1992-2017年中亚五国农作物水足迹变化特征

本研究以中亚五国为研究区域,以农作物水足迹为评估手段,分析了1992—2017年间中亚五国农作物水足迹的时空变化特征,以揭示中亚五国农作物水足迹结构,厘清引起中亚五国水足迹变化的主要农作物的贡献。结果表明:1)中亚五国农作物水足迹时间变化特征明显,1992—2017年中亚五国农作物绿水足迹(-9.7×10~9 m~3)和蓝水足迹(-5.6×10~9 m~3)均趋于减少。中亚五国农作物水足迹空间分布差异显著,哈萨克斯坦农作物绿色水足迹最高(平均4.96×10~(10) m~3),且远高于其他4国(平均3.6×10~9 m~3),而蓝水足迹以乌兹别克斯坦最高(平均1.53×10~(10) m~3)。农作物绿水足迹和蓝水足迹增长率最大的国家分别是土库曼斯坦(87.6%)和吉尔吉斯斯坦(32.3%);绿、蓝水足迹减少率最大的国家分别是哈萨克斯坦(-20.7%)和乌兹别克斯坦(-24.2%)。2)中亚地区农作物绿水足迹主要以粮食作物为主,蓝水足迹以粮食作物和油料纤维作物为主;而粮食作物水足迹结构中,主要以小麦、水稻和玉米为主,油料纤维作物水足迹结构中,主要以棉花为主。3)哈萨克斯坦作为绿水足迹减少最多的国家,大麦(51.6%)和小麦(28.2%)的贡献最大;乌兹别克斯坦作为蓝水足迹减少最多的国家,棉花(61.9%)贡献最大。通过开展中亚地区的农作物水足迹研究,发现中亚农作物水足迹整体呈下降趋势,厘清了中亚地区引起水足迹下降的主要农作物种类,相关成果可以为中亚地区的农作物优化种植和水资源节约提供支撑。

Characteristics of crop water footprint changes in five Central Asian countries from 1992 to 2017

This study analyzed the spatio-temporal characteristic of crop water footprint in five Central Asian countries from 1992 to 2017 using the crop water footprint as the assessment method, in order to reveal the structure of crop water footprint, and clarify the contribution of main crops that caused the change of water footprint in the five Central Asian countries. The results showed variation in the crop water footprints of these five Central Asian countries. From 1992 to 2017, changes in green water footprints were similar to those in their respective planting areas, and the overall trend was decreasing (-9.7×10⁹ m³). The overall blue water footprint also tended to decrease (-5.6×10⁹ m³). There were significant differences in the spatial distribution of crop water footprints in the five Central Asian countries. Kazakhstan had the highest green water footprint (average 49.6×10⁹ m³), much higher than the other four countries (average 3.6×10⁹ m³). Uzbekistan had the highest blue water footprint (average 15.3×10⁹ m³). From 1992 to 2017, the countries with the largest growth rates in the green and blue water footprints of crops were Turkmenistan (87.6%) and Kyrgyzstan (32.3%). The countries with the largest reduction rates in the green and blue water footprints were Kazakhstan (-20.7%) and Uzbekistan (-24.2%). The green water footprint of crops in Central Asia was mainly from cereals, and the blue water footprint was mainly from cereals and oil crops. The water footprint structure of cereals was mainly composed of wheat, rice, and corn, and the water footprint structure of oil crops was mainly composed of cotton. Kazakhstan had the largest reduction in green water footprint and accounted for most of crops with reduced green water footprint, barley (51.6%) and wheat (28.2%). Uzbekistan had the largest reduction in blue water footprint, with cotton (61.9%) contributing the most. The aim of this study was to examine the impact of crop yield on the virtual water content of crops and expand the virtual water content of dozens of crops in these five Central Asian countries. This avoids the shortcomings of inaccurate calculations of the long-term water footprint series in previous studies where the virtual water content remains unchanged. Research on the water footprint of crops in Central Asia revealed that the water footprint was declining, and the main crops causing the water footprint declines had been identified. These results can be used to optimize crop planting and water conservation in Central Asia.