Regional Differences and Key Influencing Factors of Fertilizer Integrated Efficiency in China

Overuse and low efficiency of chemical fertilizers have caused severe non-point source pollution in China. The investigation of regional difference and the key influencing factors of fertilization intensities (FI) and efficiency can provide references for decision-makers to establish efficient policies for fertilizer use. Using simple models of fertilizer allocation efficiency (FAE) and fertilizer integrated efficiency (FIE), it was found that the east of China excessively used fertilizers, and both the middle and west showed both excessive and insufficient fertilizer use. The average values of the FIE in the east, middle and west of China were 0.69, 0.68 and 0.64, respectively, all of which were at low efficiency. The inter-provincial differences of FIE throughout the country ranged from 0.47 in Shannxi to 0.94 in Shanghai. The population aging rate (PAR), effective irrigation rate (EIR), natural disasters affected rate (DAR) and disaster damaged rate (DDR) are considered the key factors influencing the FIE, based on the new concept of cumulative weight (CW). PAR and EIR are the positive factors, while DAR and DDR are negative. The average FIE is now 0.67 in China, which implies that the increase of chemical fertilizer use efficiency or the reduction of chemical fertilizer amount has a potential of approximate 33%, with the current grain yield and other inputs unchanged. The increase of fertilizer use efficiency should be conducted under local conditions. Optimized intensification of grain production should be given more attention in the east, and implementing disaster prevention and reduction technologies and water-saving irrigation technologies are the preference in the middle and west of China.