Study On Spatial And Temporal Variation Ofgrain Production In China

Since 2003,China's grain output has increased fourteen times because of the stimulation of the policy of strengthening,benefiting and enriching peasants and the progress of modern agricultural science and technology.However,while China's grain output is growing steadily,the quality of grain can not keep up with the increase of output in time.The structural contradiction between grain supply and consumption is becoming increasingly prominent.Under the background of the structural reform of agricultural supply side,the central document No.1 of 2019 put forward the idea of "vigorously developing the production of scarce and green high-quality agricultural products,and promoting the transformation of agriculture from the guidance of increasing production to the guidance of improving quality".Therefore,this paper focuses on the spatial and temporal distribution and coordinated development level of grain yield and quality in China,and analyses the influencing factors of their coordinated development level.Firstly,the data of grain production from 2003 to 2017 and the data of pollution-free certification and green certification from 2015 to 2017 are sorted out.On this basis,the shift of the focus of grain production and quality in China is analyzed.The results show that the grain yield center of gravity and the paddy yield center of gravity have a very obvious trend of moving to the northeast from 2003 to 2017.The maize yield center of gravity also moves to the Northeast in the fluctuation,while the trajectory of the wheat yield center of gravity is oscillating from left to right.From 2015 to 2017,the grain,rice,wheat pollution-free certification and rice green certification center of gravity all migrate to the southwest.Maize pollution-free certification focuses on Northwest migration.The results of spatial overlap and consistency of changes show that there are differences in spatial distribution of grain yield and quality between 2015 and 2017.Furthermore,the coupling coordination degree model was constructed to calculate the coupling coordination degree of grain,rice,maize and wheat yield and quality.Then from the perspective of industrial development,the determinants of coupling coordination degree are analyzed.Considering that the current development of grain industry chain may be an important determinant of industrial development,the data of national leading grain industrialization enterprises from 2015 to 2017 are sorted out as proxy variables to measure the degree of industrial chain development.The spillover of determinants of coupling coordination degree is also analyzed from the perspective of spatial econometrics.Effect.Because the coupling coordination degree of wheat yield and quality presents spatial autocorrelation,we focus on exploring its spatial agglomeration.Because of the limited use of spatial econometric model,the panel Tobit model and IV-Tobit model are used to analyze the influencing factors of the coupling coordination degree of grain,rice,maize and wheat.The results show that:(1)the leading grain enterprises have significant positive effects on the coupling coordination degree of total grain and three main grains;(2)the highway infrastructure has significant positive effects on wheat production.The impact of quality coupling coordination degree is significantly positive;(3)fiscal expenditure on agriculture,forestry and water has a negative impact on the coupling coordination degree of grain production and quality;(4)urbanization rate has a significant inhibitory effect on the coupling coordination degree of grain and wheat production and quality.Finally,the countermeasures and suggestions to improve the level of coordinated development of grain yield and quality are put forward.