Study On Indicators And Risk Assessment Of Rice Autumn Chilling In Guizhou

Meteorological disaster are inevitable in the process of agricultural production, which is a serious threat to our national food security, and a big challenge to solve the chinese resources and environment population problem. The rice is a very important to grain production in Guizhou. In early autumn, low temperature will have an effort to the rice of flowering period due to monsoon instability, sometime it accompanied the rainy weather, autumn chilling leads to reducing yield of Rice, and restricts high and stable yield of rice to a certain extent,so assessing autumn chilling of rice has great significant in Guizhuo.The paper is based on the impact mechanism of rice, establish the rice autumn chilling index which was simple and suitable for rice cultivation in Guizhou by using historical meteorological and yield data, and assess risk for rice autumn chilling disaster by using the method of geographic information system(GIS).The main findings are as follows:(1) It is selected cold accumulated temperature as autumn chilling indictors of rice in Guizhou. the light moderate, severe, most severe autumn chilling injury levels guidline of rice in Guizhou were brought forward with the contradistinctive analyzed of cold accumulated temperature of typical year(197、1980、1988、2002) and low-yield rate, in which of rice were17<LJW≤21,21<LJW≤25,25<LJW≤29,LJW>29.(2) The comparative results of cold accumulated temperature of rice and cold dew index demonstrate that the cold accumulated temperature of is superior to cold dew index in its application by referenced the rice fertility and disaster of typical year data.the new index and levels guideline could be applied to the rice autumn chilling evaluation in Guizhou.(3) The result of rice autumn chilling in space-time showed that frequency and intension of autumn chilling about the rice is obvious strengthen after70s in the20th century in middle-high elevation,and its trend could be expand to middle elevation, but there are few the disaster in low elevation. (4) Based on natural disaster risk assessment rules and economic about the rice and stony desertification and karst area data in Guizhou, the hazard of disaster-causing factors and sensitivity of disaster-pregnant environment and vulnerability of disaster-bearing body by autumn chilling dangerous of rice in Guizhou were analyzed and divided and risk regionaliazation of autumn chilling dangerous about the rice in Guizhou, its result that overall risk regionaliazation distributed broken, the highest degree of risk are mainly located in the western part, its proportion are smaller;Low-risk areas are mainly located in the fringe of southern part, southeast, northeast, and Chishui and Tongren; the moderate risk is mainly distributed in the central of province, Anshun, Xingyi.