Antagonistic and synergistic interactions dominate GHGs fluxes, soil properties and yield responses to biochar and N addition
Xiaoyu Jia, Weiming Yan, Hongze Ma, Zhouping Shangguan
Abstract
Applying biochar to soil has been advocated as an effective measure to improve soil fertility and increase carbon (C) sequestration. Biochar is often co-applied with nitrogen (N) fertilizers in agricultural ecosystems, however, the interactive effects of biochar and N addition (BN) on soil greenhouse gases (GHGs) fluxes, soil C and N fractions, and yield has not been investigated. Here, we manipulated a global meta-analysis to explore the effects of biochar and N addition and their interaction on the GHGs, soil C and N fractions, and yield by assembling 75 articles. Results indicate that across all studies, biochar, N, and BN additions all increased soil CO 2 emissions (8.5%–29.6%), yield (4.2%–58.2%), soil organic C (SOC, 1.8%–50.4%), dissolved organic C (DOC, 2.7%–30.0%), and total N (TN, 6.8%–15.6%), but had no significant effect on CH 4 fluxes. Biochar addition reduced N 2 O emissions (−21.3%), global warming potential (GWP, −19.8%), greenhouse gas intensity (GHGI, −28.2%), NH 4 + (−17.8%) and NO 3 − (−10.7%), whereas N addition increased these indexes. The interaction effects of BN on CO 2 and N 2 O emissions, GWP, TN, and NH 4 + contents were antagonistic, while CH 4 emissions, DOC, MBC, NO 3 − , and yield exhibited synergistic responses. Notably, soil GHGs responses varied depending on geo-climatic factors, edaphic properties, biochar and N treatment parameters, and experimental scenarios. These findings indicate that the co-addition of biochar and N has the potential to mitigate climate change and improve yield, providing a valuable reference for the improvement of climate-smart agriculture.