Study On Adaptability Adjustment Simulation Of Rice Production In Fujian Province Under New Emission Scenarios

Since ancient times,the development of agriculture depends on climate,agricultural production and climate is closely related.And agriculture is one of the most sensitive and vulnerable sectors of climate change,which makes the adverse effects of climate change on food production received by the international community.Therefore,the study of the effect of climate change on agriculture and the exploration of its adaptive measures has become a major research topic in the field of agriculture and climate change.Therefore,this paper chooses Fujian province as the research area to assess the impact of climate change on rice production,and to explore the feasible adaptation measures on the basis of impact assessment,which has important scientific and practical assessment of the impact of future climate change.In this study,Fujian province was divided into three rice regions(double cropping rice region in southeast Fujian,double cropping rice region in northwest Fujian and northern mountainous region of northwest Fujian).The genetic parameters of 7 rice varieties were adjusted and determined with the daily meteorological data from 2011 to 2012 and the trial yield data of the same period.Then,according to the four typical scenarios presented in the AR5(fifth assessment report of the IPCC),RCP 4.5 and RCP 8.5 are selected,and the climate model of BCC CSM(Beijing climate center system model)is used to generate two climate change scenarios for the base period(1981-2005)and future per:iod(2021-2050)based on the climate prediction results in these two scenarios.On this basis,the temporal and spatial distribution characteristics and the fluctuation regularity of the main meteorological elements in the rice growth period under different scenarios were analyzed.Finally,CERES-Rice model was used to simulate the effects of climate change on the growth period and yield of rice in Fujian province.On this basis,the best rice type and sowing dates in the different rice growing areas were simulated and analyzed,and the possible changes of rice yield in the whole province before and after adjustment were estimated.The main results of this paper were as follows:(1)In the future climate change scenario,the temperature of rice in the rice growing period in Fujian province increased significantly,the maximum increase was 2.3 ?;The total radiation in the rice growth decreased,the maximum was no more than 2%.In the aspect of precipitation,the precipitation decreased slightly during the growth period of early rice and single rice,and the total precipitation of late rice increased significantly.(2)With the increase of temperature in the future,the growth period of rice will be shortened obviously,and the growth period of single rice is the longest,which can reach more than 10 days.In the double rice region,the shortened days of the rice growth period of the late rice were more obvious than that of the early rice in southeastern Fujian.And the early rice and late rice in the double rice region in northwestern Fujian was similar.According to the simulation results of yield,without considering the effect of CO2 fertilizer effect,whether the yield of early rice,late rice and single crop is generally reduced,the yield is not more than 12%,and the yield of rain-fed rice is slightly higher than that of irrigated rice.Spatially,the rice yield reduction trend was obvious in all rice regions of Fujian province,especially the double rice region in northwestern Fujian,only in the double rice region in southeastern Fujian and the single rice region in northwestern Fujian,some sites showed a small increase in yield.Under different scenarios,the yield change of rice was also different,and the yield of rice under RCP 8.5 was significantly larger than that of RCP 4.5.When considering the effect of CO2,the simulation results are optimistic,the research stations are generally shown to increase production,the maximum yield can be up to 15.2%.The results of rice stability showed that the single rice was between early rice and late rice.The stability of late rice is lower than that of early rice,and the variation range is larger,which indicates that the annual fluctuation range of late rice yield is larger in the future.Under different climate change scenarios also showed different results,that the stability of rice under RCP 8.5 scenario is worse than that under RCP 4.5 scenario,indicating that the inter-annual fluctuation of yield will increase with the increase of future temperature,but irrigation can improve the stability of rice to some extent.And then,the effect of CO2 can improve the yield,but has little effect on the stability of rice yield.(3)According to the above simulation results,the simulation experiment of variety replacement and sowing date adjustment were carried out,and the stability of rice should be taken into account in the process of simulation selection.The results showed that the rice varieties suitable for planting in each rice area were late-maturing varieties in both scenarios.For early rice and single rice,the best sowing date of most sampling points is 5-10 days earlier than the current sowing date,while the sowing date of most areas of late rice will be delayed by 5-10 days,especially more delayed by 10 days.On this basis,if further consideration of variety replacement and sowing date adjustment,rice simulation yield can be further improved.Under the scenarios of RCP 4.5 and RCP 8.5,the simulated yield of early rice in the double rice region in southeast Fujian increased by 1.6%and 1.9%respectively,and the simulated yield of the latter increased by 13.5%and 9.8%respectively.The simulated yield of early rice in the double rice region in northwest Fujian increased by 1.4%and 1.0%respectively,and the simulated yield of the latter rice increased by 11.5%and 7.9%respectively.The simulation yield of single rice in the northern mountain area of Fujian province increased by 14.1%and 13.7%respectively.After comprehensive consideration of the adaptability measures,the total yield of each rice area in Fujian province was significantly higher than that of the current situation,which increased by 8.6%and 7.5%respectively under the two scenarios of RCP4.5 and RCP 8.5.