1. The role of conservation agriculture practices in mitigating N2O emissions: A meta-analysis.
- Author
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Li, Yue, Chen, Ji, Drury, Craig F., Liebig, Mark, Johnson, Jane M. F., Wang, Zhaozhi, Feng, Hao, and Abalos, Diego
- Subjects
COVER crops ,NO-tillage ,CLIMATE change mitigation ,AGRICULTURE ,SODIC soils ,CARBON in soils ,CROP rotation - Abstract
Conservation agriculture is often assumed to reduce soil N
2 O emissions. Yet, studies analyzing the specific effect of conservation agriculture practices on N2 O emissions give contradictory results. Herein, we synthesized a comprehensive database on the three main conservation agriculture practices (cover crops, diversified crop rotations, and no-till and/or reduced tillage (NT/RT)) to elucidate the role of conservation practices on N2 O emissions. Further, we used a random meta-forest approach to identify the most important predictors of the effects of these practices on soil N2 O emissions. Averaged across all comparisons, NT/RT significantly decreased soil N2 O emissions by 11% (95% CI: –19 to –1%) compared to conventional tillage. The reductions due to NT/RT were more commonly observed in humid climates and in soils with an initial carbon content < 20 g kg–1 . The implementation of cover crops and diversified crop rotations led to variable effects on soil N2 O emissions. Cover crops were more likely to reduce soil N2 O emissions at neutral soil pH, and in soils with intermediate carbon (~20 g kg–1 ) and nitrogen (~3 g kg–1 ) contents. Diversified crop rotations tended to increase soil N2 O emissions in temperate regions and neutral to alkaline soils. Our results provide a comprehensive predictive framework to understand the conditions in which the adoption of various conservation agriculture practices can contribute to climate change mitigation. Combining these results with a similar mechanistic understanding of conservation agriculture impacts on ecosystem services and crop production will pave the way for a wider adoption globally of these management practices. [ABSTRACT FROM AUTHOR]- Published
- 2023
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