Effective agricultural adaptation to climate change needs two pieces of information, the climatic risks posed on crop growth, and yield responses to the risks and associated mechanisms. Assessing the sensitivity and vulnerability of crop production to observed climate change is able to produce such information, facilitates the investment of the limited adaptation resources. Use the relationships between changes in rice yield and climatic variables and their spatial variations, we identified the sensitivity and vulnerability of China忆s rice production to observed climate change . The growing鄄season mean climatic variables exhibited significant changes during 1961-2007, indicating the possible climatic risks for rice growth. The increase in day time temperature was most widespread and obvious, suggesting increased risks of heat stresses. The relationships between rice yield and the climatic variables were significant in some rice areas, with the http: / / www. ecologica. cn largest percent of the rice area showed yield sensitivity to changes in diurnal temperature range. With a 1益 warming in growing鄄season temperature, 1 益 increase in diurnal temperature range, and a 10% decrease in radiation, much of the rice areas showed depressed yield to these changes. The area with yield vulnerability was largest to the change in radiation, and second largest to the change in diurnal temperature range. The combined effects of the observed trends of the three climatic variables caused significant change in roughly 30% of the rice areas, but with a small portion showed yield vulnerability. In addition, the negative effects were not pronounced in the principal rice areas, such as Yangtze River Basin, especially in northeast China, the observed climatic trends substantially increased rice yield during the past decades.

Climate data from seventy鄄one meteorological stations in the soybean planting areas in three provinces of Northeast China (NEC) during 1961 to 2010 were used to calculate the reference crop evapotranspiration using the Penman鄄Monteith formula. Then combined with the revised crop coefficient, soybean water requirement can be obtained during each growth stage. Finally, we calculated the Crop Water Deficit Index (CWDI) by considering cumulative effects of moisture surplus condition during the soybean growing season. and obtained the degree of drought Based on this index and the degree of drought, the characteristics of spatio鄄temporal variation for occurrence frequency and degree of soybean drought in NEC during the study period were analyzed. Result shows that there is a significant spatial variation in the occurrence frequency of soybean drought, which was increased from east to west. Light drought is the most frequent drought, followed by the middle drought and heavy drought during the whole soybean growing season. There could be relatively higher frequency of light drought in the western regions of Heilongjiang Province and the western and southern regions of Liaoning Province. In the western regions of Jilin Province, there is relatively less frequency of light drought, but the frequencies of middle drought and heavy drought are higher. We also found the basic vegetative phase (sowing to branching) experienced