关键词: 长江中下游地区, 双季早稻, 冷害, 热害, 风险评价

Abstract: 【Objective】Agricultural meteorological disasters are the important factors which threaten the national food security. Risk assessment on agro-meteorological disasters is the main research direction of guaranteeing agricultural production. There is the largest double-cropping early rice (DCER) planting area in Yangtze River basin in China, the DCER output in this area accounts for more than half of the country’s total production. This region is located in central China, where the hydrothermal resources are relatively abundant, but the seasonal distribution is uneven. Temperature swings in spring and hot days emerge frequently in summer, causing DCER’s cold and hot damages and affecting final yield. Therefore, it is emergency to carry out risk assessment of cold and hot damages of DCER. 【Method】The research was based on the meteorological data during 1961-2012, agricultural meteorological data during 1981-2010 and social statistics data of DCER growing region in lower-middle reaches of the Yangtze River Basin. First and foremost, four assessment models were built to evaluate cold and hot damage hazard, environmental vulnerability, exposure, disaster prevention and mitigation capacity. For laying a foundation for the formation mechanism of natural disaster risk, a risk evaluation model was developed in terms of hazard which is fine depicted in development phrase, vulnerability, exposure and disaster prevention and mitigation capacity. Weight coefficients of the four factors are calculated by entropy weight evaluation method. The results of the multi-risk assessment model is valuable for decision making to release disaster risks.【Result】 The hazard assessment model was constructed based on disaster intensities at various developmental stages, the weight coefficient of the development stage and the weight coefficient of cold and hot damages. The assessment results show that the planting area in southern Hunan and southeastern Jiangxi is suitable for DCER, where cold and hot damages are rarely happened. Hazard in center of Hunan and Jiangxi is 0.3, slightly higher due to hot damage at filling stage, while the higher hazard in eastern Hubei is caused by cold damage. Zhejiang is reduced to absolute inferior planting area for its higher hazard during the whole growing season except tillering stage, especially the serious hot damage at filling stage. Vulnerability assessment model was constructed of index of yield variation. The assessment results show that mid-east Zhejiang, mid-south Jiangxi and Hubei planting areas are the lowest vulnerable areas. Vulnerability in northeastern of Jiangxi is quite high, followed by Ningxiang and Chaling of Hunan province, where yield is quite sensible to weather condition. The exposure assessment model was constructed based on the index of vegetation coverage. The assessment results show that DCER planting area ratio is up to 85% in the eastern of Hunan and northeastern of Jiangxi, which means high exposure to the rice production. The exposure is lower in Zhejiang and Hubei, and it won’t have high impacts on DSER yield. The disaster prevention and mitigation capacity assessment model was constructed based on the total powers of agriculture machine, net income per capita and chemical fertilizers. The assessment results show that disaster prevention and mitigation capacity is highest in Zhejiang province. It is relatively higher in central Hunan, western Hubei and southern Jiangxi. Disaster prevention and mitigation capacity is lower in the other areas. The risk evaluation model was constructed based on hazard, vulnerability, exposure, disaster prevention and mitigation capacity. Mid-west of Zhejiang, northeast of Jiangxi, central Hunan and east of Hubei are divided into high-risk areas. Southern Hunan, southeastern Jiangxi, eastern Hubei and eastern Zhejiang are roughly divided into the low-risk and the other areas are divided into medium risk areas. 【Conclusion】 Diverse measures should be adopted to lesson the risk of DCER planting in each province in Yangtze River basin: in mid-west of Zhejiang, it is useful to adjust the sowing period. For northeastern Jiangxi, increasing the investment of local agriculture is needed. It is necessary to adjust the planting structure in Hunan. Science and technical inputs in Hubei should be increased to reduce the risk.

Key words: the Yangtze River Basin, early rice, cold damage, hot damage, risk assessment