农业旱灾脆弱性评价及生态减灾研究——以湖南省衡阳市为例

农业旱情是农业旱灾脆弱性和干旱风险性共同作用的结果。随着全球变暖,蒸发力增大,干旱的风险性变大,因此降低农业旱灾脆弱性是防旱抗旱的重要措施。灾害脆弱性可以看成是生态安全性的另一面,故加强生态安全建设可以降低农业旱灾脆弱性。衡阳市是湖南省重要的农业生产基地之一,也是农业旱情较重地区之一,而其农业旱情与农业旱灾脆弱性密切相关。这种脆弱性是生态环境因素和社会因素在一定的时空条件下偶合的产物。详细地分析了气候因素、植被和土壤等环境因素和水利设施、经济发展水平等社会因素在农业旱灾脆弱性形成中的作用。依据长时间序列的气象资料和经济统计数据,运用数学模型和有关优化分析方法,对衡阳市农业旱灾脆弱性进行定量评估。提出了降低农业旱灾脆弱性的生态措施。

Vulnerability of Agricultural Drought and Agricultural Losses Reduction During Drought Through Implementation of Ecological Measures-A Case Study of Hengyang, Hu'nan Province

Drought can severely reduce agricultural productivity. Since the risk of drought is likely to intensify with projected global warming and increases in evaporation potential, it is critical to identify methods for minimizing the manifestation of drought conditions and reducing agriculture's vulnerability to drought. The vulnerability of land-based production systems to natural disasters is a function of the systems' underlying ecological integrity. Therefore, ecological improvement and reconstruction may reduce agriculture's vulnerability to drought. Hengyang, an important agricultural area in China, experiences severe drought from time to time. This study demonstrates the close correlation between agricultural losses in the area during drought and certain environmental and social factors, under particular space-time considerations. Factors contributing to agricultural vulnerability, such as local weather conditions, vegetation and soil conditions, irrigation works and the level of economic development were analyzed in detail. The vulnerability of agriculture to drought in the area is assessed based on a long time series of meteorological data and economic statistical data, and by the use of a mathematical model and a correlation optimization method. The results of this assessment are used to determine optimal methods for ecological improvement and reconstruction to reduce agriculture's vulnerability to drought.