Spatio-temporal Variation Of Wheat Cultivation In China And Its Driving Factors During The Past 65 Years

Food security is directly related to the people's livelihood,social stability and the stable development of the national economy.Especially for a country with a population of over a billion people,Chinese food security has become a hot topic at home and abroad.The dynamic evolution information of crop spatio-temporal distribution reflects the human utilization of agricultural land resources,which is the important foundation of the study of biological geochemistry circulation of farmland ecosystem contribution and the impact of global change on food production system,plays a vital role to ensure national food security and optimize land use pattern.Wheat is the main grain for residents in northern China.According to statistics,the planting area of wheat in China reached 24.06 million hectares in 2014,accounting for 21.35%of the total grain area in China.In addition to Hainan province,wheat is cultivated in all provincesof China.It mainly includes the southwest wheat region,the middle and lower reaches of the Yangtze river wheat region,the huang-huaihai wheat region and the northwest wheat region,and the main producing region is located at the huang-huaihai area.In recent years,The Chinese wheat yield and total output see stable development,which could balancethe wheat supply and demand,however,due to the local climate condition,soil type,cropping systems,cultivar type,production level and management technology,the regional production presents an obvious imbalance in China.It is of great significance for us to clarify the changing characteristics of wheat planting pattern in a long-time series and large area scale and study the driving factors that affect the change of wheat cultivation.This paper takes wheat as the research object and the province as the research unit.Firstly,the basic change information of the spatio-temporal distribution of wheat planting in 1949-2014 is characterized by statistical method.Then,combined with agricultural economic data and climate data,a panel regression model was used to evaluate the driving factors that contributed to the change of wheat spatial pattern,especially the climatic factors.The main conclusions are as follows:(1)Wheat production has an obvious characteristic of the"wave of growth",the volatility was becoming"iron"over time,Henan and Anhui provinces and wheat yield fluctuations contribute significantly to the fluctuation of the total output of wheat in China.And the inter-provincial division of wheat spatial distribution is obviousin China,and the 1980s is an important turning point in the direction change of its distribution characteristics.In general,the distribution of wheat planting area showed a trend of decreasing middle-marginal increasing between 1949-1980,and the significance of this divergence gradually decreased with time.From1981 to 2014,the distribution of wheat cultivation was significantly showed a trend of increasing central-decreasing marginal,which made the imbalance of wheat distribution more obvious.(2)The cultivation center of Chinese wheat area was distributed near the boundary line between Shanxi and Henan provincefrom 1949 to 2014,the linear distance of wheat cultivation center stretched for 104 km in the northwest direction between the 65 years.From 1949 to 2014,the cultivation center of winter wheat was all distributed in Henan province,and the direct distance of the center stretched for 31 km in the northwest direction between the 65 years.Before the 1970s,the winter wheat planting area is reduced at a rate of about 0.89×10~4 ha/year,which increased mainly in Sichuan,Yunnan,and Hebei provinces and decreased mainly in Henan,Anhui and Jiangsu provinces.Therefore,the cultivation centers of winter wheat migrated to the southwest for 89 kmat this stage;After 1970s,the winter wheat planting area is reduced at a rate of about 1.99×10~4 ha/year,whose decrease mainly appeared in northern Sichuan,Shaanxi and Shanxi provinces etc,and increase only appeared in Henan,Jiangsu and Anhui provinces.Therefore,the cultivation centersof winter wheat planting stretched for 66 km to the northeast in this stage.The cultivation centers of spring wheat were distributed in the northern border region of Inner Mongolia,which migrated 692 km to the southwest direction.Before the 1970s,the annual absolute growth area of spring wheat was 8.17×10~4ha,and the province with the highest annual growth area was in Heilongjiang province.After the 1970s,the planting area was reduced by 8.46×10~4ha/year,and its planting area decreased mainly in Heilongjiang,Gansu and Xinjiang provinces.(3)The wheat cultivation area was mainly affected by socio-economic factors,and the influence of climate factors is also significant.Winter wheat cultivation area is mainly influenced by the social and economic factors,including irrigation area,the level of urbanization,the power consumption per hectare,wheat benefits as well as the agricultural output,of which the change of agricultural output showed the highest contribution to that of winter wheat area—19.38%,and the temperature and precipitation changes contributed 9.69%and 11.05%to the change of winter wheat area respectively.The study found that temperature had a positive effect on winter wheat area and the spaitial driving impact was obvious,the growing season temperature of winter wheat rose by 1%,winter wheat area would increase by 0.09%over the same period,and the growing season precipitation increase by 1%,winter wheat area would reduce by 0.56%over the same period.Spring wheat area was also mainly affected by the social and economic factors,such as the level of urbanization,wheat benefits,power consumption per hectare,irrigation area and research input.The change of urbanization level has made the highest influence on the change of spring wheat area between 65 years—18.93%,and the contribution of temperature and precipitation changes on thespring wheat area change were 14.12%and 13.19%respectively.At the same time,the temperature has a negative effect on the spring wheat area and the spaitial driving impact was significant.The growing seasontemperature of spring wheat rose by 1%,spring wheat planting area would reduce by 6.41%over the same period,and the precipitation of that increased by 1%,spring wheat planting area will be reduced by 1.95%over the same period.