A Meta-analysis of No-tillage Effects on Greenhouse Gas Emissions from Wheat-based Rotation Cropping Agroecosystem in China

Globally, agricultural soils are considered as one of the most important sources of greenhouse gas (GHG) emissions. No-tillage (NT), one of the most admired ways of climate-smart agriculture, has been deemed to have co-benefit to mitigation of GHG emissions and sustainability for crop yield, however, the effect of NT on GHG emissions is controversial. This study analyzed the overall effects of NT on GHG emissions, as well as the moderators that significantly influenced the overall effects, of the wheat-based rotation cropping systems in China through meta-analysis. The results showed that the overall effect size of NT on methane (CH4) uptake, nitrous oxide (N2O) emission, and global warming potential (GWP) was 0.70 (95% Confidence Interval (CI): 0.21–1.19), −0.27 (95%CI: −0.72–0.18), and −0.39 (95%CI: −1.01–0.23), respectively. In temperate climate zones with alkaline soils, the nitrogen application rate of 120–240 kg/ha, NT could significantly reduce GHG emissions and GWP. However, the mitigation effect will be weakened along with NT duration, except for proper straw addition. Overall, NT has the potential to reduce GHG emissions from wheat-based rotation systems in China, but it is necessary to implement NT depending on local conditions, soil characteristics, and field management.