year of application, while under the NT system, CO 2 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. • CO 2 emissions are correlated with soil temperature and microbial biomass carbon as well as with crop residue. The crop residue treatments affect these traits. • Full retention of crop residue mitigates CO 2 emissions under the no-tillage system. • The implementation of the results improves the conservation of soils' productivity, and fights climate change. [ABSTRACT FROM AUTHOR]