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Abstract: To learn the historical response of cropping system to climate change will benefit the strategy decision of future cropping adaptation. In this paper, we conducted an integrated analysis of the climate records of seventy-two meteorological stations and the records of crop yields over the period 1970–2009 in Northeast China. It was found that over these forty years, the daily mean, maximum and minimum temperatures during crop growing season increased on average by 0.34°C, 0.28°C, 0.43°C every ten years, respectively. No significant change in the precipitation was found, although the differences between years were large. After de-trending the agronomic technique contributions to the increments of crop yields, the historical warming had led to great annually increments of 16.6kgha−1, 15.5kgha−1 and 3.2kgha−1 in rice, corn and soybean yields, respectively. According to the historical warming level, present cropping boundaries can be theoretically extended northward about 80km with a prolonged growing period by 10 days compared to the 1970s. Actually, the growth durations of newly approved varieties of rice, corn and soybean have really prolonged by 14.0 days, 7.0 days and 2.7 days since the 1950s, respectively. The actual growing periods of rice and corn have also respectively prolonged by 6 days and 4 days due to the adjustment of sown and harvest dates by the farmer since 1990s. The existing rice cropping region has been extended northward 80km in the 2006 compared to the 1970. These actual responses were consistent with the theoretical calculation according to the historical warming trends. Our results demonstrate that cropping system owns the potential to progressively and actively adapt to the global warming for high yield through a comprehensive strategy. [Copyright &y& Elsevier]

Abstract: 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 303kgha−1 or 284kgha−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. [Copyright &y& Elsevier]