中亚农业水资源脆弱性空间格局及分区研究

[目的]农业水资源脆弱性是指在自然条件变动或人为条件干扰的前提下,衡量农业水资源系统影响农业可持续发展能力的指标,其评价对于农业水资源管理至关重要。在自然、社会以及人类活动变化条件下,农业水资源脆弱性研究可以结合暴露度、敏感度和适应度综合表达,这为实现农业用水系统的高效运作提供可能。研究目的是分析中亚农业水资源脆弱性空间格局,并对其进行分区与评价,为农业水资源管理提供科学依据。[方法]以中亚为研究区,依据水资源脆弱性概念框架,从暴露度、敏感度和适应度等3个指标中选取18个指标建立农业水资源脆弱性指标体系,采用等权重法和主成分分析法确定指标权重,对1992—2017年中亚农业水资源脆弱性空间格局及分区进行研究。[结果](1)中亚农业水资源暴露度、敏感度、适应度和脆弱性空间差异显著。受作物生育期的降水量、平均气温和相对湿润度指数影响,农业水资源暴露度大致由西南向东北降低;农业水资源敏感度主要受农业用水比例和农田灌溉定额影响,表现为从南到北降低的变化;农业水资源适应度受农业水分生产率和施政效率影响较大,表现为从南到北逐渐升高的变化;农业水资源脆弱性主要受敏感度和适应度因素影响,表现为自东北向西南升高的趋势。(2)根据中亚农业水资源脆弱性空间分布特征,将其划分为北部微度脆弱区、中北部轻度脆弱区、中南部中度脆弱区、南部重度脆弱区和西南部极度脆弱区5个大区,根据各分区农业水资源脆弱性地理特征,提出未来发展方向和对策。[结论]由于农业水资源供需矛盾不断加剧、水资源利用效率较低导致农业水资源脆弱性较高,因此管理农业水资源和调整农业生产布局成为中亚农业发展的重要问题。

SPATIAL PATTERN AND ZONING OF AGRICULTURAL WATER RESOURCES VULNERABILITY DURING CROP GROWTH PERIOD IN CENTRAL ASIA

The vulnerability of agricultural water resources is a vital indicator reflecting agricultural sustainability and the effects of natural changes and/or human activities on the agricultural water resources system. Vulnerability assessment is important for agricultural water resources management. The vulnerability of agricultural water resources is an indicator which expresses the restoration capacity of agricultural water system against change in natural and social conditions as well as human activities, and can be defined as an integrated result of exposure, sensitivity and adaptation. Studying the spatial pattern and zoning of agricultural water resources vulnerability can provide a scientific basis for rational utilization of regional agricultural water resources. Taking Central Asia as the study area, this research established an indicator system for evaluating agricultural water resources vulnerability with selected 18 indicators from three components, namely exposure, sensitivity and adaptation. The spatial pattern and zoning of agricultural water resources vulnerability was acquired by using Equal Weights and PCA (Principal Component Analysis) method in Central Asia according to the data collected from 1992 to 2017. The results showed that (1) There were obvious spatial differences in the distribution of agricultural water resources exposure, sensitivity, adaptation and vulnerability zone in Central Asia. Due to the differences in precipitation, temperature, and relative moisture index, the exposure of agricultural water resources gradually decreases from the southwest to the northeast in the region. The sensitivity of agricultural water resources was mainly controlled by the proportion of agricultural water and farm irrigation quota, and it showed a gradual decreasing trend from the south to the north. The adaptation of agricultural water resources was mainly determined by the rate of agricultural water productivity and administrative efficiency, and it gradually increased from the south to the north in the study area. The vulnerability of agricultural water resources in the region was shaped by the sensitivity and the adaptation of agricultural water resources, showing a gradual increasing trend from the northeast to the southwest. (2) According to the spatial distribution of agricultural water resources vulnerability, Central Asia could be divided into five zones, i.e. little vulnerable zone in north, slightly vulnerable zone in central and north, moderately vulnerable zone in north, severely vulnerable zone in south and extremely vulnerable zone in southwest. Based on the characteristics of agricultural water resources vulnerability in each zone, some suggestions were proposed for improving the agricultural production, socioeconomic development and environment protection in the future. It is concluded that the degree of agricultural water resources vulnerability is high in Central Asia because of the fierce imbalance between supply and demand of agricultural water resources as well as the weak condition of agricultural water resources utilization. Therefore, the effective management of agricultural water resources and the construction of rational agricultural systems become important issues for agricultural development in Central Asia.