We obtained the average transportation distances by train and truck in China for coal, crude oil, and N fertilizer from the National Bureau of Statistics of China (12). We adopted the IPCC (37) default emission factors for N2O, CH4, and CO2 for energy combustion by internal-combustion engines for vehicle transportation (Table S8). Combining these values, we estimate GHG emission factors for energy and fertilizer transportation (details are provided in SI Text).
GHG Emission from Postapplication Field.