Optimizing fertilization depth can promote sustainable development of dryland agriculture in the Loess Plateau region of China by improving crop production and reducing gas emissions

Aims Fertilization methods have affected the development of dryland agriculture. There is a need to understand the impacts of different fertilizer application depths on crop production and gas emissions to facilitate the sustainable development of dryland agriculture. Methods A field experiment was conducted for two years (2019-2020) in a dryland agroecosystem in the Loess Plateau region of China. Five fertilizer placement depths were tested comprising 0 cm (FD0), 5 cm (FD5), 15 cm (FD15), 25 cm (FD25), and 35 cm (FD35). N-P-K fertilizer was applied to all treatments as base fertilizer at the same rate. After sowing, the gas emission fluxes were measured 17 consecutive times. We systematically analyzed the effects of different fertilization depths on the summer maize (Zhengdan 958) yield, ammonia (NH3) volatilization, and greenhouse gas emissions (nitrous oxide (N2O), carbon dioxide (CO2), and methane (CH4)). Results The results showed that the NH3 volatilization, N2O emissions, CO2 emissions, and global warming potential (GWP) decreased as the fertilization depth increased. Compared with the traditional fertilization depth (FD5), deep fertilization at 15 cm clearly reduced the NH3 volatilization, N2O emissions, CO2 emissions, GWP, and greenhouse gas intensity. In addition, compared with FD25 or FD35, FD15 increased the capacity of the soil to absorb CH4. Critically, compared with the traditional fertilization depth, FD15 can effectively improve the summer maize biomass yield (4.2%) and grain yield (18.1%) at the final harvest. Conclusion FD15 can promote the sustainable development of dryland agriculture in the Loess Plateau region of China by improving crop production and reducing gas emissions.