Effects of Conservation Agriculture on Soil NO Emissions and Crop Yield in Global Cereal Cropping Systems.

Conservation agriculture, which involves minimal soil disturbance, permanent soil cover, and crop rotation, has been widely adopted as a sustainable agricultural practice globally. However, the effects of conservation agriculture practices on soil NO emissions and crop yield vary based on geography, management methods, and the duration of implementation, which has hindered its widespread scientific application. In this study, we assessed the impacts of no-tillage (NT), both individually and in combination with other conservation agriculture principles, on soil NO emissions and crop yields worldwide, based on 1270 observations from 86 peer-reviewed articles. Our results showed that conservation agriculture practices significantly increased crop yield by 9.1% while significantly reducing soil NO emissions by 6.8% compared to conventional tillage (CT). These mitigation effects were even greater when NT was combined with other conservation agriculture principles, such as crop residue retention and crop rotation, leading to reductions in NO emissions of over 15% and yield increases of more than 30%. Additionally, conservation agriculture was more effective at mitigating soil NO emissions in dry climates compared to humid regions. Long-term adoption of conservation agriculture practices was found to reduce soil NO emissions by up to 26% without compromising crop yields. Smallholder farm in Central Asia, South Asia, and sub-Saharan Africa appear particularly suitable for the adoption of conservation agriculture, whereas, in humid climates, high nitrogen (N) input management and silt-clay loam soil should be applied with caution. Overall, conservation agriculture holds significant potential for mitigating soil NO emissions while enhancing grain yields in cereal cropping systems.