| The quantitative evaluation of water resource consumption in crop production is highly dependent on spatial scale and has different intensity and effect with the change of spatial scale.Crop production water footprint is seen as evaluation index,scientific and accurate comprehensive agricultural water related assessment has been involved in various spatial scales is commonly used in water resources management,but the research is independent of a particular space level,to use the same methods under the same crop in the same area,the same study period,often appear between different research results of different phenomena.As a result,the research results can’ t be effectively used to make decisions related to agricultural water resources.However,in general,the current studies only focus on a specific spatial scale,and the differences among different spatial levels of crop production water footprint are in the stage of qualitative description research,and there is no quantitative study on the spatial level effect of crop production water footprint.Here,a case study on the water footprint of wheat production at different spatial levels in China’s mainland from 2000 to 2014 is used to fill in this gap.In this study,the water footprint of wheat in China from 2000 to 2014 was taken as an example,we calculated the water footprint of wheat on five different spatial levels in China during the research period.The spatial levels effect of the water footprint of crop production was quantitatively analyzed by means of spatial analysis,sequence detection and quantitative statistical analysis.The main research conclusions are as follows:(1)Ratio of blue water footprint caused by irrigation water transmission and distribution loss the proportion of blue water footprint is between 31% and 34%.According to the time series test,the water footprint,blue and green water footprint of wheat per unit production all showed a significant downward trend during the research period when the planting area and water consumption of wheat decreased continuously while the yield per unit area increased steadily,and the blue water footprint was significantly higher than the green water footprint.(2)Through the different spatial levels of wheat production water footprint contrast,it is concluded that,wheat production water footprint to show the different space levels distribution is roughly similar,but the crop production water footprint and crop growth in the value of the specific natural conditions,the level of agricultural production,such as the spatial distribution of the water footprint is show that spatial heterogeneity.In the process of ascending levels,the water footprint value of large spatial level balanced the spatial heterogeneity of many small spaces,and the spatial distribution of wheat water footprint,blue water footprint and green water footprint were different at different spatial scales,which was particularly obvious in the ascending scale to the large river basin.(3)According to the spatial autocorrelation analysis,although the water footprint of wheat yield per unit area is not significant in most regions,there is significant aggregation at all spatial levels in China.The blue water footprint of wheat production was more significant than green water footprint in each spatial level.At the county level,the significance was the lowest,and the spatial correlation was as follows: scattered areas clustered and distributed.However,the value of river sub-basin level is the largest,and the spatial correlation is concentrated and distributed in different regions.(4)The factors affecting the water footprint of crop production have different effects on different spatial scales.Especially,when the scale rises to the large river basin level,the main factors affecting the water footprint of crop production change the most compared with other spatial levels. |
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