Comparison of the modeled potential yield versus the actual yield of maize in Northeast China and the implications for national food security

A precise spatial knowledge of potential yield and actual yield is crucial to assessing an increase in grain yield and is relevant to national food security. In this paper, the potential maize yields at the county level in 2013 in Northeast China were estimated using a Miami model in combination with an integrated fertility index and the effect of chemical fertilizers on yield increase. Then, the spatial characteristics of the climate, farmland and grain production potential were presented, and the potential yield increase and food security implications were analyzed. The estimated production potentials of the climate, farmland and grain in 2013 were approximately 4.65 x 10(3)-13.06 x 10(3) kg/ha, 2.77 x 10(3)-9.38 x 10(3) kg/ha, and 2.97 x 10(3)-12.1 x 10(3) kg/ha, respectively, whereas the actual maize yield in 2013 was 1.50 x 10(3)-8.60 x 10(3) kg/ha, accounting for 41.86-95.84 % of the grain production potential. The total average potential maize increase in Northeast China was 3.32 x 10(3) kg/ha, measured from the difference between the climate production potential and the actual yield. Furthermore, the main regions with lower surplus production but a higher potential for increase were located in the eastern Liaoning, Jilin and Heilongjiang Provinces. In addition, the surplus production, which was 136.56 million tons, could feed 341.4 million people in other areas of China. In conclusion, we suggest that improving access to agronomic practices (such as fertilizer and high-yielding seed) and developing agricultural policies and strategies could increase the maize yield and further narrow the yield gap.