中亚农业水资源脆弱性及其变化特征分析

Analysis of agricultural water resource vulnerability and its variable characteristics in Central Asia

  • 摘要: 农业用水是链接自然环境和社会经济发展的重要环节,研究农业水资源脆弱性的时空变化对揭示水资源的可持续开发利用、保障水资源安全、应对洪旱灾害具有重要意义。为研究中亚地区农业水资源脆弱性变化特征,本文以中亚五国为研究区,基于气象、土地覆盖、地形和社会经济数据,依据脆弱性概念框架,从暴露度、敏感度和适应度3个方面选取18个指标,建立了农业水资源脆弱性评价指标体系,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进行了评价及特征分析。结果表明:1)中亚农业水资源脆弱性空间分布表现为“南高北低”的特征,5国中土库曼斯坦农业水资源脆弱性最强,其次为乌兹别克斯坦、塔吉克斯坦和吉尔吉斯斯坦,而哈萨克斯坦农业水资源脆弱性最弱;研究时段内农业水资源脆弱性空间分布格局变化较小。2)中亚农业水资源脆弱性随时间变化表现为“前期升高,中期降低,后期稳定”的态势,整个研究期内研究区农业水资源脆弱性变化类型以相对稳定为主。不同地区农业水资源脆弱性随时间的变化存在差异,吉尔吉斯斯坦西部和土库曼斯坦的农业水资源脆弱性升高,乌兹别克斯坦、塔吉克斯坦以及咸海地区水资源脆弱性降低,其他地区相对稳定。3)不同地区农业水资源脆弱性对各指标的敏感性不同,北部农业水资源脆弱性动态变化对农田灌溉定额和灌溉指数以负敏感为主,对其他指标以正敏感为主,而南部对各指标的敏感性正负均有;相关性分析表明,森林覆盖率、农业用水比例、农田灌溉定额、水分胁迫指数、灌溉指数和农业水分生产率是导致中亚农业水资源脆弱性空间差异的重要因素。4)为降低农业水资源脆弱性,中亚地区需发展集约型农业,调整作物种植结构,推广耐旱品种农作物,进行节水灌溉。研究结果可为中亚农业水资源规划管理、农业生产布局调整以及农业可持续发展提供参考依据。

     

    Abstract: Agricultural water utilization is a key link between natural environment and socio-economic system. It is important to investigate the vulnerability of agricultural water resources to secure water resource sustainability and mitigate flood and drought risks. To investigate the variable characteristics of agricultural water resource vulnerability in Central Asia, an index system was established with 18 indicators from three components—exposure, sensitivity, and adaptation—according to the scheme of vulnerability assessment. Based on the data on socio-economic factors, topography, land cover, and soil from 1992 to 2017, agricultural water resource vulnerability in Central Asia was calculated via the Equal-Weights and Principal Component Analysis (PCA) method. The results showed that the vulnerability of agricultural water resources in Central Asia was high in the south and low in the north. Among the five countries in Central Asia, the highest agricultural water resource vulnerability occurred in Turkmenistan, followed by Uzbekistan, Tajikistan, and Kyrgyzstan; the lowest agricultural water resource vulnerability occurred in Kazakhstan. These spatial patterns varied little over the past 26 years. Agricultural water resource vulnerability in Central Asia showed an increasing-decreasing-stabilizing pattern during the study period. Regional changes in the agricultural water resource vulnerability were dominated by a steady state during the entire study period. The variations in agricultural water resource vulnerability differed spatially over time, increasing in the west of Kyrgyzstan and Turkmenistan, declining in Uzbekistan, Tajikistan, and the Aral Sea region of Kazakhstan, and with little variation in the rest of the study area. Sensitivity analysis indicated that the agricultural water resource vulnerability varied in different areas of Central Asia. Temporal variations in the agricultural water resource vulnerability in the north were negatively related to the farmland irrigation quota and irrigation index but positively related to other indices. The sensitivities of indices were more complex in the south. Correlation analysis demonstrated that the forest coverage rate, proportion of agricultural water, farmland irrigation quota, water stress index, irrigation index, and agricultural water productivity ratio more strongly affected the spatial differences in agricultural water resource vulnerability than the other factors. Therefore, intensive agriculture practices, cropping structure adjustments, application of drought-tolerant crop varieties, and water-saving irrigation technology and measures should be implemented to reduce the vulnerability of agricultural water resources in Central Asia. This study analyzed the spatial and temporal variations in agricultural water resource vulnerability in Central Asia, explored the impact factors of these variations, and proposed recommendations to reduce the vulnerability of agricultural water resources. This work can inform agricultural water resources planning and management, adjustments of the agricultural production structure, and help to secure sustainable agricultural development in Central Asia.

     

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