| Water is an indispensable resource for human activities and social production.The contradiction between supply and demand between water demand for human activities and water resource reserves has gradually become the bottleneck of development of social.Virtual water and water footprint have been put forward one after another,enriching the ways to solve water problems.It is of great social significance for agricultural water resource management to analyze the structure,change,influencing factors,coordination and regulation of agricultural water footprint in depth and put forward effective countermeasures.Based on the calculation method of Water Footprint Evaluation Manual,combining Arc GIS software and principal component analysis,this paper studies the temporal and spatial distribution characteristics and its influencing factors of water footprint of main grain crops in Beijing Tianjin Hebei during 2000-2015.On this basis,the accounting method of agricultural water footprint is further improved,and the actual production,consumption and flow of Beijing Tianjin Hebei agricultural water footprint(virtual water)are calculated.The evaluation model and system dynamics model of agricultural water footprint coordination degree are constructed,and the time-series change of regional water footprint coordination degree and the regulation measures of agricultural water footprint are studied.The main research contents and conclusions of the paper are as follows:(1)Based on the calculation method of Water Footprint Evaluation Manual,the temporal changes and spatial differences of water footprint of main crops in Beijing,Tianjin and Hebei were calculated and the influencing factors were analyzed.The proportion of blue water,green water and grey water shows the trend of decreasing,rising and first rising and then declining respectively;the spatial distribution of water footprint shows that there are less in the northwest and North,more in the south,Southeast and middle;the first and fifth main factors affecting the total water footprint are nitrogen fertilizer application amount and crop planting area,the second are thermodynamic and dynamic factors,the third The four main components are water factor.(2)The quantitative method of crop production water footprint based on regional water use was improved,and the virtual water consumption of Beijing Tianjin Hebei 2000-2015 residents was calculated by this method,and the differences and influencing factors of virtual water consumption in different regions were compared and analyzed.The results show that the virtual water consumption of Beijing,Tianjin and Hebei residents is on the rise.The difference of virtual water consumption between Beijing,Tianjin and Hebei is obvious,which shows that the urban area is higher than the rural area,and the economically developed area is higher than other areas.(3)This paper calculates and analyzes the characteristics of agricultural virtual flow and its influence on regional water resources pressure under the production consumption mode in Beijing Tianjin Hebei region.The results show that under the influence of production structure,consumption structure and population change,the regional virtual flow has changed obviously.The output of virtual water in Hebei Province is decreasing,while the input of virtual water in Beijing and Tianjin is increasing.From 2000 to 2015,the average annual water resource pressure index shows Hebei > Tianjin > Beijing,the water resource scarcity degree shows Tianjin > Beijing > Hebei,and the water resource self-sufficiency rate shows Hebei > Tianjin > Beijing.The dependence of Beijing and Tianjin on external virtual water input increases gradually,and the problem of water resource system overload is serious.(4)The matching index of crop water footprint production and consumption is established,and the evaluation model of coordinated development degree between the two systems based on water footprint production suitability and water footprint consumption suitability is constructed to analyze and evaluate the production consumption degree of agricultural products and the coordination degree of agricultural water footprint.The results show that due to the different production structure and consumption degree,the matching degree of different products in the same region is significantly different,and the matching degree of products between regions is also significantly different.The water footprint production suitability evaluation index and water footprint consumption suitability evaluation index fluctuate between years,but the overall trend is on the rise.The water footprint consumption suitability index shows a trend of increasing first and then decreasing.The comprehensive evaluation index of agricultural water footprint coordination improved obviously in the early stage,and then tended to be stable.Regional agricultural water footprint management should improve the suitability level of both agricultural water footprint production suitability and agricultural water footprint consumption suitability.(5)In view of the lack of green water in the current agricultural water resources regulation research,the concept of green water is introduced into the model,which enriches the connotation of regional water resources management;the dynamic model of agricultural crop production system in Beijing,Tianjin and Hebei is constructed by using Vensim software,and the key factors that can be regulated in the management of agricultural water resources in Beijing,Tianjin and Hebei are discussed,including precipitation infiltration coefficient and irrigation water utilization coefficient 2 The key controllable factors are simulated separately.This method can propose specific control measures. |
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