The Impact Of Urbanization On Grain Production And Its Action Path

The economic development in China has entered a new normal,which is basically characterized by a shift from quantity-oriented sloppy growth to quality-oriented intensive development,and urbanization and food security are undoubtedly the driving force and basic guarantee in the high-quality transformation process of China's economy.Since the reform and opening up,with the reform of the urban-rural dual structure and the gradual elimination of barriers to mobility,China has experienced an unprecedentedly rapid urbanization process,which is reflected in the population agglomeration in cities and towns,the expansion of urban land for construction and the transformation of the industrial structure to industrial and service industries.In this process,grain production has borne the brunt,the loss of cropland and the structural shortage of labor gradually lead to the non-agricultural and de-grain conversion of agricultural land,and thus the mobility constraints of production factors have led to an inherent link between urbanization and grain production that can not be ignored.However,although China has the ability to guarantee the supply of grain and important agricultural products at this stage,grain production is facing many challenges such as rising costs,resource constraints,declining returns and growing rigid demand,and grain supply and demand are in a tight balance.In addition,China's grain production has not declined due to the reduction of cropland,and the marginal impact of urbanization on the productivity of cropland has not led to a corresponding proportional decline in grain production.Farmers have an intrinsic incentive to change the level of cropland intensive use and are able to adjust their production structure and methods by weighing whether increasing productive expenditure per unit area can bring objective economic benefits.Regional differences in climate conditions have also brought about a number of uncertain effects on grain production.In short,China's regional economy during the high-quality transition period is facing a trade-off and coordination between urbanization and grain production.So,what is worth paying attention to is,in the process of urbanization,what are the characteristics of temporal and spatial changes in China's grain production? What is the impact of urbanization on grain production and its path? Are there inter-regional differences? This study will focus on these issues to discuss,which are important theoretical and reference implications for grasping the development direction of grain production layout,understanding farmers' willingness and behavior to grow grain,and formulating synergistic government policies to promote urbanization and ensure food security during the transition to high-quality development in China's urbanization.This study focuses on the impact of urbanization on grain production and its path.Based on the definition of relevant concepts,literature review,theoretical reference and analysis,and comprehensive use of descriptive statistics,spatial statistical analysis,econometric models,GIS and other methods,this research focuses on detailed analysis of the spatial and temporal characteristics of China's grain production,the coordinated relationship and dynamic response between urbanization and grain production,and the spatial effects and nonlinear characteristic of urbanization affecting grain production based on the panel data of 330 prefecture-level cities from 2000 to 2018.Further,construct a theoretical analysis framework of “Urbanization--Cropland intensive use--Climate conditions--Grain production”,and investigate the path that urbanization affecting grain production under the dual effects of mediation of cropland intensive use and moderation of climate conditions.Based on the comprehensive analysis of the above content and China's actual national conditions,the corresponding policy implications are put forward.Specifically,the main research content of this study and the findings obtained include the following aspects:First,historical changes and development trends.Based on national and provincial statistics,this section analyzes the urbanization process in China since the reform and opening up,and compares the development trends and regional differences of urbanization in different dimensions of population,land and economy among provinces.Analyze the current trends and functional area differences of grain production in terms of grain production,grain sown area and grain yield per unit area,and the trends and differences in the three major crops of wheat,corn and rice are analyzed.The provinces with higher urbanization rates in China are mainly located in the eastern coastal areas,but the growth rate of urbanization in the central and western regions is faster than that in the east.China's grain production and grain yield per unit area have experienced obvious fluctuating growth processes,but the grain crop sown area overall has shown a declining trend.Grain production in China is still dominated by the main grain-producing regions,with the grain balancing areas steadily increasing,while the scale of the main marketing areas continues to decline,with wheat,corn and rice production showing varying trends of change.Second,spatial and temporal variation and agglomeration characteristics.Analysis of spatial correlation and differentiation characteristics of grain production at the prefecture level based on ESDA,the temporal evolution and agglomeration characteristics of grain production by Kernel density and Markov chain model,and use standard deviation ellipse and gravity shift model to analyze the change route and agglomeration direction of the grain production gravity center.From the perspective of spatial distribution changes,China's grain production has formed a stable spatial pattern of high-high agglomeration areas dominated by the main grain-producing areas in Northeast and North China,spreading to low-low agglomeration areas in the main marketing areas and balance areas,and sporadic distribution of high-low outlier and low-high outlier areas in the periphery.The gravity trajectory of grain production center shows an obvious trend of shifting along the "northeast-southwest" direction.China's grain production has formed the distribution characteristics of "one-main,multi-small,singlepeak dominant" and right trailing tail,and it has the stability to maintain the original relative scale state,but there are multi-level differentiation and spatial imbalance phenomenon.Third,interaction relationship and dynamic response.The indicators are selected from the dimensions of population,land and economy,and use the entropy method to evaluate the comprehensive level of urbanization,then the interaction between urbanization and grain production at the prefecture-level city level and its dynamic response are analyzed by the impulse response function and variance decomposition in the panel VAR model.Both urbanization and grain