Water Footprint Of Food Crops And Regional Virtual Water Movement In China

Under the increasingly tense pressure of agricultural water resources and food security,China is facing the challenge of producing more grain under the premise of zero or negative growth of agricultural water,reducing agricultural water expenditures is imperative.Therefore,on the one hand,we should improve the utilization efficiency of agricultural water resources and reduce the consumption of water resources per unit grain yield.On the other hand,at the national level,based on the strategy of suitable water planting,we should make a reasonable plan for the planting of major grain crops in our country,increase the utilization of green water,reduce the consumption of blue water,and adjust the blue water resources from the efficiency point of view.This is of great significance to ensuring the safety of grain and water,improving the sustainability of water resources,and solving the growing demand for water in the non-agricultural sector and promoting the sustainable development of the society and the economy.First of all,through the study of grain production and consumption in 31 provinces and cities of China in 2014,the inter-provincial virtual water transport of grain is calculated,and the suitability evaluation is carried out,the adjustment area is clear.Based on the study of water footprint of per unit yield of four main grain crops,rice,winter wheat,spring wheat and corn in 31 provinces and cities,we find the suitable crops for planting in different regions.Based on this,we optimize the existing virtual water migration and put forward the optimization direction.The main results are as follows:1.The total amount of grain production(excluding beans)in 2014 is 590 million tons,the total amount of grain consumption(no bean)is 568 million tons,and the grain production is bigger than consumption,but the center of gravity of grain consumption is obviously southward.The grain production and consumption space are mismatch,food is short in the south and surplus in the north.Compared with 2007,the "three zone" of grain has changed significantly.The main production areas are reduced and concentrated in the north.The expansion of the main sales area in the South has led to the grain transportation from the north to the south of China.The main reason for the grain gap in the main sales area is corn feed and industrial food.Taking grain transportation as a carrier,water resources have been migrating among China,and become an important component of water resources development and utilization in China under the new social background.2.In 2014,the water footprint of grain crops in 31 provincial administrative regions in China passed the significant test.There were significant positive spatial autocorrelation characteristics,that is,high value provinces and cities are adjacent to high value areas.Low value provinces and cities are adjacent to low value areas.The high value areas are concentrated in Southeast,southwest,central and South China and southeast of China,and the low value areas are concentrated in the northeast of China.North China,Northwest China,central China and East China.The main grain demand water index(the ratio of water footprint to the national average)and the blue water demand index(the ratio of the blue water footprint to the national average)were divided into four intervals according to the suitability of the crops.The results showed that the suitable areas for rice cultivation were Sichuan,Chongqing,Guizhou,Zhejiang,4 provinces,and winter wheat.The suitable areas for planting are 3 provinces of Anhui,Henan and Jiangsu.There are more suitable areas for maize planting,including 15 provinces and cities in China.Through full use of green water and efficient use of blue water,we hope to provide a basis for improving the utilization efficiency of agricultural water resources and optimizing the layout of grain production.3.In 2014,the blue water attached to the surplus grain in main production provinces reached 18 billion m3,the blue water attached to the grain shortage in main market was about-247 billion m3,the grain in the balanced province was slightly surplus and the blue water attached to the grain was about 2 billion 300 million m3.The water footprint of the unit grain yield in north is less than that in south,and the main production area is less than the equilibrium area.It shows that under the current grain production conditions,the water use efficiency of grain production in northern China is higher than that in the south,the main production area is the highest,the balance area is the second,and the main market is relatively small.The current movement of grain virtual water flows from the water shortage area to the abundant water area,is reverse configuration with water resources,and the North Grain South transportation further aggravate the pressure of the water resources in the north.In this paper,the suitability index of grain virtual water transport in all provinces of China in 2014 was calculated by selecting five major factors,including water resources endowment,agricultural water resource management level,agricultural development status,ecological environment and social and economic development level,and 27 evaluation indexes.The results show that the suitable flow and outflow areas of China's grain virtual water transport are concentrated in Northeast China and the large part of Southwest Southern China.Among them,particularly in Heilongjiang,Jilin,Yunnan,Guizhou,Sichuan,Hunan,Jiangxi,Guangxi and Chongqing.Suitable inflow areas are mainly concentrated in the northwest and North China,especially in Ningxia,Beijing,Tianjin and Shanghai.Based on the matching of grain virtual water transport suitability and the current status of grain virtual water migration,Heilongjiang,Inner Mongolia,Gansu and Henan are divided into sustainable areas.Qinghai.Tibet,Hebei,Jiangsu,Zhejiang,Fujian and Guangdong are the key adjustment areas,and the rest provinces and cities are classified into general adjustment zones.Based on the strategy of increasing the utilization of green water and reducing the water consumption of blue water,combined with the analysis of four kinds of crops blue water demand index,the optimization direction of the current virtual water migration is put forward.The regions need to drop output are Hebei,Jiangsu,Shanxi,Ningxia,Xinjiang and Liaoning.The region need to improve output mainly concentrates in the southern regions of China.It is necessary to strengthen the production of rice in Fujian,Guangdong,Zhejiang,Sichuan,Chongqing and Guizhou.The production of winter wheat in Anhui need strengthened,and the production of spring wheat in Jilin needs strengthened.Sichuan,Chongqing,Guizhou,Yunnan,Guangxi,Hainan,Jilin,Hunan and Shandong should expand the production of maize.The innovation points are as follows:1.The grain consumption of 31 provinces and cities of China in 2014 was calculated by classifying grain ration,feed,grain,seed grain and grain loss.The three indexes of grain production,self-sufficiency and production and consumption balance were identified and divided into main grain production areas,balance areas and main selling areas.2.The water footprint and blue water footprint of four main grain crops of rice,winter wheat,spring wheat and corn were calculated.Spatial clustering and heterogeneity were identified by spatial data exploration and analysis.The suitable,more suitable,less suitable and unsuitable planting of the main grain crops were divided into the water footprint and the blue water demand index Area.3.Quantitative evaluation of the transport volume of the virtual water region of grain crops,the advantages of the subjective analytic method and the objective entropy method,the evaluation index system of the virtual water regional transport of grain crops is confirmed by the combination weighting method.