Effects of climate change on phenophases and annual climate resources distribution and utilization of major food crops under a double-cropping system in Anhui Province

To examine the effects of climate change on the phenophases and annual climate resources distribution and utilization of major food crops under a double-cropping system in Anhui Province, this study analyzed variations in the phenophases of different cropping systems in different regions and the effects of climate change on distribution and utilization of accumulated temperature, radiation, and precipitation. The analyses included linear fitting, correlation analysis, and regression analysis and incorporated data of the daily average temperature, daily sunshine hours, and daily precipitation from 1992 to 2013 of twelve meteorological stations in the Jianghuai area. The results showed that the sowing date of winter wheat was significantly advanced (P < 0.05) by 3.03 days (d) per decade, on average, under the double-cropping system of winter wheat-soybean in the area along Huaihe River from 1992 to 2013. Changes in the maturity stage of winter wheat were not significant, but the average increase in the whole growth period was 3.54 d per decade. The soybean sowing date and flowering date were significantly delayed (P < 0.05) by 3.06 and 0.86 d per decade, respectively, and the average decrease in the whole growth period was 3.65 d per decade. For the double-cropping system of winter wheat-single rice in the Jianghuai region, the sowing date, heading date, and maturation date of rice were significantly advanced (P < 0.05) by 5.12, 3.87, and 2.92 d per decade, respectively; and the whole growth period increased by 2.20 d per decade Wheat showed the same trends as rice, though non-significant, and the whole growth period was shortened by 0.8 d per decade. For the double cropping rice, the change in phenophases for early rice was non-significant, and the whole growth period was shortened by 0.6 d per decade, on average. The sowing date of late rice was delayed by 1.14 d per decade, on average, whereas the heading date and maturation date were advanced by 0.71 and 6.85 d per decade, respectively. The advance of the maturation date was extremely significant (P < 0.01). The whole growth period of late rice was shortened by 5.17 d per decade. The accumulative temperature increased for winter wheat in Huaibei, single rice in Jianghuai, and double rice along the Yangtze River but decreased for soybean and winter wheat in Jianghuai. The radiation of winter wheat, early rice, and late rice increased, whereas that of soybean and single rice decreased. The precipitation of the first-season crops decreased, but that of the second-season crops increased. The climatic productivity of winter wheat-single rice planting patterns was the highest of all cropping systems. Linear regression analysis showed that the accumulative temperature and radiation were significantly positively correlated with the yield of double-cropping rice and winter wheat in Huaibei (P < 0.05), and radiation and temperature were the main limiting factors for further improvements to its production. Excessive temperature and precipitation of single-season rice in the Jianghuai region also limited yield improvements. Climate change has affected the phenophases of crops in double-cropping systems and influenced the allocation and utilization efficiency of climate resources. The adverse effects of climate change on crops can be offset by improving the varieties, changing the sowing dates, and enhancing stress tolerance.