production have their own inertia characteristics that trend to weaken over time,and the inertial time lag effect of grain production is longer.Urbanization can have a negative impact on grain production in the short-term,but can have a facilitating effect in the long-term evolution,while grain production can have a boosting effect on urbanization in the short-term,but a dragging effect in the long-term evolution.The interaction relationship between urbanization and grain production exhibits dynamic and long-term characteristics,and grain production is more strongly influenced by urbanization.Fourth,the impact effect: non-linear characteristics.The next empirical contents focus on examining the effect of urbanization on grain production at the prefecture level based on different perspectives and the action path.Based on the ordinary panel model as the baseline regression to examine the impact of urbanization on grain production,in view of the stage differences of urbanization development in different regions,a dynamic panel threshold model is constructed to test the non-linear threshold characteristics of the impact of urbanization on grain production.The increase in the level of urbanization significantly reduced grain production,but there are significant regional differences in the degree of negative effects,which shows that there is a need to consider the non-linear effect of urbanization.The relationship between urbanization and grain production has the nonlinear characteristic of a single threshold,and regions with urbanization higher than the threshold have a stronger negative inhibitory effect on grain production.Currently,the spatial distribution across the urbanization threshold forms a gradual characteristic of predominantly eastern main marketing regions and spreading to central and western regions.Fifth,the impact effect: spatial spillover characteristics.Considering the spatial correlation characteristics and path dependence of grain production,a dynamic spatial econometric model is established to examine the direction and extent of the impact of urbanization on grain production,as well as regional heterogeneity.Urbanization can negatively affect grain production,and there are significant path-dependent and spatial spillover effects.Further,urbanization can negatively affect grain production in the region and its neighboring regions in the short-term,and the short-term indirect effect is larger than the short-term direct effect,while the long-term negative effect is not significant.The negative impact of urbanization on grain production from a spatial perspective still varies between regions,with the difference between the north and the south mainly showing that urbanization in the north does not significantly affect grain production,while the impact of urbanization on grain production in the south is significantly negative;the degree of negative impact of urbanization in different grain functional areas is still "main marketing area > main-producting area > grain balance area",which is similar to the nonlinear threshold characteristics and reflects the robustness of the model results.Sixth,the path of action: the dual effect of mediation of cropland intensive use and moderation of climate conditions.On the basis of measuring the level of cropland intensive use using the entropy method,and selecting temperature,precipitation and sunshine hours as the main climate indicators,the mediation role of cropland intensive use in urbanization affecting grain production is first examined by the traditional Bootstrap mediating test,further,considering the regional differences in climate conditions,under the dual effect of the mediating role of cropland intensive use and the moderating role of climate conditions,a moderated mediation model(MMM)is constructed to examine the path of urbanization affecting grain production,and reveal the regional differences in the moderating effect of different climate indicators.Although urbanization can directly negatively affect grain production,the mediating effect of cropland intensive use can partially weaken the negative effect of urbanization,and the moderating effect of climate conditions can further mitigate this negative effect,but there are differences in the degree and direction of the moderating effect played by climate indicators such as temperature,precipitation and sunshine hours.The moderation of temperature can contribute to the positive mediating effect of cropland intensive use in most areas south of the Huhuanyong population line,while the moderation of temperature in most areas north of the Huhuanyong population line helps to weaken this negative mediating effect.The moderation of precipitation can weaken the negative mediating effect of cropland intensive use only in areas south of the Qinling-Huaihe River and above the800 mm precipitation line,but it is difficult for other areas to produce an effective weakening effect.For sunshine hours,the positive mediating effect of cropland intensive use is moderated by sunshine hours in Northeast,North and Northwest China,and high-altitude areas in Yunnan and Sichuan,while other areas have a partially weakening effect,and there are no areas where the weakening effect is difficult to weaken.In summary,the dual effects of mediation of cropland intensive use and moderation of climate conditions can help weaken or even offset the negative effects of urbanization.Finally,based on the summary of research findings,the following policy implications are proposed:(1)We should correctly understand the historical law of the change in "northern grain transportation to the south" in grain production,and should give full play to regional comparative advantages,scientifically plan grain production,and reasonably arrange advantageous production areas.(2)We should take a comprehensive look at the coordinated relationship between urbanization and grain production,control the disorderly expansion of urbanization,scientifically and reasonably plan the urban and rural land use structure,accelerate agricultural technology progress,appropriately expand the scale of agricultural production and operation,improve the efficiency of grain production,and ensure the sustainability of urbanization and grain production activities.(3)Grasp the spatial allocation characteristics of production factors flowing across regions in the process of urbanization,deepen the agricultural division of labor and cooperation between regions,and explore the interest linkage mechanism between mainproducing areas and main marketing areas.(4)It is necessary to reasonably improve the level of cropland intensive use,consolidate food productivity through fallowing and crop rotation,promote specialized and large-scale production of cultivated land,enhance the government's ability to monitor climate change and farmers' ability to respond to climate change in a timely manner,and actively respond to the impact of climate change on grain production in accordance with local climatic characteristics.