Research On Distribution Rule Of High Temperature Damage And Yield Risk Of Middle-season Rice In Anhui Province

Anhui is the main and important food production province in China. Its crop production has always ranked in the sixth in all national provinces for perenniale years. Rice is the one of the main food crop in this province, the perennial area is above30million acres. The growing area is more than1,000million acres along Changjiang River,which is the main rice growing area in Anhui territory and the terrain is flat. Rice is thermophilous crop, if it happened to the daily average temperature and highest temperature are respectively above30and35℃,and this situation is lasting three days or more in the stage of rice booting,heading and flowering, it will reduce the Pollen vigor and setting percentage,and caused the Inestimable loss for rice yield.The frequency of national high temperature and the high temperature days in summer increased with the process of global warming and the average temperature rising in recent50years. In many countries and regions, high temperature has become one of the main ecological environment factors which affect crop growth and development. The days of high temperature and daily average highest temperature tend to rise in recent years, the July and August after mould rains is the stage of booting,heading and flowering of middle rice.High temperature damage has become the main Agro-meteorological disasters that restrict rice stable and high production in Anhui province.First, the temporal and spatial distribution of the high temperature damage in Anhui province with high temperature damage index is studied in this paper. Then the risk of high temperature damage to rice along Changjiang River where the high temperature damage is frequent is analyzed and evaluated. At last, the insurance premium is calculated by basing on the theory of risk analysis of disasters and agricultural insurance. The main content and the results as follows:The more days and the higher level of the high temperature damage, the less probability is appeared. The days of high temperature and the high temperature damage which days are three or more appeared in the whole province. It formed a high temperature belt from west to east along Changjiang River. The general trend of high temperature damage distribution is low-high-low from south to north in whole province. The high temperature weather happened in every year, and for the high temperature damage also occurred in each year from1960to2009except1982.In the whole province, the high temperature weather and damage has shown different increasing tendency, especially in the areas along Changjiang River.The average disaster rate, coefficient of variability, risk index and complex risk index for the single-season middle rice yield along Changjiang River are analyzed Then, the index of high temperature damage is designed according to the critical temperature, high temperature days and high temperature damage times. The relationship between regional yield risk and high temperature damage index is significant, the correlation coefficient is0.80. So the final average annual disaster rate which is calculated by the disaster rate and the index is0to50percent.Because the data we have obtained is incomplete and the character of the probability of disaster occur in time and intensity is uncertain. In this paper, the information diffusion method was used to change single sample observations into fuzzy sets, this is better than the pure probability analysis and can increase the system risk identification. The disaster index Probability in different level and drawn exceed probability curve is calculated by the method of information diffusion method.Insurance rate, insurance combined with the probability of different disaster rate though normal distribution probability functions and the average annual disaster rate are dropped out though the method of information diffusion. Finally, the counties along Changjiang River in Anhui province were divided into three areas by comprehensive clustering analysis: The first district included Wuwei and Anqing city. The pure insurance premium for this two areas is3.40yuan. The insurance premium is2.50yuan in the second district which included the areas of Hexian, Ma’anshan city, Fanchang, Wangjiang. The third district premium is1.70yuan, and the areas in this insurance district are Taihu, Dongzhi, Wuhu and Tongling city.