The Spatio-temporal Variation,Matching Relationship,and Regulation Of Food-land Use-water Nexus On Perspective Of Supply And Demand Balance

With the social and economic development,the availability of food has increased,the living standards of urban and rural residents have been improved,and the food consumption structure has been upgraded.The food consumption structure of Chinese residents has changed which the main food transformed from grain to both animal food and plant food.And the research on grain security has been gradually transformed into the food security.Water and land resources are the main factors restricting food production.The total shortage of water and land resources and its spatial imbalance have a direct impact on the sustainable development of regional agriculture and food security.From the perspective of food supply and demand,based on the situation of food production,land use and water resource utilization,this paper measures the virtual water and virtual land content of food production and food consumption,discusses the matching of agricultural water and land resources and its driving mechanism,and puts forward countermeasures for the rational utilization and optimal regulation of water and land resources.The main results are as follows:(1)The food production shows an increasing trend in China.From 1990 to 2020,food production increased from 701 million tons to 1.85 billion tons,with an increase of 164.17%in 30 years and an average annual growth rate of 3.29%.There are obvious differences in food production in main grain producing areas,grain production and marketing balance areas and main grain marketing areas.The center of gravity of food production in China is generally moving northwest.The area of agricultural land showed a decreasing trend in China.The agricultural land area from large to small is: grassland,cultivated land,garden.The change of water resources in China presents an obvious two-stage characteristic of "rising-falling" in time,and a spatial characteristic of abundant in the south and less in the north,more in the west and less in the east.(2)From 2000 to 2020,the total amount of virtual water and virtual land for food production both showed an increasing trend.The virtual water and virtual land for food production in south China are smaller than those in north China.The results show that the virtual water and virtual land content of food production in China from large to small is: main grain producing areas > grain production and marketing balance areas > main grain marketing areas.From the perspective of food types,the differences of total virtual water and total virtual land in plant food and animal food production in different regions gradually decreased.The flow direction of food virtual water and virtual land in China is basically the same,mainly from the main grain producing areas to the main grain marketing areas.(3)Set three food consumption scenarios of animal-based food(scenario 1),balanced animal and plant food(Scenario 2)and recommended by dietary guidelines(Scenario 3).There are similarities among the three scenarios: The virtual water and land measured by the household population and permanent resident population have obvious differences.Population mobility leads to a decrease in the consumption of virtual water and virtual land in the main grain producing areas and grain production and marketing balance areas,and an increase in the consumption of virtual water and virtual land in the main grain marketing areas.As a result,the consumption of virtual water and virtual land decreased in the south and increased in the north.The consumption of virtual water and virtual land in the south was higher than that in the north.There are differences among the three scenarios: The consumption of virtual water and virtual land in the three scenarios is significantly different.In scenario 1,the consumption of animal food is too high,resulting in relatively more virtual water and virtual land consumption.(4)As can be seen from both Gini coefficient and Lorentz curve,agricultural water and land resources in all provinces of China present a significant imbalance,but as a whole present a positive trend of small fluctuation.According to the matching coefficient of agricultural water and land resources,the spatial distribution pattern of the matching degree of agricultural water and land resources in the southeast is better than that in the northwest,the main grain marketing area is better than that in the main grain producing area and the grain production and marketing balance area,which shows a drastic fluctuation in time.(5)Analyze the driving mechanism of matching agricultural water and land resources.The results of geodetector indicated that precipitation and temperature have the largest contribution to the spatial differentiation of matching agricultural water and land,and are in a dominant position.The contribution of agricultural social economic factors is greater than the non-agricultural social economic factors.As the time went by,the influence of agricultural social economic factors such as the effective irrigated area and the agricultural plastic film usage has gradually become prominent,and it is a secondary factor that produces the spatial differentiation of agricultural water and land matching.Results of multiple linear stepwise regression analysis showed that the population,urbanization rate and urban residents per capita income,the proportion of primary industry,the proportion of the tertiary industry and water and land resources matching degree present a positive correlation.There is a negative correlation between the sown area of farm crops,effective irrigated area,agricultural fertilizer,agricultural plastic film usage and water and land resources matching degree.(6)Based on the research results of driving mechanism,suggestions are put forward for the optimization and regulation of water and land resources.Improve the utilization efficiency of agricultural water resources.Maintain the stability of cultivated land productivity: establish cultivated land quality protection mechanism,reduce the harm of chemical fertilizers and pesticides.Considering the influence of non-agricultural economic factors: adjusting industrial structure and promoting green ecological development.