Abstract: According to the scenarios A2 and B2 in IPCC Special Report on Emissions Scenarios (SRES), the climate change scenarios based on regional climate model PRECIS were combined with rice growth model ORYZA2000, and, on the basis of many years experimental data and of model suitability verification, the growth period and yield of middleseason rice in base period (1961-1990) and in 2011-2050 under scenarios A2 and B2 were simulated, aimed to analyze the impacts of future climate change on the growth and yield of middleseason rice in Central China. In the next 40 years, the growth period of middleseason rice in Central China would be shortened, with an average of 3.5 days under scenario A2 and of 1.3 days under scenario B2, as compared with that in 1961-1990. The areas where the growth period would be shortened by more than 4 days would be in west Hubei. Without considering the effect of CO₂ fertilization, the yield of middleseason rice in Central China would be decreased in the next 40 years. Under scenario A2, the yield reduction of rainfed middleseason rice would be averagely 17.8%, and that of irrigated middleseason rice would be 14.2%; under scenario B2, the yield reduction of rainfed middleseason rice would be averagely 16.4%, and that of irrigated middleseason rice would be 12.7%. The more yield reduction under scenario A2 than under scenario B2 indicated that the greater the increment of air temperature, the greater the negative effect of the increment on middleseason rice. Under the same scenarios, the yield reduction of irrigated middleseason rice would be smaller than that of rainfed middleseason rice, indicating that irrigation could offset the adverse effect of rising temperature to some extent. Considering the effect of CO₂ fertilization, the variation trend of the middleseason rice yield in Central China would be inconsistent in the next 40 years. Under scenario A2, the yield reduction of rainfed middle season rice would be averagely 4.3%, but  irrigated middle season rice yield would be increased by  4.3%; while under scenario B2, the yield  would be increased by 3.6% and 11.8%, respectively. As compared to without considering the effect of CO₂ fertilization, under the consideration of the effect of CO₂ fertilization, the yield reduction of rainfed middleseason rice under scenario A2 would be decreased while the yield of irrigated middle season rice under scenario A2 and that of rainfed middle-season rice and irrigated middle season rice under scenario B2 would be increased, but the yield increment would be smaller than the yield reduction under the same scenarios, which indicated that CO₂ fertilization could increase the yield of middleseason rice to some extent, but be not enough to offset the adverse effects of rising temperature. Whether considering the effect of CO₂ fertilization or not, and rain-fed or irrigated, the future climate change would increase the instability of middle-season rice yield, and thus, increase the risk of middleseason rice production in Central China. The stability of irrigated middle-season rice would be greater than that of rainfed rice, and the stability of rice yield with CO₂ fertilization would be greater than that without CO₂ fertilization. Therefore, irrigation and adequate CO₂ fertilization would be the effective measures to improve the stability of middle-rice yield.

Key words: cadmium stress, Salix variegata, root vigor, metal elements.