华北平原主要种植模式农业地下水足迹研究——以河北省吴桥县为例

本研究采用地下水足迹分析方法,以华北平原传统冬小麦-夏玉米两熟区河北省吴桥县为例,开展冬小麦、夏玉米两熟复种体系农业地下水资源消耗研究,在此基础上分析了不同作物地下水足迹对地下水资源的影响,以期为华北平原地下水超采区种植结构调整提供理论依据。研究结果表明,自1949年以来,吴桥县冬小麦地下水足迹均高于夏玉米,历年冬小麦和夏玉米的地下水足迹均值分别为89.02 km~2和29.84 km~2。从变化趋势来看,吴桥县冬小麦和夏玉米的地下水足迹均呈波动上升的趋势。而作物地下水足迹胁迫指数(GF/Aaq),冬小麦基本处于中等程度胁迫(0.1GF/Aaq1),夏玉米绝大多数年份处于较轻程度胁迫(0.01GF/Aaq0.1),但两种作物胁迫指数近年来不断增加。对该区域其他作物地下水足迹计算结果表明,夏花生和马铃薯的每平方米地下水足迹较低,分别为2.08×10~(-7)km~2和1.94×10-7 km~2,且两者的每平方米地下水足迹胁迫指数在被比较作物中同样最低,分别为3.57×10~(-10)和3.34×10~(-10)。根据作物比较认为传统冬小麦-夏玉米种植模式可以通过在农作制度调整过程中将花生、马铃薯作为替代作物引入到当地的种植结构中,可在一定程度上减少对地下水资源的消耗,从而缓解区域环境中的地下水资源压力。因此,为改善华北平原农业地下水资源的利用状况,可以通过调整作物种植结构,增加低耗水作物与主粮作物复种轮作的面积有效控制地下水资源的开采,实现农业的可持续发展。

Agricultural groundwater footprint of the major cropping system in the North China Plain: A case study of Wuqiao County, Hebei Province

As a newly developed concept and research method for water footprint studies in recent years,groundwater footprint (GF) could be used to evaluate potential use of renewable groundwater to increase agricultural production or in combination with water footprint and virtual water calculations. The GF method was used to analyze the groundwater resources utilization in agriculture and to assess the environmental impacts in wheat-maize crop rotation system at Wuqiao Experiment Station-a traditional region where wheat-maize crop rotation is practiced in the North China Plain. This study was based on the latest developments in theories and methods of GF in combination with agricultural practices. In addition,GFs of crops were calculated at county scale,and the impact of the different crops on GF analyzed for Wuqiao County in Hebei Province. The results showed that since 1949,GF of winter wheat was higher than that of summer maize,with respective mean values of 89.02 km² and 29.84 km² for Wuqiao County. Also based on the trend of change,GF of winter wheat and summer maize had an increasing trend of fluctuation. In terms of GF stress index (GF per unit area,GF/A_aq) for the crops,winter wheat basically had a moderate stress (0.1 < GF/A_aq < 1) and the stress index for summer maize was less (0.01 < GF/A_aq < 0.1) for most the years,which increased for recent years. Thus if reasonable measures were not taken to control cultivation,GF would increase and have a significant impact on the balance of water circulation in regional environmental system in the coming years. This would put considerable pressure on groundwater resources to meet water needs of crops in Wuqiao County. The research suggested that to reduce groundwater pressure and ensure effective restoration of groundwater resources,the traditional wheat-maize cropping system could be adjusted through the cultivation of peanut and potato,whose GFs were 2.08×10^-7 km²·m^-2 and 1.94×10^-7 km²·m^-2,around 40% and 58% less than that of winter wheat. Thus through the exploration of GF,cropping structure in Wuqiao County could be adjusted or the area of crop rotation between low water-consumption crops and staple grain crops could be increased to enhance the use of water-saving technologies and improvement of water-saving measures. The study showed that GF analysis had the potential for application in agricultural research. It was concluded that in future,basic GF research should be enhanced and GF parameter database construction at various scales and for various crops were required to provide a solid basis for research on sustainable use of groundwater resources and the development of sound government policies.