兼顾水质与水量的长江经济带农业水土资源匹配时空格局

SPATIAL-TEMPORAL PATTERN OF AGRICULTURAL WATER AND SOIL RESOURCES MATCHING IN YANGTZE RIVER ECONOMIC BELT, CHINA WITH CONSIDERATION OF BOTH WATER QUALITY AND QUANTITY

关键词:  农业水土资源匹配  灰水足迹  农业用水  时空格局  长江经济带

Key words:  match of agricultural water and soil resources  grey water footprint  agricultural water  spatial-temporal pattern  the Yangtze Economic Belt, China

摘要:

目的 农业水土资源匹配是农业可持续发展的重要基础，但是当前农业水土资源匹配方面的相关研究主要侧重水量，往往忽视了农业污染问题，因此文章研究兼顾水质和水量，以长江经济带为研究区，揭示农业水土资源匹配的时空演变特征，为缓解农业水资源的供需矛盾、优化水土资源配置等提供科学依据。方法 综合考虑灰水足迹与农业用水，构建水土资源匹配系数，并采用局部空间自相关法揭示水土资源匹配的时空变化格局。结果 将农业污染纳入水土匹配测度不仅对整体水土资源匹配类型影响较大，对水土资源匹配类型的数量和空间分布影响也较大：（1）在时序上，2000—2019年长江经济带水土资源匹配系数在小幅下降后处于稳定状态；匹配系数平均值为1.04，保持相对均衡的状态。（2）在空间上，四川、重庆、湖南等地水土资源匹配较好，并且四川等地呈持续向好的趋势，然而湖北、安徽、江苏等地却恰恰相反。（3）水土资源匹配较差的地区多表现为双重型缺水，主要分布于云南、湖南等地，并且该类型在下游减少、上游增多；水量主导型缺水区主要分布于贵州、江苏等地，而水质主导型缺水区主要分布于湖北、安徽等地。结论 有必要将水质与水量同时纳入水土资源匹配评估体系中，研究表明长江经济带水土资源匹配程度提高，总体上空间格局较稳定，但是区域差异明显；当前存在的主要问题是“双重型缺水”；明确各地区的缺水类型为提出针对性的调控策略提供了依据，例如可以通过合理调控生产要素投入、调整作物种植结构等措施，降低农业水土资源不匹配的风险。

Abstract:

The match of agricultural water and soil resources is essential for sustainable agricultural development. However, the existing studies related to the match of agricultural water and soil resources mostly only considers the quantity of water while ignoring agricultural pollution. So, this study, taking the Yangtze River Economic Belt, China as the study area, considers both the quantity and quality of water to reveal the characteristics of spatial-temporal changes in the match of agricultural water and soil resources, and it may help to provide scientific references for alleviating the conflicts between the supply and demand of water resources in agricultural production and optimizing the allocation of water and soil resources. This research both considered grey water footprint and agricultural water use, proposed the matching coefficient of water and soil resources, and applied the local spatial autocorrelation method to reveal the characteristics of spatial-temporal changes in the match of agricultural water and soil resources. The results were listed as follows. Including agricultural pollution in the assessment of the match of water and soil resources not only had an impact on the type of match of water and soil resources but also had an impact on the number and spatial distribution of that match. In detail: (1) In time series, the matching coefficient of water and soil resources slightly declined and then maintained stably in the Yangtze River Economic Belt from 2000 to 2019. Its average was 1.04 and kept relatively balanced. (2) Spatially, the water and soil resources matched well in Sichuan, Chongqing, and Hunan, and the matching degree in Sichuan showed an increased tendency. Comparatively, it was totally opposite in Hubei, Anhui, and Jiangsu. (3) The areas with low match degrees were mostly faced with a “double shortage in water” (which meant a shortage in water quantity as well as a lack of enough water to dilute agricultural pollution). These areas were mainly distributed in Yunnan and Hunan, and the number decreased down-stream but increased the up-stream. At the same time, the type of “water-quantity dominated & water shortage” was mainly distributed in Guizhou and Jiangsu, while the type of “water-quality dominated & water shortage” was mainly distributed in Hubei and Anhui. In summary, it’s necessary to incorporate both the quantity and quality of water into the assessment of the match of water and soil resources. The results indicate that the matching degree of water and land resources improves in the Yangtze River Economic Belt, China, and showing a stable spatial pattern but obvious spatial differences. The main problem needed to deal with is a “double shortage in water”. So, clarifying the types of water shortage in different areas can provide scientific references for proposing specific regulating strategies, for example, changing the input of production elements, and adjusting cropping planting structure to reduce the risk of the mismatch of agricultural water and land resources.