Will higher minimum temperatures increase corn production in Northeast China? An analysis of historical data over 1965–2008

Recent crop model projections have shown that crop production may benefit from warming, especially in the high latitudes, but hard evidence is limited. In this study we conducted correlation and regression analyses of climate records of seventy-two meteorological stations and records of corn yield over the period 1965–2008 in Northeast China. It was found that over these forty-four years, the diurnal mean, minimum and maximum temperatures during corn growing season increased on average by 0.31 °C, 0.42 °C and 0.23 °C every ten years, respectively. No significant change in precipitation was found, although differences between years were large. The daily minimum temperature was the dominant factor to corn production. Corn yield was significantly correlated with the daily minimum temperature in May and September. According to a regression analysis of the anomalies of corn yield and air temperature, a 1.0 °C increase in daily minimum temperature in May or September will lead to an increment of 303 kg ha−1 or 284 kg ha−1 in corn yield, respectively. Corn varieties with longer growth duration will profit most from the climatic changes but agronomic practices may have to be modified to address expected weather extremes such as droughts and periods with heavy rainfall.