Abstract:

The change of rice growth period is dominated by the climatic conditions and variety renewal as well as the corresponding field managements. Thirteen agro-meteorological stations data in Northeast China from 1992 to 2012 were used to analyze the changes of rice growth period and its relationship with the warming trend and the adjustment of rice varieties. The results show that the mean temperature and more than 10℃ cumulative temperature of rice growing season increased significantly from 1992 to 2001, the maximum value of the difference in ≥10℃cumulative temperature could reach as high as 500℃?d, then the warming trend slowed down and slightly declined from 2002. Corresponding to the warming trend, it shows an overall opposite feature of the changes of rice phenology in 2002-2012 vs. 1992-2001, the heading stage, milky maturing stage and maturing stage were obviously advanced from 1992 to 2001 by 3.1, 2.9, 4.5 d/10a, respectively, while the transplanting, tillering and maturing stages delayed by 4.6, 4.7, 2.0 d/10a, respectively, in 2002-2012. Though the changes of growth period were affected by many factors, but the sowing to transplanting period and milky maturity to maturing period were shortened by 0.7, 1.6 d/10a in 1992-2001, respectively, and were prolonged by 2.9, 2.8 d/10a, respectively, in 2002-2012. In general, the whole rice growth period was prolonged by 3.7 d/10a in 1992-2012, which was mainly attributed to the extension of vegetative growth periods. The analysis of 12 stations with complete experimental data shows that the rice variety adjustment is constantly implemented in Northeast China to adapt to the changes of climatic conditions, it is shown that over most of the selected stations there was a small deviation between the observed rice growth period and the certificated growth days of variety registration, which means that the selected rice variety could match the in situ climatic conditions for the effective utilization of the local climatic resources, however, there are still some stations (such as Yanji, Meihekou, and Tonghua) in which the deviation between the observed rice growth period and the certificated growth days of variety registration was getting larger due to the enhanced climatic variation, besides, in some stations (such as in Ning’an and Qian Gorlos) there were almost no changes for the certificated growth days of variety registration. Therefore, there is an urgent need for a systematic summary of the climate sciences and the lessons how to adapt the rice production to climate change in Northeast China, and then providing solid scientific support to climate change adaptation for rice production in Northeast China.

Key words: Climate warming, Northeast China, Rice varieties, Phenology, Growth period