| Water and land matching is a spatio-temporal combination of the quality and quantity of water and land resources.The matching directly affects the comprehensive utilization efficiency of water and land resources and restricts the development of agriculture and related economies.At present,the research on the water and land matching is mostly based on the analysis of municipal administrative units,which blurs the differences in water and land resources caused by different river basins.The river basin,which is integrate and correlated,takes rivers as a link to communicate with various internal areas through a network of main and tributary streams,and the internal connections continue to deepen with the use of water resources.Therefore,it is of great significance to analyze the changes of water and land resources and explain the evolution mechanism from a multi-scale,multi-level,and river basin-based unit.This paper takes the Huang-Huai-Hai river basin as the research area,and establishes a river network vector model by the relationship between main and tributariries.The characteristics of river basin were extracted with multi-source data information.Based on them and underlying surface data of the research area,the water and land resource object relational database was made.Found on the municipal data of water resources and land use in 2000,2005,2010,2015 and 2018 of the Huang-Huai-Hai river basin,the Spatio-temporal pattern and its change characteristics were quantitatively analyzed through the multi-scale water and land network model using river basin as units.Combining previous studies and selecting natural factors,agricultural socio-economic factors,non-agricultural socio-economic factors and other factors according to certain principles,a stepwise regression model was established to obtain regression equations,and the driving mechanism of multi-scale water and land resource matching in the Huang-Huai-Hai river basin was explored.Research indicates:(1)The river basin features are extracted by fusion of multi-source information through the vector data of one to five levels of rivers,and the spatial network of water and land resources in the Huang-Huai-Hai river basin is constructed.The main branches and tributaries of the Huang-Huai-Hai river basin have complex structures and relatively fragmented landscapes.The Huang-Huai-Hai river basin has 31 main streams,152 first-level tributaries,132 second-level tributaries,39 third-level tributaries,and 12fourth-level tributaries.The sub-basins are divided according to the main and tributaries.The Huang river basin mainly includes 176 sub-basins such as the main stream of the Yellow River,the Tao River,and so on.The Huai river basin mainly includes 108 sub-basins such as the main stream of the Huaihe River,the Honghe River,the water systems of the Shandong Peninsula,and the Yishusi water system.The Hai river basin area mainly includes 82 sub-basins such as the main stream of the Haihe River,the main stream of the Luan River,the Tuhai River,and the Majia River.Abstract and generalize river data.Establish relevant data sets.Establish spatial network data model of water and land resources.There are 59 tertiary water resources areas and 128 prefecture-level administrative areas in the Huang-Huai-Hai river basin.The evaluation unit of the three-level water resources area is 429.In the spatial network of water and land resources,the grassland in each evaluation unit of the Huang river basin is mainly grassland,and the evaluation units of Huai and Hai river basins are mainly cultivated land.According to the analysis of landscape index,the spatial network of water and land resources in the Huang river basin is the most fragmented.The Hai river basin has the most irregular landscape shape,with long boundaries of evaluation units in the area,and active exchange of energy with external materials,which is susceptible to external influences.(2)Based on the above-mentioned water and land resource network model,a standard grid size of 5km in 55688 study areas was established,and relevant data indicators based on grid scale were obtained through steps such as density calculation and intersection.The total amount of water resources in the Huang-Huai-Hai river basin is more in the south and less in the north,and the annual water consumption is more in the east and less in the west.The annual water consumption in the Hai river basin is greater than the total water resources,and water resources are in serious shortage.The area of arable land in the study area is decreasing year by year.From 2000 to 2018,the total amount of water resources in the Huang and Huai river basins were relatively large by basin division.The total amount of water resources in the Huang-Huai-Hai river basin showed a fluctuating trend over time.In 2005,the total amount of water resources was the highest,and in 2015,the total amount of water resources was the lowest.In terms of annual water consumption,it is divided by river basin,and the annual water consumption of all levels in the east is significantly more than that in the west.The main stream of the Yellow River water system has the largest annual water consumption,at 14.7 billion m~3.The trend of total annual water consumption in the Huang-Huai-Hai river basin is relatively stable,and the stratification of annual water consumption in the three major river basins is not significant.Comparing total water resources and water consumption,the total annual water consumption in each period of the Hai river basin is higher than the total water resources.From 2000 to 2018,the area of arable land in each period in the Huang-Huai-Hai river basin decreased year by year,with the largest decrease in the period from 2015 to 2018.The Huai river basin has the largest area of arable land in the three major watersheds,the Huang River basin is slightly smaller than the Huai river basin,and the Hai river basin has the smallest area.The area of the three major areas of arable land has shown a downward trend.The utilization of land resources(mainly arable land)is divided by watershed.The upper and middle reaches of the Yellow River,the Loess Plateau,and the upper and middle reaches of the Luanhe River system in the Huang river basin have low reclamation rates,which are less than11%.Reclamation rates in the basins of the northern bank of the Huai River,the lower Yellow River and the southern Haihe River are relatively high,all above 65%.(3)The coefficients of water and land resource matching in three river basins are different.The overall trend of coefficient in the Huang river basin is relatively stable;The coefficient in the Huai river basin has a large interannual variation,showing an inverted"U"shape and the coefficient in the Hai river basin has a downward trend.The average coefficient of water and land matching in the Huang-Huai-Hai river basin was0.1452 from 2000 to 2018.Among the three major river basins,the Huang river basin was the lowest,followed by the Huai river basin,and the Hai river basin was the highest.In terms of changes in the coefficients of water and land matching,the coefficients have decreased in most areas of the Hai river basin,while they have increased in most areas of the Weihe in Huang river basin and in the Huang river basin.(4)A total of 22 natural factors,socio-economic factors and accessibility factors were selected to construct an index system.A stepwise regression model is adapt to analyze the driving forces of the changes in the coefficient of water and land resources,and rely on regression coefficients to judge the degree of influence of each driving factor on it.The results show that the natural factors that affect the changes in the coefficient of water and land matching at all levels of river basin are mainly meteorological factors such as annual precipitation,sunshine hours,temperature,humidity,and leaf area index.Among them,annual precipitation has the largest impact and is positively correlated;Non-agricultural factors such as the proportion of the secondary industry,changes in the urbanization rate,the disposable income of urban residents,and the proportion of the primary industry,changes in the sown area of crops and changes in the amount of chemical fertilizers and other agricultural factors have a certain impact on the water-land match and vary in degree.Non-agricultural factors such as the proportion of the secondary industry,changes in the urbanization rate,the disposable income of urban residents,and agricultural factors such as the proportion of the primary industry,changes in the sown area of crops and changes in the amount of chemical fertilizers have a certain impact on the water-land match and vary in degree. |
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