Effects of no-tillage, mulching, drip irrigation, and nitrogen fertilization on greenhouse gas emissions, soil carbon sequestration, and crop yields in dryland agroecosystems: A meta-analysis

Dryland agriculture contributes substantially to greenhouse gas (GHG) emissions, primarily due to flood irrigation, excessive nitrogen fertilization, and intensive soil disturbance. However, the influence of climate-smart agriculture (CSA) practices in mitigating GHG emissions under dry conditions remains inconsistent. This meta-analysis was conducted by reviewing 87 peer-reviewed papers to assess the impact of CSA practices, such as no-tillage (NT), drip irrigation (DI), plastic mulching (PSM), straw mulching (STM), and nitrogen fertilization (NFY), on soil organic carbon (SOC) content, global warming potential (GWP), GHG intensity (GHGI), and crop yields in arid and semi-arid agroecosystems. DI was the most effective single practice, reducing CO 2 , N 2 O, GWP, and GHGI by 9.8 %, 54.7 %, 9.5 %, and 10.6 %, respectively. Compared to conventional tillage (CT), NT with straw retention (NTS) significantly increased SOC content by 14.8 % and wheat yield by 5.2 %, while long-term (>5 years) NT reduced GWP and GHGI by 14.2 % and 14.1 %, respectively. Conversely, STM and high NFY rate increased GWP by 27.7 % and 41.5 %, respectively. Although the high NFY rate increased overall crop yield by 70.6 %, indicating at a substantial environmental cost. In contrast, a low NFY rate reduced GHGI by 42.6 %, suggesting a viable mitigation pathway. Overall, these findings underscore a fundamental trade-off between yield and emissions, indicating that integrating precise nutrient management, drip irrigation, and no-tillage with optimized residue retention can provide a synergistic strategy to enhance productivity while simultaneously mitigating GHG emissions in dryland agroecosystems.