Inhibiting N2O emissions and improving environmental benefits by integrating garlic growing in grain production systems

The grain–economic cropping system combines grain production with economic benefits. Under this system, decreasing the N2O emissions from farmland soil will be more conducive to the development of green agriculture. Therefore, we determined the soil N2O emissions and ecological benefits of garlic–maize and wheat–maize cropping systems from 2019 to 2020. Compared with wheat–maize, garlic–maize significantly decreased the soil urease activity and dissolved inorganic nitrogen (DIN) content, which significantly decreased the N2O emission fluxes by 44.6% and 36.4% in the crop growing seasons during 2019–2020, respectively, thereby indicating that planting garlic could effectively inhibit the soil N2O emissions. Moreover, garlic enhanced the ecological benefits of the planting system by 2.1 times as an economic crop. Path analysis showed that the soil temperature, water-filled pore spaces, and DIN significantly promoted soil N2O emissions in the wheat–maize system but weakened them in the garlic–maize system. However, the urease activity significantly affected the DIN content, which indicates that garlic could significantly decrease DIN production by inhibiting the urease activity to reduce N2O emissions. Our findings demonstrate that garlic can be used as an environmentally friendly economic crop to optimize planting systems.