Research On Vegetable Production In Metropolis From The Perspective Of Factor Substitution

China is the world's largest vegetable producer and consumer country,it has become the world's largest vegetable market.Vegetable is the most competitive industry in economic field.Vegetable in large cities is an important economic industry and the economic benefits of vegetable production in large cities was obviously higher than that of grain and cash crops production in rural areas,which formed strong attraction of capital and labor.With continued changes of the whole economic structure and influence of accidental fluctuation factors,the capital and labor factors of vegetable production in big cities will also appear certain trend and fluctuation.This paper analyzes the transformation of urban vegetable production mode in China from the perspective of factor substitution.From the view of the basic elements in vegetable production,the labor input declined steadily year by year,capital investment increased first then decreased,land investment before 2008 fluctuated largely then gradually stabilized;From the view of input-output efficiency in vegetable production,labor productivity has increased annually,land productivity has experienced the process of large fluctuation early and rapid increase lately;From the view of the proportion of elements investment in vegetable production,capital labor ratio and capital land ratio also stabilized first then increased year after year..Since 2009,the structure of factor inputs in Guangzhou vegetable production has changed,capital deepening alternative labor and land which promote the improvement of land productivity and labor productivity.After 2011,the acceleration of capital investment has caused the double improvement of labor productivity and land productivity in Guangzhou vegetable production,which began to break the previous "Involution" mode of production,and turn to ?De-involution? mode of production.By taking Beijing,Zhengzhou,Xi'an,Chengdu,Shanghai,Wuhan and Guangzhou as the representative cities,using outdoor facility tomatoes,outdoor cucumber,facility cucumber,outdoor eggplant,facility eggplant,outdoor pepper as examples,this paper applied VES model to analyse the changes of capital-labor substitution elasticity of these seven kinds of vegetables.The estimation of VEC model parameters shows that the basic elements of alternative elasticity remained unchanged in Shanghai,Chengdu,Wuhan and Guangzhou during 2001-2014,The substitution elasticity of factors in Beijing and Xi'an has obvious fluctuation,and there is a slight upward trend.Zhengzhou's volatility is relatively large,it rised continually from 2004 to 2008 then decreased significantly,but the overall upward trend is very clear.The substitution elasticity of capital to labor is greater than 1 in each year,which shows that there is an obvious substitution relation between capital and labor during the process of vegetable production in big cities.Industrial capital and the technology represented by the capital of the continuous replacement of labor is an important way to promote the development of urban agriculture,which is in the general theory of economics of free competition market economy.China's accelerated urbanization has led to a steady increase in the urbanization rate.Aa a result,vegetable production is more and more inclined to capital alternative labor,and agricultural development began to change substantially.An important way to promote agricultural development in big cities is the constant replacement of labor by agricultural capital and by the productive technologies represented by capital.